progress at lampf - ipen · 2015. 3. 30. · lampf organizational chart x i. lampf news 1 ii....

DISCLAIMER

This report was prepared as an account of work sponsored by an agency of the United StatesGovernment. Neither the United States Government nor any agency thereof, nor any of theiremployees, makes any warranty, express or implied, or assumes any legal liability or responsi-bility for the accuracy, completeness, or usefulness of any information, apparatus, product, orprocess disclosed, or represents that its use would not infringe privately owned rights. Refer-ence herein to any specific commercial product, process, or service by trade name, trademark,manufacturer, or otherwise does not necessarily constitute or imply its endorsement, recom-mendation, or favoring by the United States Government or any agency thereof. The vjewsand opinions of authors expressed herein do not necessarily state or reflect those of theUnited States Government or any agency thereof.

LA-10070-PRProgress Report

UC-28Issued: April 1984

Progress at LAMPFJanuary—December 1983

Clinton P. Anderson Meson Physics Facility

Editor

John C. Allred

Scientific Editorial Board

Olin B. van DyckRichard L. Hutson

M. Stanley LivingstonMario E. Schillaci

Production Staff

Kit RuminerBeverly H. Talley

LA—1007 0-PR

DE84 011027

ABSTRACT

Progress at LAMPF is the annual progress report of the MP Division of the LosAlamos National Laboratory. The report includes brief reports on research done atLAMPF by researchers from other institutions and Los Alamos divisions.

n Los Alamos National LaboratoryLos Alamos, New Mexico 87545

luilllOH OF ?ss sftiyr;;- -., :.-:',,,r^

PROMISES vs ACHIEVEMENTS

This year marks the fifteenth anniversary of the publication of a paper in Science Journal

[Science J. 5 A, No. 1, 39 (1969)] in which I documented our hopes for the construction and

operation ofLAMPF. It is interesting to compare what we promised more than 15 years ago with

what we actually achieved. A forthcoming paper will make this comparison in some detail, but a

simple table shows many of the salient points.

The following table does not show how our research program has evolved compared to initial

predictions, or how LAMPF has served the national scientific and academic communities. Here

too, we need make no apologies.

As the realization that basic science and derivative technologies are absolutely vital to our

Nation's well being continues to invade our civilization's consciousnessjhe scientific community's

obligations toward its credibility and responsibilities become even more important. Making

worthwhile promises that can be kept and then keeping them are two ways we can achieve those

goals.

Louis Rosen

Director, LAMPF

LAMPF PROMISES vs ACHIEVEMENTSParameter

• Energy• Intensity• Extraction efficiency• Energy spread at 5 max• Duty factor• rf power sources

• Accelerator structures

• H+ and H" beams

• Secondary beams

• Practical applications

Promised

Variable up to 800 MeV1 mA>99%0.5%>5%Computer-controlled rf power sources,

modulators, and switch gear

High-efficiency accelerator structures

Simultaneous beams

Six beam lines

National defenseIsotope productionRadiation damageRadiobiology

Achieved

Variable up to 800 MeV>1 mA>99.8%0.15%>9%Computer-controlled reliable and stable if

power>80% beam availability

At 1 mA, 30% of rf power is converted tobeam power

Simultaneous dual-beam operation andenergy variability

20-nA average90% polarized H~

12 experimental ports plus 6 neutron lines atWNR

WNRIsotope productionPion therapy

(successfully initiated, now in abeyance)

IV PROGRESS AT LAMPFLos Alamos National Laboratory

Jtnuvy-Otcwntm 1383

^ CONTENTS

EXPERIMENTAL AREAS viii

LAMPF ORGANIZATIONAL CHART x

I. LAMPF NEWS 1

II. MEETINGS 6

III. RESEARCH 15

Nuclear and Particle Physics 15

Transverse Spin Dependence of the Proton-ProtonTotal Cross Section (Exps. 504/505) 15

Measurements of the Spin-Rotation Parameters forpd —*• pd Elastic Scattering at496, 647, and 800 MeV (Exp. 635) 17

Studies of the Spin Dependence of p | p -* nX (Exp. 336) 17Measurement of Parity Violation in the pp and /^-Nucleus Total Cross Sections

at 800 MeV (Exp. 792) 21Inelastic Pion Scattering from 17O and 18O (Exp. 369) 23Excitation of 8" States in 54Fe (Exp. 565) 28Inelastic Pion Scattering from MMg and 2dMg: The New Year's

Experiment (Exp. 573) 30Isovector Properties of Collective States and the Interacting

Boson Approximation Model (Exp. 671) 32Studies of Giant Resonances in 208Pb with Inelastic Pion Scattering (Exp. 672) . . 35Measurements of Large-Angle Pion-Nucleus Scattering (Exp. 681) 36J I V J T on I5N (Exp. 703) 39

Energy Dependence of Pion Double-Charge Exchange Angular Distributionsfor the Reaction 16O(7i+,7r)l6Ne (g.s.) (Exp. 749) 40

Isospin Dependence of Nonanalog Pion Double Charge Exchange (Exp. 780) . . . 41Inelastic Scattering from 12C at Intermediate Energies (Exps. 432 and 531) . . . . 43Proton Scattering from 20Ne and 22Ne at 0.8 GeV (Exp. 475) 46Measurement of Spin-Dependent Observables for pd —»• pd Elastic Scattering at

500, 650, and 800 MeV (Exp. 540) 47Measurement of the Depolarization Parameters in Proton-Nucleus Scattering

to Very High Excitation Energies (Exp. 626) 48Inclusive (p,p') Cross Sections and Analyzing Powers for 'H and I2C

in the Delta Region (Exp. 642) 49The 9Be(p,Ji+)10Be and 9Be(p,7t-)10C Reactions at 650 MeV (Exp. 649) 51Measurement of Spin Excitations in the 48Ca(p,p')'8Ca and ' " Z r ^ f Z r

Reactions (Exp. 660) 52Giant Resonance Studies with Medium-Energy Protons (Exp. 670) 54Measurement of the Third-Order Spin-Dependent Observables for thepc!—>pd

at 800 MeV with a Polarized Deuterium Target (Exp. 685) 56

Jmutry-Dtcvnbtr 1S83 PROOMEM AT LAMPFLos Altmot Nitionml Laboratory

Neutron Transition Densities in 2mPb (p,p') at 318 MeV (Exp. 686) 57Measurement of ANN forpp Elastic Scattering in the Coulomb-Nuclear

Interference Region at 650 and 800 MeV (Exp. 709) 60Development of 0° Capabilities at the HRS Facility (Exp. 768) 61Measurement of^4NN for the/5p—»• dn* Reaction at

650 and 800 MeV (Exp. 790) 63Spin-Depolarization Measurements on the Oxygen Isotopes (Exp. 643) 64Energy Dependence of the Two-Nucleon Effective Interaction (Exp. 718) 65Study of Isobaric-Analog States in (n+,n") Reactions (Exp. 412) 67Pion Elastic-Scattering Single- and Double-Charge-Exchange Reactions

on I4C (Exps. 523, 539, and 558) 69A Dependence of the Excitation Energy, Width, and Cross Section

of the Isovector Monopole Resonance (Exp. 607) 73Study of the Mass and Energy Dependence of Low-Energy Pion Single

Charge Exchange (Exp. 688) 76Muon Decay Spectrum (Exp. 455) 79Tensor Polarization in nd Scattering (Exp. 673) 82Pion-Induced Pion Production on the Deuteron (Exp. 783) 84The Crystal Box Experiments (Exps. 400/455 and 726) 89Deformation of Rare-Earth Nuclei and the Sternheimer Effect (Exp. 698) 9!Formation of Muonium in the 25 State and Observation

of the Lamb-Shift Transition (Exp. 724) 93E2 and E4 Moments in "3-«4."5-»»u (£Xp. 745) 95

Atomic and Molecular Physics 97Theory of Muon-Catalyzed dt Fusion: Resonant Mesomolecule

Formation 97Experimental Investigation of Muon-Catalyzed dt Fusion (Exp. 727) 102

Materials Science 106Dilution Refrigerator for uSR Measurements (Exps. 499, 640, and 771) 106Muon Longitudinal and Transverse Relaxation Studies in

Systems with Random Exchange (Exp. 499) 106Fusion Materials Neutron Irradiations (Exp. 545) 112Muon-Spin-Rotation(fiSR) Studies of Dilute Magnetic Alloys (Exp. 571) 113Muon-Spin-Rotation Study on Muon Bonding and Motion in

Select Magnetic Oxides (Exp. 639) J 115Effects of Superconductivity on Rare-Earth Ion Dynarr/ics in

(HoxLu,_x)Rh4B4 (Exp. 640) 117

Biomedical Research and Instrumentation ^.. ; 120Instrumentation / . \ 120

\

Nuclear Chemistry 121Time-of-Flight Isochronous (TOFI) Spectrometer for the

Mass Measurements of Nuclei Far from Stability 121Helium-Jet Transport of Fission and Spallation Reaction Products (Exp. 679) . . 125

VI PROGRESS AT LAMPFLos Alamos National Laboratory

January-Oacambw 1983

Radioisotopc Production 129Isotope Production and Separation 129Radiopharmaceutical Labeling Research 132Monoclonal-Antibody Labeling: ml, 77Br, and 67Cu H5

Theory 139Spin Dependence of NN and NNn Reactions and the Question

of Dibaryon Resonances 139Medium-Energy Probes and the Interacting Boson Model . . . 146Implications of Using Approximate Chiral-Dynamics JtiV —*• irrtA' Amplitude

in the Calculation of A(n,2it) Cross Sections' 155Report of the T-5 Theoretical Group . .-J5.9-- '

MP-Division Publications 163

IV. PROTON STORAGE RING CONSTRUCTION ANDy RESEARCH PROGRAM DEVELOPMENT 172

V. STATUS OF LAMPF II 191

VI. FACILITY AND EXPERIMENTAL DEVELOPMENT 198

VII. ACCELERATOR OPERATIONS 209

MILESTONES 211

APPENDIX AEXPERIMENTS RUN 214

APPENDIX BNEW PROPOSALS 217

APPENDIX CACTIVE AND COMPLETE EXPERIMENTS BY CHANNEL 221

APPENDIX D

ACTIVE SPOKESMEN, INSTITUTIONS, AND EXPERIMENTS 261

APPENDIX EVISITORS TO LAMPF 264

INFORMATION FOR CONTRIBUTORS 269

January-December 19B3 PROGRESS AT LAMP? VIILos Alamos National LMborttory

Experimental Areas

Primary beam lines in experimental areas:

Line A — Main Beam Line for Pion and Muon ChannelsLine B — Neutron and Proton Beams and Nuclear Chemistry FacilityLine C — High-Resolution Proton SpectrometerLine D — Weapons Neutron Research Facility

Experimental beam lines:

Area A:BSAEPICSLEPP3SMCTTA

— Beam Stop A— Energetic Pion Channel and Spectrometer— Low-Energy Pion Channel— High-Energy Pion Channel— Stopped Muon Channel— Thin Target Area

Area B (AB or Nucleon Physics Facility):BR — Neutrons and ProtonsEPB — External Proton BeamLB-NC — Line B, Nuclear Chemistry

Area C:CCHHRS

— Area C Control and Counting House— High-Resolution Proton Spectrometer

Area A-East:Biomedical Pion and Muon ChannelTA-5 — Target A-5ISORAD — Isotope Production and Radiation Effects FacilityNeutrino Area

vut PROGRESS AT LAMPFLot Alamos National Laboratory

Janmy-Otctmbtt 19«3

BEAM AREA"C"

/ • * B-

LAMPF EXPERIMINTAL ARIAS

PftOCMEM AT LAMPFLot AltmotNttlorfl Laboratory

ix

Astoc. Division LeaderChief of Operations

D. C. Hagerman

Accelerator DevelopmentCommittee

D. C. Hagerman, Chairman

Group UP-1Electronic Instrumenta-

tion 4 Computer SystemsE. W. Hoffman

Group UP-BEngineering Support

£. D. Bush

LAMPF DirectorMP-Division Leader

Louis Rosen

Deputy MP-Division Leader

D. E. Nagle

LAMPF SchedulingCommittee

D. C. Hagerman. Chairman

Group UP-2Accelerator Operations

J. Bergstein

Group MR-11Accelerator Support

J. D. Wallace

Asst. Division LeaderFacility Planning, BudgetControl, • user Liaison

J. N. Bradbury

Group MP-3Applications-Oriented

Research

J. N. Bradbury

Group MP-ULAMPF II Development

H. A. Thiessen

Asst. Division LeaderLAMPF II

H. A. Thiessen

Asst. Division LeaderLAMPF Safety

D. R. F. Cochran

Assl. Division LeaderUsers Safety Officer

D. R. F. Cochran

Group MP-4Nuclear ft Particle

Physics

D. E. Nagle

Asioc. Division LeaderExperimental Areas

L. E. Agnew

Group MP-7Experimental Areas

L. E. Agnew

Group MP-IOHRS * EPICS

R. L. Boudrie

Group MP-13Beam-Line Development

R. J. Macek

Experimental AreasDevelopment Committee

L. E. Agnew, Chairman

Group UP-1Electronic Instrumenta-

tion ft Computer SystemsE. W. Hoffman

Group M P - IEngineering Support

E. D. Bush

LAMPF ORGANIZATION December 1983

PROGRESS AT LAMPFJANUARY — DECEMBER 1983

CLINTON P. ANDERSON MESON PHYSICS FACILITY

I. LAMPF NEWS

• At its March J983 meeting, the Board of Directors ofthe LAMPF Users Group, Inc., established a new award,the Louis Rosen Prize. This prize, consisting of $1000anil a certificate, is awarded annually for the outstandingPh.D. thesis based on LAMPF research. Judging is doneby the Board of Directors. Theses should be submitted tothe Users Group Office at LAMPF by August 31 forconsideration. To be eligible, a thesis must have beencompleted since the previous August. Announcement ofthe winner of the prize is made at the annual UsersMeeting in November.

• At the Users Meeting of November 7, 1983, Chair-man George Igo announced the award of the first LouisRosen Prize to Stephen A. Wood for his thesis entitled"An Experimental Study of Inclusive Pion Double-Charge-Exchange Reactions in the Delta-Resonance Re-gion."

• On February 7, 1983, at the end of a production run,the LAMPF accelerator was tested for maximum protonbeam current. An average current of 1.2 mA, 20% abovedesign, was produced for several hours.

On behalf of the LAMPF Users Group, Inc., Director Andy Bacher presents to Stephen Wood theLouis Rosen Prize. Left to right: Rosen, Wood, Bacher.

January-December 1983 PROGRESS AT LAMPFLos Alamos National Laboratory

George J. Krausse, MP-4, with the prototype H beam modulator he designed and built. The beammodulator will siiape the beam pulse for injection into the PSR. Extended-life tests were performedsuccessfully in December 1983; the slew rate of the modulator is 500 kV/us.

• With the Proton Storage Ring (PSR) coming on line in 1985, major necessarymodifications of the LAMPF accelerator are proceeding. (1) An H~ beam modulatorprototype that will shape the beam pulse for injection into the PSR (see photographabove) has been designed, built, and tested; (2) a new high-intensity H" ion source hasbeen designed and a prototype built; and (3) components are being built for a newinjector and for a reconfigured switchyard.

2 PROGRESS AT LAMPFLos Alamos National Laboratory

Jimmy-DKtmbtt I9S3

During summer/fall of 1983 a collaboration (Japan, UCLA, University of Minnesota,Los Alamos) worked at the HRS making nucleon-nucleon measurements in theCoulomb-nuclear interference region at forward-scattering angles. Polarized beamstruck polarized p and d targets cooled to 25-50 mK by a dilution 3He/4He refrigeratorfurnished by KEK. Shown in the photograph, left to right, are George Igo (UCLA),Hiromi Hasai (Hiroshima University), Akira Masaike (KEK), Steven Greene (LosAlamos), and Yuji Ohashi (Nagoya University).

January-December r983 PROGRESS AT LAMPF 3Los Alamos National Laboratory

LAMPF Satellite? Jerry Davis, MP-11, displaying the 805-MHz intermediate driver amplifler hedesigned. This amplifler, with an output power of 1 kW, drives a vacuum-tube amplifler which in turndrives the klystrons of the side-coupled-cavity linac.

• On August 5, 1983 a serious eiectrical accidentoccurred at LAMPF. Three technicians from MP-8began what they thought was routine maintenance of aportion of the power supply to the klystron test stand atthe Engineering Test Laboratory.

Through an unexpected sequence of circumstances —things that "could not happen" — a key interlock wasunknowingly by-passed and a hand-held grounding hookcontacted an energized 4160-V, 60-Hz power bus. Theresulting fireball caused burns to all three persons ex-

posed; the person holding the grounding hook waspainfully burned. Injuries were fortunately much lessserious than they might have been.

Of greater interest than the actual details are theboundary conditions. The person closest to the accidentwas a senior, skilled technician, who believed (as did hissupervisors) that he understood the hazards and how tomanage them. All three persons involved believed,without doubt, that the circuit in question was de-energized. The mechanical and key interlocks were in


Jtntmy-Dtctmbe 1383

place and were functioning properly, but the system wasby-passed. It is now clear that none of the people involvedrealized the seriousness of the risks associated with theoperation.

The hazards at LAMPF are many — electrical,chemical, cryogenic, radiation and radioactive materials,pressurized and evacuated systems, and magnets —practically every hazard that can be imagined. Ex-perimental areas can be especially hazardous becauseconditions are constantly changing. Even for a singleexperiment, in a matter of weeks an experimental areamay undergo a drastic rearrangement.

An accident such as the one of August 5 must remindall of us that safety is always paramount. The safety

record at LAMPF is outstanding because all the peoplehere, Users and lab employees alike, work at safety.Safety requires continuous vigilance; it is not a matter ofgood luck.

• The radiation monitoring system at the entrance to theLAMPF site paid an unexpected dividend. A truckcarrying construction steel from Mexico independentlywandered onto the LAMPF site and triggered our radia-tion alarm system. Sure enough, the entire load of steel-was sufficiently radioactive to set off a search in theUnited States and Mexico for other steel from the samemill. Once again LAMPF served the national interest inan unexpected way.

Janutry-Oacemtxr 1983 PROGRESS AT LAMPF 5(-03 Alamos National Laboratory

II. MEETINGS

LAMPF Users Group, Inc.

Seventeenth Annual LAMPF Users Group Meeting

The LAMPF Users Seventeenth Annual Meeting washeld in Los Alamos on November 7-8, 1983, with 222attendees. Chairman George Igo (UCLA) presided at thefirst session, which opened with a welcoming address byWarren F. Miller, Associate Director of Los AlamosNational Laboratory. The session continued with aLAMPF Status Report presented by Louis Rosen, Direc-tor of LAMPF, and a report on LAMPF operations byAndrew A. Browman.

During the second portion of the morning session,George Igo gave the Annual Users Group Report,followed by a presentation of the election results. RobertRedwine (MIT) is the Chairman-Elect of the Board ofDirectors, and new members are Peter D. Barnes(Carnegie-Mellon University), Barry Preedom (Univer-sity of South Carolina), and John D. Walecka (StanfordUniversity). Members whose terms continue in 1984 areCharles Glashausser, Chairman, and George Igo, Past-Chairman. A presentation was given by Charles Bowman(Los Alamos) on Proton Storage Ring Research.

The afternoon session was conducted by incomingChairman Charles Glashausser (Rutgers University).

The following talks were given during this session:"New Approach to Polarized-Proton Scattering Based

on Dirac Dynamics," Steven J. Wallace (Universityof Maryland),

"Progress Report—LAMPF II" Henry A. Thiessen(Los Alamos), and

"Muon Neutrino Physics Before the PSR," GerardStephenson (Los Alamos).

The afternoon session concluded with a panel dis-cussion on the present LAMPF II conrept in the contextof nuclear and particle physics needs of the 1990s.

Talks given during the Tuesday morning session,presided over by Igo, were

"Energy and Angular Dependence of the TensorPolarization T20 in n Elastic Scattering," WilliGriiebler (ETH),

"Tensor Polarization in Pion-Deuteron Elastic Scat-tering," Roy Holt (Argonne),

"Simple features of (pn~) Reactions NearThreshold" Steven Vigdor (Indiana University),

"pp and np Phase Shifts up to 800 MeV" CatherineLechanoine-LeLuc (University of Geneve), and

"Status of Exp. 225, A Study of Neutrino-ElectronElastic Scattering" Herbert Chen (University ofCalifornia, Irvine).

Working group meetings were held the rest of the day.

Visitors Center

During this report period, 572 research guests workedon LAMPF-related activities or participated in experi-ments at LAMPF; of these, 126 were foreign visitors. Atotal of 656 check-ins and 625 check-outs were processedby the Visitors Center.

• MEMBERSHIP

Non-Los Alamos National Laboratory 706Los Alamos National Laboratory 171

TOTAL 877

• INSTITUTIONAL DISTRIBUTION

Membership by InstitutionsLos Alamos National LaboratoryNational or Government LaboratoriesU.S. UniversitiesIndustryForeignHospitals

NonaffiliatedTOTAL

Number of InstitutionsNational or Government LaboratoriesU.S. UniversitiesIndustryForeignHospitalsNonaffiliated

TOTAL

17196

36441

16230

13877

19108

308225

7271

PROGRESS AT LAMPFLos Alamos National Laboratory

• REGIONAL BREAKDOWN

East (Pennsylvania, New Jersey, Delaware, Washington DC, Massachusetts New York,Connecticut, Vermont, Rhode Island, New Hampshire, Maine) 132

Midwest (Ohio, Missouri, Kansas, Indiana, Wisconsin, Michigan, Illinois. North Dakota.South Dakota, Nebraska, Iowa, Minnesota) 102

South (Maryland, Virginia, Tennessee, Arkansas, West Virginia, Kentucky. North Carolina,South Carolina, Alabama, Mississippi, Louisiana. Georgia. Florida) 71

Southwest, Mountain (Montana, Idaho, Utah, Wyoming. Arizona. Colorado. New Mexico.Oklahoma, Texas) (excluding Los Alamos) 128

West (Alaska, Hawaii, Nevada, Washington, Oregon, California) 110Foreign 163Los Alamos National Laboratory 171

TOTAL 877

1984 WORKING GROUP CHAIRMEN

High-Resolution Spectrometer (HRS)M. GazzalyUniversity of Minnesota

Neutrino FacilitiesThomas A. RomanowskiOhio State University

Stopped-Muon Channel (SMC)Fesseha MariamLos Alamos National Laboratory

Nuclear ChemistryYoshitaki OhkuboLos Alamos National Laboratory

Energetie Pion Channel andSpectrometer (EPICS)

William CottingameNew Mexico State University/Los Alamos National Laboratory

High-Energy Pion (P3) ChannelJon EngelageUniversity of California,Los Angeles

Nucleon Physics Laboratory (NPL)/Polarized Facilities

Tarlochan BhatiaTexas A&M University/Los Alamos National Laboratory

Computer FacilitiesJames F. AmannLos Alamos National Laboratory

Solid-State Physics andMaterials Science

Walter F. SommerLos Alamos National Laboratory

Muon-Spin Rotation (u£R)Art DenisonUniversity of Wyoming

Low-Energy Pion (LEP) ChannelMichael J. LeitchLos Alamos National Laboratory

Jtnutry-Dtcember 19B3 PROGRESS AT LAMPFLos Alamos National Laboratory

LAMPF PROGRAM ADVISORY COMMITTEE (PAC)

The PAC consists of about 25 members appointed for staggered 3-year terms.Members advise the Director of LAMPF on the priorities they deem appropriatefor the commitment of beam time and the allocation of resources for thedevelopment of experimental facilities. The PAC meets twice each year for 1week during which time all new proposals that have been submitted at least 2months before the meeting date are considered. Old proposals, and the prioritiesaccorded to them, may also be reviewed.

Terms Expiring 1983

Richard ArndtVirginia Polytechnic Inst.and State University

Dieter KurathArgonne National Laboratory

Robert Redwinc S. Peter RosenMassachusetts Institute of Technology Los Alamos National Laboratory

Louis RemsbergBrookhaven National Laboratory

Stephen J. WallaceUniversity of Maryland

Terms Expiring 1984

Franz L. GrossCollege of William & Mary

Barry HolsteinUniversity of Massachusetts

Sheldon B. KaufmanArgonne National Laboratory

Leonard S. KisslingerCarnegie-Mellon University

Darragh NagleLos Alamos National Laboratory

June L. Matthews Bruce VerWestMassachusetts Institute of Technology Arco Oil and Gas Company

Daniel W. MillerIndiana University

Robert Lee WalkerTesuque, New Mexico

Terms Expiring 1985

David AxenTRIUMF

Frieder LenzSIN

Barry Barish Harold M. Spinka, Jr.California Institute of Technology Argonne National Laboratory

Dietrich DehnhardUniversity of Minnesota

Victor E. Viola, Jr.Indiana University

Larry ZamickRutgers University


January-December 1983

1984 TECHNICAL ADVISORY PANEL (TAP) OF THELAMPF USERS GROUP, INC.

The TAP provides technical recommendations to the Board of Directors and LAMPF manage-ment about the development of experimental facilities and experiment support activities. The TAP has12 members, appointed by the Board of Directors, serving 3-ycar staggered terms. The Chairman ofthe Board of Directors serves as TAP chairman. The TAP membership and term expiration dates arelisted below.

1984 Billy E. BonnerLos Alamos National Laboratory

1984 Thomas J. BowlesLos Alamos National Laboratory

1986 George R. BurlesonNew Mexico State University

1984 Gerald DuganFermi National Accelerator Laboratory

1985 Donald GeesamanArgonne National Laboratory

1985 KazuoGotowVirginia Polytechnic Institute and State

University

1985 Christopher L. MorrisLos Alamos National Laboratory

1986 Michael A. OothoudtLos Alamos National Laboratory

1984 Barry PreedomUniversity of South Carolina

1985 Thomas A. RomanowskiOhio State University

1986 Gary SandersLos Alamos National Laboratory

1986 Charles A. WhittenUniversity of California, Los Angeles

Los Angeles

SCIENCE POLICY ADVISORY COMMITTEE (SPAC)

A Science Policy Advisory Committee was formed during 1983 to advise the Board of Directors onthe long-term development of research and facilities at LAMPF. The first charge to the SPAC was theexamination of the LAMPF II concept and justification in the context of nuclear and particle physicsneeds of the 1990s.

Barry C. BarishCalifornia Institute of Technology

Frederick ReinesUniversity of California, Irvine

Leonard S. KisslingerCarnegie-Mellon University

Alan D. KrischUniversity of Michigan

Malcolm MacFarlaneIndiana University

Sydney MeshkovNational Bureau of Standards

S. Peter RosenLos Alamcs National Laboratory

Lee C. TengFermi National Accelerator Laboratory

Akihiko YokosawaArgonne National Laboratory

John D. WaleckaStanford University

Januwy-December 1983 PROGRESS AT LAMPF 9Los Mamas National Laboratory

1984 BOARD OF DIRECTORS OF THELAMPF USERS GROUP, INC.

The Board of Directors consists of seven members elected by the LAMPFUsers Group, Inc., whose interests they represent and promote. They concernthemselves with LAMPF programs, policies, future plans, and especially withhow users are treated at LAMPF. Users should address problems and sugges-tions to individual Board members.

The Board also nominates new members to the Program Advisory Committee(PAC).

The 1983 membership and term expiration dates are listed below.

1985 Charles Glashausser (Chairman) 1984 Andrew D. BacherRutgers University Indiana University

1986 Robert Redwine (Chairman-Elect) 1985 Peter D. BarnesMassachusetts Institute of Technology Carnegie-Mellon University

1984 George Igo (Past-Chairman) 1985 Barry PreedomUniversity of California, Los Angeles University of South Carolina

James Bradbury (Secretary/Treasurer) 1985 John D. WaleckaLos Alamos National Laboratory Stanford University

1 0 PROGRESS AT LAMPF JsnauyOtcinbtr 1983Los Alamos National Laboratory

LAMPF USERS GROUP, INC., (LUGI)

BOARD OF DIRECTORS

The LAMPF Users Group Board of Directors (BOD)met on March 6-7, July 20-21, and November 8, 1983.All meetings were chaired by George Igo; selected topicsof discussion are provided below.

The 1983 Annual Users Meeting was very successful.There were 222 registrants, of whom 119 were fromoutside the Laboratory. The panel discussion aboutLAMPF II, involving the BOD, the Science Policy Ad-visory Committee (SPAC), and the attending users,received favorable comments for being stimulating andinformative. A summary of the discussion is provided inthese proceedings.

Sixty-one new proposals were received for review bythe Program Advisory Committee (PAC) at the January1984 meeting. The breakdown by channel is: EPICS -15,HRS-10, NPL-"?, LEP-I2, P3 -11, SMC - 3, Neu-trino - 1, Radiation Effects - 1, and Nuclear Chemistry -1. Because of the proposal load, the Low-Energy PionChannel (LEP) and High-Energy Pion Channel (P3) PACsubcommittees will be augmented by one member (eitherfrom the Laboratory or from another subcommittee) forthe January meeting.

Those PAC members whose terms nominally expire in1983 have been asked, as usual, to serve in January andalso to serve at the summer meeting in 1984, as there wasno meeting in the summer of 1983. The summer 1984meeting will thus be the "overlap" meeting. New PACmembers will be recommended by the BOD at their nextmeeting.

Four new members were appointed to the TechnicalAdvisory Panel from the lists provided by the LUGIworking groups. The appointees are Michael Oothoudt,Computer Facilities; Gary Sanders, Stopped-MuonChannel (SMC); George Burleson, Energetic Pion Chan-nel and Spectrometer (EPICS); and Charles Whitten,High-Resolution Spectrometer (HRS).

The Board agreed to employ Users Group funds toestablish and support a new award, the Louis RosenPrize. This prize, consisting of $1000 and a certificate, isto be awarded annually for the outstanding Ph.D. thesisbased on LAMPF research. The judging is to be done bythe Board of Directors. For consideration, theses shouldbe submitted to the Users Group Office at LAMPF byAugust 31; announcement of the winner will be made atthe Users Meeting in November. To be eligible, a thesismust have been completed since the previous August.

The criteria for thesis evaluation were discussed. Inaddition to intellectual content, quality of presentation,and significance of results, the level of the contributionsto the work by the student is obviously important.Contributions to the experiment design, data analysis,and data interpretation are to be assessed by requiringexplanatory letters from both student and advisor.

The BOD selected Stephen A. Wood as the recipient ofthe Louis Rosen Prize for 1983. The title of the thesis is"An Experimental Study of Inclusive Pion Double-Charge-Exchange Reactions in the Delta ResonanceRegion."

MP Division has purchased a 10- by 55-ft trailer to beequipped as a Users lounge. The trailer will be locatedto the east of the Data-Acquisition Center and will arriveabout December 1, 1983. The lounge will contain spacefor a library, kitchen, and computer terminal as well as alarge open area; some landscaping <n the vicinity isplanned. Users representatives will be asked to considerfurnishings for the lounge and arrange for their purchasewith User funds available for this purpose.

George Igo announced the formation of a SciencePolicy Advisory Committee (SPAC) whose role is toadvise on the long-term development of research andfacilities at LAMPF. The following persons participatedin an organizational meeting on July 26, 1983.

Barry BarishLeonard KisslingerAlan KitschSydney MeshkovFredrick ReinesPeter RosenDirk WaieckaAkihiko Yokosawa

CaltechCarnegie-Mellon UniversityUniversity of MichiganNational Bureau of StandardsUniversity of California/IrvineLos Alamos National LaboratoryStanford UniversityArgonne National Laboratory

The first charge to the SPAC is to examine the presentLAMPF II concept and physics justification in thecontext of nuclear and particle physics needs of the1990s. The committee is to advise the LUGI-BOD on

• specific strengths and weaknesses in the LAMPF IIconcept and justification,

• the highest priority experimental programs andfacilities to be developed at LAMPF II, and

• the best strategies for advancing the case anddeveloping support for LAMPF II in the nuclearand particle physics communities.


11

The SPAC met on October 22, 1983 at UCLA.Preliminary reports were presented on four topics impor-tant to the LAMPF II concept: accelerator design (AlanKrisch), experimental facilities (Akihiko Yokosawa), andphysics justification and community support (BarryBarish). George Igo will assemble the written report* andsend them, together with a summary of the panel dis-cussion during the Annual Users Meeting, to the Users.This is a crucial period for LAMPF II because theconcept and justification must become firm very soon inorder to produce a proposal by the end of 1984. Strongsupport of physicists in both nuclear and particle physicsmust be garnered and maintained. Consequently theBOD feels that the SPAC should be requested to con-tinue to provide input to the LAMPF II plan. A nuclearphysics subcommittee of the SPAC will be organized byC. Glashausser to define more precisely the potential ofLAMPF II in this area.

Following a suggestion by Louis Rosen, plans arebeing made to hold a comprehensive workshop in May of1984 on the interface between particle and nuclearphysics. To members of the SPAC, Alan Krisch andMalcolm MacFarlane, have agreed to head an organizingcommittee for this workshop. A one-half-day session ofinvited papers on the interface region will be held at thespring APS meeting.

To bolster the case for LAMPF II, it is important topublicize the achievements of existing meson factoriesand their impact on the development of nuclear physics.Members of LUGI are encouraged to give presentationsat universities and an article should be prepared forPhysics Today. A semitechnical brochure on LAMPFaccomplishments could also be prepared for widespreaddistribution.

The Annual Users Meeting in 1984 will be held onOctober 29-30 (November 6 is election day). The nextBOD meeting will be on February 17, 1984 at LAMPF.

TECHNICAL ADVISORY PANEL

The Technical Advisory Pane! (TAP) met on July 29and November 6,1983. Some excerpts of the minutes arepresented below. After noting that the budgetary positionof LAMPF appears reasonable for FY 1984, LouisRosen made some general comments about the LAMPFneutrino program. The proposed neutrino program usingthe Proton Storage Ring (PSR) is in abeyance at this time,primarily because the neutron scattering and defenseprograms have first priority on PSR beam and it is notclear that an adequate amount of current will be availablefor the neutrino program. However, as neutrino physics isan important component of LAMPF research, experi-ments are being conducted at the beam stop and Line E.At Line E, neutrino cross sections will be measured usinga 5-ton liquid scintillator detector (Exp. 764). LAMPFwill provide up to $200 thousand to prepare Line E,which is expected to be ready to receive beam in January1984. If approved by PAC, a modular detector may beconstructed, which might eventually be used atLAMPF II.

Louis Rosen commented that for long-term survival,LAMPF needs a major upgrade. He feels that theLaboratory top management will support such a project,as it clearly will provide important opportunities forperforming high-quality research and for extending thebase for education of young scientists. Interested mem-bers of the scientific community must make the DOE and

Congress aware that they need and will use a LAMPF II.In addition to the in-house work of Los Alamos in termsof proposal preparation, there must be a well-establishedeffort by external users to define and support LAMPF II.

Richard Boudrie reported that the new Low-EnergyPion Channel (LEP) spectrometer project is proceedingvery well. The spectrometer will be useful for pion-inelastic scattering ir the 20- to 80-MeV range and willprovide <0.1% resolution with large acceptance. Thepole pieces and yoke are presently being machined at acost much less than anticipated; the vacuum can has beencast and vacuum tests will soon be performed. It isexpected that the poles, yoke, and vacuum can will beassembled and doweled at the machine-shop facility bylate September. One coil has been fabricated and thesecond coil is expected by October.

A conceptual design and drawing have been completedfor the scattering chamber and target mechanism. Com-ments are being solicited from potential users and engi-neers. Studies have been made regarding the relativemerits of the vertical drift (YDC) and MP-10 driftchambers Tor the focal plane. Tests of the MP- 10-stylechambers at a 45° angle of incidence for the incomingparticle will be made at the end of cycle 38 to evaluatetheir performance. The project is on schedule and withinthe budget of $350 thousand. A working system ready toaccept beam is expected by April 1984.

1 2 PROGRESS AT LAMPF

Los Alamos National Laboratory


Helmut Baer reviewed the development history andcurrent performance characteristics of the JC° spec-trometer. Highlights of the research program include thestudies of isobaric analogs to determine the isovectorcomponent of the optical potential, and the studies ofgiant resonances with (n^Jt0) reactions. Of particularsignificance is the presence of the nuclear monopolesignal.

The JT° spectrometer is capable of obtaining a resolu-tion of 2-MeV FWHM, although 4 MeV is more typical.To make a significant improvement in resolution, the y-ray energy resolution must be improved. If the photonresolution were 5% FWHM at 100 MeV, the 7i° energyresolution could be improved to approximately 0.5 MeVFWHM. Monte Carlo design studies are being performedto determine the advantages of replacing the lead-glassphoton detectors with either Nal or BGO modulararrays. Such an improvement might cost about $1million. If the modification project is deemed worthwhile,the group will prepare a detailed proposal for evaluationby the TAP.

LAMPF may be able to acquire a new polarized ionsource with I to 2 orders of magnitude higher intensitythan the present source at a cost of several million dollarsand several man-years of effort. Perhaps AcceleratorImprovements Project (AIP) funds (estimated to be about$1 million per year after FY 1984) could be used. It isnecessary, however, to evaluate the physics justificationfor such a source, and a workshop will be convened forthat purpose in November.

Billy Bonner discussed his investigation of newpolarized ion source possibilities for LAMPF. The Na-tional Laboratory for High-Energy Physics in Japan(KEK) has developed an optically pumped source withdemonstrated output of 10-25 uA and an anticipatedoutput of about 60 |tA. An atomic beam ion source(Gruebler, SIN) has produced 6 uA with projections(perhaps optimistic) of 100 uA. A 20-uA source wouldprovide an increase in intensity by a factor of 50-100 overthe present LAMPF source.

Lewis Agnew reported on experimental-area develop-ment projects. The A-2 target cell was rebuilt during the1983 shutdown. Production currents up to 900 uA havebeen achieved on Line A. Replacement of the A-1 targetcell is planned for the 1984 spring shutdown. Both theLEP and time-of-flight-isochronous (TOFI) spectrom-eters are making reasonable progress: first use of the LEPspectrometer is planned for next summer. The polarized-target program at the High-Resolution Spectrometer(HRS) was successful; plans for the 1984 continuation of

this program are being reviewed. Design work for theHRS focal-plane shielding is complete, but installation in1984 will be in conflict with the polarized-target setup.The shielding will be deferred until 1985 if the polarized-target program is scheduled for 1984.

Planned modifications to the beam-stop area werepresented by Walter Sommer. The major design consider-ations and goals are to provide:

• improved environment for beam-line diagnostics,• improved shielding and elimination of cracks to

reduce leakage of activated gas,• new facility for proton- and neutron-radiation-

effects studies that allows multiple bulk samples andcontrol of irradiation parameters,

• improved facility for high-speed and ultra-high-speed isotope transport and identification,

• access for additional experiment initiatives in nu-clear and solid-state physics,

• remote handling and shielded transport of radioac-tive material, and

• one-day repair/replacement of components or ex-perimental hardware.

Design of the new facility is nearing completion andaccelerator improvement funds are available for theproject. Material procurement and fabrication have beeninitiated, and a schedule calling for completion in thespring of 1985 has been established.

A status report on the Long-Range Planning Commit-tee for LAMPF Computing Needs was presented byMartha Hoehn. The committee met for 3 days, October24-26, 1983.

The committee generally discussed topics in two areas:data acquistion and data analysis. A few notable points ineach section were presented to the TAP.

Five topics were discussed for data acquisition:(1) front-end processing, (2) hardware standards, (3) buf-fer processors, (4) data-acquisition program Q, and(5) networks in the experimental area. These are brieflysummarized below.

1. Front-end processing. The committee heard a pres-entation by James Amann summarizing the statusof the committee looking into this topic. The micro-programmable branch driver (MBD) does notsatisfy all the needs of the users, but there is noobvious candidate for a replacement. It appearsthat auxiliary crate controllers may solve someproblems for some applications. A new high-speedflexible electronics system, FASTBUS, looks like apromising technology to pursue, and the committeerecommended that Group MP-1 should do that.

January-December 1983 PROGRESS AT LAMPF 1 3Los Alamos National Laboratory

2. Hardware standards. The committee felt that weshould be moving toward 32-bit VAX-class ma-chines for data acquisition, primarily to solve the16-bit address space problem with PDP-lls . Thecommittee also felt that LAMPF should beginupgrading tape units to 6250/1600 bpi.

i . Buffer processors. Michael Oothoudt presented tothe committee a simple idea for taking advantage ofthe processing capabilities of the new machineswithout adding overhead from peripherals. Thebasic idea is to attach multiple processors to acentral unit. As an event comes in, it is sent to thefirst processor, the second event to the second, andso on. Thus, the analysis of events would be carriedon in parallel and increase the computing capacityof the central unit.

4. Data-acquisition system Q. The committee identi-fied a few Q projects that should be completed, forexample, VAX data acquisition and documentationof internals of Q. However, they felt that theQ programmers should not spend time adding"bells and whistles" to Q but should direct theirefforts in more productive areas such as FASTHUSand buffer processors.

5. Networks. Networks to the experimental area arelong overdue and should be implemented with ahigh priority.

Three topics were discussed under data analysis: (I)Data Analysis Center (DAC) functions, (2) problems,and (3) external networks. Each of thestt are.is is dis-cussed below.

1. DAC functions. The committee discussed at somelength the functions that the DAC can serve andthose that should be addressed elsewhere. Specifi-cally, the DAC should provide interactive graphics

capabilities, should be able to handle tapes effec-tively, and should serve as a convenient computingtool for the LAMPF community. However, itshould be recognized that the DAC cannotnecessarily satisfy all the needs of the users and thatLAMPF should be willing to use other resources atthis Laboratory, namely the Central ComputingFacility (CCF).

2. Problems. Two main problem areas were identified:(1) unacceptable interactive response time on the

current systems, and(2) inadequate disk space.These problems are being addressed.

3. External networks. The committee recognized aneed to provide convenient lunmunications withother locations. Specifically, MP 1 should investi-gate implementation of a network system such asTelenet and should provide a convenient method todial out of the DAC. This communication enhance-ment can, for example, facilitate distribution ofdrafts of papers.

The TAP members had several comments and ques-tions concerning this presentation. These questions arelisted here.

• Did the committee consider small (personal) com-puters as a standard (or data acquisition?

• Has parallel processing been considered for theDAC?

• Has the committee properly considered options forthe long term -specifically, writing dala acquisitionsystems in portable languages?

• Has the committee considered other standard oper-ating systems, such as UNIX?

These points will be brought up at the Long RangePlanning Committee meeting before the final report isprepared.

14 PROORESS AT LAMPF(.01 Alamos National LalmlHluiy

.lintMyDocdmbar 1983

III. RESEARCH

Nuclear and Particle Physics

Transverse Spin Dependence of the Proton-ProtonTotal Cross Section(Exps. 504/505, EPB)

(Rice Univ., Univ. of Houston, Institute "RuderBoskovic," Univ. or Bonn, Los Alamos)Spokesman: G. C. Phillips (Rice Univ.)Participants: W. P. Madigan. D. A. Belt, J. A. Buchanan.M. M. Calkin, J. M. Clement, M. D. Corcoran, K. A.Johns, J. D. Lesikar, //. E. Miettinen, G. S. Mutchler, C.J. Naudet. G. P. Pepin, G. C. Phillips, J. B. Roberts. S. E,Turpln, A. D. Hancock, B. W. Mayes. L. S. Plnsky, K. K.Sekharan. M. Fiiric. V. Valkovic, W. von Witsch. J. C.Allied. B. E. Bonner. and C. Hollas

Final analysis of the total-cross-section difference dataA o , = o ( | | ) - o ( ff ) for proton-proton scatteringwith the protons in transverse .spin stales has beencompleted. The measurements were made for 12 incidentproton energies from 300 to 800 MeV. The experimentwas performed during the period from June to November1980, using the LAMPF variable-energy polarizedproton beam and the Rice University polarized protontarget, The detectors were precision ioni/.atioii chambers.

The measurements were made by holding the spinorientation of the larget constant and reversing the spinorientation of the beam every minute. Thus a measuremenl of An, i.-. made every 2 inin. The target polarity wasreversed every hour, and in this way 60-80 values of An,were obtained for each target polarity. As a result of thecurrent and position-dependent responses of the ionization chambers, the Ao, values were systematically dependent on the changes of beam position and current, whichwe found were correlated with the beam spin reversals.

These dependences were removed by regressionsagainst the measured changes in vertical position,horizontal position, and beam current. The remainingsmall systematic dependences were adequately randomi/.ed by the target polarity reversals to producenearly complete cancellation on averaging the positive

and negative-target polarity data. This procedure wasapplied to the data from each of the six transmissionchambers (each subtending a dilferent solid angle).Coulomb-nuclear interference corrections were applied ateach solid angle, and an extrapolation to zero solid anglewas made.

The results are tabulated in Table I. The total error isthe pure statistical error added in quadrature with thesystematic errors in the target polarization, beampolarization, and the target constant, which is the recipro-cal of the target density and larget length. The lastcolumn lists the Coulomb-nuclear interference correc-tions.

Figure 1 is a plot of An, (nib) vs ir(MeV), the kineticenergy of the incident proton. All the published data " inthis energy range are plotted. The four experimentalgroups used a variety of techniques: Rice University atLAMPF (this experiment) used ionization chambers;Rice University at ZCiS and Hugg et al., scintillators;Byslricky el al.,' Gray encoded scimillalors with afrozen spin target; am1 !)il/.ler et al.,' scintillators with afrozen spin larger. The Rice data indicate a sharperstructure al '/' 562 MeV than thai previously observed.

These results were reported at the l')83 meeting of theDivision of Particles and Fields, lilacksburg, Virginia. APh.D. thesis based on this work is in preparation.

lU'll'KI'NCI'S

1. J. H. l.csikiir. I'h.lJ. thesis, I'H»I.

2. 1). V. Ituggct ill. I I'lUMI- Amuiiil Report, June I')!!.!.

.1. J. llyMricky et al., preliminary results of Ao, lit Satiny, Tominissarsiil a l.'lnergie Alnmit|iie nolr CI\A N 22 Id. ISSN07M) A67H, IVHO BHI.

'I. W. K. Dit/.lcr el 11!., I'hys. Kt:v. I) 27, <>«<)( IW.i).

5. K. A. Arnilt ei ill.. I'hys. Rev. I) 2H, '>7<IWU).

PROOflEMATLAMPF 1 5Liu Almntn Nuloml

Table I. Summary of Results from LAMPF Exp. 504, a Measurement of the Total Cross-SectionDiflerence (Ao) for Transversely Polarized Protons. The energies quoted are the laboratory beamenergies at the center of the target. The Ac's are final values, corrected for Coulomb-NuclearInterference (CNI). The total error is the pure statistical error added in quadrature with thesystematic errors in the target polarization, beam polarization, and target constant C (thereciprocal of the product of the target density and target length). The CNI corrections aretabulated in the last column.

Errors (mb)

Energy(McV)

304436485519536571587620637689741791

Momentum(GeV/c)

0.811.001.07.12.14.18.20.24.27.33.39.45

Ao(mb)

-0.29765.84158.33818.6139

10.469712.26969.83867.86717.15265.62565.63605.8884

Total

1.00100.72960.96691.18430.87671.42261.29440.49351.07630.53370.31221.0627

Statistical

0.54860.30510.28160.21060.20560.20790.64100.07780.21840.11910.10060.1231

TargetPolarization

0.83020.61320.83751.09500.68881.26981.01530.30790.99540.44980.12991.0177

C

0.10110.23340.36460.37050.46610.56340.44890.35070.32160.24270.24640.2604

BeamPolarization

0.04040.09340.14590.14820.18640.22540.17960.14030.12860.09710.09860.1041

CNI

1.72361.17291.04521.20421.14861.00140.86070.85220.72070.77120.70720.6809

12

II

to

8

_ 7

1 E 65

, > - 4

< 32I

0-I-2 O.7 0.8 0.1

* This .experimento Lesikar, Ret. Ifi Bugg et al . , Ref. 2a Byslricky et al., Ref. 3

v Ditzler et al., Ref. 4- Arnclt, phase-shift-analysis solution FA83

jef_51.0 I.I 1.2 1.3 1.4 1.5 1.6

200 300 400 500 600

T(MeV)

TOO 800 100

Fig. I.Plot of Aor (mb) vs 7"(Mev), the kinetic energy of the incident proton. Error bars show statisticalerrors only.


Las Alamos National Laboratory

January-OecamtMr 1093

Measurements of the Spin-Rotation Parameters forpd-^pd Elastic Scattering at 496, 647, and 800MeV(Exp. 635, EPB)(Los Alamos, UCLA, Univ. of Texas at Austin, RiceUniv.)Spokesmen: B. E. Bonner (Los Alamos) and G. J. Igo(UCLA)

This collaboration has completed pd-*pd clastic-scattering experiments at 500, 650, and 800 MeV1 "3 atthe EPB area. These experiments used a polarized protonbeam and an unpolarized liquid-deuterium target, andmeasure the outgoing proton polarization in the "Janus"polarimeter, which incorporates a carbon analyzer (effi-ciency ~10%/. A two-arm counter system is used toobtain a clean two-body trigger.

A publication is in progress on the 1981 measurementsol Z)NN, Dss, Dls, P, andAN at 500 and 800 MeV1 (D isthe polarization memory parameter). In 1982 we re-measured the above parameters with a faster data-acquisition system, thereby obtaining smaller statisticalerrors in addition to measuring DSI and D,, at 500 and800 MeV. The measurement of L in the final staterequired a bending magnet to process the outgoing protonspin direction sideways (S) in order that it be observable:the magnet also serves as an analyzer for momentum.

In Augu' t 1983 we measured Ds>l, / } s s , Z>, s, Z>S1_, Du,P, and A at 650 MeV for the four-momentum transferrange --/ = 0.4-1.18 (GeV/c)2 (30-60° lab).

All the data taken since September 1982 have beenanalyzed and a compilation has been submitted to Physical Review C. The EPB experiments complement HRSexperiments at smaller angles.

REFERENCES

1. A. Knhhar, Ph.D. thesis. University of California at Los Angele.;,1982, unpublished.

2. Sun Tsu hsun ct al., submitted to Phys. Kev. C.

3. Sun Tsu-hsun et al., in Proe. of the 10th Int. Conf. on Few liodyProblems, Karlsruhe, Germany (198.1), p. 233.

Studies of the Spin Dependence of p !/>—»• nX(Exp. 336, EPB)(Rice Univ., Univ. of Houston, Los Alamos)Spokesmen: G. S. Mutchler (Rice Univ.) and L. S,Pinsky (Univ. ofHouston)Participants: S. D. Baker, J. A. Buchanan, J. M. Clem-ent, M. D. Corcoran, I. M. Duck, M. Fitric, G. P. Pepin,G. C. Phillips, E. A. Umland, A. D. Hancock, E. V.Hungerford. B. W. Mayes, Y. Xue. J. C. Allred, T. M.Williams, M. W. McNaughton, and C. Hwang

Analysis of the pp -* ppn" data from Phase II of thisexperiment has been completed. In Phase II the spin-dependent cross section d!a/dpldQldii2 for the reactionsp f p—* pn*n and ppn" were measured at EPB at 500and 647 MeV, along with some repeated measurementsat 800 McV. This was a kinrmatically complete experrment using a liquid-hydrogen target and a polarizedbeam. The angles 6, and (>, and momentum p , of theproton were measured in a magnetic spectrometer, incoincidence with the angles 0, and <t>2 of the pion (secondproton) in a time-of-flight arm. The data were takenduring the summer of 1982.

Of the 17 angle pairs measured in Phase II, 14 havegood statistics for the reaction pp —• ppn0. There are sixangle pairs at 800 MeV and four each at 500 and647 MeV. The asymmetries and fifth-order differentialcross section d'a/dp^il^li; arc plotted against p , , themomentum of the proton in arm 1 in Figs. 1-3. The dataappear as dots; errors arc small on the scale of thefigures.

The solid lines are the predictions of Dubach et al.,who have provided us with their nucleon-nuclcon com-puter code, which incorporates a relativistic, unitary,three body pion exchange model. Since the system had asolid-angle acceptance of 9 j? 10 .sr or more in each arm,it was necessary to average the theoretical predictionsover the actual geometry used. The theoretical curvesshown in the figures thus have been averaged over thesystem acceptance using a Monte Carlo program.

Comparison of .the data with theory shows excellentagreement at 800 MeV. At lower energies the generalshape of the asymmetries is reproduced, but the cross

January December 1963 PROGRESS AT LAMPF 1 7Los Alamos National Laboratory

600 700 800 900 1000

Proton Momentum (MeV/c)

1100

vnet

ry

>

tc•oG

%"

"I

0.6

04

u

-0.2-tt4

- 0 *

-0.8

40

30

20

10

•

•

•

.1N

>

P22S40MeV/c

*

/

//

/r

/ • »

/

/ * •

500 600 700 800 800 1000 1100


500 600 700 800 800 1000

Proton Momentum (MeV/c)•00 700 600 900 1000 1100


Fig. 1.Cross sections and asymmetries p f p-*ppn° at 800 MeV.

1 8 PROGRESS AT LAMPF£.05 AlMmos National Laboratory

Januvy-Dacvnbar 1963

20*iB,*25"

>

1w

m

tc•o

35

30

25

20

15

10

5

300 400 500 600 700 800


500 800 700 800 800

Proton Momenhm (MeV/c)

0.8

O.«

0.4

0.2

o

-o.2

-0.4

-0.6

-0.8

a

a

f

25

20

15

10

5

0

• •

300 400 500 600 700 800


Fig. 2.

500 600 700 800 BOO


Cross sections and asymmetries p |/> —>ppn° at 647 MeV.

Jenuary-December 1983 PROGRESS AT LAMPF 1 9Los Alamos Nation*/ Laboritory

300 400 500 600 700


300 400 500 000 700 800


300 400 500 BOO 700


Fig. 3.

500 600 700

Proton Momentun (MeV/c)

Cross sections and asymmetries p | p —»• ppn° at 500 MeV.

20 PROGRESS AT U.MPFLos Alamos National Laboratory


sections are underestimated, with the discrepancy gettingworse at the lower energy.

Preliminary results of this work were presented inApril at the American Physical Society meetings inBaltimore.

REFERENCE

1. J. Dubach, W. M. Kloet, A. Cass, and R. R. Silbar, Phys. Lett.

I06B, 29 (1981), and J. Phys. C (Nucl. Phys.) 8, 475 (1982); and

W. M. Kloet and R. R. Silbar, "Nucleus-Nucleon Dynamics at

Medium Energies" (I and II), Nucl. Phys. A 338, 231 (1980).

Measurement of Parity Violation in the pp and p-Nucleus Total Cross Sections at 800 MeV(Exp. 792, EPB)(Los Alamos, Univ. of Illinois, Princeton Univ., Univ. ofMaryland)Spokesman: V. Yuan (Los Alamos)Participants: J. D. Bowman, R. Carlini, D. MacArthur,R. E. Mischke, D. E. Nagle, H. Frauenfelder, R. W.Harper, A. B. McDonald, andR. L. Talaga

The goal of Exp. 792 is to measure the contribution ofthe weak force to nucleon-nucleon scattering at800 MeV. Although the scattering is dominated by strongand electromagnetic interactions, the weak interactionmay be identified by the signature of parity violation.

In the experiment, longitudinally polarized protons arescattered from an unpolarized target; parity violationmanifests itself as a small helicity dependence in the totalcross section. A longitudinal asymmetry can be definedas AL = (a+ -a_)/(a+ + o_), where a+(o_) is the total

cross section for positive- (negaiive-) helicity protons onthe target.

Experiment 792 was active for two run periods duringthe second half of 1983: a 1-week run in August, whichserved as a tuneup to test several important improve-ments to the experiment, was followed by a 2-week-longdata run in November with a liquid-hydrogen target. Inthe November run a statistical sensitivity in AL of1.5 x 10~7 was achieved.

This experiment is one of a series to measure thecontribution of the weak force to nucleon-nucleon scat-tering as a function of energy. At 15 and 45 MeV, theexperiments1"3 yield /4L=-(1.7 ± 0.8) x 10~7 andAL = -(3.2 ± 1.1) x 10~7, respectively, in good agreementwith theoretical predictions based on a meson-exchangemodel4" and a hybrid quark model. In contrast, for 6-GeV/c protons on a water target, a value ofAL = (2.65 ± 0.60) x 10~6 has been reported.8 This valueis larger than the meson-exchange prediction by morethan an order of magnitude.9 It is in agreement, however,with recent calculations that treat wave-function re-normalization and the parity-violating effects of thequark constituents of nucleons.''

The basic experimental layout is shown in Fig. 1. Theexperiment uses the LAMPF polarized proton beam atan intermediate energy of 800 MeV, with polarizationreversed at a rate of 30 Hz at the injector. Two low-noiseion chambers determine the cross section by measuringthe transmission of the polarized beam incident on thetarget. By analyzing the signal for a component cor-related with the 30-Hz polarization-reversal frequency,we can determine the magnitude of any helicity de-pendence of the total cross section. Auxiliary detectorsmonitor 30-Hz changes in beam properties that may

POSITIONSERVOELECTRONICS

!STEERINGMAGNET

POSITIONSERVOELECTRONICS-o

SPLIT ION CHAMBER

/FOR BEAM POSITIONDETERMINATION

SPLIT ION CHAMBERFOR BEAM POSITIONDETERMINATION

SCATTERINGTARGET

^ POLARIMETER

POL ARI METERTARGET

Fig. 1.Schematic of experimental apparatus.


Table I.

Normal

Reverse

Results for November

Data

RawCorrected

RawCorrected

/ *Combined Result 1 -

(-1.9 ±( 0.3 ±

(-7.2 ±(-2.1 ±

fN-RR

2

19831

A7

1.7) x2.1) x

1.6) x1.9) x

) - •

ilun.

10-'io-'

io-'io-'

Chi-Squared

79.5I 64.4

4 200.085.6

1.2 ± 1.4) x 10-'

Number ofRuns

7474

8383

mimic a true parity-violation signal. The beam propertiesmonitored include intensity modulation, position motion,residual transverse polarization, and a phase-space dis-tribution of residual transverse polarization across theprofile of the beam.

In August 1983 we implemented and tested twoimportant improvements to the experiment. The first wasto supplement our split-foil position monitors with newposition/size detectors of multiwire design. Not only didwe obtain pulse-by-pulse information on beam size forthe first time, but we were able to calculate beam positionin a way that takes the beam spot size into account. Thesecond improvement was to use the EPB precessor toprovide longitudinal polarization in EPB. In the Novem-ber data run that followed, this change greatly improvedthe compatibility of Exp. 792 with other experimentsrunning concurrently in Line C.

Following the successful conclusion of the Augusttests, an extensive data run on hydrogen was undertakenin November. In this run, a third important improvementwas introduced: a rotating stripper wheel that gave abetter measurement of our sensitivity to intensity modula-tion. With proper synchronization of the rotating wheel,the effects of intensity changes correlated to the polariza-tion reversal could, for the first time, be examineddirectly.

Sufficient LH2 data were taken in the November run toreach a statistical error limit of 1.5 x 10"' in AL forhydrogen. As had been done in the past, equal amountsof data were taken in both the "normal" and "reverse"configurations of the polarized source. By using the dualsource configurations, we can measure and remove sys-

tematic contributions not included in the corrections thatare applied for systematics of known origin.

Obtaining final results for the November run is underway, but awaits completion of a careful determination ofsystematic corrections. However, an initial estimate ofthe asymmetry has been made, based on a rough calcula-tion of the systematic corrections.

Table I shows the results for "normal" and "reverse";the combined value is ^L = (1.2± 1.4) x 10"'. Such avalue is consistent with predictions for 800 MeV based onthe meson-exchange9 and hybrid quark7 models. It dis-agrees, however, with the large value predicted by thewave-function-effect analysis of NardulH et al.13 Wepoint out that all errors quoted are based only onstatistical uncertainties and do not include anynonstatistical contributions.

Systematic corrections used in the calculation of AL

are listed in Table II. The nonstatistical uncertainties inthe determination of systematic corrections are estimatedto be 10-15% as large as those corrections.

Table II. Systematic Contributions to AL.

Quantity

Intensity

Position

Polarization

Source

NormalReverse

NormalReverse

Contribution to AL

-3.7 x 10-'-7.0 x 10-'

1.6 x 10-'1.3 x 10-'

<9 x 10"8

2 2 PROGRESS AT LAMPFLos Alamos National Laboratory

Janutry-Decsmbm f 963

REFERENCES

1. D. E. Nagle et al., in High Energy Physics with Polarized Beamsand Targets, G. H. Thomas, Ed., AiP Conf. Proc. 51,224 (1978).

2. R. Balzer et al.. Phys. Rev. Lett. 44. 699 (1980).

3. M. Simonius. in Hfck Energy Physics with Polarized Beams andTargets, C. Joseph and J. Softer, Eds., Experientia. Suppl. No. 38(International Symposium. Lausanne. 1980), p. 355.

4. V. R. Brown, E. M. Henley, and F. R. Krejs, Phys. Rev. C 9, 935(1974).

5. M. Simonius, Nucl. Phys. A 220, 269 (1974).

6. B. Desplanques, J. F. Donoghue, and B. R. Holstein, Ann. Phys.124,449(1980).

7. L. S. Kisslinger and G. A. Miller, Phys. Rev. C 27, 1602 (1983).

8. N. Lockyer et al., Phys. Rev. Lett. 45, 1821 (1980).

9. E. M. Henley and F. R. Krejs, Phys. Rev. D II, 605 (1975).

10. G. Narduiii and G. Preparata, Phys. Lett. 117B, 445 (1982).

11. T. Goldman and D. Preston, Nucl. Phys. B 217,61 (1983).

12. J. D. Bowman et al., Nucl. Instrum. Methods 216, 399 (1983).

13. G. Narduiii, E. Scrimeri, and J. Soffer, Centre de PhysiqueTheorique, CRNS, Marseille, France, preprint CPT-82, p. 1420(to be published in Z. Phys. Chem.).

Inelastic Pion Scattering from 17O and I8O(Exp. 369, EPICS)(Univ. of Minnesota)Spokesman: D. Dehnhard (Univ. of Minnesota)

The analysis of data taken during Exp. 369 has beencompleted and a manuscript is being prepared forpublication. The JI+ and n~ scattering cross sections weremeasured on I7O, using version I of the EPICS cooled-gas target. Because the gas was made up of =;50% "O,25% 18O, and 25% 16O, extensive I8O runs were made forbackground subtraction. Here, we report on some of theresults of the analysis of the "O and I8O data.

Octupole transitions in I7O had been studied before byinelastic electron scattering1'2 and the strength had fol-lowed approximately the rules of a weak-coupling modelassuming a

multiplet.In this work the angular distributions (Fig. 1) for the

4.55-MeV |(|)-J, 3.85-MeV |(f)-], 5.69-MeV |(|)-],5.22-MeV |(f)-|, and 7.76-MeV |("/2r i states in "Oclosely resemble those of the 3" states in 16O (6.13 MeV)and I8O (5.09 MeV), even though the transitions in 17Ocan proceed by other than the total angular momentumtransfer 7=3, as in 16O and 18O. For example, the (§)~state can be reached by J=\, 2, 3,J4, 5, and 6.Nevertheless, judging by the similarity fof all angulardistributions, the contributions with J =A 3 appear to benot very important for these states in "O. An exceptionmight be the (f)~ state, for which J= 1 is predicted to bequite important, but the data are not sufficiently good toextract the relative contributions from J'= 1 and 3. |Nocross sections could be extracted for the very weaklyexcited {{)' state.)

If we compare the relative cross section for thesetransitions with the prediction of the simpie version of the\3~ xld"n\ model (that is, without proper antisym-metrization), we find that the octupole strength is not splitamong the states according to this model. For instance,for the (H/2)~state we observe only about 50% of thepredicted strength (Table I).

To analyze the data in the distorted-wave impulseapproximation (DWIA), calculations were done with thecode ARPIN.3 Microscopic transition densitites from threedifferent models were used. Here, we report the resultsthat were obtained using the large-space shell-model

Table I. Renormalization factor R* = o*xp

at 9C m = 44° for Octupole Transitions in"O and I6O Calculated Without (8 = 0)and With (5 = 0.6) Polarization Charges.

17O

16Q

("/7r(!r(?)~

(fr©~3"

Ex (MeV)

7.765.225.693.844.55

6.13

(6R+

3.56.0

10.03.55.0

4,0

= 0)

R-

8.012.09.02.54.5

4.0

(8 = 0.6)

R+

1.01.11.20.81.1

1.0

R-

1.21.01.00.80.9

1.0

January-December 1983 PROGRESS AT LAMPF 2 3Los Altmoi NUiontl Laboratory

calculations.* Both the lp —*2s\d and 2s\d-+ \flpexcitation amplitudes are included for the transitions tolow-lying np"ative-parity states in 17O and 18O. TheDWIA curves for " O (rc,7i'), with these transition densi-ties and without any effective charge enhancements, areshown in Fig. 1 as broken lines.

For all states, the predicted cross sections are signifi-cantly smaller than the data because these transitions arecollectively enhanced. The ratios of experimental andtheoretical cross sections, R1 = o±

exD/o±DWIA, are given

in Table I, columns 2 and 3. Clearly, there is no system-atic behavior in R. Next, the \LSJ) = {303} parts of theneutron and proton transition densities pn and pp weremultiplied by enhancement factors En and EB, respec-tively—that is, pn '=£npn and pp' = £DpD. (Here, L, S,and J are, respectively, the transferred orbital, spin, andtotal angular momenta.) This calculation has been donein Ref. 3 for the {202} parts of the L = 2 transitions in thep shell. For the (n/2)~ state, we found that En = 4J andEB = 1.7 are needed to fit the data. For the other states,very different factors were necessary, which makes thisapproach quite unattractive. Similar erratic behavior inthe enhancement factor was found for the [3~x ld"n\model, even when the wave functions were Droperlyantisymmetrized.

A consistent description of the data was obtained byenhancing only the isoscalar, spin-independent part of thetransition density. Use of 5n = 6P = 0.6, or equivalently80 = 1.2 and 8, = 0, resulted in the absolute cross sections,shown as solid lines in Fig. 1. The ratios are nowstrikingly close to 1. The same isoscalar enhancementfactor (1 + 50) = 2.2 gave a good fit to the pion data forI6O(3-,6.13MeV).

We have used the same parameters for the DWIAanalysis as in Ref. 4. The oscillator parameter,b = 1.63 fm, is smaller than the value (b = 1.76 - 1.78 fm)needed to fit the ground-state densities of I7O (Refs. 1 and3). Using 6=1.76fm results in smaller polarizationchanges slightly larger 7t+/n~ asymmetries, anc1 a slightshift of the angular distribution toward smallerangles—that is, the fit to the pion data is not as good aswith b = 1.63 fm. It is worth mentioning that b = 1.63 fmand 5p = 6n = 0.6 give good agreement (just as b- 1.76and 8P = 8n = 0.35 do) between the large-space shell-model calculations and the experimental .5(2? 3) values.An exception is the value for the (l)~ state, for which the(e,er) data1 are suspect.

"The large-space shell-model calculations used in this experi-ment are from D. J. Millener, private communication.

Cross sections for 18O(II,JI') were extracted for the firstthree 2+ (1.98-, 3.92-, and 5.26-MeV) states, the I" (4.45-MeV) state, and the 3" (5.10-MeV) state. In the previous18O experiment,5 cross sections for the second and thin2+ states could not be extracted because of poor energyresolution. Figure 2 shows the jt+ and z~ data for thethree lowest 2+ states. The ratio R = a(n~)/a{n+) = 2.1 forthe 2+ (1.98-MeV) state is consistent with that previouslymeasured for this transition by Iversen et a!.5 For thesecond 2+ (3.92-MeV) state, the JI+ and n~ cross sectionsare more nearly equal, R = 1.27. The third 2+ (5.26-MeV)state is somewhat surprising in that the cross section ismuch larger than most models predict for I8O wavefunctions and there is a large ir+ enhancement, R - 0.2.

The jr+ and iC cross sections for the 3" state at5.10MeV are essentially equal. The dashed curves areDWIA calculations using the transition densities of thefull lhco shell-model calculations of Millener. Thepredicted cross sections are too small, and the n+/n~asymmetry is not observed in the data. The data can bereproduced by enhancing the isoscaiar J(LS) = 3(30)amplitude by a factor of 2 and completely omitting theisovector amplitude. This implies a very large neutronpolarization change, which indicates a lack of under-standing of the neutron components in the wave functionof 18O.

The data obtained for the 1" state at 4.45 MeV wereinitially very surprising. The n+ and Jt~ angular distribu-tions are very similar, with the n+ being slightly largerthan the iC. The angular-distribution shapes are com-pletely out of phase with calculations using simple singleparticle-hole transition densities, such as lpl/2 —»• 2sU2 orIp3/2—*• I<af5/2- The DWIA calculations, using one-bodydensity-matrix elements (from shell-model calculations)as transition densities,4 produce angular-distributionshapes closer to that of the data. The magnitudes for both7t+ and n~ are more than an order of magnitude smallerthan the data [Fig. 3(a) and (b)).

The two calculations use the full lhco shell-modelcalculation of Millener (solid curve) and the p-sd calcula-tions of Brown.* The addition of the sd-fp components inthe full lhoj calculation decreased the large ratioa(n+)/o(7i~), but it is still much larger than experimentallyobserved. It should be noted that a calculation using anI6O shell-model calculation that included core polariza-tion in pertubation theory produces agreement with thedata for both the I8O, 1" (4.45-MeV) and I6O, 1" (7.12-MeV) states.

B. A. Brown, private communication.


January-December 198:

1.0

0.01

001

IP VVT.T.T6WW)

0.01

(T/k~, 5.69 MtV)• •

0.01

. W. 5.22 U»V)

QOli- -'O(%".5.69M*V)

20 40 60 80 20 40 60 80

Fig. 1.Angular distributions for states in 1 70. The curvesare DWIA calculations with (solid-line) andwithout (broken-line) effective charge enhance-ments.

Jtnufy-Otctmtm 1SB3 PROGRESS AT LAMPF 2 5Los Alamos HMiontl Ltbontoy

_ XX

1a

10.-1

10"

10"

S

I

iaO(7T,7T018O 2 + S t a t e s• = 7T+, 1.98 MeV• = IT'. "• = 7T*. 3.92

• = 7T+, 5.26x = IT" "

Ii

I

5

1

X

!i

20 30 40 50 60 70 80 90

Fig. 2.Angular distributions for the three lowest 2+ states in " 0 .

2 6 PIKX1RESSATLAMPFLot Altmot Niloml Ltborttory

J*mivy-Dtc»mim 19B3

a

B•o

I 180(n,n')1l>0, 1", 4.45 MeV

10° p

20 40 60 BO 1009cm. (deg)

10'1 ?

c5

10-' r

10'3

1 1

• "O(n,n')1»O,

*

...

i * * *

11

i

1-

..i

z

1 1

,4.45 MeV :

JM (xlO)

•

(b)

t i

20 40 60 60 100

»..«.. (deg)

Fig. 3(a) and (b).Angular distributions for the 1" state in 18O for (a)ir~ and (b) it4 scattering. The curves are describedin the text.

REFERENCES

1. J. C. Kim et al., Phys. Lett. 57B, 34) (1975). and Nud. Phys. A297.301 (1978).

2. J. Kelly et al., Bull. Am. Phys. Soc. 25, 575 (1980).

3. T.-S. H. Lee and D. Kurath, Phys. Rev. C 21. 293 (1980).

4. T.-S. H, Lee and R. D. Lawson, Phys. Rev. C 21. 679 (1980).

5. S. Iverson et al., Phys. Rev. Lett. 40, 227 (1978).

jMiwtry-Otcamber 1983 PROGRESS AT LAMPF 2 7Lot Alamos Nttlonsl Ltbortloty

Excitation of 8~ States in 54Fe(Exp. 565, EPICS)(Argonne National Lab.; Univ. of Birmingham, UnitedKingdom; Indiana Univ.; New Mexico State Univ; LosAlamos; Univ. of Massachusetts; Montana State Univ.;Northwestern Univ.; Oregon State Univ.)Spokesman: B. Zeidman (Argonne National Lab.)

We have investigated the excitation of 8~ states in 54Fewith 162-MeV pions at EPICS. At large momentumtransfer, such high-spin particle-hole (stretched) statesare selectively excited in pion inelastic scattering.1 Bycomb' iing the analysis of the pion data and previouslypublisned electron data, isoscalar and isovector transitionstrengths were extracted for each 8" state.

The selectivity of pion inelastic scattering for isoscalarspin-flip strength is particularly valuable because noother probe shares this selectivity. This fact makes pionscattering a natural complement to 180° electron scatter-ing, which selectively excites isovector spin-flip states.

With the 54Fe results obtained in this work, it is clearthat in high-spin particle-hole states much less isoscalarspin-flip strength has been identified than isovector spin-flip strength. This phenomenon persists from p-shellnuclei, at least up to the middle of the f-p shell. It isalready well known that the isovector spin-flip strength tosuch high-spin states is only 30-50% of simple single-particle estimates.2 This amount of quenching also hasbeen observed for Gamow-Teller resonances (L = 0,isovector spin-flip excitations),* where it has been inter-preted as evidence for non-nucleonic degrees of freedom,and in particular isobar-hole states.4 Since non-nucleonicdegrees of freedom contribute only weakly to isoscalarexcitations, the large unexplained relative quenching ofthe isoscalar strength compared to the isovector strengthimplies that the nuclear-structure input must be examinedmore critically for both modes of the nuclear response.

The experiment was carried out on the EPICS channeland spectrometer system. A large (10- by 20-cm)isotopically enriched (>97%, 54Fe, 151-mg/cm2) targetwas used. Spectre with JT+ were accumulated in 10° stepsfrom 40 to 100°; it" spectra were accumulated at 70,80,and 90°. Short runs were taken at 5° intervals toestablish the elastic-scattering yields. The channel andspectrometer were used in the conventional fashion. Inaddition to the 8" states at 8.31, 8.95, 9.97, 10.68, and13.26 MeV identified in electron scattering, two new 8~

states at 9.80 ± 0.05 and 11.65 ± 0.05 MeV excitationwere observed.

The inelastic yields to the different 8~ states differgreatly for n+ and n~. This difference is the result ofinterference of isoscalar and isovector amplitudes, sincefor a transition with a pure isospin structure (either pureAT=0 or pure L\T= 1) ,>he n+ and n~ yields must beequal, as they are for the 13.26-MeV T=2 state. Bycombining the pion data with the electron inelastic-scattering results,5 it is possible to separate the isospinamplitudes for each state. The experimental cross sec-tions and 2?(M8) satisfy the following relations for eachstate i:

B\M8)e=

In these equations, M"o (M *) is the square root of thecross section for exciting an isoscaiar (isovector) trans-ition to a pure one-particle one-hole state in a closed-shellnucleus by n~ inelastic scattering. The M% and M\ aresimilar amplitudes [B(MS)\m for electron inelastic scat-tering. The coefficients Zo and Z, contain the nuclear-structure amplitudes of isoscalar and isovector excitationof each state. The reaction dynamics is contained in theM factors, which can be obtained from distorted-waveimpulse approximation 'DWIA) calculations. Based onthe free-nucleon properties,

f = -O.l87 M\

*See. for example. Ref. 3 and references therein.

where \ia and pp are the neutron and proton magneticmoments, respectively.

For electron scattering, the absolute values of Ml andM\ can be obtained from DWIA. However, the uncer-tainties in the reaction dynamics make the DWIA calcu-lation of the absolute values of Ml and Ml more

2 8 PROGRESS AT LAMPFLas Alamos National Laboratory

January-Otctmbar 1983

uncertain. To avoid this uncertainty, M] can be obtainedfor the T= 2 state, since Z, is determined by the electron-scattering data. Then, only the ratio M^/M* need beextracted from the DWIA calculations.

This procedure renders the results insensitive to theexact choice of the radial form factor or the pion opticalpotential. Because the ratio of isoscalar to isovector crosssections is determined essentially by an isospin Clebsch-Gordan coefficient, it is not expected to be sensitive to thereaction dynamics. This is particularly true for high-spinstates where the transition density is surface localized.Recent calculations indicate that although medium cor-rections may modify the ratio of M"o/M1 for low-spinstates, they have little effect for high-spin states, therebysupporting the procedure used here. It should also benoted that in the few cases where the isoscalar pionresults have been checked with proton inelastic scatter-ing, the results have agreed very well, although there areconsiderable uncertainties in the reaction dynamics in theproton case.6

The structure coefficients Zo and Z, for each 8 stateare tabulated in Table I. For comparison, the coefficientsobtained in a |(/7/l

3) x gm\s- calculation are also given.In this model space, the structure coefficients satisfy asum rule — that is,

VT"

r'*= 1

and

v rz'V -

The isovector strength can be further subdivided intostrength in T = 2 states,

Table I. Isospin Amplitudes for S4Fe 8~ States.

Excitation Energy

8.31

8.95

9.80

9.97

10.68

11.65

13.26

\p-3h sum rule

Fraction of lp-3h sum'Only the eight states withlisted.

Experiment

OA2±°n02

0.04

0.02 ± 0.04

™*%0.08 ± 0.04

0.20 ± 0 0 4

0.02

0.12 ± 0 - 0 3

0.06

0

0.102

0.875

12%

Theory8

2, Excitation Energy Zo

0.24 ± 0.02

0.20 ± 0.04

0.04 ± 0.04

-0.20 ± 0.02

-0.14 ±0.04

0.04 ± 0.08

0.44 ± 0.02

0.354

0.875

40%

the largest expected cross sections in ]

8.31

9.58

10.3710.80

11.014

11.5711.98

13.26

0.336

0.226

0.3120.204

0.432

0.3530.380

0

0.759

z.0.444

0.193

-0.3490.202

-0.192

0.1250.064

0.601

0.815

pion or electron inelastic scattering are


v ( Z ij ,o 2/ ' 8

and T= 1 states,

v -8

The sum of the experimental isoscalar strength is only12% of this limit, and the sum of the isovector strength isonly 40% of this extreme three-hole one-particle calcula-tion.

It is significant that the quenching of the particle-holestrengths is similar to the values obtained in other nucleifor high-spin particle-hole states. The ratio of the summedisoscalar strength to the summed isovector strength forall cases of stretched particle-hole states, where informa-tion on the isoscalar strength exists, exhibits a consistenttrend in which the isoscalar strength is more stronglyquenched than the isovector strength. (A stretched stateis one that has the maximum angular momentum avail-able for a lhoo excitation—that is, 4~ in the Op shell, 6~ inthe Is-Od shell, and 8" in the Of-lp shell.) The presentdata therefore give a clear indication that the strongquenching of isoscalar spin-flip strength is a rathergeneral phenomenon.

In summary, data for pion inelastic scattering to 8~levels in S4Fe have been presented. By combining thesedata with previous electron-scattering data, isoscalar andisovector transition amplitudes were extracted for each8~ state. Only 12% of the simple one-particle three-holestrength was observed for the isoscaiar excitations, andonly 40% of the one-particle three-hole strength wasobserved for the isovector excitations. This strongerquenching of the isoscalar spin-flip strength compared tothe isovector strength appears to be a general feature forhigh-spin particle-hole states; the present case representsthe heaviest nucleus where such an isospin decompositionhas been done thus far.

REFERENCES

1. C. Olmer, B. Zeidman. D. F. Geesaman. T. S. H. Lee. R. E. Segel.L. W. Swenson. R. L. Boudrie. G. S. Blanpied, H. A. Thiessen. C.L. Morris, and R. E. Anderson. Phys. Rev. Lett. 43. 612 (1979).

2. R. A. Lindgren, W. J. Gerace, A. D. Batiier, W. G. Love, and F.Petrovich, Phys. Rev. Lett. 42. 1524 (1979).

3. C. Goodman. Nucl. Phys. A 374. 241c (1982).

4. M. Ericson. A. Figureau, and C. Thevenot, Phys. Lett. 4SB, 19(1973); E. Oset and M. Rho, Phys. Rev. Lett. 42, 47 (1979); A.Bohr and B. Mottelson. Phys. Lett. 100B. 10 (1981); and R. D.Lawson, Phys. Lett. 125B, 255 (1983).

5. R. A. Lindgren, J. B. Flanz, R. S. Hicks, B. Parker, G. A. Peterson,R. D. Lawson, W. Teeters. C. F. Williamson. S. Kowalski. and X.K. Maruyama, Phys. Rev. Lett. 46, 706 (1981).

6. C. Olmer et al., to be published in Phys. Rev. C.

Inelastic Pion Scattering from 24Mg and 26Mg: TheNew Year's Experiment(Exp. 573, EPICS)(Univ. of South Carolina, Univ. of Texas, Univ. ofPennsylvania, Los Alamos, Drexel Univ., Univ. ofMassachusetts)Spokesman: G. Blanpied (Univ. of South Carolina)

This experiment first ran at EPICS during New Year'sDay 1983, using about one-half of the allotted time. Thesecond half is scheduled for New Year's, 1984.

In the first run, n+ and n~ data were taken on 26Mg atthree energies. Angles were chosen to provide steps ofmomentum transfer i ~ qR, where R was determined bythe ratio A " ' for 28Si and compared with •"+ data on 28Si(Refs. 1-3). Data were obtained at scattering anglescorresponding to qR~2. 3, 4, and 6 at 116 and292 MeV, and qR ~ 2-8 at 180 MeV, where R ~ 3.3 fm.Inelastic spectra up to an excitation of more than 20 MeVwere acquired with a resolution of better than 250 keV atmost angles. The normalization was done relative to n*/?scattering. Of interest is the comparison of the relative7i~/it+ strengths for the excitation ofJ" = 2+, 3~, and 4*collective states to shell-model predictions.


January-Oictmtm 1963

400

to 300c

IU

•g 200 -

100 -

0 10 20Relative Excitation (MeV)

Fig. 1.Spectrum of JI+ scattering from 26Mg at a laboratory angle of 78° where the momentum transfer isrelatively large.

-

-

-

0*

1

1fiy

i

1 Ji ,

2 6Ma(,

IB6",

|

B 7 8 ° '

MeVT=2

pit

1 I

, 180 MeV :qR~6 J

-

—

Seen in the Jt+ spectrum (Fig. 1), obtained at an anglecorresponding to qR ~ 6, is the (6~, T= 2) state at18 MeV. This state also has been seen in 180" electronscattering4 at Bates and with {p,p') at the Indiana Univer-sity Cyclotron Facility (IUCF).* The n+ and n~ crosssections are approximately equal, as expected for a pureisovector transition, and are equal to i 1 nb/sr at thepeak. The same cross section for the (T= 1, 6") state in28Si excited by 162-MeV pions was observed to be24 ub/sr (Ref. 2).

REFERENCES

1. B. M. Preedom et al.. Nucl. Phys. A 236. 385 (1979).

2. C. Olmer et al.. Phys. Rev. Lett. 43, 612 (1979).

3. B. Zeidman et al., Phys. Rev. Lett. 40, 1539 (1978).

4. R. A. Lindgren et al.. Bull. Am. Phys. Soc. 27, 697 (1982); andLong Don Pham, University of Massachusetts B.S. thesis. May1983. unpublished.

5. D. F. Geesaman et al.. Bull. Am. Phys. Soc. 27, 697 (1982).

*D. F. Geesaman et al., Ref. 5, and private communication.

Janutry-Dtctmbtr 1983 PflOOREMATUMPF 3 1Los Alvna Nmtiont) Ltbortory

Isovector Properties of Collective States and theInteracting Boson Approximation Model(Exp. 671, EPICS)(Northwestern Univ.)Spokesmen: A. Saha and K. K. Seth (NorthwesternUniv.)

Isovector (or, equivalently, proton-neutron) propertiesof nuclear states provide extremely sensitive tests ofnuclear-structure models.1'2 For heavy nuclei, one model,which has gained increasing attention in recent years, isthe Interacting Boson Approximation (IBA) model.3 Inthe latest version of this model, called the IBA-2 model,4

the active part of the nucleus (outside a supposedly inertcore) is described in terms of a small number of mutuallyinteracting proton and neutron bosons that can be eitherin the SOT dstate. This model can make explicit predic-tions regarding the isovector properties of nuclear trans-itions. Here we report on the first successful experimentspecifically designed to test these predictions.

We have measured differential cross sections forelastic and inelastic scattering of 180-MeV n+ and rc~from enriched targets (>95%) of "><•»>«.«>«.'iopd at theEPICS facility. As illustrated in Fig. 1, the energy resolu-tion obtained was =:165 keV. To extract Mn and Mp fromour data, we have made distorted-wave impulse approx-imation (DWIA) calculations with the coordinate-spacecomputer code DWPI5 using a Kisslinger-type opticalpotential and collective form factors. As is well known,the proton transition matrix element MB is related to (3P as

The Mn is defined in exactly the same manner in terms ofN and pn . We note that our values of Mv for the 2,+

states agree well within errors (<5%) with those fromlifetime measurements^ For the 3 ," states, no otherdirect results for Mn are available for comparison.

In the IBA-2 model the neutron and proton quadrupoletransition matrix elements are defined7 as

and

40 80 120

CHANNEL NUMBER

Fig. l.

Excitation-energy spectra for the reaction Pd(n,n')

The nuclear-structure information is contained in thereduced boson proton-neutron transition matrix ele-ments, Apn and £„,„, for the d-boson nonconserving andrf-boson conserving parts, respectively. The a p n and p0<n

are the corresponding values of the quadrupole operators.We relate our experimental results to the IBA-2 model

at two different levels, with or without core polarization.Further, we can treat a,,<p and P n p as adjustableparameters, as was done in Ref. 7, or we can use thevalues calculated in a generalized seniority scheme using

3 2 PROGRESS AT LAMPFLos Alimo) Nttlmtl Ltborttorf

Jvxjtry-Otcvnbtr 1S63

a surface delta interaction.8 These calculations forpalladium give the following results.

IO8pd 110pd

(fm2)

an

Pn

ap

Pp

18.5- 8 2

14.7

-4.3

16.6-8.2

15.1

-3.9

15.6-3.7

15.3

-2.6

14.82.4

15.6

-3.3

In all these comparisons we take A. and Bi from Ref. 7.We first consider the IBA-2 model without core

polarization. If we follow the phendmenological proce-dure, using Xp^Op/Pn a n d 3Cn = an/Pn» a s optimized inRef. 7, and setting Mn = eQn and Mp = eQp for the 2,+

states, we obtain the average values <an> = 21.2 fm2 and<cto> = 38.8 fm2. These lead to a constant Mp w 86 e-fm2

and to the rapidly changing Mn/Mp, shown by the thinsolid curve in Fig. 2. Neither of these results is inagreement with the data. Further, the Mp for the 22

+

states are predicted to be «2.5 times larger than theexperimental results. If we use the calculated values of aand p, we obtain even poorer agreement with the data.We obtain Mn, which are x75 (±8)% of the experimentalresults; Mp , which are «41 (±4)%; and Mn/Mv, whichare a uniform factor of ~2 larger than the experimentalresults (thin dashed curve in Fig. 2). The Afp for the 22

+

states fare better, being only x2\ (±5)% smaller than theexperimental values.

From the above results, we conclude that irrespectiveof what approach is adopted toward a's and P's, we mustcompensate for the truncation of the valence boson spaceby including core polarization. As in the shell model, onecan do this by introducing "effective" charges ev and en

for proton and neutron bosons and note that for a self-conjugate core (here N =Z= 50),

Mn and Mp . We first use g's, as empirically optimized inRef. 7, and <an> = 16.4... -5.2 fm2 (which areaverages of the calculated resting to obtain Qv and Qn foreach isotope. Comparison with MB and Mn then leads toa set of ep and en that is essentially the same (withina±5%) for all isotopes: <<?„> = 1.13e, <en> = 0.49e. Theresults for Mp and Mn/Mp obtained by using theseeffective charges are shown in Table I and by the thicksolid curve in Fig. 2. The fit to the data is quite good. Thesame effective charges (Table 1) predict MD for the 2-fstates, which are in fair agreement with the data. Inaddition, they lead to very distinctive predictions forMJMP that should be tested in future experiments.

Unfortunately, if we use a's and P's, as obtained fromthe microscopic calculations referred to earlier, the re-sults are much poorer. Individual ea are fairly constant(en = 0.46e—*-0.50e), but eB show an unacceptableamount of variation (ep= 1.02e—>• 1.35e) in going fromI04Pd to "°Pd. Equivalent^, we note that if we use theaverage values, <en> =0.48e and <ep> = 1.17e, we failto reproduce the trend of Mp and Ma individually,

For a given nucleus, once Qp and Qn are known, ep and en

are determined uniquely by fitting the measured values of

104 106 108 110

Palladium Isotopes

Fig. 2.The (MJMP)/{N/Z) for the 2+ states in palladiumisotopes. The curves refer to IBA-2 calculationsdescribed in the text.

Without core polarization: thin solid line forempirically adjusted <a>, <P>; thin dashedline for microscopically calculated a, p.

With core polarization: thick solid line for em-pirically adjusted <a> , <p> and<en> = 1.12c, <en> = 0.49e; thick dashedline for microscopically calculated a, P and<ep> = 1.17e, <en> = 0.48c.

January-December 1983 PROGRESS AT UMPFLos Alamos National laboratory

33

Table I. Summary of Results for Excitation of 2+

J" A

2\ 104106108110

2% 104106108110

3"; 104106108110

Ref. 6

Mp

74(2)83(3)88(3)94(3)

16(1)13(1)13(1)11(1)

Experimental Results

M p

77(2)83(2)89(2)98(2)

365(9)360(9)334(8)315(8)

(«,*')

Ma

106(3)118(3)136(3)156(4)

542(14)533(13)539(13)523(13)

MnlM,

1.38(5)1.43(5)1.52(5)1.59(6)

1.49(5)1.48(5)1.61(6)1.66(6)

States in

N/Z

1.261.301.351.39

1.261.301.351.39

Palladium Isotopes.'

Model Predictions

;os125135150

6109

14

IBA-2

Mpb

79858995

17181516

Mn<

119126129136

13192130

83868790

17191821

W,,n, in units of e-fm2 for 2+, and e-fm3 for 3".hAverage <ep> = 1.13e, <cn> =0.49e, and empirical a's and P's.'Average <ep> = 1.17e, <cn> = 0.48e, and calculated a's and P's.

although MJMB agree with the data (thick dashed curvein Fig. 2). For the 22

+ s tates, the predicted MB differ fromthe experimental ones by 43 (±23)% and the predictedMa /Mv differ by a factor of 2 from those with empiricallyadjusted a's and P's. -

Because of the limited success obtained above with theIBA-2 model without empirically adjusted parameters, itis instructive to examine what other simple phenomeno-logical models predict. In the hydrodynamical model,nuclei in the palladium region are well described asvibrational nuclei, with

M2B =

By analogy, Mn is defined in terms of N, Rn, and(£{tCi)n. The parameters BA (related to the mass trans-port associated with the vibration), CA (related to theeffective surface tension or restoring force), and R, in

principle, can vary from nucleus to nucleus and betweenneutron and proton fluids, but generally are consideredconstant in a small region of N and Z. Thus, this modelpredicts A/p = constant for a series of isotopes andMn/MP = N/Z. As seen in Table I, the experimental Mg

increased by ~25% from IMPd to n 0Pd. Also, theexperimentally observed ratios of MJMV for the 2 , + and3,~ states are, respectively, ~12 and ~18% higher thanN/Z (see Table I). Better agreement with the experimentalresults can be obtained by treating BK, CA, and R asadjustable parameters. For example, we can obtain ex-cellent fits to the measured Mo by simply varying C2 withneutron number. Similarly, the experimental Ma/Mp forboth 2,+ and 3," can be fitted perfectly by assumingeither that the effective-radius parameters Rn and Rv aredifferent, or that {BA,CA\ and (BA,CA)B are different.

We can summarize our results as follows. The IBA-2model without core polarization is clearly unsuccessful inexplaining the experimental results. By including core-polarization effects, using effective charges, the IBA-2model can provide a good description of the data if oneallows empirical adjustment of its parameters. However,

3 4 PROGRESS AT LAMPFLos Alimos Niliontl labaitory

Mnu*ry-O»c*mbv 1963

at this level, it is worthwhile to remember that other, evensimpler models, also can explain the experimental results,vovided that their parameters are also adjusted from

. .sotope to isotope. Our first attempts to calculate some ofthe IBA-2 parameters on a microscopic basis have so farbeen unsuccessful. Clearly more theoretical work isrequired. At the experimental front, measurement ofMJMV for other quadrupole transitions, particularly 0,+

to 22+, would help narrow the range of alternative

explanations.

REFERENCES

1. A. Saha el ai., Phys. Lett. I 14B, 419 (1982), and references therein.

2. S. G. Iversen et al., Phys. Rev. Lett. 40, 17 (1978); and S. G.Iversen et al.. Phys. Lett. 82B, 51 (1979).

3. A. Arima and F. lachello, Phys. Rev. Lett. 35, 1069 (1975); and F.Iachello. in "Interacting Bosons in Nuclear Physics" (PlenumPress, New York, 1979), p. I.

4. T. Otsuka, A. Arima, F. Iachello, and I. Talmi, Phys. Lett. 76B,139 (1978); and T. Otsuka, A. Arima, and F. Iachello, Nucl. Phys.A 309, 1 (1978).

5. R. A. Eisenstein and G. A. Miller, Comput. Phys. Commun. 11,95(1976).

6. Nuclear Data sheets, 18, 125 (1976); 30, 305 (1980); B7, 33(1972); and 22, 135(1977).

7. P. Van Isacker and G. Puddu, Nucl. Phys. A 238, 125 (1980).

8. O. Scholten, Michigan State University preprint #MSUCL-416(1983).

Studies of Giant Resonances in 208Pb with InelasticPion Scattering(Exp. 672, EPICS)(Los Alamos, Univ. of Minnesota)Spokesmen: T. A. Carey and J. M. Moss (Los Alamos)and S. Seestrom-Morris (Univ. of Minnesota)

To broaden our base for investigating the high-lyingnuclear response, we have used 162-MeV inelastic pion

scattering to study giant resonances in 2OIPb at excita-tions <40 MeV.

Pions cause isovector transitions relative to isoscalarones much more strongly than do either 200- or 800-MeV protons, so (n,;i') should be better for txciting theisovector giant quadrupole resonance. Comparisons ofn+ and n~ scattering are also a powerful tool for identify-ing the isospin character of specific transitions.Furthermore, in view of the intrinsic energy dependencesof Coulomb excitation, we expect that this mechanismwill be much weaker in the excitation of giant resonanceswith 162-MeV pions than is the case with 800-MeVprotons. In general, then, (n,7t') should nicely complementour (p,p') studies and be most helpful in unraveling thespecific natures of the observed resonances.

High-precision data were acquired in November 1982at LAMPF. Replay of these data is now complete andseveral avenues of theoretical analysis currently are beingpursued. Both Jt+ and n~ spectra exhibit a definiteresonance at £x = 21 MeV. Analysis thus far suggeststhat its quantum numbers are J*,T= l",0, but conclusiveassignments await ongoing considerations of Coulombexcitation and the underlying continuum. Still, we mayhave the first strong evidence for a surface-compressionalmode as opposed to the volume-compressional modeassociated with the isoscalar giant monopole resonance.

To date the most extensive analysis has concentratedon the lower lying isoscalar giant quadrupole resonance(ISGQR) and 3]~ states because they have beenthoroughly studied with other probes and because theextraction of precise absolute yields for them is lesshindered by underlying backgrounds. These excitationsare believed to involve strongly collective, isoscalar tran-sitions. The generally successful pure collective modelpredicts R=a(n~)/a(K+)^N/Z = 1.5 for such states in208Pb. Surprisingly, we find that our data giveA =1.8 ±0.1 for the 37, whereas for the ISGQRR = 3.0 ± 0.5.

The data for ISGQR transitions, shown in Fig. 1,indicate an even more serious discrepancy than thatrecently reported for the ISGQR from an independentll8Sn(n,n') experiment.1 Also, a preliminary analysis ofour data for the isoscalar high-energy octupole resonancegives R = 3.3 ± 1. These results could imply the presence

PROGRESS AT LAMPFLos Altmos NulontJ Ltboruay

35

icT r

ltf r

1

•§

10".-I

10"'

-

-

N

r

i

1 1 i

208Pb(n,n')20'Pb (GQR) :• 71*

o rr

1 1 /

r i ^ j

-

-

;

i i

i i

t i

111

' i

i

1/ Y \10 20 30

cm.

40 50

(deg)

60 70

Fig. 1.The jt+ and jt~ angular distributions andcollective-model calculations for the giant quad-rupole resonance in 208Pb.

of substantial isovector contributions to these pur-portedly isoscalar transitions, but the rather systematicnature of the disagreement between experiment andtheory for more than one giant resonance in more thanone nucleus may also be indicative of a breakdown in thestandard collective model. Further analysis is in progress.

REFERENCE

I. J. L. Ullman et al.. Phys. Rev. Lett. 51, 1038 (1983).

Measurements of Large-Angle Pion-Nucleus Scat-tering(Exp. 681, EPICS)(New Mexico State Univ., Univ. of Texas, Univ. otMinnesota, Los Alamos)Spokesman: G. Burleson (New Mexico State Univ.)

The motivation for this experiment was to explorepossible systematics of pion-nucleus scattering in thelarge-angle region, where the behavior is poorly knowiifrom an experimental point of view and poorly under-stood from a theoretical point of view. In general, thereare many models of pion-nucleus scattering that give agood description of elastic and inelastic scattering overthe angular range for which data are abundant (to~100°) but that diverge drastically for large angles. For arealistic description of pion-nucleus scattering, a fairamount of data is required in the backward hemisphere toconstrain the calculations. The results of this first experi-ment on large-angle pion-nucleus scattering at LAMPFhave begun to reveal some of these features.

The experimental configuration is as follows. Basically,a circular magnet is placed at the EPICS pivot point,which is displaced laterally from its normal position. Theincident pion enters parallel to a line through the center ofthe magnet, effectively bends through the arc of a circle,and is incident upon the scattering target at the center ofthe magnet. A pion scattered at a large angle is bent so asto enter the spectrometer when it is positioned within itsnormal operating angular range. With this design, theeffective solid angle of the spectrometer should be inde-pendent of the scattering angle.

Wire-orbit measurements of the magnet were made inplace before the experiment began. No indication ofazimuthal asymmetry was found over the angular regionof the scattered pion. During the experiment, the yield ofpions scattered from protons tracked the pion-protoncross section calculated from the phase shifts of Rowe

tetal. ' to within ±5% over the full range of scatteringangles, 115-180°, confirming the design characteristics ofthe system.

Some of the preliminary results are shown in Figs. 1-4.AH data points were normalized to pion-proton scattering



1 -

1c;

0.1

I ' l l 1 1 ' I

12C(7T+,7T+)12C

:

, 1 , 1 . 1 . 1

162 MeV

f SIN

• Early EPICS

» EPICS

hlllf ^

••

-

• • •

-

0.03100 110 120 130 140 150 160 170 180

cm. Angle (deg)

Fig. 1.Preliminary results for the n+-'2C angular distribu-tion at 162 MeV, compared with previous data(Ref. 2).

}0.1 -

0.03

1 6 O ( T T , 7 T + ) 1 6 O

162 MeV

f Albanese et al ji EPICS ii Bason elaL -j

1 Jl

100 110 120 130 140 150 160 170 180cm. Angle (deg)

Fig. 2.Preliminary results for the n+-I6O angular distribu-tion at 162 MeV, compared with previous data(Ref. 3).

measured under spectrometer conditions identical inangle and magnetic-field settings with those used for thepion-nucleus scattering measurements. The experimentaldifferential cross sections for n+-12C scattering at162 MeV are shown in Fig. 1. The agreement withprevious EPICS data is good, but there is a disagreementwith the previous SIN backward data2 in that the SINresults show a fairly strong backward peaking, whereasthe new results do not, and in that there is a difference inabsolute value of about a factor of 2.

The results for n+-16O scattering at 162 MeV areshown in Fig. 2, with previous data from SIN' andCERN.4 The agreement with the CERN results is satis-factory, considering the large error bars, but there isagain a disagreement with some previous results fromSIN, this time with data taken with the "normal" spec-trometer setup.

An excitation function for Ji+-deuteron scattering at176° is shown in Fig. 3 and compared with previousdata5"7 at 180°. There is disagreement with the absolutevalues of some of the previously measured cross sections,but the new data points join smoothly onto the recentdata from KEK.7 An excitation function for TT+-I2Cscattering is shown in Fig. 4, with a prediction of theoptical model of Cottingame and Holtkamp.8 It is inter-esting that this model, which has had good success inpredicting pion-nucleus cross sections at angles up to~100°, makes a fairly good prediction of the structureobserved between 130 and 170 MeV, even though itmisses the magnitude of the cross sections.

Further studies of these results are in progress.

January-Dtcember f 983 PROGRESS AT LAKPFLos Alamos Nttimal Laboratory

37

10 r

•B 0.11

o.oi

5 EPICS

I Holt etal.

§ Frascari etal

i Akemoto etal.

50 100 150 200 250 300 350 400T, (MeV)

0.1

0.001

0.000560 100 140 180 220 260 300

TB(MeV)

Fig. 3.

Preliminary results for the n+-deuteron excitation

function at 176°, compared with previous data

(Refs. 5-7) at 180°.

Fig. 4.

Preliminary results for the n*-12C excitation func-

tion at 180°, compared with the prediction of the

model of Cottingatne and Hoitkamp (Ref. 8).

REFERrNCES

1. G. Rowe, M. Saloman, and R. H. Landau, Phys. Rev. C 18, 584(1978).

2. B. Chabloz et al., Pbys. Lett. 81B, 143 (1979).

3. J. P. Albanese et al., Nucl. Phys. A 3S0,301 (1980).

4. E. Bason et al., contribution to the Ninth Int. Conf. on High-Energy Physics and Nuclear Structure, Versailles, France, 1981.

5. R. J. Holt et al.. Phys. Rev. Lett. 43, 1229 (1979).

6. R. Frascaria et al., Phys. Lett. 9IB, 345 (1980).

7. M. Akemoto et al., Phys. Rev. Lett. 50,400 (1983).

8. W. B. Cottingame and D. B. Hoitkamp, Phys. Rev. Lett. 45, 1828(1980).

3 8 PROGRESS AT LAMPFLos Altmos NMonil Llboralory

it+/*~ on I 5N(Exp. 703, EPICS)(Univ. of Minnesota, Los Alamos, Univ. of Texas)Spokespersons: D. B. Holtkamp (Los Alamos) and S. J.Seestrom-Morris (Univ. of Minnesota)

Experiment 703 ran during January 1983, measuringn+ and n~ cross sections for excitation of states in 15N.Replay of the data is complete, as is the peak stripping forstates below about 8-MeV excitation energy. Calculationof the absolute normalization of the data is currentlyunder way.

Figure 1 shows spectra of n+ and n~ scattering atTn = 164 MeV near the maximum in the angular distribu-tion for A/4 transitions. Arrows indicate those groupsthat have been identified as due to MA transitions, (f)+

states; n+/n~ asymmetries have been observed for someof these transitions, for example,

)^7>3forl0.6MeVt )

n)-Z7~ 5 for 12.5 MeVt )

Although the MA transitions were the primary goal ofthis experiment, interesting data also were obtained onthe low-lying excited states. One example is the transitionfrom the (j)~ ground state to the ($)~ state at6.32 MeV. Li the extreme shell model, the IJN groundstate can be described as a single proton hole in the \pm

shell and the {\)~ state as a single proton hole in the \pm

shell. In this model the transition from $—•(§)"would be a pure protonPn2—*-Pin single-particle tran-sition. Such a transition would yield a ratio of

The preliminary data of Exp. 703 for this transitionshow a significantly smaller value of R = l.S. This dif-ference probably is due to contributions of collectiveelectric quadrupole components. To try to account forthis, distorted-wave impulse approximation (DWIA) cal-culations were performed using a combination of a pureproton Pin~*PinPn component and a J(LS) = 2{20)component scaled by neutron and proton polarizationchanges (1 + 8n) and (1 + 5P). The data and resultingcalculations are displayed in Fig. 2. These values ofSp = 0.3 and 6n = 1.0 and an additional renormalization ofthe DWIA amplitude by 1.13 produce electromagneticproperties in agreement with those measured using otherprobes.

ITS

)(A

RB

.

D *_ iUJ

>~

rg

<VJfO

|

U l

w

U. "Nhr.ir1)

S . £• •"+ \ l•i <x> a•I'M m 11» 2! . J

10.6

1 i L#

II "-I

7 7 " 1 IL |

8 II 14 17 20

EXCITATION ENERGY (MeV)

Fig. l.The nr and n" spectra for ISN at a scattering angle where the momentum transfer for MA transitionsis maximum. States labeled have been identified as MA transitions.

Jtnuary-Otcembar 1983 NKMItEttATUMPF 3 9tot Altmot Nilontl Ltborttory

1?

Ia

101

0.01

15N(n,ny5N(3/2-, 6.32 MeV)

Tw = 164 MeV ;

0.00320 40 60 80

6cm (deg)

100

Fig. 2.The n+ and «~ angular distributions for the (f)~ state at 6.32 MeV in 1SN. The curves are DWIAcalculations described in the text.

Energy Dependence of Pion Double-Charge-Ex-change Angular Distributions for the Reaction16O(jt\jr)16Ne (g.s.)(Exp. 749, EPICS)(Univ. of Texas, Los Alamos, New Mexico State Univ.,Univ. of Pennsylvania)Spokesmen: L. C. Bland and H. T. Fortune (Univ. ofPennsylvania)

Experiment 749 is one of a series of EPICS experi-ments, including Exps. 310, 448, 577, and 701, that haveinvestigated the features of nonanalog pion double-charge-exchange (DCX) transitions between groundstates of T=0 and T= 2 nuclei. The previous experi-ments have measured 6 = 5° excitation functions,Tn = 164-MeV angular distributions, and the mass de-pendence of nonanalog DCX. The observed systematicsincluded the following.

(1) Forward-angle excitation functions show a peakedenergy dependence.

(2) The peaks all have similar widths.(3) Angular distributions at T^= 164 MeV are consis-

tent with being diffractive.(4) The target-mass dependence of 0 = 5° cross sec-

tions at r , = 164 MeV is approximately A~413.The proposal for Exp. 749 suggested that these fea-

tures are consistent with a single-step process leading toA(3,3) components of the residual nuclear wave function.The explanation included the following.

(1) The rapid energy dependence results from theintermediate A propagator.

(2) The shape of the angular distributions follows fromthe surface domination of the single-step process.

(3) The single step should lead to an A~413 massdependence.

(4) The deduced size of the A-component admixture in16Ne (g.s.) is reasonable.


Januiy-Oecambtr 7963

ia

I0.1

0.01

160(TT+,7r-)16Ne fes)

N20 60

Fig. I.Comparison of angular distributions at threeenergies for the DCX reaction l6O(n+

fjr)"Ne(g.s.). The curves are described in the text.

Experiment 749 was designed to investigate the energydependence of the 16O(jt+,n~)l6Ne (g.s.) angular distribu-tions to see if they changed in a diffractive manner. Theexperiment was run during cycle 39 (replay and analysisare continuing). Some on-line results for the two angulardistributions obtained are displayed in Fig. 1 along withthe previously measured (Exp. 577) angular distributionfor 16O(7t+,n~)16Ne (g.s.) at Tx = 164 MeV. The curvespresented are damped Besse) functions,

where the radius R = 3.3 fm and damping lengthd= 1.2 fm are independent of energy. The quantity N isan energy-dependent normalization factor. The resultsappear consistent with a diffractive process.


Isospin Dependence of Nonanalog Pion DoubleCharge Exchange(Exp. 780, EPICS)(Univ. of Texas, Los Alamos, New Mexico State Univ.,and Univ. of Pennsylvania)Spokesmen: R. Oilman (Univ. of Pennsylvania) and P. A.Seidl (Univ. of Texas)

Experiment 780, which was run during cycle 38, is themost recent in a series of experiments that have in-vestigated the features of nonanalcg pion double-charge-exchange (DCX) reactions. Previous experiments, includ-ing Exps. 310, 448, 577, and 701, have measured 6=5°excitation functions, Tn = 164-MeV angular distributions,the mass dependence of nonanalog DCX, and recently inExp. 749 (this Progress Report, above), the energy de-pendence of the angular distributions. All of thesemeasurements were made for transitions between Jn,T= 0+,0 and / J = 0+,2 ground states.

These experiments had determined that the target-mass dependence of 9 = 5° cross sections for nonanalogtransitions is approximately A'4'3. Experiment 780proposed to measure transitions between T= 1 and T= 3nuclei to investigate possible effects of isospin de-pendence or nuclear structure on the size of the crosssection. Data obtained include

(1) a 9 = 5° excitation function for the reaction18O(jr,7t+)I8C ground state (g.s.);

(2) a Tn_ = 164-MeV angular distribution for the reac-tion I8O(;T,7r+)18C (g.s.);

(3) a 9 = 5°, Tn_= 164-MeV cross section obtainedfor the reaction 14C(n",n+)14Be (g.s.); and

(4) a 0 = 5°, Tn = 164-MeV cross section obtainedfor the reaction 58Ni(7T,jr+)i8Fe (g.s.).

Figure 1 compares the 18O angular distribution to a fitwith earlier measurements (Exp. 577) of the16O(jt\jr)16Ne (g.s.) reaction; Fig. 2 compares the 18Oexcitation function to a fit to earlier measurements(Exps. 310/448/577) of the same reaction. The energyand the angular dependence of nonanalog DCX areobviously similar in the two cases. Figure 3 compares9 = 5°, TK ~ 164-MeV, on-line cross sections for the 7= 1to T= 3 transitions of Exp. 780 with an A~4'3 fit to theT= 0 to T= 2 cross sections. There is an enhancement ofthe T= 1 to 7= 3 transitions of about 30% over the fit tothe r = 0 to T=2 transitions. Thus, we may haveevidence for an isospin dependence or nuclear-structureeffects in the nonanalog reaction mechanism.

PROGRESS AT LAMPF 4 1Los Alamos National Laboratory

10.1

0.01

1

10

18O(7T-71+)18C

Tn = 164 MeV

20 30 40

(deg)50 50

Fig. 1.Comparison of on-line angular distribution for thereaction l8O(n~,n+)'8C (g.s.) with a fit to thepreviously measured angular distribution ofl6O(jt+,jr)l6Ne (g.s.). The fit has been renormalizedto the value of the 6 = 5° point.

0.01120 140 160 160 200 220 240 260

T n (MeV)

Fig. 2.Comparison of on-line excitation function for thereaction l8O(«~,n+)l8C (g.s.) with a Breit-Wigner fitto the previously measured excitation function for16O(n+,n~)16Ne (g.s.). The fit has been renormalizedby 30%.

30 40 SO

Fig. 3.Comparison of on-line 6 = 5°, 7", = 164-MeV data from Exp. 780 with best-fit A~*13 curve for T= 0 toT= 2 transitions.

4 2 PROGRESS AT LAMPFLos Alimos Ntllonil Laboratory

J*nu»ry-O»c*mbtr ?9ft'

Inelastic Scattc..ng from 12C at IntermediateEnergies(Exps.432and53i,HRS)

, (Rutgers Univ., Los Alamos, Univ. of Minnesota, Saclay,Univ. of Texas, UCLA, Univ. of Pittsburgh)Spokesmen.' C. Glashausser (Rutgers Univ.) andJ. Moss(Los Alamos)

Analysis of the data from Exps. 432/531 is in the finalstages, and some results have already been published. Wepresent here a brief summary of the current status of thiswork.

Differential cross-section and analyzing-power angulardistributions spanning the momentum transfer rangefrom 0.3 to 2.4 frrT1 have been obtained for elastic andinelastic (up to an excitation energy of 21 MeV) protonscattering from UC at 398, 597, and 698 MeV. Analysisof the data has been performed using the recently im-proved version of the nucleon-nucleon / matrix of Loveand Franey. This analysis has yielded several interestingresults, both for the energy dependence of various com-ponents of the interaction and in the identification of the2" strength in the high-excitation region (18-20 MeV) of12C (Rcf. 1).

Carbon-12 is a nucleus well suited to the study ofsystematic effects as it provides a full complement ofwell-resolved states excited by all possible combinationsof spin transfer (AS = 0,1) and isospin transfer(Ar=0 , I ) . Microscopic wave functions for these levels,such as those derived by Cohen and Kurath and Millener,have been tested extensively in inelastic electron scatter-ing, which also establishes oscillator parameters forbound-state orbitals.

Cross-section and analyzing-power data for the 4.44-and 12.71-MeV states are shown in Fig. 1 at a variety ofincident energies. Typical data for the states at 15.11,16.11, and 16.58 MeV are shown in Fig. 2. The moststriking feature of the data is the energy independence ofthe cross section (both the absolute magnitude and theangular distribution) for all classes of transitions exceptisoscalar states of natural parity. The solid curves in thefigures show the results of distorted-wave impulse ap-proximation (DWIA) calculations. Renormaiization fac-tors required to bring the calculations into agreementwith the data are included and are listed in Table I. Thesefactors necessarily include some arbitrariness because ofimperfect fits.

The analysis shows that there is considerable room forimprovement in the DWIA description of the energydependence of the cross sections and analyzing powers.

Whereas the shapes of the angular distributions for thecross sections are generally adequately predicted at400 MeV and above, the angular distributions for Ay(AN),with the exception of the 12.71-MeV state, are not. Inaddition, normalization factors required to match theoryand experiment show substantial variation with energy.The origin of these problems is not clear. Certainly, thewave functions may be partly responsible. A detailedexamination of the effect of coupled-channels correctionsand of changes in the optical potentials and singlecomponents in the AW force is currently under way.Furthermore, it will be useful to determine whetherdensity-dependent forces or relativistic theories yieldsignificant improvements.

Analysis of the 18- to 20-MeV region of excitation forthe beam energies mentioned previously has yieldedinteresting results. States at 18.30 and 19.40 MeV ofexcitation with widths of 380 ± 30 and 480 ± 40 keV

q(frrf')

Fig. 1.Cross-section and analyzing-power data for the4.44- (solid circles) and 12.71- (open circles)MeV states at a variety of incident energies. Solidand dashed curves are DWIA calculations forthese states.


10- I

EX«I6.58M«V(2M:. Tp«398MtV

cc in-1

o

10-2 -

10

VEx» 16.58 MeV(2",l)Tp « 398 MeV

Ex«l6.IIMeV(2*,1)Tp«698MeV

-30.0 0.8

0.5

0.0

-0.5

EX«I5.II MeV(1*,DTp«597MeV

EX«I6.II MeV ( 2 \ I )

1.6 2.4 0.0 0.8 1.6 2.4

q(fm"f) q(frrf')

Fig. 2.Cross-section and analyzing-power data for the states at 15.11, 16.11, and 16.58 MeV at a varietyof incident energies. Solid curves are DW1A calculations.

Table I. Renormalization Factors. The theoretical cross sections were multiplied by thefactors shown below to achieve the best fit to the experimental cross sections.See text for additional factors for the 16.11 MeV state.

£„ (MeV)

4.4412.7115.1116.1116.58

Jn;T

21", 0l+, 0I\ 12\ 12', 1

2.0...1.01.00.67

200 MeV

1.00.31.00.600.20

398 MeV

2.01.01.00.780.30

(P,P')

597 MeV

2.681.401.441.320.50

698 MeV

3.01.301.150.900.58

800 MeV

2.651.151.381.150.38


Jtnuiry Decambv 1983

10

. ( a )

010

8

lzC(p.p')'2c"E,«398M«VE, • 18 30 MtV

£ 02g o o

i

00 34 OS 12 I t 20 24

q(fm')

(JC(p.p')'2C*E, • 398 MtVE, >I9 4 0 MtV

Fig. 3(a) and (b).Cross-section, analyzing-power, and spin-flip data for the 2 ,0 and 2 , 1 states at (a) 18.30 and(b) 19.40 MeV. Solid curves are renorinalized DWIA calculations for 2 ,0(2) and 2 ,1(2) configura-tions, as discussed in the text. Dashed curves are 2 ,0(1) mid J ,J configurations for the 18.30- and19.40 MeV states, respectively.

have been identified. Angular distributions of cross sec-tions, analyzing powers, and spin-flip probabilities areshown in Fig. 3. Analysis of the data in the DWIA, usingthe Love-Franey / matrix and transition densities ofMillener, have permitted identification of these two statesto be 2~,0 and 2 , 1 , respectively. In particular, the stateat 18.30 MeV is very well described by the secondtransition density predicted by Millener. This state isdominated by the (ldi/2,lpy'2) configuration, whereasthe remaining states, such as the third shown as thedotted line in the figure, are dominated by the(2svi, lpf/2) configuration. A renormalization factor ofabout 0.7 is required at all energies to bring the calcula-

tions into agreement with the data. The 19.40-MeV stateis best described by the second (2~, I) transition density ofMillener. Renormalization by factors of 0.33 is requiredto bring the calculations into agreement with the data. Ingeneral, I ,0 and 1~,1 transitions may be ruled outbecause of poor agreement with the data. The results ofthis work substantiate and verify previous ambiguousassignments of spin, parity, and isospin in this region.

REFERENCE

I. K. W. Jones et al., Pliys. Lett. I28B, 281 (198.1)

January December 1Q83 PROGRESS AT l-AMPFLos Alamos National Laboratory

45

Proton Scattering from 20Ne and 22Ne at 0.8 GeV(Exp. 475, HRS)(Univ. of South Carolina, Univ. of Texas, Drexel Univ.)Spokesman: G. Blanpied (Univ. of South Carolina)

In several recent publications,1'6 coupled-channelanalyses of ~l-GeV proton inelastic scattering from s-dshell nuclei and heavy rare-earth nuclei have been shownto be generally successful, provided deformation andmuttistep processes are properly treated. These collectiverotational-model calculations provide an excellent de-scription of the data for the lowest 0+, 2+, and 4+ states inMlJ6Mg and 20Ne (Refs. 6 and 7). The results of the firsthalf of this experiment confirmed the large hexadecapoledeformation of 20Ne. Data on the negative-parity rota-tional bands in 20Ne also were explained in the coupled-channels framework.

These results motivated the measurement of (p,p')inelastic scattering from 22Ne. The experiment consistedof scattering 0.8-GeV protons from a 22Ne gas target

enriched to 99%. Angular distributions were obtainedusing the high-resolution spectrometer (HRS). Data wereacquired for 2"Ne and |p|N using a gas target of identicalgeometry and were compared to the data from theprevious run. The absolute cross section is obtainedrelative to a solid melamine target and a 208Pb foil. Theresulting angular distributions are given in Fig. 1.

Coupled-channel calculations using a deformed opticalft

potential have been performed using the code EC1S. inwhich the 0 ' . 2 \ and 4T states, and a 6+ state that is notavailable, are treated as members of the ground-staterotational band and are coupled with deformation up toP6. The results are given in Fig. 1, using |32 = +0.42,p4 = +0.10. and fi6 = 0.0 ± 0.05. This range for p\ is largerthan that observed for other 6* states in this mass region,although in general the 6' data are poorly explained. Thisrange in p6 has no effect on the 0+ and 2* angulardistributions, although the results for the 4+ are small, asseen in Fig. I. The values for the multipole moments of

10

t i \ i j ) i i • i i i i i i • ] • T r t i | i > l ifc

"Ne(p,p), 0.8 GeV _I

= 0.00

10

9c

15 20 25 30

Fig. I.Angular distributions of 22Ne (p4>) at 0.8 GeV for the 0 f . 2+ , and 4+ members of the ground-staterotational band. The curves result from coupled-channel calculations, as discussed in the text.

4 6 PROGRESS AT LAMPFLos Atamos National tabofatory

Jtmiary-Otc*mb*r 1963

Table I. Deformation Moments of Some Neon and Magnesium Isotopes.

MatterM(E1) (eb)

ChargeB{E2) (eb)

Neutron MatterA/(f 4) (eb2)

20Ne"NeMMgMMg

"Ne/20Ne26Mg/24Mg

0.1640.1320.1870.1520.800.81

0.171(11)0.151(3)0.207(2)0.174(4)0.880.84

0.1550.1350.1620.1500.870.93

+0.0253+0.0109+0.0073-0.0025

Difference = 0.0144Difference = 0.0098

the matter distribution, the known B(E2) charge mo-ments, the inferred neutron moments |AfN(£2)|, and thematter M(E4) are given in Table I for 2(U2Ne and 24iMMg.In both elements, the M(E2) and M(E4) deformationsdecrease when adding a neutron pair to the N = Zisotope. The inferred neutron deformations are essentiallyequal to that of the protons in the cases studied. Calcula-tions are under way for other excited states in 20Ne and"Ne.

REFERENCES

1. L. Ray et al.. Phys. Rev. Lett. 40, 1547 (1978).

2. G. S. Blanpied et al.. Phys. Rev. C 23, 2599 (1981).

3. G. S. Blanpied et al., Phys Rev. C 20, 1490 (1979).

4. L. Ray, G. S. Blanpied, and W. R. Coker, Phys. Rev. C 20. 1236

(1979).

5. M. Barlett et al.. Phys. Rev. C 22, 1168 (1980).

6. G. S. Blanpied et al., Phys. Rev. C 25,422 (1982).

7. G. S. Blanpied et al., submitted to Phys. Rev, C.

8. J. Raynal, International Atomic Energy Agency report IAEA-

SVVR-918. 281(1972).

Measurement of Spin-Dependent Observables forpd->-pd Elastic Scattering at 500, 650, and

800 MeV(Exp. 540, HRS)(UCLA, Los Alamos)Spokesmen: G. J. Igo and M. Bleszynski (UCLA)

An extensive program for measuring the spin-depen-dent observables in pd—f-pd elastic scattering at inter-mediate energies continues at LAMPF at the HRS andEPB experimental areas.

A UCLA-Los Alamos collaboration is measuring thecomplete set of proton spin-transfer observables forpd-*pd elastic scattering at 500, 650, and 800 MeV atthe HRS using the focal plane polarimeter (FPP). InSeptember 1982. we measured DNN, Dss, Dsl, DLL, DLS,P, and Ay at 800 MeV over the four-momentum transferrange -t = 0.006 - 0.46 (GeV/c)2 (3-28° lab). These datahave been analyzed and are being prepared for publica-tion.

As an example, the preliminary results for Z)LL an&Ay

are shown in Figs. 1 and 2. As seen, the multiple-scattering calculation ' is not in good agreement with thedata. The multiple-scattering calculation includesnoneikonal and several kinematic corrections and has thenucleon-nucleon (AW) amplitudes and the deuteron wavefunction as input. Energy dependence in the AWamplitudes has been included. Further work with thiscalculation is in progress.

Jtnu*ry-O€C»mbv JB»3 PftOMEUATUMPF 4 7Lot Alvnos ritlioni Ltxxttory

0.75

0.50

0.25

4

\ * •• \ V

\\\V

D(p,p)D600 MeV

• HRSD EPB— Multiple-Scattering

A Calculation

—

0.0 0.2 0.4 0.6 O.B 1.0 1.2

- t (GeV/c)

Fig. 1.Spin-transfer parameter DLl at 800 MeV for theEXp,p)D reaction compared to multiple-scatteringcalculation.

I .U

0.7

< 0.4

0.1

-

' \ /

D(p,p)D800 MeV

• HRSD EPB— Multiple-Scattering .

Calculation

/ \ :

D D '_

LJ

0.0 0.3 0.6 0.9 1.2 1.5 I.B

-t (GeV/c)

Fig. 2.Asymmetry parameter Ay at 800 MeV for theD{p,p)D reaction compared to multiple-scatteringcalculation.

In November 1983, the same experiment was done at500 MeV, again using an unpolarized liquid-deuteriumtarget. A proposal has been submitted to measure thesame spin-transfer parameters at the HRS with a 650-

MeV incident proton beam over the same four-momen-tum transfer range.

REFERENCES

1. G. Alberi, M. Bleszynski, and T. Jaroszewicz, Ann. Phys. 142.299(1982).

2. M. Bleszynski. Phys. Lett. 92B, 91 (1980).

Measurement of the Depolarization Parameters inProton-Nucleus Scattering to Very High ExcitationEnergies(Exp. 626, HRS)(Rutgers Univ., Los Alamos, Univ. of Texas at Austin)Spokesmen: J. A. McGill and C. Glashausser (RutgersUniv.)

During cycle 35 (1982), data were taken for theinclusive reaction l2C(p,p')X for DNN,, DLL,, Dss,, andDSL, at laboratory angles of 5, 11, 15, and 20°. Themomentum of the outgoing protons extended from thequasi-elastic peak to ~600 MeV/c at each angle. Inter-pretation of these data, however, awaited the correspond-ing data for the reactions ^(p.p'yx and 2H(p,p')X.

In cycle 39 (1983), the data for hydrogen and deute-rium were taken at comparable lab angles and momenta.The experiment ran for approximately 120 h. Normallypolarized beam was delivered in the usual slow-reversalmode, but both longitudinal and sideways polarizationscame during the rapid-reversal mode of the polarizedsource. The RR mode precludes a regular quench meas-urement of the beam polarization, so that PB cannot bemonitored when longitudinal polarized beam is delivered.The experiment therefore ran with orthogonal spin direc-tions, precessed about 40° from sideways and long-itudinal directions, respectively. This provided some side-ways component to the beam polarization for both spindirections, which was monitored with the Line Cpolarimeter. The arrangement was a first for the HRS.

With the exception of a few minor problems in thedouble-flask cryogenic target (another first), the run wentsmoothly. The data are in the process of being analyzednow.

Work for this experiment was supported by the Na-tional Science Foundation, the USDOE, and the RobertA. Welch Foundation.


Jwiy-Otcvnbf 1983

Inclusive (p,p') Cross Sections and AnalyzingPowers for !H and 12C in the Delta Region<Exp. 642, HRS)(Rutgers Univ. and Univ. of Texas at Austin)Spokesmen: G. W. Hoffmann (Univ. of Texas) andJ.A.McGill (Rutgers Univ.)

The delta isobar plays an important role as an inter-mediate state in pion-nucleus scattering to low-lyingexcited states; it has also been suggested that excitation ofthe isobar leads to quenching of Gamow-Teller and Mltransition strengths observed in (p,n) and (p,p') reactions.Yet, the region of nuclear excitation around 300 MeV.where'the direct excitation of the delta resonance can beseen as a (decaying) final state, has been little exploredthus far in intermediate-energy proton scattering.

Thus, to examine the spin structure of the NN~+ NAinteraction and to investigate deviations from quasi-freescattering, we have carried out experiments using theHRS in which the inclusive {p,p') cross sections andanalyzing power were measured for 'H(p,p'X) andl2C{p,p'X). An 800-MeV proton beam was scattered

from either a 267-mg/cm2 liquid-hydrogen target or a174-mg/cm2 12C foil. Cross sections and analyzingpowers were measured between 5 and 20°. At each angle,the HRS fields were changed by 20-30 MeV/c to searchfor detailed structure in the delta region. In the figurespresented here, each point represents a single spec-trometer setting, corresponding to a momentum accep-tance of ± 1%. The cross-section data were normalized tothe lH(p,p) elastic data of Barlett et al.1

Figure 1 shows the hydrogen cross sections at 5, 11,and 15° plotted vs the laboratory momentum of theoutgoing proton. The cross sections agree with our earlierwork, but show the structure, particularly near pionthreshold, in greater detail. The solid lines in the figure arethe result of a calculation carried out with the code byVerWest,3 which uses a Born approximation treatment ofAW scattering and includes n and p exchange.

The analyzing powers in Fig. 1 fall from a maximumvalue of about 0.3 at threshold to small values with littlestructure at low outgoing momenta. When the product ofa and Ay is formed, an interesting feature is observed — aclear peak, which crosses zero at the maximum of the

2 ^ 0.10

O 2 0.05<O Is 0.02

g i O1CC w 0.005

uCM

1.2

0.8

0.0

-0.4

i 'Htp.p'X) Ep = 800MeV

•*•*'•* • *~*~

1.2 1.0 0.8 0.6 0.4Pout

1.2

0.8

0.4

0.0

11°

• •

* •••*•.. '

1.2 1.0 0.8 0.6 0.4Pout

0.6

0.4

0.2

0.0

QftttoO

1.2 1.0 0.8 0.6 0.4pout (GeV/c)

0.3

0.2

O.I

0.0

0.6

0.4

0.2

0.0

-O.2

crAu

Fig. 1.Differential cross sections, analyzing powers, and the products oAy for inclusive ip.p') scattering from'H at lab angles of 5,11, and 15°. The abscissa is the laboratory momentum of the outgoing proton.The solid curves are from a Born calculation of o and Ay (Ref. 3). The dashed curves are the phasespace available to a nucleon in the AW —*• NNn reaction. The arrows correspond to an excitationenergy of 300 MeV.


49

Ep-800 MeV ° 5

0.4

2 0 *

V I5»

1.4 10 0.6

Fig. 2.Differential cross sections, analyzing powers, and the products oAy for inclusive (p,p') scattering fromi2C at lab angles of 5, 11, 15, and 20°. The curves for a are taken from Ref. 6.

cross section. In fact, the oAy spectrum resembles thelogarithmic derivative of the cross section with respect tooutgoing proton momentum; such a relation is surpris-ingly simple for an inclusive reaction. (Note that theproduct cAy eliminates processes with zero analyzingpowers and so can be a sensitive indicator of weakprocesses.) An attempt to predict Ay with the VerWestmodel fails badly, as shown in Fig. 1. A unitary-modelcalculation recently has been shown to be more success-ful in predicting spin-observables for exclusive finalstates; it is currently being adapted for application tothese inclusive data.4

Examples of corresponding data for I2C are shown inFig. 2. Even with the greater accuracy of these measure-ments, they are strikingly similar to those for 'H, as in theearlier work/ The cross sections for I2C are about 7times larger than for lH; the value of aAy at themaximum in 12C is 3 times larger.

It is important to note that the peak in the ov4y data for12C moves with angle approximately according to 'H, notI2C, kinematics, even though it is shifted down by about50MeV/c from the 'H peak position. A smaller shiftwould be expected from binding-energy effects. We alsonote that at 5° the peak in the cross section is shifted by~100 MeV/c to higher outgoing momenta. Fermi broad-ening can be expected to lower the threshold and washout the structure of the nucleon-nucleon spectrum. Also,a peaking of the nucleon-nucleon cross section at some

energy away from the incident beam energy can causesuch a "Fermi shift" (as has been suggested for thequasi-free pp —*• dn+ reaction), but the pion-productioncross sections involved here are relatively flat above750 MeV.

The solid curves in Fig. 2 have been calculated in aplane wave impulse approximation using an isobar-doorway model by Alexander etal. The curves arearbitrarily normalized in the region of the quasi-elasticpeak. Some of the discrepancies between the data andthese curves, particularly at low outgoing momentum,can be attributed to the absence of distortions in thecalculation. It would be useful to have a more detailedcalculation of the theoretical expei ations, including dis-tortions. No calculations at all are available for theanalyzing power in 12C, partly because the pp data arethemselves not explained.

In summary, we have reported the measurement ofcross sections and analyzing powers for inclusive (p,p')reactions on 'H and I2C at 800 MeV. The cross sections,but not the analyzing powers, for 'H can be reasonablyexplained in the Born-approximation model of VerWest.The data for 12C are qualitatively similar to those for 'H.A narrow peak is observed in the aAy spectrum for bothnuclei; even in UC, it moves with 'H kinematics. Never-theless, there are differences in detail, notably energyshifts, between the data for 'H and I2C.

5 0 PBOOnCSSATLAMPFLos Alamos National Laboratory

Januvy-Otcwnbar 19SS

This work was supported by the National ScienceFoundation, the USDOE, and the Robert A. Welchfoundation.

REFERENCES

1. M. L. Barlett et al., Phys. Rev. C 27, 682 (1983).

2. J. A. McGill et al., Phys. Rev. C (to be published).

3. B. J. VerWest, Phys. Lett. 3B, 61 (1979).

4. W. M. Kloet and R. R. Silbar, Nucl. Phys. A 338, 231 (1980); andJ. Dubach. V M. Kloet, A. Cass, and R. R. Silbar, Phys. Lett.I06B, 29(19t!l).

5. H. Toki, to be publuhed in Phys. Lett. B.

6. Y. Alexander, J. W. VanOrden, E. F. Redish, and S. J. Wallace,Phys. Rev. Lett. 44, 1579(1980).

o.e

0.6

0.4

0.2

-0.2

-0.4

-0.6

-O.B

Tp * 650•

1

. f I

- V

MeV

{

I" '6T

•B«(p.ir-)IOC* gs6 3.36 MeV

t-

9Betp.ir*)l0Be "

$ 3.37 MeV '

10 20 30 40 50 60 70

The 9Be(p.n+)10Be and 9Be(p,jT)10C Reactions at650 MeV(Exp. 649, HRS)(Los Alamos, Univ. of California, Univ. of Minnesota,Univ. of South Carolina, Univ. of Texas at Austin)Spokesman: Bo Hbistad (Un:». of Texas al Austin)

Tentative results from the differential cross section aswell as the analyzing power for the 9Be(/5,Jt+)10Be and9Be(p,7t~)I0C reactions are now available at 650 MeV.The angular distribution of the analyzing power Ay ispresented in Fig. I. The (p.Jt+) data from 10 to 30° wereobtained in April 1981 and the rest of the data are from arun between December 28, 1983 and January 3, 1984. Inaddition, this experiment will receive beam time January12-16, 1984, during which time more (p.n~) data will becollected.

From the present data, the salient features of Ay appearclearly. The Ay(n

+) is negative out to ~35°, where itbecomes positive. This trend is the same as observedpreviously for the '•4He(p,Ji+)4>5He reactions at800 MeV. Also, there is an indication of nuclear-struc-ture dependence in the detailed shape of Ay.

The present data represent the first measurement ofAy(n~) far above the energy threshold. We note withinterest that Ay(n~) has opposite sign compared toAy(n

+)in the observed angular range. In fact, this generalbehavior was predicted from a "pion knockout model"and was used as an argument to measure Ay(n~) as a testof this reaction model.

Fig. 1.Analyzing power as a function of scatteringangle in the center-of-mass system for both9Be{p,n+) and 9B(p,n~) going to the ground stateand first excited state.

A diagram of the model is shown in Fig. 2. In thisprocess, a virtual pion is emitted from the target nucleusand knocked out by the incident proton. Since the uppervertex in the diagram corresponds to pn+ scattering forthe (p,n+) and pn~ scattering for the ip.iC) reaction, wecan use Ay data from elastic nN scattering to predictA^n*) for "Be. A procedure for how this can be done isgiven in Ref. 1. If the large momentum transfer involvedin the (p,n) reaction is assumed to be equally sharedbetween the two lower vertices in Fig. 2, and if thecaptured proton is assumed to be on its mass shell (thatis, the emitted pion is off shell), we get a shape otAy for

Fig. 2.Diagram for pion knockout in the (p,7i) reaction.

muary-Oecember 1983 PROGRESS AT LAMPF 5 1Los Alamos National laboratory

'Be(p,jr+)'°Be that is in qualitative agreement with theexperimental data. Moreover, Ay for *Be(p,7t~)10C ispositive up to ~45°, which is consistent with the two datapoints available.

A further analysis will be performed when the datafrom the run in the middle of January 1984 can beincluded.

REFERENCE

1. B. Hoistad et al., Phys. Rev. C 29, to be published.

Measurement of Spin Excitations in theASCa(p,p')4SCa and 90Zr(p,p')90Zr Reactions(Exp. 660, HRS)

(Rutgers Univ., Los Alamos, Arizona State Univ., North-western Univ., Tokyo Institute of Technology)Spokesman: C. Glashausser (Rutgers Univ.)

The Ml transition in 4SCa is an excellent test case forthe study of magneiic dipole transitions because of theexpected simple shell structure and the small fragmenta-tion of the observed Ml strength. A strong Ml state wasfirst observed at an excitation energy of 10.23 MeV ininelastic electron scattering ; the analog of this state hasbeen observed in (p,n) measurements. Previous (p,p')experiments with proton energies in the range of45-200 MeV also have reported observation of this state,which is believed to be mostly a pure neutron(vfiri<fii2> ^ configuration. The experimentally ob-served strength for the 10.23-MeV transition is approx-imately 30% of the predicted theoretical value obtainedfrom the pure independent-particle model with bare gfactors.

We have measured the cross section o(6), the analyz-ing power Ay(Q), and the spin-flip probability 5NN(G) forthe 10.23-MeV state in the 4BCa(p,p')48Ca* reaction at319 MeV. The data were taken at the HRS with avertically polarized (N) proton beam. The polarization ofthe outgoing particles was measured with the focal planepolarimeter. An isotopically enriched 4BCa (94.7%) target100 mg/cm2 thick was used; the total energy resolutionwas 120 keV. The data were taken at 3.5 and 5.0°laboratory angles.

Angular distributions for a(A), Ay, and 5 N N are shownin Fig. 1. The shape of the o angular distribution plottedvs momentum transfer q agrees well with the 200-MeVdata3; the absolute cross section is about 10% higher.The curves represent distorted-wave impulse approxima-

5 2 PROGRESS AT LAMPFLos Alamos National Labowory

104 eCo(p,p')4 8Co

Tp* 319 MeV

E»* 10.23 MeV

DW1A

O.2-

0.00.0 1.5 3.0

ec m .

4.5 6.0

(deg)

7.5 9.0

Fig. 1.Measured values of o(6), Ay, and SNN for the 10.23-MeV A/1 transition in 4SCa(p,p')'*Ca* at 319 MeV.The solid curves correspond to DWIA calculationsdescribed in the text.

tion (DWIA) predictions with the code DW81 for the Mltransition assuming a (vf,^1 ,fin) + transition; exchangewas included exactly. The 325-MeV / matrix of Love andFraney was used; optical parameters were extrapolatedfrom nearby energies. The a angular distribution is welldescribed by the DWIA calculation. The absolute crosssection is about 28% of the DWIA prediction, which isconsistent with the quenching observed in the (e,e') resultsof Ref. 1 and the previous (p,p') results at 200 MeV ofRef. 3.

The values of Ay for the 10.23-MeV state shown inFig. ! are small and mostly positive, similar to thosemeasured for the 15.11-MeV 1+ state in I2C at energiesfrom 400 to 800 MeV. There is a hint of structure in the48Ca data that has not been observed in 12C. The DWIAcalculations for 48Ca agree reasonably well with the data;there is no indication of structure. Note that the pureneutron transition assumed here has equal amplitudes ofisovector and isoscalar components in the wave function.

Januery-Oaamtm 191

A pure isoscalar transition yields a negative Ay of about-0.30 at these q values, both in data for the 12.71-MeV1 % T= 0 state between 400 and 800 MeV and in calcula-.ons for I2C and 48Ca at 319 MeV. The /*, for the pure

neutron transition is very similar to the Ay for a pureAT= 1 transition, however, because of the weakness ofthe A7"=0 components in the effective interaction atthese energies.

In the plane-wave impulse approximation using onlycentral forces and excluding exchange effects in thereaction, an L = 0, 0+ to I+ transition should yield an SNN

value of 2/3, independent of q. Distortion effects, noncen-tral forces, and exchange effects tend to produce struc-ture in the angular distribution of 5N N . In contrast,transitions with AS = 0 yield SNN values close to zero.Our measured values of 5 N N are 0.44 ± 0.08 at 3.5° and0.20 ± 0.07 at 5.0° for the 10.23-MeV state; the angulardistribution is in good agreemeni with the DWIA predic-tions.

In summary, our measurements at small q for the10.23-MeV transition in 48Ca show large values of SNN

and small values of Ay in good agreement with theDWIA. The measured a is about 28% of the single-particle DWIA prediction, consistent with previous work.The results support the usefulness of SNN measurementsin searching for Ml strength in heavy nuclei, as well asthe validity of a DWIA descriptio" of such data.

To determine whether significant unnatural-paritystrength exists at excitations above the Ml giant reso-nance in 90Zr, we measured o(0), y(6), and SNN(0) in the9CZr(/7,/7')9°Zr reaction at 319 MeV. As with back-angleelectron-scattering cross sections, the spin-flip cross sec-tion oSN N is a measure of AS = 1 excitations, whereas adata by themselves can seldom distinguish betweenAS - 0 and AS = 1. The data were taken at the HRS, asdescribed above. A thick target (250 mg/cm2) was re-quired, so the energy resolution was 180 keV and theins'rumental background was significant.

Shown in Fig. 2 are the spectra of SNN and oSN N at3.5° without background subtraction; data at 5° aresimilar, but they extend only to 16 MeV. As expected,spin-flip cross sections are small at low-excitation energyin the region of isolated states; they rise to significantvalues around 8 MeV. Compared to the higher excitationenergy region, however, the region around 9 MeV is in noway remarkable. Rather, spin excitations are observed upto at least 25 MeV where only natural-parity statespreviously have been seen.

If a simple background is drawn in the 9-MeV region, avalue of 0.62 ± 0.20 is obtained for SNN, but because of


90Zr(p.p'FZr I

0.0 10.0 20.0E y (MeV)

30.0

Fig. 2.Spectra of SNN and o5 N N for the 90Zr(p,/>')90Zr*reaction at 3.5°.

the uncertainty in the background, the systematic error inthis value is large. To calibrate the value expected for apure Ml transition, SNN was measured for the48Ca(p,/?')48Ca* reaction to the 10.23-MeV T state asdescribed above. The value obtained, 0.44 ± 0.08 at 3.5°,is consistent with an Ml assignment for the 9-MeV bumpin 90Zr. The poor resolution of the present SNN data doesnot permit isolation of individual El states.

We have closely examined many possible sources oferror in obtaining the spectra of Fig. 2, but because of theuniform spreading of the spin-flip strength, it is difficult tobe certain that all sources of error have been eliminated.Nevertheless, our results strongly suggest that the spin-flip cross section at 3.5° is approximately0.8 mb/sr/MeV throughout the region from 8- to 25-MeVexcitation.

Although no spin excitations previously have beenobserved above 10 MeV, it is important to note that noexperiments really sensitive to such strength have beenperformed. The uniform spreading of the oSN N strength issuggestive of the apparent quasi-free background ob-served in the {p,n) reaction; Osterfeld explains this asA S = 1 excitations up to spin 3+ even at 0° . It isinteresting to observe that the SNN predicted by Arndt'sphase-shift solutions at 3.5° are 0.37 and 0.20 for freep/)and pn scattering, respectively. Comparison with the SNN

PROGRESS AT LAMPF 5 3Los Alamos National Laboratory

values in Fig. 2 shows that the nuclear response is notdramatically different from that of a Fermi gas, eventhough this is a region of high natural-parity collectivity.This result disagrees with the conclusions of Moss et al.4

for 2O8Pb at 400 MeV.

REFERENCES

1. W. Stefan et al., Phys. Lett. 95B, 23 (1980).

2. B. D. Anderson etal., Phys. Rev. Lett. 45, 699 (1980); and C. D.Goodman, Nucl. Phys. A 374, 241 (1982).

3. G. M. Crawley et al., Phys. Lett. I27B, 322 (1983).

4. J. M. Moss et al., Phys. Rev. Lett. 48, 789 (1982).

Giant Resonance Studies with Medium-EnergyProtons(Exp. 670, HRS)(Los Alamos, Univ. of South Carolina)Spokesmen: T. A. Carey and J. M. Moss (Los Alamos)and G. S. Adams (Univ. of South Carolina)

Our efforts in the development of unique small-anglescattering techniques for the exploration of Ml strengthat the HRS have proved equally fruitful in searches fornew giant resonances (GRs).

Starting with our discovery of an isoscalar high-energy octupole resonance (ISHEOR) occurring system-atically at Ex ~ 1 l0A~tn in heavy nuclei, increased atten-tion has been focused on the high-excitation spectrum of20«Pb. In addition to the ISHEOR at Ex ^ 19 MeV,theoretical calculations have predicted the existence ofboth isoscalar giant dipole resonances (ISGDRs) andisovector giant quadrupole resonances (IVGQRs) atabout 22 MeV of excitation in 208Pb. Since they areisospin partners of the well-known isovector giant dipoleresonances (IVGDRs) and i^oscalar giant quadrupoleresonances (ISGQRs), an experimental determination oftheir existence and properties would place importantgeneral constraints on theoretical models of the nuclearresponse and of the residual interaction in nuclei. Previ-ous investigations of this region have led to stronglyconflicting interpretations; a group from Jiilich using

172-MeV a particles favors the ISGDR at £„ = 21 MeV,whereas a group from Orsay has claimed strong excita-tion of the IVGQR near Ex ^ 22 MeV with 200-MeVprotons.

In our opinion, both of these experiments suffered from"low sensitivity because of large backgrounds and neitherprovided adequate evidence to support their respectiveconclusions. On the other hand, the small-angle system atthe HRS is virtually free of instrumental background.Furthermore, we have previously shown that in 800-MeV proton inelastic scattering the nuclear continuum isdominated by quasi-free scattering, and at small momen-tum transfers, Pauli-blocking suppresses it in such a wayas to considerably enhance the signals of weakly excitedGR.

Exploiting ihese two facts in a February 1983 run, weobtained GR data of the unparalleled quality illustrated inFig. I. At the larger scattering angles the previouslyobserved ISGQR (AL = 2) and ISHEOR (AL = 3) areclearly evident, and as we move to very forward angleswe see the definite appearance of other broad structuresnear 13 and 22 MeV of excitation in 2O8Pb. The domi-nantly isoscalar character of 800-MeV protons, in con-junction with the angular distribution of the high-excita-tion bump as compared with that for the ISGQR,strongly suggests an isoscalar dipole (AL = 1) assign-ment.

We have identified similar svuctures in comparabledata for U4Sm and "6Sn, and together their excitationenergies exhibit a target-mass dependence close to thatpredicted for the ISGDR. The peak near Ex = 13 MeV in2MPb that is strong at 6!>b= 1.8° and completely disap-pears by 0|ab = 2.5° might tentatively be identified withthe isoscalar giant monopole (AL = 0) resonance(ISGMR), but such extreme forward peaking could alsobe indicative of Coulomb excitation of the standardisovector dipole mode. Therefore, a considerable fractionof the concentrated strength seen near Ex = 22 MeV atthe smallest angles may be due to Coulomb excitation ofthe IVGQR. Theoretical analysis of these possibilitiesemploying microscopic transition densities in extensiveinelastic-scattering calculations is in progress.

To further aid us in sorting out this region of the 208Pbspectrum, we have also explored it with pion inelasticscattering, since (n,nf) incorporates an isospin selectivityfundamentally different from that of ip.p').

5 4 WOOREMATLAMPFLos Alimos Nttioml Libontory

Jtmitry-DtcembM f i

zo

10.0 20.0 30.0 40,0

E x (MEV)

50.0

50.0

Fig. I.On-line excitation spectra for 208Pb at various laboratory scattering angles. The relative normaliza-tions between different angle bins were arbitrarily selected for display purposes only.

REFERENCES

1. T. A. Carey et al,, Phys. Rev. Lett. 45, 239 (1980).

2. J. M. Moss et al., Phys. Rev. Lett. 48, 789 (1982).

*nu*ry-O*ctmbw 1083 WtOQUEMATLAItWf 5 5Lot Aitmot Ntilontl Labortloy

Measurement of the Third-Order Spin-DependentObservables for the pid —>• pd at 800 MeV with aPolarized Deuterium Target(Exp. 685, HRS)(UCLA; Los Alamos; KEK Lab.; Hiroshima Univ.;Kyoto Univ. of Education, Japan; Univ. of Minnesota)Spokesmen: G. J. Igo and M. Bkszynski (UCLA)

A collaboration has measured some third-order spin-dependent observables for p d -+pd elastic scattering at800 MeV at the HRS. This experiment uses a polarizedproton beam and a polarized deuterium target whilemeasuring the polarization of the scattered proton. Dur-ing the period September-October 1983 we used an iV-type (perpendicular to the scattering plane) polarizeddeuterium target. By using an N-type polarized targetwith al! three independent proton beam spin directions,we plan to extract roughly 14 obse; vables that have neverbeen measured for the spin-1/2 on spin-1 system at800 MeV. The analysis of these data has just started, sono results are available yet.

To completely determine the pd scattering amplitude,23 independent observablcs must be measured. Duringthe next 2 years, we plan to complete the measurement ofthese third-order pd—* pd observables with L- and 3-type polarized deuterium targets using a superconductingmagnet. This should allow us to completely determine thepd scattering amplitude at 800 MeV for the four-momen-tum transfer range -t ^ 0.03-0.22 (GeV/c)2 (7-19° lab).As a result of this work, we also hope to better under-stand the multiple scattering theory.

In these experiments with a polarized deuteron target,we use a horizontal dilution refrigerator,2'3 thus pumpingon the 3He/"He dilution phase. The propanediol-D8target can be cooled to ~20 mK and can be polarize,using microwaves (~69 GHz) to ~30% deuteron vectorpolarization (tensor polarization ~7%) in a 25-kOe mag-netic field. Because of the low temperature attainable, weoperate the polarized target in a spin-frozen mode using aholding magnetic field of 10 kOe and still have a deuteronspin-relaxation time > 100 h. A drawing of the experimen-tal floor layout is shown in Fig. 1. After the scatteringtarget, the HRS was used in its standard configurationwith the focal plane polarimeter. Wire chambers Cl andC2 and scintillntors M1 through M8 make up the monitortelescope used to measure the target and beam polariza-tions.

Fig. 1.Experimental floor layout for polarized dcuterontarget, including layout of target polarizationmonitor.


JanuaryDecember 198

We hope to measure the deuteron target polarization inthree ways. The first technique involves measuringleft/right (±22° cm., near maximum of deuteron analyz-ng power) with the HRS. Using the proton analyzingpower with the deuteron vector and tensor analyzingpowers previously measured allows one to extract thetarget and beam polarizations. The second method usesthe monitor telescope. By monitoring the pp quasi-freescattering asymmetry from the deuterium target, we hopeto determine both the target and beam polarizations. Inaddition to these scattering asymmetry measurements, athird method uses coio positioned around the target flaskto obtain deuteron magnetic resonance (DMR) data,which determine the average target polarization through-out the target flask. This method should provide a relativemeasure of the target polarization. All three of thesetechniques are presently being pursued.

REFERENCES

1. G. Alberi, M. Bleszynski, T. Juroszewicz, and S. Santos, Phys.

Lctl. 92B, 41 (1980).

2. S. lsliimoto etal., Nucl. instrum. Methods 171, 269 (1980).

i. A. Masaikc, "Polarized Target with Dilution Refrigerator,"

Argonne National Laboratory report ANL HfcP PR-77 88.

4. M. Bleszynski et al., Phys. Lett. 87B, 198 (1979).

Neutron Transition Densities in 2MPb {p#') at318 MeV(Exp. 686, HRS)(Univ. of Minnesota, Los Alamos, Univ. of Texas)Spokesman: N. Hintz (Univ. of Minnesota)

The purpose of this experiment was to obtain high-resolution (A£ = 35- to 45-keV) data on inelastic protonscattering to the low-lying "collective" states and thehigh-spin particle-hole states of 20*Pb. From these datawe plan to extract neutron transition densities, makinguse of collective or microscopic models and protondensities from electron scattering.

In our earlier experiment (Exp. 347) at 800 MeV, thehigh-spin natural-parity states (10+, 12f) were poorlyresolved, and the unnatural-panty states (12~, 14") werenot seen above background. However, at 318 MeV,because of improved resolution and the increased ratio ofthe spin-dependent to spin-independent parts of the AWforce, the high-spin states are better (though not com-pletely) resolved. In January 1983, data were obtained upto an excitation energy of E* ~ 12 MeV over an angularrange of 0L = 3-40°. A spectrum at 0, = 28° is shown inFig. I.

The {'round-state angular distribution is shown inFig. 2. The absolute normalization is still tentative but isbelieved to be good to ± 10%. The elastic angular dis-tribution was lit with a 2PF phenomenologicai optical

160 -

c 120 -o

SIO

£ 80 hoo

EeK (MeV)

Fig. 1.Spectrum for proton scattering from I0"Pb at an incident energy of 318 McV.

January December 1983 PROGRESS AT LAMPF 5 7Los Alamos National Laboratory

f

Fig. 2.Elastic-scattering angular distribution for :c'Pb.The curves are with (solid line) and without (dashedline) a spin-orbit potential.

ec.m.

potential by searching with the program RELOM, bothwith and without a spin-orbit potential. The results arenot completely satisfactory, even with the spin-orbitpotential included, in contrast to the situation at800 MeV where excellent fits were obtained both withand without spin orbit. We are now attempting, withfolded [first-order Kerman-McManus-Thaler (KMT)]and with phenomenological optical potentials with re-pulsive real cores, to obtain a better representation of theelastic data for the inelastic analysis.

For the low-spin states, we have, as a first step, usedcollective form factors (vibrating potential model) toobtain deformation lengths 6, for comparison with thoseobtained at other energies. Figure 3 shows predictions(theory normalized to data to obtain PA) for the 3~ state(using the optical potential with a spin-orbit term) withthe spin-orbit deformation p, varied. The best fit is for Pc

(central potential deformation) = p,. However, as Fig. 4shows, there is some indication that the fits improve forhigher spin collective states (/ > 6) with p, > pc. Our

b|CS•O|TJ

10°

-110

: ' 1 ';

- \ ^

• v

r \: '

— JQr PcE ft.-- —fto"

1 1 I

1

fv/i

••"ft•5/3c

I ,

1 '

\fV

1 . 1

VV r

w

• i •

1 ' 1 ' :

208Pblp.p') ''•-T>\ (2.61 MtV)

Ep>3l8MtV

TTT-

.

_

\ \\ ' \ " ~

1 i 110 26 30 34 3814 IB 22

9c.m. <de9>

Fig. 3.Angular distribution for the 3" state in 20lPb. The curves are described in the text.

5 8 PROGRESS AT LAMPFLot Alimot Ntllonal Ltborttory

JanmyDtctaifr 1BB3

10 (4 18 22 26 30 34 38

Fig. 4.Angular distribution for the 6+ state in 20*Pb. The curves are described in the text.

tentative fits are not of the same quality as the 800-MeVfits.1

Another purpose of this experiment was to examinehigh-spin "strevched configuration" states in 20*Pb. InFig. 5 the angular distribution for the 14" (6.74-MeV)state is shown. The calculation was done in the distorted-wave impulse approximation (DWIA) with bound stateWoods-Saxon wave functions (r= 1.2, a = 0.65) for apure K'ii/2'./u/j) configuration, using the free Love-

Franey NN force to represent the interaction. The theo-retical curve has been normalized to the data, withCTEXP/<TTHEO=0.25. However, as can be seen in Fig. ] ,

there is significant background under this peak, whichleads to an uncertainty in oEXP well above that resultingfrom the absolute normalization alone.

REFERENCEI. M. Gazzaly et al., Phys. Rev. C 25.408 (1982).

I0"1

id2

.0°

: ' 1

r

— '

1

1 1 '

-i

1

1

1

1 1

1

• | • | • | :

20.8Pb(p,p') :

14 (6.74 MeV)Ep • 318 MtV

\ -.

-

I . I . I18 26 30 34 38 46

9c.m.<de9>

Fig. 5.Angular distribution for the stretched 14" state in 20"Pb. The curve is described in the text.

jtnuiry-Otctmbw f M3 MOOMMSATLAMPF 5 9LaiAHmot NKIorml Ltboruory

Measurement of/fNN for pp Elastic Scattering in theCoulomb-Nuclear Interference Region at 650 and800 MeV

(Exp. 709, HRS)(Univ. of Minnesota; UCLA; Los Alamos; K.EK Lab.;Hiroshima Univ.; Kyoto Univ. of Education, Japan)Spokesmen: M. Gazzaly (Univ. of Minnesota), G.Pauletta (UCLA), and N. Tanaka (Los A tamos)

The first of a series of experiments to measure the realparts of the forward, double spin-flip amplitudes atintermediate energies was completed in September 1983.Measurements were made at 650 and 800 MeV with anTV-polarized proton beam and /V-polarized frozen-spiniarget an HRS. The dilution refrigerator and polarizedtarget expertise were provided by a team from KEKLaboratory, Hiroshima University, and Kyoto Univer-sity of Kducation. Japan.

Whereas the imaginary parts of the forward, doublespin-flip pp amplitudes at intermediate energies have beendetermined by measurements of the total pp cross sec-tions (a(ot. AoL, ACT,) with polarized beam and targetcombinations, we still rely on the semiphenomenologicalpredictions of the forward dispersion relations" (FDRs)for our knowledge of the real parts. These predictions areused as constraints on current phase-shift analyses. Theexperimental determination of the real parts by measure-ments of ANN, AXh, ASH, and /iL S in the Coulomb-nuclearinterference region are therefore desirable, but have notyet been attempted because of experimental difficulties.At intermediate energies, the motivation for experimentaldata is enhanced by the observation of energy de-pendence in the imaginary parts. This structure leads tosimilar structure in the FDR predictions of the real partsand to counterclockwise rotations of their Argand dia-grams, which have been interpreted as evidence for theexistence of dibaryon resonances.

Motivated by the interests outlined above, a series ofexperiments to detennine the real parts of the forward ppdoub'e spin-flip amplitudes at 650 and 800 MeV has beeninitiated. Here we report on the first of these measure-ments, namely, that of .4NN.

To extend such measurements to small angles, onemust be able to distinguish between scattering from theheavier target and cryostat components and scatteringfrom hydrogen. Since the energy cf the recoil proton istoo small to allow detection, one must rely entirely onmomentum resolution for the forward-scattered proton to

separate out the hydrogen elastic-scattering component.The intrinsic momentum resolution of the HRS is morethan adequai.. so that the total experimental momentumresolution is determined by the combined thickness of tr.polarized target and the cryostat walls.

For our experiment, the outermost and thickest of thecryostat walls was modified so that the incident beam andthe scattered protons passed through thin (0.2-mil)titanium windows and so that the effective target thick-ness was 0.5 cm. The polarizing field of 25 kG wasprovided by a C-type magnet (Zoltan) obtained fromLawrence Berkeley Laboratory. After the target polariza-tion had been frozen, the field was reduced to 3 kG tominimize deflections of the incident and scattered protonsin the field of Zoltan. Using calculations based on fieldmaps, the scattering angle measured by the HRS wascorrected for these deflections.

Spectrometer calculations were performed using aseries of wire targets, and the beam position on target wasdetermined by inserting a phosphoi at the target position.The cryostat could be removed from the target positionand replaced reproducibly by means of a system ofsynchronized servo-motors that moved the cryostat andassociated liquid helium dewar in unison. The targetposition was checked by x-ray photographs. Upstreamand downstream wire chambers were used to monitorbeam profiles, which were typically 3 mm (horizontally)by 4 mm (vertically) FWHM. At larger angles, wheremomentum and angular resolution were not critical, thebeam was wiggled ~ ± 3 mm about its central horizontalposition, with a frequency of ~60 Hz to reduce theincident beam density, permitting higher beam currentswith acceptable target depolarization. A beam flux of~2 x 107s in a stationary spot of size given aboveproduced an ~5 h target polarization relaxation time.

Mean target polarizations were measured by NMR,but since the polarization in the target volume illuminatedby the beam varied more rapidly than the averagepolarization, it was necessary to measure and monitor therelevant target polarization by other means. Apolarimeter made up of two scintillation countertelescopes at ± 18.5° and two conjugate recoil telescopesat ~.t-61.5° was used to monitor both beam and targetpolarization. Each of the recoil arms consisted of amultiwire proportional chamber (MWPC) and two scin-tillators. The scattering-angle information from theMWPCs was used to distinguish between elastic ppscattering and quasi-free pp scattering from boundprotons in the nuclei of the target material and cryostat

60 PHOGRESS AT LAMPFLos Alamos National Laboratory

Jimmry-Dtcembw 1993

windows. Since AN is known to ~ ± 3 % for 800-MeVelastic scattering at 18.5°, tiie beam and target polariza-'i^ns could be determined to this accuracy. The beampolarization also was obtained independently by thequench method." The beam intensities were monitored bymeans of high-gain ion chambers filled with xenon andkrypton gas, respectively, at 2-atm pressure.

Four independent measurements were made at eachspectrometer angle: Y{ ft )< >'( I t )> *"( t l I an<*Y( j j ). where the first arrow in the parentheses refers tothe direction of the beam polarization relative to thescattering plane, and the second arrow refers to that ofthe target. The target polarization was reversed once ateach angle, whereas the beam polarization was reversedevery 120 s in a repetitive cycle: up-quench-down-quench . . . . From the above measurements, four inde-pendent quantities were calculated:

= n t t ) - n i t ) - n U)+ n II )=

=ntt)+ n m - n t l ) - n u ) ^

= Y( tt)- nit)+ n n)- n u M

wliere Ya is the spin-averaged yield, PT is the targetpolarization, and /"B is the beam polarization. Since boththe beam and target polarizations were determined in-dependently as described above, values of ^ N N and AN

could be extracted at each angle. A more sophisticatedanalysis that lakes into account differences in the valuesof the beam and target polarizations as a function of thepolarization direction is needed to eliminate spuriousasymmetries; such an analysis is in progress.

REFERENCES

1. 1. P. Auer, Nucl. Phys. A 335, 193 (1980); and D. Bugg, Nucl.Phys. A 374,95(1982).

2. W. Grcin and P. Kroll. Nuc!. I'hys. H 136. 42( ', 197(5).

3. M. A. McNaughlonctal., Phys. Rev. C 23. 1128(1980

Development of 0° Capabilities at the HRS Facility(Exp. 768, HRS)(Los Alamos, Univ. of Minnesota, Rutgers Univ.)Spokesmen: J. B. McClelland and T. A. Carey, (LosAlamos) and S. Seesirom-Morris (Univ. of Minnesota)

A great deal of time and effort has been devoted in thepast several years to obtaining very forward-angle in-elastic proton spectra on medium to heavy nuclei atdifferent medium-energy facilities. The thrust of thiseffort has been directed toward the identification of giantmonopole and dipole excitation in these nuclei. The mostsuccessful measurements have been made at low energies(200-300 MeV) where the interaction causes a selectivityof spin-flip over non-spio-flip transitions, especially forlow momentum transfer to the nucleus.

The ultimate goal of this experiment is to obtain high-quality spectra on medium to heavy nuclei in an effort toidentify A/1 strength systematically. The added selectivityof 0° measurements might disentangle the question ofMl, El. and M2 assignments.

We have recently run this experiment at 318 MeV on avariety of targets, and show here some preliminary on-line spectra taken during this run. This is the lowestenergy at which 0° spectra have successfully been ac-quired at HRS. These spectra were taken without the useof either the active collimator system or focal-planebeam-pipe setup. The primary source of background wasdue to rescattcring of particles from the exit flange of thespectrometer, provided that all other parameters hadbeen optimized.

The quality of the preliminary spectra is good. The >2Cspectrum j Fig. l(a)| is comparable to the best obtained atTp = 500 MeV [Fig. l(b)|. The 14 state in 48Ca is clearlyseen in Fig. 2, and the periodic structure seen in thesespectra likely will be removed when calibrations areoptimized. Evidence for increased Coulomb scatteringbecause of the heavier mass target may be seen at lowexcitation in the '"'Ca spectrum.


61

ISO

g .00

Fig. l(a) and (b). «Spectra for "C at a 0° scattering angle §for incident proton energies of (a) o S Q

318 MeV, and (b) 500 MeV.

Tp « 318 M«V

»*,T-I 15.11 M«V

0*,7.65M«V

10 15 20

Missing Mass (MeV)

25

I*,T«O 12.71 M*V

10Ex {MeV)

1Om

"c=iou

200

100

O

: '^ (P .P- )"Tp «497

L

•

-

!cMeV

-

-(b) ;

( 0 )

100

m

coo

75

50

25

Fig. 2.Spectrum for 4$Ca at a 0° scattering angle for anincident proton energy of 318 MeV.

6 2 MfJrtESSATlAMWLot Afmot Nttiontl Lttxriory

. 48 eCa*Ca(p,p')4eCaT p - 318 MeV

1*10.2 MeV

Ex(MeV)

Jtnuif-Dtcvntm )M3

O

ou

aw

200

100

"vip.p'yVV 318 MeV U

r n

/ i i

I

* » \

1 1 \

II 15 19(MeV)

Fig. 3.Spectrum for 9IV at a 0° scattering angle for an incident proton energy of 318 MeV.

Figure 3 shows a spectrum for ilV at 0°. The qualityof this spectrum is comparable to, if not better than,small-angle spectra taken at Orsay at 200 MeV.Furthermore, preliminary results show that the resonanceis at about the same excitation energy as that seen at200 MeV. Inadequate calibrations preclude any state-ment about fine structure in the resonance at this stage.Absolute normalization data have been taken, and it ishoped that absolute cross sections with reasonable errorbars may be extracted from these data.

Measurement of ANN for the />/»-»• dn+ Reaction at650 and 800 MeV(Exp. 790, HRS)(UCLA; Univ. of Minnesota; Los Alamos; KEK Lab.;Hiroshima Univ.; Kyoto Univ. of Education, Japan)Spokesmen: G. Pauletta (UCLA), M. Gazzaly (Univ. ofMinnesota), and N. Tanaka (Los Alamos)

The ANN(pp —*-dn*) was measured at 650 and800 MeV for laboratory angles of 2, 3.5, 5.5, and 7.5°.The aim of the experiment is to measure ANN, ALL, Ass,and ALS for this reaction at angles not previously ac-

cessible. When combined with measurements from previ-ous experiments, complete angular distributions will beobtained. This can be integrated to obtainAaL(pp-+dn+) and Aoj(pp -*• dn+). The decomposi-tion of the total cross sections AoL(pJ5) and Aa-^pp) intotheir inelastic components will be obtained by furthercombination of these data with complete elastic p"pangular distributions (Exps. 583 and 709). The measure-ment of ALL at 0 and 180° is of particular interest since itwill provide the only measurements for the deuterontensor polarization T20. These data will contribute to ourgeneral understanding of the / = 1 nucleon-nucleon inter-action and of the specific problem of the reaction mecha-nism involved in the/>/>-> dn+ reaction.

This experiment was performed at the HRS using thesame experimental setup as Exp. 709. Figure 1 presents adot plot of energy loss vs time of flight. Since the deuteronmomenta are greater than any proton momenta from thebeam-target interactions, a clear deuteron group is ob-served in Fig. 1 along with a proton group caused byprotons that scatter ofT the spectrometer magnet polefaces. Figure 2 presents a missing-mass spectrum for thedeuterons. A clear peak is observed that corresponds tothepp —r dn+ reaction. The data from this experiment arebeing analyzed.

lanutry Daeembf IM3 PftOOftEMATLAMPf 6 3Los Attmot Nuloni Lmbaiory

1-

o_Ju.u_Oui5»-

ENERGY LOSS

Fig. 1.A dot plot of energy loss vs time of flight measuredby the detector array at the focal plane of the HRS.Deuterons are designated by the box.

MISSING MASS (Arbitrary Units)

Fig. 2.A deuteron missing-mass spectra measured at theHRS focal plane. A clear peak corresponding to thepp —*• dn+ reaction is observed.

Spin-Depolarization Measurements on the OxygenIsotopes(Exp. 643, HRS)(MIT, Indiana Univ., UCLA, Lawrence Livermore Lab.,Los Alamos)Spokesmen: James J. Kelly (MIT) and M. V. Hynes andB.Aas (Los Alamos)

This experiment will use measurements of the spin-depolarization coefficients DaS to enhance the study ofthe two-nucleon effective interaction in the nuclear me-dium and to improve the precision with which nuclear-structure comparisons can be made among the oxygenisotopes. Ultimately, we wish to obtain spin-rotationmeasurements for elastic scattering by " " 0 and spin-depolarization measurements for as many inelastic ex-citations of all three isotopes as possible. Data taking hasbeen completed for I6O but has not yet begun for I7O orI8O.

The central data-analysis problem is to apply line-shape analysis techniques to many spectra simultane-ously and to obtain the maximum statistical precisionwithout introducing bias. Because we believe that thetechniques currently available are inadequate, we haveformulated the maximum-likelihood estimators for theobservables of interest and are studying the application ofthese estimators to line-shape fitting. An extensive MonteCarlo simulation program for the HRS and focal-planepolarimeter lias been written, but the optimal data-reduction strategy has not yet been decided. It is clearfrom the volume of magnetic tape requiring processingthat a careful decision is advisable before replaying thedata.

A preliminary analysis of the cross-section and analyz-ing-power data obtained with AT-type beam has beenperformed. These data have been compared with impulse-approximation calculations. Qualitatively, the same sys-tematics is observed at 500 MeV as was observed at318 MeV, with a somewhat stronger enhancement of theinterior states over the predictions.


Energy Dependence of the Two-Nucleon EffectiveInteractionGxp.718, HRS)

VMIT, Indiana Univ., UCLA, Lawrence Livermore Lab.,Los Alamos)Spokesmen: James J. Kelly (MIT) and M. V. Hynes (LosAlamos)

The two-nucleon effective interaction is modified in thenuclear medium by the local density in the vicinity of theinteracting nucleons. These modifications have been mostcarefully studied for incident proton energies between100 and 200 MeV

The magnitude of these medium corrections is ex-pected to decrease slowly with energy. To study thisenergy dependence, we have measured the cross sectionand analyzing power for the excitation of all narrowstates of "O below 13-MeV inelasticity by 318-MeVprotons. These data will be combined with comparable135- and 180-MeV data taken at the Indiana UniversityCyclotron Facility (IUCF) and 500-MeV data taken atLAMPF(Exp. 643).

Approximately one-half of the data has been reduced,forming angular distributions with twice the expectedfinal-step size. These data have been compared withimpulse-approximation calculations based on the Love-Franey interaction, and with local density approximationcalculations using a G matrix based on the Paris poten-tial. The nuclear structure was specified by transitiondensities fitted to electron-scattering data.

To summarize the comparisons between theory andexperiment, it is convenient to divide the states into twoclasses: (1) interior states whose transition densities peakin the high-density nuclear interior, and (2) surface stateswhose transition densities peak in the low-density nuclearsurface. The predicted cross sections for surface statesagree well with the data at the peak of the angulardistributions. For interior states the predicted peak crosssections are about 30% below the data. The high momen-tum-transfer (q) predictions for all states are substantiallybelow the data.

These results allow us to draw several conclusionsabout the 318-MeV effective interaction. First, the low-<7amplitude is approximately correct for small density.Second, the strength of the dominant imaginary part ofthe isoscalar spin-independent central component isenhanced as the density increases. And third, the high-<?

interaction needs to be enhanced, but it is not yet clearwhether this effect depends on density. These conclusionswill be quantified using the modeling techniques brieflydescribed below.

Direct Reaction Analysis with Linear Expansions

James J.Kelly (MIT)

A general modeling technique has been developed thatcan fit a variety of linear expansions to any set of directreaction observables. This technique has been im-plemented for nucleon-nucleus scattering, but can bereadily expanded to include eleciron scattering and pionscattering.

If we expand the scattering operator U in a linear basissuch that

the distorted-wave matri/ element for the reactionA{aJ))B may be written

= LV. _

(mBmbmAma

(6 ) ,

where the C/,W|)'s are the spins and spin projections of theparticles involved, and oamm, represent the Pauli spinoperators for the projectile. It is convenient to constructthe quadratic forms

(up

( 9 ) O H" (0) oa amama mBm6mAma V

The observables are then contractions of these quadraticforms (sum on six repeated indices):

January-December (983 PROGRESS AT LAMPf 6 5/.os Alamos NallonMl LaborMtory

simultaneous fit to the cross-section and analyzing-powerdata for many multipolarities We have performed thistype of fit at several projectile energies using the 0^, 1"2\, 37, and 4"J states of " 0 .

(2) Neutron Densities. For normal parity transitionswhose spin and current contributions are negligible, theproton distribution can be fully specified by electron-scattering measurements. The neutron distribution pn canthen be fit to proton-scattering data using linear ex-pansions of the form

Pnw= X

A very simple search algorithm can minimize the total %2

for an arbitrary set of observables with respect to theexpansion coefficients aa. Several applications that haveused this technique follow.

where fn{r) are any convenient complete set of radialfunctions. We have used both Fourier-Bessel expansionsand polynomial-times-Gaussian expansions. The errorenvelope Spn{r) is obtained from the covariance matrix V^using

(I) Effective Interactions. We expand medium correc-tions to the effective interaction in the form

1. fln'nOZ'P) •n=l Fits have been made for several states of "O and "Sr.

Pseudodata studies also have been made.

For a given projectile energy, the effective interaction iscommon to all transitions excited. The maximum sensitiv-ity to the density (p) and momentum transfer (q) de-pendence of the medium corrections is obtained in a

(3) Longitudinal Spin Density. The 0+ to 0" tran-sitions are driven by the longitudinal spin density, whichcan be expanded as above. The i6O(p,p') 0", T=0reaction has been studied at 135 MeV.

6 6 PROOHESSATLAMPFLos AlMmos N$tlontl LtboMory

Jtnutry-Otambtr 1f83

Study of Isobaric-Analog States in (ft*,n°) Reactions(Exp. 412, LEP)\ o s Alamos, Tel Aviv Univ., Arizona State Univ.)

.spokesmen: H. W. Baer and J. D. Bowman (Los Ala-mos)

We completed1 a series of measurements of 0° dif-ferential cross sections for isobaric-analog states (IASs)on nuclei ranging from 7Li to 20*Pb. The measurementswere performed with the n° spectrometer at the LEPchannel at four energies between 100 and 300 MeV. TheA dependence at each energy is shown in Fig. 1. Thesedata showed that 0° IAS cross sections follow a re-markably regular pattern when plotted against

10'

Using the determined parameters g{E) and a(2f), itappears first that one can estimate a 0° IAS cross sectionon any nucleus in the periodic table to an averageaccuracy of 20% for beam energies between 100 and300 MeV. Second, the regular pattern in the data estab-lished that the parameters g and a constitute a goodmeeting ground for comparisons between experimentsand theories, particularly those theories that attempt todescribe the general features of 7i-nucleus scattering. Forexample, the data show that a decreases from 1.35 at theresonance energy (165 MeV) to 1.10 at 295 MeV (Fig. 2).Generally, this reflects the changing nature of pion single-charge-exchange (SCX) scattering, going from approx-imately black-disk scattering at 165 MeV (a value ofa = f is given in Ref. 2) to increased volume scattering athigher energies. A third consequence of these measure-ments is that it now becomes possible to recognize withsome degree of confidence an "anomalous" 0° IAS crosssection.

At resonance energies, deviations from the generaltrends are expected to arise primarily from unusualneutron-proton density distributions in the surface re-gion; 90Ar appears to be such a case.1 Since it is generallybelieved that pion SCX to the IAS is one of the mostsensitive tools available to study the relative neutron-to-proton density distributions (Ap) in nuclei, determiningthe systematic features is particularly desirable.

Figure 3 presents o,AS(0°) as a function of incomingpion kinetic energy. For comparison we show in Fig. 3the energy dependence of the free cross sectionOJJ- non (0°). In general, the maximum of the 0° IAScross section is observed on the1[3,3) resonance energy. Itdrops quickly when belbw and slowly when above theresonance. These trends follow the shape of the free crosssection but are less pronounced.

wvy-Dactmbar 1983

i nn i t nri

295 MeV.10°

10

J I O Z

NJI

6- x l O

Id4

10"

10*

i 0.03

±0.03

Fig. I.Measured (Ref. 1) o,AS (0°). The straight lines rep-resent g(E){N- Z)A-°.

An anomalous behavior is observed for the MZrnucleus where the cross section is monotonicalJy increas-ing with the energy and does not reflect the (3,3) reso-nance as do the other nuclei. This effect might be relatedto the neutron-proton density difference at the surface. Ingeneral, the ratio of the number of neutrons to protons,evaluated as

PMXMEMATLAMPF 6 7Lot Altmot Union* Ltbormcuy

1.4

CJ L2

10

1

- \

-

1

1

1

1

1

-

-

-

1100 200

T_.(MeV)300

Fig. 2.The energy dependence of the exponent a in thefunction g{N - Z)A~" deduced from the measure-ments shown in Fig. 1.

, 0

JRP p *

with the use of density-matrix expansion or Hartrcc-FockSkyrme III force densities, " exceeds the N/Z ratio in thesurface region probed by the strongly absorbed pions;''°Zr is an exception, as the calculated ratio is very closeto N/Z. This means that for "°Zr the SCX cross sectionnear the (3,3) resonance is relatively suppressed becausethe interaction occurs near the surface, which has acomparatively low neutron density. At higher energies,with a larger penetration depth, the behavior is closer tothat of an average nucleus. This interpretation agreeswith the observation that the reduced cross section (secFig. I) of '°Zr at 165 MeV is lower than the fitted linewhereas that of l2"Sn (a nearby nucleus with a large"neutron halo") is higher.

We have proposed (Exp. 728) to extend the (jr\7i°)IAS measurements into the 300- to 500-MeV regionusing the n" spectrometer at the P ' pion channel. A majormotivation is to see whether the remarkably regularpatterns found for the 0° cross sections in the 100- to300-MeV region continue at the higher energies. Asecond goal is to provide more evaluation of the dis-

5 -

X I

t> 05

•

/

7 /I /

/

- ; /

; /

i

il \ 1 j :

--i

t —••

100 200

(MeV)

300

Fig. 3.Excitation function of the 0° IAS cross sections(cm. system) for 'Li (solid circles), I4C (opencircles), '"'Zr (solid triangles), U0Sn (open triangles),and 20"Pb (open squares). The solid line representsthe cm. cross section of the free charge-exchangereaction n+ + n-*n°+p plotted vs the laboratorykinetic energy; the dashed line, vs the cm. kineticenergy.

tortcd-wave impulse approximation (DW1A) theory. Ifthe DWIA theory is more accurate at higher energies,<T|AS (0°) should increase* in the 300- to 500-MeV inter-val. If this behavior is not observed, it will show un-equivocally that a major ingredient is missing in thetheoretical description.

If o,AS (0°) continues to follow the shape of the freea(itW), the excitation functions for most nuclei shouldfollow the shape shown in Fig. 4. The a(irAr) curve wasnormalized to the 295-MeV data point.

It is our belief that the experimental determination ofthe systematics for IAS excitation as a function oTE and

Sec, for example, LAMPF proposal 728, where calculationsperformed with the code I'lliSDEX arc presented.

6 8 PROQRESJ AT LAMPFLos Alamos National Laboratory

Jamw'-Dtamtwr IM

UJ

en

50

10

5

: 1 I I

- i

- /

i i i

I I :

—,

V -

-

i i100 200 300 400 500

T [MeV]

Fig. 4.The deduced values of g(E) obtained by fittingg(E){N-Z)A~a to the measured oIAS(0°). Thecurve represents the shape of o(np •-*• n°n) at U°;it is normalized to the 295 MeV data point.

A constitutes a basic characterization/of the n-nucleusinteraction between 100 and 500 MoV. We have com-pleted the first part of this study at the LEP and plan toperform the high-energy pan of the study at PJ in 1984.

REFERENCES

1. U. Sennhausc-r el ul., Phys. Rev. Lell. 51, 1324 (1983).

2. M. B. Johnson, Phys. Rev. C 22, 192 (1980).

3. J. W. Nc-gclc and D. Vautherin, Phys. Rev. C 5, 1472 (1972).

4. M. Beiner et al., Nucl. Phys. A 238, 29 (1975).

Pion Elastic-Scattering and Single- and Double-

Charge-Exchange Reactions on 14C

(Exp. 523, LEP)(Los Alamos, Univ. of Colorado, Arizona State Univ.,Tel Aviv Univ.)Spokesmen: H. W. Baer (Los Alamos) and J. L. Ullmann(Univ. of Colorado)

(Exp. 539, EPICS)(Los Alamos, Univ. of Minnesota)Spokesmen: H. W. Baer (Los Alamos) and D.Hohkamp (Univ. of Minnesota)

B.

(Exp. 558, EPICS)(Los Alamos, New Mexico State Univ., Univ. of Texas,Univ. of Minnesota)Spokesmen: H, W. Baer (Los Alamos) and G. R.Burleson (New Mexico State Univ.)

This set of experiments is intended to provide completedata on a single nucleus for pion reactions that are relatedby isospin invariancc: K1 :ind JI elastic scattering, (JI4,IT0)to the isobaric-analog state (IAS), and (JI+,JI~) to thedouble-isobaric-analog stale (DIAS). Carbon-14 waschosen because it has the most favorable level separa-tions among the T > I nuclei.

The measurements are being made at various energiesbetween 35 and 300 MeV. These data should provide agood picture of the changing nature of the pion-nuclcusinteraction with energy. Specifically, comparisons will bemade with theories that attempt to describe in a continu-ous manner the dynamical changes that occur in thepion nucleus interaction at energies below, on, and aboveI he A resonance.

Elastic-scattering data now have been measured at164 MeV (Exp. 539) and at 80 and 65 McV.1 The 164-MeV data are shown in Fig. I. The difference in the angleof the first minimum between it' and n scattering isapproximately 2.5°, indicating a slightly larger effectiveradius for neutrons than for protons in I4C.

Forward-angle single-charge-cxchange (SCX) crosssections have been ineasured at 35, 50, 65, 80, 100, 165,230, and 295 MeV. The dramatic energy dependence inthe forward-angle IAS cross sections is exhibited inFigs. 2 and 3. At energies between IOC and 300 MeV, the

mmryOKtmtnr 1983 PROGRESS AT IAMPF 6 9Los Alamos National Laboratory

10000

1000

100

01 r

0.01

r r i • r • i • i

MC ELASTIC164 MEV

O JT

• n*zlO

s*

• 1 , 1 . 1 , 1 . 1 . 1 . 1 . 1

10 20 30 40 50 60 70 80 90 100

Fig. I.Elastic-scattering cross sections for n+ and n~ on14C.

HC(n+ . T T T N 0AS)

- 30 -

295 MeV' 3.3"

• ^ A

£!_

4 0 0

300

ZOO

IOO

300

200

100oU

i i

65 MeV0-25*

50 MeV0-25*

190

100

50

r 35 MeV n,

(b) -

20 40 60 SOir' Energy (MeV)

100

Fig. 3(a)-(c).Measured spectra for the uC(n+,n°) re-action at low energies.

Fig. 2.Measured K° spectra for the l4C(n+,n°)

50 70 90 110 130 250 270 290 310 330 reaction.

n" KINETIC EXERGY (MeV)

7 0 PHOOMS«ATLAM!»FLot Altmot NtllonH Ltborilory

Jmnuwy-Oecwnbw 70

0 10 20Excitotion Energy (MeV)

120

100

j» 80c

Jeo

20 -

1

-

-

_

' 1 ' 1DIAS n

* J 1

p)P \

" . » 1 1 1 -

1 1 '

5O50

AcceptanceCulolt

151 Line

-TT"Shape

1 '•Aw*,MeV-120°

J •

1IT ) .

-

(c) J

1-10 20 30 40 50

Ex(MeV)

Fig. 4(a)-(c).Measured spectra for the "C(n\n~) reaction at (a)292 MeV, EPICS; (b) 164 MeV, EPICS; and (c)SO MeV, TRIUMF TPC.

IAS is a prominent feature of forward-angle (n+,n°)reactions. At 50 MeV the IAS vanishes. An upper limiton the 0° cross section, based on the data of Fig. 3(b), is5 ub/sr. At 35 MeV the IAS is again a prominent featureof the spectrum [Fig. 3(c)|.

The deep minimum in the 0° cross section near50 MeV would seem to be a direct reflection of thecorresponding deep minimum in the iCp —» JI°« reaction.

However, calculations by Siciliano2 have shown thatsizable isovector-correlation (p1) terms are required toobtain a deep minimum in the 0° cross section at 50 MeVfor the l5N(n*.n°) reaction. The 14C data are beinganalyzed in the framework of the Johnson-Siciliano3

theory and the Kauffman-Gibbs* multiple scattering the-ory.

The first double-chargc-exchange (DCX) cross sec-tions for a DIAS transition at 50 MeV were measured in1983 using the time-projection chamber (TPC) at the M9channel at TRIUMF.* These measurements at a lowenergy were made possible by a large solid-angle detector(TPC) and a sufficient quantity (7 g) of MC packaged intosuitable target cells. In Fig. 4 the spectrum measured withthe TPC at 50 MeV is compared with spectra measuredat EPICS at 165 and 292 MeV. The measured angulardistributions at these energies are shown in Fig. 5. Thehigh resolution in the EPICS data is attractive, but notnecessary, to measure l4C(n+,n~)MO (DIAS) because thefirst excited state in I4O is at 5.9 MeV.

EPICS, because of its long length, is not well suited tomeasure 50-McV cross section;!. It is interesting to seethat the 50-MeV cross sections for angles 0 > 50° arelarger than the cross sections at 165 and 295 MeV for0 > 20°.

This first measurement of DCX at low energy shouldput constraints on the very uncertain theoretical calcula-tions. The main features that can be observed in theresults follow.

• The shape of the angular distribution has someresemblance to the shape of elastic scattering, butthe minimum at 70° is much shallower.

• The angular-distribution seems to increase at smallangles, unlike SCX,1 which has a minimum at 0°.

Optical-model calculations, using a modified version ofthe code PIESDEX, were done by E. Siciliano. Theparameters were the same ones that gave good agreementwith the 50-MeV SCX of I5N (Ref. 3) and 50-McV elasticscattering on "O. The results of the calculations with andwithout the isotensor Lorentz-Lorenz term are shownwith the experimental data in Fig. 5(c).

The calculations have the right magnitude, but theshape has only a modest resemblance to the data. Clearlya better theoretical understanding and more data aredesirable.

•Experiment TPC-DCX at TRIUMF, "Pion Double ChargeExchange at Low Energy," by a TRIUMF collaboration andII. W. Baer of Los Alamos as Spokesmen.

J$nuiryO*ctmbtr 7063 PftOOMStATLAMW 7 1Lot Alvnot Nillorml LtbOfUory

I

b•o

- o.i

20 40 60

Laboratory Scattering Angle (deg)

Fig. 5(a)-(c).Differential cross sections for the reaction14C(jr+,Jt) at (a) 292 MeV, EPICS; (b) 164 MeV,EPICS; and (c) 50 MeV, TRIUMF-TPC.

- O.I

- 0.01

20 40 60

Laboratory Scattering Angle (deg)

' i

0.7

0.3

0.2

-

: LLIT = O

, L L I T = 1 ^ .

i i i i

i^*

i

t

i

\

^ * "

« .

i

i

—

i ,

) 50 MeV

(c)

i i i

20 40 60 60 100 120

REFERENCES

1. M. Blecher ct al., Phys. Rev. C 28, 2033 (1983).

2. M. D. Cooper et al., submitted to Phys. Rev. Lett.

3. M. B. Johnson and E. R. Siciliano, Phys. Rev. C 27, 720 (1983).

4. W. Kaufmann and W. R. Gibbs, Los Alamos National Laboratorydocument LA-UR-83-736 (1983).

7 2 PHOGRESSATLAMPF

Lot Alamos National Laboratory

January December I9i

A Dependence of the Excitation Energy, Width, andCross Section of the Isovector Monopole ResonanceBxp. 607, LEP).uos Alamos, Tel Aviv Univ., Arizona State Univ., SIN}

Spokesmen: J. D. Bowman and H. W. Baer (Los Ala-mos) andJ. Alster (TelAviv Univ.)

We have used tne (n~,n°) charge-exchange reaction at165-MeV kinetic energy to study the T+ 1 component ofthe isovector monopole resonance (IVM). The nuclei40Ca, 60Ni, 90Zr, 120Sn, U0Ce, and 208Pb were used astargets. We also observed the T + 1 component of thegiant dipole resonance (GDR) in the lighter targets. The(n+,n°) reaction cross sections showed the presence of theT- I component of the IVM and GDR in 40Ca, '"Ni, and"°Zr.

Pion charge exchange is well suited to the study of theisovector giant resonance, and particularly the IVM, for anumber of reasons. The pion is spinJess, and at forwardangles the excitation of spin-flip states is strongly in-hibited. The charge-exchange reactions proceed throughthe T • T piece of the rc-nucleon / matrix; hence, charge-exchange reactions must excite isovector states. This is incontrast to inelastic hadron scattering, which stronglyexcites isoscalar states.

Giant resonances have large transition densities in thenuclear surface. Because 165-MeV JI'S are strongly ab-sorbed, they couple efficiently to these surface-peakedtransition densities. This point is crucial for monopolemodes where the volume integral of the transition densityvanishes. The excitation of a monopole mode by a weaklyabsorbed probe therefore is strongly suppressed at for-ward angles. The angular distributions produced by thestrongly absorbed 165-MeV it's are sharply difl'ractiveand allow a direct determination of the angular momen-tum of the final states. Finally, the Coulomb energy shiftsthe T +• I component of the 1VM to a low excitationenergy in the (it ,n°) daughter nucleus. The decay widthof this state, therefore, is reduced.

Figure 1 shows plots of doubly differential cross sec-tions for the (n",jt°) reaction vs the kinetic energy of thedetected n°'s. Representative targets, 6UNi and 140Ce, areshown. The top spectra arc for a scattering angle of 4.5°near the forward direction where the 1VM cross section islargest; the middle spectra are for 15° where the IVMcross section is small and that of the GDR is largest; andthe bottom spectra are for 33° where both the IVM andGDR have small cross sections. The dashed lines rep-resent a smoothly interpolated background.

In Fig. 2 we plot the normalized cross section 5 in themonopole region of the spectra vs momentum transfersquared (q = k^ sin 9). The monopole-region cross sec-tions were divided by the observed differential crosssection

dildTdT (monopole region)

C" _

d2o

dtldTdT (E, < 70 MeV)

It is the excess of cross section above the linearlyextrapolated background that we identify as caused bythe IVM. The first minimum of the IVM angular distribu-tion occurs where qR = JI/2, where R is the n-absorptionradius. This point is indicated on Fig. 2. The observedbreak points between the background and the forward-peaked IVM feature are near the n/2 point foi eachnucleus.

Angular distributions, excitation energies, and widthswere extracted by fitting the doubly differential crosssections to a sum of IVM, GDR, and nonresonantbackground components. The background was smoothlyinterpolated under the resonances as a function of q1 andTn<>. The angular distribution for the IVM and GDRpeaks in the h0Ni(n +-.7i") data is shown in Fig. 3. The solidlines are the angular distribution of Aucrbach and Kleinnormalized to the data.

In Fig. 4(a) we show the extracted maximum mono-pole and dipole cross sections compared to calculationsof Auerbach and Klein for the different targets.

In Fig. 4(b) we show excitation energies and widths,again compared to the random-phase-approximation(RPA) theory of Auerbach and Klein. The agreement isremarkable.

We observed no hint of isovector quadrupole signal.For example, in the 60Ni (nT,rcu) data where we observe70% of the IVM and GDR cross sections predicted bythe RPA distorted-wave impulse approximation (DWIA)theory, we observe <25% (90% confidence level) of theisovector quadrupole predicted cross section.

Our conclusions are that the IVM is a systematicfeature of nuclei from 40Ca to 208Pb. Its excitation energyand width are well reproduced by RPA calculations. Itscross section is large, indicating the collective nature of


73

0-4.5*

0200'

L (w

110 130 150 170T 0(MeV)

40

90 110 !30 150 170T o (MeV)

Fig. 1.Doubly differential cross sections vs n° kinetic energy for MNi(n~,it°) and M0Ce(ji",n0) at laboratoryangles of 4.5, 15.0, and 33.0°.

7 4 PROGRESS AT LAMPFLos AJimoj Ntlijntl Ltborvory

a:

"'Pbnr.nf'_ l 4 O C e ( F " T [ 0 )

t !IV I 2 0SN (TT.IT9)' ^ • 1 1

</)

t {*zr(rr,n°)

^ V . - , i Niarjn

0.25 NKTT'.TT0) V 10.2 0.4

qz(fm2)

Fig. 2(a) and (b).The ratio S plotted vs momentum-transfer squared.The region of integration is (a) centered on theexpected IVM energy, and (b) centered above theIVM energy.

800-

S— 400-b i d

-,._„. Iw

XI

•ore

. ( a )

r-•

7T-.TT0

IVM

6DR

d§m°

-idcd,

i

TT

X

rT m o x

I H

0

-

-

f-i- I

0)

5

IVM Ex

IVM Width

Co Ni ZrSnCePbCoNi ZrSnCePb

Al/3

Fig. 4(a) and (b).(a) Maximum cross section for the isovecto.monopoie and giant dipole resonances in the(n1,)!0) reactions, and (b) excitation energiesand widths of the isovector monopoie resonancein the (n*,;!0) reaction. The (n",Jt°) reactionexcites the T + \ component and the (n+,n°)excites the T- 1 component of each resonance.

10 20 30 10 20 30

0^0(deg)

Jtnuvy-D*ctmb»r 1983

Fig. 3.Angular distribution for the IVMs and GDRs in

MKX>r.cMATLAMPf 7 5Lot Altmot Ntliontl Ltxttoty

the state, and is in qualitative agreement with RPA-DWIA theory. The IVM and GDR cross sections deviatefrom RPA-DWIA theory by the same ratio. The absenceof the isovector quadrupole resonance poses an interest-ing problem.

REFERENCE

1. N. Auerbach, Proc. of the Conf. on Highly Excited States andNuclear Structure (HESANS), 1983 Int. Symp., Orsay, France,September 5-8, 1983.

Study of the Mass and Energy Dependence of Low-Energy Pion Single Charge Exchange(Exp. 688, LEP)(Los Alamos, Tel Aviv Univ., TRIUMF, Arizona StateUniv.)Spokemen: M. D. Cooper and M. J. Leitch (Los A lamos)

At low energies the free-nucleon charge-exchangeangular distribution is strongly backward peaked with adeep forward minimum. Furthermore, phase-shift analy-ses predict that the 0° excitation function has a minimumaround 50 MeV. These minima are the result of a nearperfect cancellation of s- and /J-wave n-nucleonamplitudes. If the nucleus is transparent, the nuclearsingle-charge-exchange (SCX) reaction to the isobaric-analog stale (IAS) should show the same features. Of

course, in nuclear matter these features will be distortedby effects such as absorption and Pauli blocking.

In this experiment we have measured forward-angledifferential cross sections for 7Li(n+,n°) (IAS) at th33.5-, 41.1-, 48.5-, and 58.8-MeV incident pion energy.Also, angular distributions for 3 9K(JI+ ,JI°) (IAS) and48Ca(n+,jr°) (IAS) were measured at 48-MeV incidentpion energy. The experiment was performed at the LEPchannel using the Jt° spectrometer.1

Typical n° spectra for incident pion beam energies of33.5, 41.1, 48.7, and 58.8 MeV on the 7Li target areshown in Fig. 1. The n° energy resolution (FWHM) inthese measurements was 3.0-3.5 MeV. In the analysis ofthe data, angle-dependent line shapes, together withkinematic constraints on the energies of states in residualnuclei and three-body thresholds, were used to separatethe IAS peak from continuum charge exchange andbackground. The line shapes were obtained by MonteCarlo simulation of the beam, target, and spectrometerconditions.'

The decomposition of the spectra into background andthe IAS peak for the 7Li(re+,n°) measurement can be seenfrom the dashed lines in Fig. 1. The data were fitted bythe maximum-likelihood method described in Ref. 2. Thestatistical and instrumental error in the extraction of theIAS area was 20-30%; the error caused by the unfoldingof the IAS peak was typically 50% of the statistical error.The normalization procedure is described in detail inRef. 3.

7Li(n*,n°)7Be (IAS)

Fig. 1.Measured it0 spectra for the 7Li(jt+,n°)(IAS) reaction at 33.5-, 41.1-, 48.7-, and58.8-MeV incident pion energy. Thedashed curves show the fits to the IAS andto the second excited state.

12058.8 MeV

8.3°

35 45 55 65 75 25 35 45

n° KINETIC ENERGY (MeV)

55 65 75

7 6 PROGRESS AT LAMPFIds Alamos National Laboratory

Jtnuary-Dacambtr 1983

In Fig. 2 we show the measured cross sections for 7Li,"K, and 48Ca taken near 50-MeV incident pion beam•nergy, and for comparison we also include the•5N(n+1,ir°) (IAS) data of Cooper et al.3 taken at 48-MeVpion energy. These data show that as we increase nuclearsize, the shape of the angular distribution continues toreflect the forward-angle minimum and backward anglepeaking nature of the free-nucleon charge-exchange crosssection. Also shown in Fig. 2 is the prediction of thePIEKDEX code* for SCX on "N at 48 MeV. In thiscalculation, second-order terms representing isovectortrue pion absorption and the Lorentz-Lorenz effect areincluded in the optical potential; optical-model calcula-tions without second-order terms are unabJe to reproducethe deep minimum at 0° seen for "N (Ref. 3).

*E. R. Siciliano and M. B. Johnson, private communication,1983.

For 7Li data, the 0° cross sections were extrapolatedby fitting the angular distributions with A + Bd7 func-tional form. This is based on expansion of angulardistribution at small angles in terms of the Legendrepolynomials. The measured 0° excitation function for 7Liis shown in Fig. 3. The error bars are the combined errorfrom the extrapolation to 0°, the uncertainty in thenormalization, and the statistical liuctuations. The datapoints at 70 and 98 MeV were taken previously with thejt° spectrometer. To estimate the location of the mini-mum, we fit the four data points with a parabola (Fig. 3).The minimum of the parabola is at 42.3 ± 1 MeV. It isinteresting to note that the minimum in 'Li data obtainedin this work is different by 3-8 MeV from predictions ofdifferent phase shifts for the minimum in a free nNexcitation function. For comparison we show only theprediction of Rowe et al. in Fig. 3.

1000 p

in3 .

E

cf"BTO

100

10

-

" s $

• * /

i

i

•i• • 1

•

X

•

, 1

ITT

Tn+ = 50 MeV I

7Li(n*,n°) (IAS) -t6N(n-,n°) (IAS) :a9K'(n*,n°) (IAS) I<8Ca(n*,n°) (IAS) -PIESDEX (Siciliano).

i . i . i ,

30 60 90 120 W 180

Fig. 2.Angular distributions for the 7Li(n+,n°) (IAS),I5N(n\jt°) (IAS), 39K(nf,n°) (IAS), and 48Ca(7t\n°)(IAS) at incident pion energy near 50 MeV. Thesolid curve is an optical-model calculation thatincludes the second-order isovector terms describedin the text.

10

IOS

IOJ

io'

10°

o'

: 'Li(n4

: v=r

•

\ \

1 I

r~,n°)7Be

0°

1 1 ! I 1

(IAS) :

/ •^

,'sl

kf \

z

20 30 40 50 60 70 80 90 100

Pion Lob Kinetic Energy {MeV)

Fig. 3.The 7Li(n+,n°) (IAS) excitation function. The dot-dashed curve is a least squares fit to the data. Thedashed curve represents the free JIN cross sections(Ref. 4).

January-December 1 PROGRESS AVLAMPF

Los Alamos National Laboratory77

The differences in forward-angle behavior among 7Li,I5N, J9K, and 4SCa indicate that n-nucleus charge ex-change is sensitive to the medium effects. These mediumeffects cause changes in the delicate cancellation betweenTt-nucleon s- and p-wave amplitudes that result in a shiftin position of the minimum of the excitation function withincreasing nuclear size (A), or alternatively in a change inthe depth of the 0° minimum for different nuclei at aparticular energy.

Presently there are very few low-energy SCX data,with the exception of several angular distributions near50 MeV and one excitation function. To understand theeffect of the second-order terms and establish the system-atics of the A dependence and energy dependence of

forward-angle SCX at low energies, a larger body of datais needed. Future experiments using the n° spectrometerare planned to study the mass and energy dependence oflow-energy SCX.

REFERENCES

1. H. W. Baer et al.. Nucl. Instrum. Methods 180,495 (1981).

2. M. D. Cooper el al., Phys. Rev. C 25,438 (1982).

3. M. D. Cooper et al., "Angular Distribution for "U(:i',nv)"O(g.s.)at 7", = 48 MeV." submitted to Phys. Rev. Lett

4. G. Rowe et al., Phys. Rev. C 18, 546 (1987).

7 8 PROGRESS AT LAMPFLos Altmos National Laboratory

Jtnutry-OtctmbtriBVl

Muon Decay Spectrum(Exp. 455, P3-West)Los Alamos; Univ. of Chicago; National Research

. Council, Canada)Spokesmen: H. L. Anderson and W. Wayne Kinnison(Los Alamos)

The measurement of the positron spectrum of muondecay is one of the most fundamental experiments inparticle physics because it is the best way to determinethe attributes and magnitudes of the weak interaction. Weare making a new measurement to improve the existingaccuracy by a factor of 5. The spectrum can be calcu-lated precisely from the accepted theory, based on asimple symmetry proposed by Feynman and Gell-Mann,in which the neutrinos are massless, with two rather thanfour components. The theory also is characterized by thefact that the only interactions entering are vector andaxial-vector interactions, of equal magnitude and op-posite sign, referred to as V-A. In this theory thecurrents are purely left-handed. All searches to date tofind right-handed currents or massive neutrinos havebeen unsuccessful. (We discount the Russian experiment,which has reported a finite neutrino mass, because ofdoubts about the correctness of the result.)

The weak-interaction theory is beautiful in its simplic-ity, but we do not know whether that beauty is more thanskin deep; that is the purpose of this experiment. We planto measure the spectrum with high resolution andstatistics IOC *bld greater than previously obtained. Wewill compare the spectrum with its well-known theoreticalvalue.

As part of the comparison of the spectrum to theory,the experiment first will attempt to improve the high-energy shape parameter p to a new level of precision,nearly ±0.0003. This will represent an improvement inthe existing limits on this parameter by about a factor of10. Beg et al.1 have shown that such an improvement in pcan place a constraint on possible left-right weak-interac-tion theories. In such theories, there are two chargedintermediate-vector bosons, IVL and fVH, that couple toleft- and right-han Jed currents, respectively. These bos-ons are not necessarily themselves eigenstates of the massmatrix. Instead, the mass eigenstates Wx and W1 may beexpressed as Cabibbo-like mixtures of fVL and WK,

Wt = WL cos £ - WK sin I ,

W1 = W^ sin £ + WR cos £ .

Jtnwry-O<Ki>mtx>r 1983

Thus , it is of interest to place limits ontc = [M(W2)/M(W,)]2, the mass-squared ratio, and <L themixing angle. An improved measurement of p can reducethe allowable range of £ almost independently of the valueof K. This is shown in Fig. 1, where the current limits on K

015

0.05-

-0.05

-0.5

-015

0.15

Fig. 1.Experimental 90% confidence-limit contours on themass-squared ratio, K~\M(W2)/M(WdY* andmixing angle X, for possible left-right symmetricweak-interaction theories. The two bold solid linesrepresent the constraint that would result from thisexperiment's improved 0.3-per-mil measurement ofp. The current limits are from the recently improvedmeasurement of the end-point spectrum 1C,PU (dot-dashed curve, Ref. 2); the previous measurement of?/>u (dotted curve, Ref. 3); the present value for thep parameter (solid curve, Ref. 4); and a comparisonbetween Fermi and Gamow-Teller P polarization(dashed curve, Ref. 5). (n all cases, the allowedregions are those that rnriude the origin, £ = K = 0.

PMXMESSATLAMP? 7 9Lot Altmos Nilontl LtborMory

and ? are given.* As seen in the figure. Ihese limitscurrently come predominantly from the recently im-proved measurement of § by Mark Strovink's group2 atTRIUMF. The figure also shows how the limit on £ willbe improved by ihc proposed 0.3-per-mil measurement ofp, which is Ihe immediate goal of F.xp. 455. Figure 2shows a schematic view of the Exp. 455 apparatus. Themajor component of the detector i- a time-projectionchamber (TPC), which has a sensitive volume 52 cm inlength and 1 22 cm in diameter. The TPC magnetic field isprovided by an iro.venclosed solenoid that supplies amaximum field of 0.7 T, which is uniform to better than0.6% over the entire TPC sensitive volume. Such amagnetic field will allow a precision measurement of thepositron momentum absolutely.

'References 2-5. The cJotted and solid curves in Fig. 1 representworld-average values, with primary contributions from Rcfs. 3and 4, respectively.

The muons for the experiment, which are from asurface muon beam in P'-Wcst, are brought to rest in theTPC gas at the center of the chamber. An event triggerrequires that a muon enter the TPC as determined by the0.25-mm (10-mit) muon transmission scintillator at theTPC entrance during the LAMPF beam gate, and thatthis muon stop in the central 10 cm of the TPC gas, asdetermined by signals from the TPC sense wires. When amuon enters the chamber, the deflector/separator is usedto turn off the beam. In this manner, the experiment looksat events that have one, and only one, muon in thechamber. The momentum of the decay positron is thenmeasured by analysis of its helical track in the knownmagnetic fiek1.

Figure 3 shows the three pi me projections and a three-dimensional view of a typical event. In the figure theincoming muon is indicated by coordinates drawn withthe letter M, and the helical trajectory of the decaypositron is indicated by coordinates drawn with a small

TPC CANISTER 6HKjH-VOLtAGE TOWER

SEAMDEFLECT0R7

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IHON YOKE

POLE HANDLER

.ELECTRONICSRACK

REMOVABLEPOLE

COILS

1—BEAD-OUT PLANE

HIGH-VOLTAGE ELECTRODE

Fig. 2.A pictorial view of the LAMPF Exp. 455 experimental apparatus. The detector consists of a 122-cm-diam by 52-cm-long TPC inside an iron-enclosed solenoid. This TPC drift region, which is filled withan 80-20 Ar-CH4 gas mixture, is bounded on one end by a high-voltage electrode and on the other endby the read-out plane. The read-out plane consists of 21 modules, each of which has 15 sense wiresspaced on 1 -cm centers. Under each sense wire there are seventeen 0.8- by 0.8-cm pads spaced on 1 -cm centers for determination of coordinate positions along the sense wires. The muons enter the TPCthrough a hole in the magnet pole after passing through a deflector/separator that is used to turn oilthe surface muon beam when a muon enters the TPC, as determined by a coincidence signal from thephototubes attached to (lie 0.25-mrr>- (10-miT) thick scintillator covering the TPC entrance hole.

8 0 PROGRESS AT LAMPF£.05 Alamos National Laboratory


Fig. 3.Three plane projections and a three-dimensional view of a typical muon decay event, as measured inthe TPC apparatus. The entering muon coordinates, indicated by the letter M, arc fitted to a straightline, as shown in three of the views. (No attempt is made to fit them to their actual helical track.) Thedecay positron coordinates, which are fitted with a helix, are indicated by square boxes.

box. To obtain the necessary experimental precision,about 10" such events will be analyzed. The experimentalapparatus is designed to collect events at a rate of I perLAMPF macropulse (usually 120 per second).

In 1983, Exp. 455 had two data-collection runs. Dur-ing the first run. the high-speed data-acquisition elec-tronics was not in place and the resulting event rate wasapproximately I per second. About 4 x 105 events werecollected during the 4-week running period and these datawere analyzed to study the TPC resolutions and accep-tance. Ft was found that the coordinate resolution alongthe drift direction was about 900 ujn. more than a factorof 2 better than the proposed value of 2 mm. and that theresolution along the wire direction, uncorrected forknown systematic errors, was about 600 |im. The result-ing positron momentum resolution was 0.6% rms

averaged over the Michel spectrum, which is only slightlyworse than the proposed resolution of 0.5%. However,the combination of detector acceptance and software cutsresulted in only about 25% of all triggers being analyzed.Some of the rejected events will be recoverable by moresophisticated software algorithms, but mostly the accep-tance is limited because of the length of detector. Ways ofgetting around this problem are currently under investiga-tion.

The second data-collection run during 1983, of 1-weekduration, was devoted to the development of the high-speed data-acquisition electronics. This new electronics,which consists primarily of three asynchronous, bit-slicecomputers in the read-out system, was installed andsuccessfully tested during the run. It was found that amaximum event rate of about 50 per second could be

January December t983 PROGRESS AT LAMPF 8 1Los Atamos National Laboratory

handled. This was somewhat below the 120-per-secondgoal, but the test run was limited by diagnostic codes thatwere in the bit-slice computers.

In the coming year, two large data-collection periodsare planned and considerably more time will be spentoptimizing the detector parameters, such as drift electricfield voltage, gas mixtures, and magnetic fieid settings.We expect to achieve, or in some cases surpass, thedesign goals for the detector.

REFERENCES

1. M. A. B. Beg, R. V. Budny. R, Mohapatra, and A. Sirlin. Phys.Rev. Lett. 38, 1252(1977).

2. J. Carr, G. Gidal, B. Gobbi, A. Jodidio, C. J. Oram, K. A.

Shinsky, H. M. Steiner, D. P. Stoker, M. Slrovink, and R. D.

Tripp, Phys. Rev. Lett. J I, 627 (1983).

3. V. V. Akhmanov, I. I. Gurevick, Yu. P. Dobretsov. L. A.Makarina, A. P. Mishakova, B. A. Nikolskii. B. V. Sokoiov. L. V.Surkova, and V. D. Shestakov, Yad. Fiz. 6, 316(1977).

4. J. Peoples, Nevis Cyclotron report 147, 1966 (unpublished).

5. J. Van Klinken, K. Stam, W. Z. Venema, V. A. Wickers, and D.

Atkinson, Phys. Rev. Lett. 50, 97 (1983).

Tensor Polarization in nd Scattering(Exp. 673, P3)(Argonne National Lab., Indiana Univ. Cyclotron Facility, Los Alamos, MIT)Spokesman: R. J. Holt (Argonne)Participants: W. S. Freeman, D. F. Geesaman, J. R.Specht, E. Ungricht, B. Zeidman, E. J. Steph.enson, J. D.Moses, M. Farkfjondeh, S. Gilad, and R. P. Redwine

The prospect of measuring the quadrupole form factoror Z)-state probability of the dcuteron by observing thetensor polarization t20 in nd scattering led to an earlyinterest in measuring i1B at backward angles.1 During thepast few years this interest has been spurred by questionsregarding true pion absorption in nuclei and the possibleexistence of dibaryon resonance in the nd system.

In this experiment the angular dependence of /j'Jb forrecoiling deuterons in nd elastic scattering was measuredas a function of incident pion energy in the range134-256 MeV. No evidence was found for rapid e^rgyor angular dependences in /20< contradicting rtcentpublications that clwm the observation of dibaryonresonances in /20. Our results agree most favorably withtheoretical calculations in which the Pn nN amplitudehas been removed altogether. This suggests that pionabsorption has a small effect on t10 in the elastic channel.

The experimental apparatus used to measure t20 isillustrated in Fig. 1. Pions from the P3-East channel atLAMPF were focused onto a liquid-deuterium target of5 mm thickness. Scattered pions were detected in anarray of three plastic scintillators. in coincidence with the

POLARIMETER

VETO

LIQUID-DEUTERIUMTARGET

C E L L Si(Li)

WEDGEDEGRADER

Fig. 1.Apparatus to measure i10 in nd scattering (not to scale).


January-D«c*m£>Br 1963

recoil deuterons that were focused onto the polarimeterwith a QQD system.

The key feature for performing measurements of f20 inJ scattering is the development of a high-efficiency

deuteron tensor polarimeter. The polarimeter employs the3He(af,p)*He reaction, which has a large cross section andtensor-anaJyzing power TM at forward angles, and a largeRvalue, 18.4 MeV.

The polarimeter was calibrated in a separate experi-ment at the Berkeley 88-in cyclotron. The calibration ofthe polarimeter was determined as a function of incidentdeuteron energies, position, and angle of incidence on thepolarimeter. The calibration was checked 2 years afterthe primary calibration by measuring the efficiency e0

again at the Los Alamos three-stage tandem Van deGraalT. We conclude from this test that the measurementof the efficiency €0 is reproducible to ~2%. The samepolarimeter was used in previous measurements of thetensor polarization in nd scattering at 142 MeV and inan ed scattering experiment.

As shown in Fig. 2, our excitation function at9"m ^ 144° differs from recent data of Griie'oleret al.In that experiment the deuteron beam size, when theeffects of second-order beam optics are taken into ac-count, is comparable with the size of the polarimeteraperture (30 mm). This problem is not encountered in thepresent work because the deuteron beam size is 20 mm(FWHM) but the polarimeter aperture is 89 mm. Clearly,there are no dramatic energy or angular dependences

1.0

0.5

"" -0.5

-1.0

-1.5

S

-

— 1

100

1

ss

5

in

150

i

• PRESENT° GRUEBLER

1 i200

,(MeV)

WORK,etal.

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Fig. 2.Excitation function at 0u = 18° tsolid dots) compared with the results of Griiebler et al. (Ref. 2) atGj = 15° (open circles). The angular acceptancesare ±1.5 and ±2.5°, respectively.

observed in our work, so there is no apparent evidence fordibaryon-resonance effects.

Angular distributions at pion energies of 142, 180,220, and 256 MeV are compared with recent theoreticalpredictions in Fig. j . Presently, the theoretical calcula-tions of the nd system have achieved a high level ofsophistication. These calculations are typically three-body in nature and include both the absorptive channel

0.5ANL-P-17,302

Fig. 3.Angular distributions at pion energies of142, 180, 220, and 256 MeV (open cir-cles are from the previous experiment)(Ref. 3). The calculations ere solid line,from Blankleider and Ai'nan (Ref. 6);long-dashed line, from Betz and Lee(Ref. 7); short-dashed line, from Fayard,Lamot, and Mizutani (Ref. 8); and dot-dashed line, from Rinat and Starkand(Ref. 9), all including true pion absorp-tion. The dotted lines are results withoutPu amplitude, that is, without pionabsorption. ' 0° 40° 80° 120° 160° 0° 40° 80° 120° 160°

ftcm.

.nuary-Oecembtr 1983 PROOREStATLAMPF 8 3Lot Alimot Nttlontl Ltboritury

nd —» AW and pion scattering. All calculations without aPu ITA' amplitude give very similar results (dotted curvesin Fig. 3) and are remarkably close to the present ex-perimental data.

Omitting the P,, channel has the effect of both remov-ing pion absorption and Pu nA' rescaltering from thecalculation. Although omitting the Pu channel from thecalculation is a somewhat drastic measure, especiallysince absorption is removed, it may not be as unreasonable as ii appears. Afnan and Hlankleider haveshown that the dominant absorptive effects in nil—- ndand nd -- pp occur in different spin-isospin channels.Therefore, it seems possible that the absorptionamplitudes can be adjusted to improve /,„ withoutworsening the results for other observables. Since itappears that absorption affects the elastic amplitudes farless than previously predicted, the chance for constraining the deuteron qundrupolc form factor has improved,but more theoretical and experimental work must bedone.

We are grateful to S. J. St. Loranl for the loan of the'He gas and to N. Jarmie and R. Martinez for assistanceduring the calibration at the Los Alamos tandem. Inaddition, we thank K. Stephenson, J. S. Frank, and M. J.I eiich for their substantial part in developing the ncvpolarimeter.

This research was supported by the USDOi: and theNational Science Foundation.

ltl-1 •"URI N C 1 S

1. W. It. G i l ' K I'hys. Itcv (' .1, 1I27(I<>7IJ.

2. W. Gruchlcr. J. Dlhricht. V. Riling, I' A. Scliim-l/huch. K. 1-lsciiei,C. Sclnvci/.cr. M. Mcrd/.;m. find A. Chisholm, I'hys. Itcv. Lett. 49 ,•VI4 (1982); fin.1 5th Inl. Symp. on High Hnergy Spin Particles,Hrookhavcn, New York (I9K2).

?. It. J. Hull, J. It. Spcchl, K. Slcphcnson. H. Zcidtnan. I. S l-iaiik,M. J. l.cilcli, J. I). Moses. I-'. J. Slcpltcmon, am) It. M. l.iiNzevvski,Phys. Itcv. Lett. 4 7 . 4 7 2 ( 1 9 8 1 ) .

4. M. I- Schul/.e. I). Heck. M. l ;arkhondch. S. Gilnd, S. Kowulski, It.I'. Itcdwine W. lurchine!/ . It. J. Hull, .1. It. Speclil, K.SlcplicnsDii. B. Zcidman, It. M. I.as/cwski. 11. J. Slcphcnson, J. D.Moses , M. J. l.cilch. It. Ooloskie, and 11. P. Saylor, Tenth Inl.f'onf. on I'cw Itody Prohltins in Physics, Kurlsiuiic, Germany.1983.

5. I. R. Afnnn and H. Blnnk'ciilcr. I'hys. Letl. 93B. 367 (1980).

f>. II. Hliinklciilcr and I. It. Afnan, I'liys. Itcv. C 2-1, 1572 (1981).

7. M. Bet/, and T. S. 11. Lee, Phys. Rev. C 23, .175 (I9BI).



8. C. I'ayard. G. M. Lamol. and T. Muulani. Phys. Rev. Lett. 45 . 524

f I'JHO).

9. A. S. Kinal and Y Starkand, Nucl. Phys. A 397. 381 (19B3)

Pion Induced Pion Production on the Deuteron(Exp. 783, P'West)(Los Alamos, Univ. of Wyoming, Colorado College,MIT, Tel Aviv Univ.)Participants: E. Piasetzky, P. A. M. Gram, D. W.MacArihur, G. A. Rebka. Jr., C. A. Bordner,S. Hiiibrdten, E. R. Kinney, J. L. Matthews, S. A.Wood, D. As/wry, andJ. Lichtenstadt

One way to characterize the study of pion-nucleusreaction mechanisms is to say that we are trying to findout how many nucleons it takes to scatter a pion. Forexample, pion quasi free scattering appears to be almostentirely a single scattering process, but even in thisreaction the single scattering peak in the momentumspectrum is thought to exist only because multiply scat-tered pions tend to be absorbed. Thus, information aboutpion multiple scattering is difficult to extract from therather extensive measurements of quasi-free scatteringthat have been performed.

Recent editions of Progress at LAMPF ' havepresented our observations of inclusive pion doublecharge exchange. In this reaction a pion must interactwith at least two nudeons and then escape from thenucleus. Comparisons of the momentum spectrn ofdouble charge exchange with the low energy tail of quasi-free scattering are beginning to shed light on the contribu-tion of multiple scattering to pion reactions."

Another reaction in which the participation of morethan one nuclcon might be seen is in pion-induced pionproduction. Because the intermediate states that maycontribute to (TT,2JT) reactions are different from thosethat contribute to either quasi-free scattering or to doublecharge exchange, the balance between single and multiplescattering may be altered in an observable way.

Pioninduced pion production on the proton has beenstudied* systematically to obtain nit-scatteringparameters, but there is virtually no information aboutthis process in nuclei. The simplest system in whichmultiple-nuclcon processes may occur is the deuteron.The reactions

*A bibliography of previous work is given in Rcf. 4.

January-DocorrttMr 79,

:t d -—• x' r, nn

•ind

can be studied and compared with - p • - ' - / ! tosearch for two nucieon mechanisms.

One two-nucicon mechanism for (~.2~) was proposedby Brown et al. who predicted, based on the St'{-i)quark model, the existence of a strong A.V • A.\ ir-msition in systems of two or more nucleons. Subsequentdecay of the two A"s contributes to the (;!.2:i) reaction.The n nn or the x'pp component of the final state hasT --•• 2. If the A'.Y system is formed at low momentum, it islikely to be in a 'Su state with 7' I. The pion may thenbe attracted to it through the Pu interaction to form astate that ma\ be considered an off shell AN.

In heavier nuclei these T 2. A/V states can bedoorways to the formation of /"- 2, AA slates. Since aAN state cannot decay by either the strong or theelectromagnetic interaction, it may appear in the reac-tions studied here as a narrow resonance or even as abound state. This subject was recently discussed byOarcilazo.' who showed that with cer':nn parameteri/.ations of the rtA' and AW interactions, the calculationspredict the existence of a bound state. However, theuncertainties in our knowledge of these parameteri/.ations, and in particular of the nN effective range, leaveample room to doubt its existence.

We report an experimental study of theJt*d— * n'n fAW reactions that was performed at thehigh energy pion channel (I>J). The doubly differentialcross section d'aldilJT foi the production of pious withcharge opposite to that of the incident beam wasmeasured at uniformly distributed locations in barycen-tric /'-cos 0 phase space. Double charge exchange isimpossible on the deuteron, so this method unam-biguously identifies pion production. Measurements weremade with n* and n beams at an incident kinetic energyof 256 MeV and with i< it beam at 331 MeV. Themomentum spread of the beams was Ap/p = 4% FWHMand their intensities were approximately 2 x 10* n h andlO'n'/s.

Outgoing particles were detected by a 180° double-focusing magnetic spectrometer" (the "Little YellowSpectrometer") with a solid angle of 15 msr and momen-tum acceptance of 9.5%. The detector system consistedof a multiwire proportional chamber between Hie twodipole magnets of the spectrometer, a pair o<" multiwire

proportional chambers immediately behind the focalplane. :>. 1.6 mm thick plastic scintillation detector, afluorocarbon (FC 8S> threshold Cerenkov counter, andlast, an Aerogel (n - 1.055) Cerenkov counter.

A quadruple coincidence among signals from thethree wire chamber delay lines and the sciniillator deUnco an acceptable event. The last two wire chambersestablished the trajectory of a particle as it crossed thefocal plane. l-\>r events that corresponded to an allowabletrajectory, pulse heights from the sciniillator andCerenkov detectors and the lime of (light through thesecond bending magnet discriminated against electronsor, when set for positive charge, positrons, protons, andother light nuclei. Corrections for pions decaying in therelatively short 3.5-m flight path and for unions that wererecorded as good events were calculated with the MonteCarlo simulation m CAY TURTLI-..'

A cylindrical target flask 2.5 cm in diameter, whichwas concentrically mounted on the axis of rotation of thespectrometer, contained liquid deuterium (99.83% deute-rium) for observing pion production or liquid hydrogenfor calibration. Background from the 50 urn Mylar wallswas observed with the flask empty. The incident pion fluxwas measured with an ioni/.ation chamber as 'veil as witha scattering monitor downstream from the spectrometer.

The measured pion production cross sections werenormalized to np elastic scattering. At each incidentenergy, relative ixp elastic cross sections were measuredat several angles und the angular distribution was normalbed to fit the "known cross section:;" with a scalefactor that calibrated the system as a whole. Below300 MeV, known cross sections were derived from thephase-shift analysis of Carter. Bugg. and Carter usingthe routine SCA'l'l'l. Above this energy, they were interpolaled directly from the measurements. The interpola-tion procedure is described in detail in Ref. 4 and is thesame procedure used to normalize the n /> - IT n'ncross sections of Kef. I.

Figure I shows the doubly differential cross sectionsfor the it d - * n'n nn reaction at 256 and 331 MeV. At256 MeV the measured cross sections for then'd-~*n n';.•;> reaction are equal to those for then d--*n'n nn icaetion within the experimental uncertainties. To this accuracy the Coulomb force appears tohave no influence on this reaction. The errors shown inthe figure represent the combination of statistical uncertainly and those systematic uncertainties that depend onthe outgoing momentum. Overall normalization is uncer-tain by a further 4%.

anuary Decomtw 1983 PROGRESS AT LAMPF 8 5Los Alamas National Laboratory

T_ • 2 5 6 M«V

400

400

300

ZOO

100

400

300

200

100

• £ ^

• - 1 x1

cot 6

cot i •

<< 1•-OS'

•

I •

-O751

•

.

IO 30 50 70

T [MeV]

ir*d- •ir IT nn

TT • 331 M«V

2000 Fco»8»0 65

2000 F co»8«-O 7 5 '

20 60 100

f [MeV]

140

Fig. I.Doubly differential cross section for the n~d—>- n*n~nn reaction at 256 and 331 MeV. Tand 0 arc theoutgoing n¥ kinetic energy and angle in the center-of-mass system. The arrows mark the energycorresponding to the two-body n(n/VA0 production, with zero binding energy for the TtAW system. Thesolid curves represent four-body phase space normalized to the data. The dashed and dotted lines arequasi-free calculations in plane-wav; Born approximation (see text).

8 6 mOOREM AT LAMPPLot Alimos Ntllonil Laboratory

January-D^cwnbv 79

The solid curves in Fig. I represent the distribution ofevents in four body phase space, normalized so that itsintegral over energy and angle will equal (he integratedcart ion cross section determined from the data. The

dashed curves are the predictions of a simplecalculation. in plane-wave Born approximation, ofquasi-free pion production on the onc-nucleon usingphcnomenological on-shell amplitudes deduced from the,i p — n"n n data.

The qu.isi-frce calculation is in good agreement withthe general features of the data, although some discrepan-cies do exist. At 256 MeV the quasi-free calculationreproduces the shape of the spectra very well, but theabsolute value of the cross section is 20% below themeasured result. The dotted curve in Fig. I is the quasi-free calculation normalized by the ratio of the measuredand calculated integrated cross sections. At 331 MeV theintegrated reaction cross section obtained from the quasi-free calculation is in agreement with that measured,within the experimental uncertainty, but a slight dis-crepancy exists between the measured and calculatedshape of the spectra at forward angles. These effectscouid hi attributed either to Tcscalterihg of the pion bythe second nuclcon or to the formation of nNN systems.

In pion production on protons, the average squaredmodulus of the matrix element4'7 increases by a factor of2 at forward angles and low outgoing pion energies,presumably because of the onset of significant contribu-tion from' a it A intermediate state. Indeed, in an isobar-model analysis of it p - • n it';/, the Pn partial wave firstbecomes important above 300 McV. One is tempted tospeculate that a two-nucleonreaetion mechanism, citherthe AV\ —» AA transition or a rescatlering process, wouldbecome significant where the itA state formation is mostpronounced.

The measured doubly differential cross .sections wereintegrated over the energy and angle of the produced pionto determine an integrated reaction cross section. Toestimate the contribution from the unobserved kinematicrange, we assumed the form of the cross section given bythe plane wave Horn approximation and assigned a 25%uncertainty to the contribution from the extrapolatedregion. The integrated-rcaction cross sections forit d -»jt'n nn are 160 i 10 ub at 25ft MeV and1000 i 100 ub at 331 McV. The corresponding crosssections for it p~* n'n n arc 166 t 6 ub and 1160 i 50ub at 256 and 331 MeV, respectively.

In October 1983 we continued these measurements atan incident energy of 450 McV. including a measurementof n~p-* j t ' rOi , which had not previously been done,for comparison. These data are presently being analyzed.

We intend ^ extend these observations to the 'Henucleus in the next scries of experiments, studying it' 'He--* nn'ppp. The 'He nucleus differs from the deutcronby [he addition of a proton, but also and more im-por'antly because it is a much denser structure. Thedensity of JHc approaches that of normal nuclear matter,and one expects that two nuclcon effects will be strongerin 'He than in deuterium. The second proton in 'He doesnot contribute to the quasi-free part of the interaction,and the proton pair cannot contribute to the two-nucleonmechanism of pion production.

As for it'c/ —* it n'pp. the quasi-free pion productionis only from the neutron, and the two-nuclcon mechanismcan only be attributed to the np pair. To first order, thequasi free contribution in 'He is expected to be equal tothat in the dcuteron, whereas the two-nucleon contribu-tions are expected to be twice as large. The advantage ofand interest in obtaining a larger and clearer signal for thetwo-body mechanism is obvious. Even if. disappointingly,no large two-nucleon contribution is found for pionproduction on 'He. this result itself would be critical forpossible application of the (rt,2it) reaction to nuclear-structure studies' in the future and for understanding theN\ —* AA process.

RKH'RI-NCUS

1. Los Alamos National Laboratory report LA-9256-PR (March1982), p. 55.

2. Los Alamos National Laboratory report LA 970') PR (March

198.1). p. 57.

i. S. A. Wood, PhD. thesis, Massachusetts Institute of Technology,19H.1 (unpublished).

4. C \V. lljork cl al.. Phys. Rev. Lett. 44. 62 (1980).

5. G. i i . Brown. I I . Toki, W. Weise, and A. Wirzba, Phys. Rev. Lett.I I8B. .19(1982).

(>. H. Gnrciln/.o. I'hys. Rev. C 26, 2685 (1982).

7. A. T. Oyer, Los Alamos National Laboratory report LA-659**-T(1976); J. H. Walter. Los Alamos National Laboratory reportLA 8.177 T (1979); and D. Manlcy, Los Alamos National Labo-ratory report LA 9101 -T (1981).

1tanuary Uocom PROQREM AT LAMPFLos Altmot Ntuonti Lttmuory

87

8. J. R. Carter, D. V. Bugg, and A. A. Carter, Nucl. Phys. B 58,378 10. P. J. Bussey et al., Nucl. Phys. B 58,363 (1973); H. R. Rugje and(1973). O. T. Vik. Phys. Rev. 129, 2300(1963); and Philip M. Ojden «t

al., Phys. Rev. 137, Bl 115 (1965).9. J. B. Walter and G. A. Rebka, Jr., Los Alamos National

Laboratory report LA-7731-MS (1979). 11- L.-C. Liu, R. S. Bhalerao, and E. Piaseizky, contribution to ti..Symp. on Delta-Nucleus Dynamics, Argonne, Illinois, 1983.

8 8 PROGRESS AT LAMPF JtnuKy-OKinbf 191Los Alamos National Laboratory

The Crystal Box Experiments(Exps. 400/445 and 726, SMC)'Los Alamos, Univ. of Chicago, Stanford Univ., TempleJniv.)Spokesmen: (Exps. 400/445) — C. M. Hoffman, J. D.Bowman, and H. S. Mat is (Los Alamos);(Exp. 726) —V.L. Highland (Temple Univ.) and G. H.Sanders (Los Alamos)

Discussions of these experiments have been presentedin the past several Progress Reports. The aim of theseexperiments is to search with unprecedented sensitivityfor several rare decay modes of the muon and the pion.Experiments 400/445 are searching for the muon-number-violating decays u+ —• e+e+e , n+ —* e+y, andfi+ —* e+yy, with branching ratios somewhat smaller than10~". Experiment 726 will search for the charge-con-

jugation-violating decay n° —> 3y with a sensitivity to abranching ratio as low as 10"'.

Experiments 400/445

A schematic of the apparatus is shown in Fig. 1. Thedetector consists of a modular array of 396 Nal(TI)crystals that surround an array of plastic scintillationcounters and a high-resolution drift chamber. Approx-imately 5 x 103 n+/s are stopped in a thin target located inthe center of the apparatus. The major source of back-grounds is the random coincidence of e+'s and v's fromthe uncorrelated decays of several muons. These back-

0RIFT CHAMBER8 PLANES,

10 CRYSTALS DEEP9 CRYSTALS ACROSS

120 cm-

-36 MOOOSCOPE COUNTERS

Fig. 1.Schematic of the Crystal Box detector.

JtnuaryOactmbar 1983

grounds are eliminated by requiring that the detectedparticles be in time coincidence and satisfy the conserva-tion of energy and momentum. For the u+ -* e*e+e~mode, there is the additional constraint that the threetracks must emerge from a common vertex. To reject thebackgrounds to an adequate level, excellent resolutions intiming, energy, and position are required.

A short tuneup run was taken in January 1983, withtwo of the four Nal(TI) quadrants instrumented. The-purpose of this run was to measure trigger rates andcheck all parts of the system. Several problems wereuncovered. The \i* —* e*e+e~ trigger rate was unaccep-tably high because of particles that trigger the scintilla-tion counters but that deposit little or no energy in thesodium iodide; some of these are from low-energy parti-cles present in the electromagnetic showers in thecrystals. After analyzing data tapes, it was determinedthat the best way to eliminate these triggers is lo requireat least one discriminator from the crystals behind thescintillator fire. The electronics needed to implement thislogic was constructed in the spring and summer andinstalled this fall; it performed according to expectations.The photon definition in the tune-up run also was foundto be inadequate (a photon is defined as a quadrant with asodium iodide discriminator firing but no scintillatorfiring). The major improvement needed here was theinstallation of separate leading-edge discriminators forthe scintillators to provide the photon veto. Otherchanges involved minor improvements in how the cornercrystals were apportioned between the two quadrantsstraddling the corner, and the removal of the mostupstream and downstream rows from the photon defini-tion.

The final major problem uncovered was the need for amore sophisticated system to detect pileup in the Nal(Tl).The system we had designed was not efficient enough atdetecting low levels of pileup and also rejected manyevents that were, in fact, not piled up. A compactCAMAC-based sample-and-hold system was purchasedand installed to solve this problem. It also was necessaryto modify the circuits that clip the Nal(TI) output pulsesand to use higher quality delay lines to shorten the lengthof the pulse at the circuit that measures the pulse area (forthe energy determination). All these improvements andmodifications were installed by the fall of 1983.

As discussed in the last Progress Report, the methodused to mount photomultiplier tubes on the first twoquadrants led to several vacuum leaks in the hermeticallysealed container housing the crystals. An alternativemounting scheme that subjects the container to much

PROOREMATLAMPF 8 9Los Alamos National Laboratory

smaller stresses was designed and has been used on allfour quadrants. In the 5 months since this was done, novacuum leaks have occurred and we believe the problemis solved.

During several test runs in the fall, the entire systemwas connected, timed, calibrated, and debugged. Thisincluded all the electronics and the on-line data-acquisi-tion code. A nagging problem in the LSI-11-based sys-tem, which reads out the Nal(Tl) pulse height and timinginformation, was fixed with the aid of Jerry Potter, GroupMP-I; this system now works flawlessly. We also in-stalled a crystal calibration system that uses a xenon flashtube and fiber optics cables; this system is working quitewell.

In addition to all the above hardware changes,substantial progress was made in our analysis programs.For example, the track reconstruction efficiency in thedrift chamber has risen from 86 to 97%. This is due to acombination of improvements in the software and hard-ware.

During our last run in 1983, we took data for 5 days ata reduced muon rate of 2 x 10s u+/s, and we are nowanalyzing these data. A typical u —»• ey candidate isshown in Fig. 2. At the end of this run, the drift chamberwas removed, a small liquid-hydrogen target was in-serted, and data were taken with incident it". Figure 3shows a spectrum from it°'s produced in the reactionrc~p—>-JTon at rest. These data are used to help calibratethe apparatus.

Plans call for a 3-week data run in January 1984 andmore runs next summer.

Experiment 726

During the aforementioned running with a n~ beamand a iiquid-hydrogen target, a data tape was taken whiletriggering on z° —*• 3y. A study of this tape will beinvaluable for designing the details of the trigger elec-tronics.

Data taking for this experiment will take place after themuon data have been obtained.

(a)

..-•O

I I I I I I I I. 10 CF.

(b)

Fig. 2(a) and (b).A typical u —»• ey event: (a) view along beam lineshowing drift chamber vire hits, the struck scin-tillator, and the sodium iodide row sum energies;and (b) a three-dimensional view of the sodiumiodide.

9 0 PflOOMSSATLAMPFLos Altmos Nulontl Ltbmttory

Fig. 3-An on-line spectrum of single y-ray energies from stopping n~ in hydrogen. The units for the abscissaare not MeV.

Deformation of Rare-Earth Nuclei and the Stern-heimer Effect(Exp. 698, SMC)(Purdue Univ., Los Alamos, Princeton Univ.)Spokesmen: R. M. Steffen (Purdue Univ.) and E. B.Shera (Los Alamos)Participants: Y. Tanaka, W. Reuter, M. V, Hoehn, andJ.D. Zumbro

Values of nuclear quadrupole moments Q, deducedfrom electronic-atom hyperfine measurements are ratheruncertain even though measurements of optical hyper-fine-splitting energies are very precise. The reason lies inthe difficulty of exactly calculating the electrostatic gra-dient at the nucleus produced by the multielectron en-vironment. In general, the nonspherical shape of theiiuclear quadrupole field causes a nonspherical distribu-tion of the core electrons (the Sternheimer effect) that inturn affects the electronic valence states.

In a muonic atom, however, the (single) muon isoverwhelmingly responsible for the field gradient at thenucleus, allowing nuclear quadrupole moments to beprecisely extracted from measurements of the hyperfine-splitting energies of muonic 3d and 4/states (that is, byobservation of the muonic-Af x rays).

We have measured the ground-state quadrupole mo-ments of 11 odd/4 nuclei in the region from Z = 63 to 77by observing the hyperfine structure of their muonic-Mx rays. The total errors of the present quadrupole mo-ments, including the uncertainty arising from the model

Jtnuary-Dgcembtr 1983

assumed for the radial quadrupole charge distributionwithin the nuclear volume, are less than 1%.

Our data for the odd-<4 nuclei demonstrate that, afterthe abrupt onset of deformation at N= 90, the deforma-tion parameter P2 varies smoothly with neutron number(see Fig. I). Contrary to the rather scattered electronic-atom results (see Fig. 2), the present results indicate thatthe deformations of the oddv4 nuclei are quite consistentwith those of the adjacent even/1 neighbors.

We expect that our precise new quadrupole-momcntvalues will stimulate theoretical calculation of the ground-state deformation of odd-A nuclei. Correct prediction ofthe equilibrium deformation of the ground state is acentral issue in gauging the success of mean-field theoriesof nuclear structure.

By comparing our muonic-atom quadrupole-momentvalues with electronic-atom values, we have computedexperimental Sternheimer shielding factors for severalelectronic orbitals relevant to rare-earth atoms. We arethus led to the following conclusions.

1. The shielding factors have the same value forisotopes of the same element, even though thenuclear quadrupole moments may be quite different(by almost a factor of 3 for europium isotopes).

2. The R(5d) shielding factors vary irregularly from-0.16(13) to -0.75(17), in serious disagreementwith the theoretical estimate of R(5d) = -0.25(5).Whereas the R(4f) shielding factors for terbium,dysprosium, and erbium, and the R(6p) shieldingfactors for europium and gadolinium, arc close to

MOOMMATLAMPfLotAltmoiN*lon1L*x>rwtoiy

91

0.3 -

CM

00.Sm

i

J

Tb

/Nd

Eu

1

Gd ,

?*&Ho Er

J . .<»Luc

c

• present

Yb

VIr

data

0s02 -

0.185 90 95 XX) 105 110 115 120

NEUTRON NUMBER

Fig. i.Systematics of the deformation parameter P2 in the rare-earth region. The new muonic data for odd-Anuclei are shown as solid dots.

0.4

0.3

0.2

0.51 t

-Euj

0.1

Os

• electronic-atom data | r

NEUTRON NUMBER85 90 95 100 105 110 115 120

Fig. 2.Similar to Fig. 1, except that the widely scattered optical data are shown for the odd-A nuclei.

9 2 PMXMESSATLAMPFLot Alamos Nallonil Ltborttory

Jmnuvy-Dtcwntw 1983

the theoretical values, the R(6p) value for dys-prosium is several times smaller than the theoreticalvalue. Clearly, the theory of the Sternheimer shield-ing effect in the Sd and dp electronic valence statesof rare-earth atoms must be reexamined.

Although our understanding of the electronic elec-trostatic gradients at the nucleus in rare-earth atoms is farfrom complete, it seems that no matter which effectscontribute to the shielding phenomena, the same shieldingfactor is valid for all isotopes of a particular elementregardless of the value of the nuclear quadrupole mo-ment. Hence electronic-atom hyperfine measurements,which require only small amounts of target material, arewell suited for determining accurate ratios of ground-state nuclear quadrupole moments of different isotopes ofthe same element. Furthermore, if the appropriatemuonic-atom data are available for empirical calibrationof the Sternheimer effect, the electronic-atom measure-ments can furnish absolute measurements of the quadru-pole moments of otherwise inaccessible nuclei.

Further information concerning this work can beobtained from Phys. Lett. 108B, 8 (1982) and Phys. Rev.Lett. 51, 1633(1983).

Formation of Muonium in the IS State and Ob-servation of the Lamb-Shift Transition(Exp. 724, SMC)(Yale Univ., Univ. of Heidelberg, College of William andMary, Los Alamos, Univ. of Mississippi)Spokesmen: P. O. Egan and V. W. Hughes (Yale Univ.),and M. Gladisch (Univ. of Heidelberg)Participants: A. Badertscher, S. Dhawan, P. O. Egan, V.W. Hughes, D. C. Lu, M. W. Ritter, K. A. Woodle, M.Gladisch, H. Orth, G. zu Putlitz, M. Eckhause, J. Kane,F. G. Mariam, and J. Reidy

Muonium (A/) is an atom consisting of a positive muonand an electron and is an ideal system to test quantumelectrodynamics (QED). High-precision measurementsof the hyperfine-structure interval Av and of the Zeemaneffect in its ground state have provided very sensitive testsof QED, as well as precise values of the fine structureconstant a and the ratio of the muon ahd proton magneticmoments. In these experiments muonium was formedby stopping n+ in gaseous targets.

Another important QED test would be a precisemeasurement of the Lamb shift in muonium in the n = 2state, since it would be free of the effects of proton

structure that complicate the interpretation of the Lambshift in hydrogen.4 For this measurement muonium in the25 state must be obtained in vacuum to avoid collisionalquenching of M(2S) atoms. Using a method similar tobeam neutralization in proton beam foil spectroscopy,we have shown that muonium in its ground state isformed by passing a u+ beam through a thin foil invacuum. From proton data we expect that metastableM(2S) atoms will be formed as well, and thatM(2S)/M(]S) will be about 0.1. Higher excited states willalso be formed, but their formation probabilities are lowerand most of these excited-state atoms will decay rapidly.

Here we report on further developments for producingmuonium in vacuum, detecting M(2S) by a static electric-field quenching method, and observing the Lamb-shifttransition 25 —>2P induced by an electric rf field of about1140 MHz.

Our experiment was done at the SMC at LAMPF.Figure ! shows a diagram of our apparatus.

Figure 2 is the energy-level diagram for muonium in itsn = 1 and n = 2 states, including fine structure, Lambshift, and hyperfine structure. The value of the Lamb-shift interval of 25,„ to 2Pl/2 for muonium has beencalculated from QED. The 25 atomic state is metastablewith the mean lifetime of 1/7 s for two-photon decay tothe 15 state; however, the mean life of 2.2 us for u+

decay determines the lifetime of Af(25). Our first ap-proach to observation of M(2S) was to detect the staticelectric-field quenching of Af(25).

We searched for M(25) by modulating the staticelectric field between on (600 V/cm) and off and bylooking for a difference in the event rate due to Lyman-aphotons emitted during the field-on phase. An eventrequired a triple coincidence between an incoming muon,a delayed Lyman a photon in one of the four ultravioletphototubes, and a further-delayed M( 15) atom detectedin the microchannel plate. The time gates were set toaccept M(25) atoms with kinetic energies between 4 and26 keV. The asymmetry between quenching field on andfield off, defined with the events (£) normalized to thenumber of incoming muons,

(£7u)on-(£/u)olr

(E/u)on + (£Ai)o(r '

was A =(41.5 ±5.8)%.The next step in establishing the formation of M(2S)

atoms was to search for the Lamb-shift transition 25, ,,,

Jaauary-Dacember 1983 PROOAESSATUUMPF 9 3(.05 Alum* Nmlontl Ltbortory

Seponrted(L* beom

Vacuum chamber

Pa>IO"*torr light pip«

Quenching grid!

III u \MicroChannel plate

—Copper shielding

Fig. 1.Diagram of the apparatus.

2P.

F= I -»• 2PU2, F= 1 driven with an electric rf field. In

Fig. 2.Energy-level diagram of the n = I and « = 2 statesof muonium.

Fig. 3 the solid curve shows the theoretical non-powcr-broadened resonance lines for two transitions betweenthe hyperfine sublevels of the 2SU1 and 2P1/2 states. Thenatural linewidth of !00 MHz (FWHM) is due to the

rf POWER T• -25 wo-IOOW

1000 1200

v (MHz)

Fig. 3.

Muonium 2Sl/2 = 2Pl/2 resonance lines. The solidcurve shows the theoretical non-power-broadenedresonance line shape. The data points for 100- and25-W rf input power are shown.

9 4 PROGRESS AT LAMPFio( yVamos Niionml Laboratory

lifetime of the 2Pl/2 state. Our rf interaction region(Fig. 1) consisted of a coaxial line. The experimental dataare shown.

*V5 conclude from our data that we have formedmuonium in the 2S state with the expected rate and thatwe have observed the Lamb-shift transition. We aremaking measurements of the 2S I /2 —• 2Pm transitions todetermine the Lamb shift and hfs intervals.

REFERENCES

1. V. W. Hughes and T. Kinoshita, in Muon Physics / , V. W. Hughesand C. S. Wu, Eds. (Academic Press, New York, 1977), p. 12.

2. F. G. Mariam et al., Phys. Rev. Lett. 49, 993 (1982).

3. J. R. Sapirstein et al., Phys. Rev. Lett. SI, 982 and 985 (1983).

4. S. R. Lundeen and F. M. Pipkin, Phys. Rev. Lett. 46, 232 (1981).

5. H. G. Berry, Rep. Prog. Phys. 40, 155 (1977).

6. P. R. Bolton et al., Phys. Rev. Lett. 47, 1441 (1981).

7. G. Gabriels*, Phys. Rev. A 23, 775 (1981).

8. D. A. Owen, Phys. Lett. 44B, 199 (1973).

£ 2 and £ 4 Moments in M M M . » » . « « U

(Exp. 745, SMC)(Princeton Univ., Los Alamos, Purdue Univ., Oak RidgeNational Lab.)Spokesmen: J. D. Zumbro (Princeton Univ.) and E. B.Shera (Los Alamos)Participants: Y. Tanaka, C. E. Bemis, Jr., R. A.Naumann, M. V. Hoehn, W. R. Renter, and R. M.Steffen

The rigid-rotor model postulates that the low-lyingexcited nuclear states arise from rotations of an in-trinsically deformed ground state. With this model thequadrupole and hexadecapole moments of the low-lyingstates are related by well-known geometrical factors(Clebsch-Gordon coefficients). In a heavy, highly de-formed nucleus like uranium it is possible to test the(adiabatic) rotational-model predictions by studying theinteraction of the nucleus with a bound muon. This ispossible because in heavy nuclei several excited nuclearstates are mixed appreciably in the tnuonic 3d and 2pstates. By simultaneously analyzing the muonic 2p -*• Is(AT), 3d-* 2p (L), and 4/-»- 3d (M) x-ray transitions, alarge number of £ 2 matrix elements can be independently

trnmyOtcnnbu 19B3

determined. We therefore are able, for the first time, tomake a detailed electromagnetic test of a principal under-lying assumption of the rotational model.

Figure 1 summarizes our results for 2"U. The uppersection of the figure shows the E2 matrix elements thaiwere independently determined; the lower part of thefigure indicates that the measured matrix elements areconsistent with an adiabatic intrinsic state at the level of afew per cent.

The present muonic-atom experiments on uraniumalso represent the first direct measurement of spec-troscopic hexadecapole (£4) nuclear moments. Themeasurements are direct in the sense that the hyperfinesplitting produced by the interaction of the nuclear EAmoment with the (readily computed) electric-tield gra-dient at the nucleus is observed directly.

The muonic-atom method stands in contrast to previ-ous methods that have employed strongly interactingprobes and that have sometimes yielded inconsistentresults, presumably from model dependence or inter-ference from strong-interaction effects. Discrepanciesbetween different types of experiments have suggested

200-

| i5On

| IOOH

,K 50-\

233U9/2

7/Z

5/2

x:±:

0 J

10-

^ c 5-c oo ««•° .2 0-a. Q _5-

Fig. 1.Results for El matrix elements in 233U that wereindependently deteri 'ned. The upper part of thefigure indicates ths. J.2 moments that were in-dependently determined. A line between two levelsindicates a dynamic £2 moment \B(E2)\, and thecircular line closing on a level indicates a static £ 2moment. In the lower part of the figure the devia-tion of each moment from the rotational-modelvalue is shown; these deviations indicate that themeasured matrix elements are consistent with anadiabatic intrinsic state at the level of a few percent. The dashed lines are ± 3%.

PROQOEUATLAMfF 9 5Lot Altmot National Ltxntory

that nuclear shapes depend somehow on the probe orreaction mechanism used to explore them.

The results of our muonic E4 measurements are shownin Fig. 2. These results, while more precise, are in reason-able agreement with the Coulomb excitation work ofBemis et al.2 The hexadecapole moments have approx-

c 4 -

« 3 -QO.

s<o 2 -X<0Xo

3 l -

t—•

rr

II

v Brack et al., Ref. 3& Bemis etal., Ref. 2x Close et al., Ref. SCThis experiment

' • • . ,

\ 2 j Theory

Coulombexcitation

1 Previous^,^'~ muonic-atom

•*'' experiment

234 236 238A Uranium

240

Fig. 2.Intrinsic hexadecapole moment vs A for theuranium isotopes.

imately the same value (~2.5 eb2) for all four uraniumisotopes that we have studied. This result is in agreementwith equilibrium shapes of the uranium isotopes predictedby Brack etal.3 using the Strutinsky shell-correctionmethod with a Woods-Saxon potential. We are now usingthe Hartee-Fock deformed density-matrix-expansion the-ories from Negele and Rinker to perform calculationsfor these nuclei.

The early muonic-atom results of Close etal.5 are inserious disagreement with the present results, withCoulomb excitation, and with theoretical calculations(see Fig. 2). The present work indicates thai a carefullyanalyzed muonic-atom experiment produces results inagreement with other methods, thereby removing onepiece of evidence for probe dependence of nuclear shapes.

REFERENCES

1. V. A. Madsen, V. R. Brown, and J. D. Anderson, Phys. Rev. Lett

34, 1938 (1975); and V. A. Madsen et al., Phys. Rev. C 12, 1205

(1975).

2. C. E. Bemis, Jr., F. K. McGowan, J. L. C. Ford, Jr., W. T. Milner,

P. H. Stelson, and R. L. Robinson, Phys. Rev. C 8. 1466 (1973).

3. M. Brack, T. Ledergerber, H. C. Pauli, and A. S. Jensen, Nucl.Phys. A 234, 185(1974).

4. J. W. Negele and G. Rinker, Phys. Rev. C 15,1499 (1977).

5. D. A. Close, J. J. Malanify, and J. P. Davidson, Phys. Rev. C 17,

1433 (1978).


J»nu»ry-Dtc*mb»riae3

Atomic and Molecular Physics

Theory of Muon-Catalyzed dl Fusion: Resonant.vfesomolecule Formation(Biomed)Spokesman: M. Leon (Los Alamos)

Muon catalysis of deuterium-tritium fusion has re-cently become a topic of widespread interest On onehand, experiments probing this process under a variety ofconditions are being performed at several muonfacilities. On the other, the sustained assault mountedby Ponomarev and his colleagues on many of the theoret-ical problems involved has made impressive progress inremoving many of the gaps in our understanding.*

The most crucial and perhaps the most fascinatingaspect of the muon-catalysis cycle is the role played bythe resonant formation of the t/Cu molecule. This reso-nant formation occurs because of the existence of a veryloosely bound J=l, v=l excited state in the <tf/umesomolecule. The binding energy (~0.64 eV) is smallenough that the energy released in the dtp formation fromthe t[i + d state can go into vibration and rotation of theresulting dt\i-d (or dt\i.-t) molecule instead of into Augeremission. The resulting molecular-formation rates are atleast two orders of magnitude larger than the nonreso-nant (Auger) rates. '6

In developing the theory of resonant dt\x formation, wehave generalized the calculation of Vinitsky et al.6 (here-after referred to as VP) to include the very importanteffects of the (1) orbital angular momentum carried intothe reaction by the tii-D2 (or DT) relative motion, and (2)initial D2 (DT) angular momentum K{ > 0. We show as aresult that, rather than a single resonance as in VP, themolecular formation reactions are dominated by aplethora of resonances, with a variety of initial and finalmolecular angular momenta. We also find that both thev = 2 and v = 3 vibrational levels of the final dtii-dmolecule contribute significantly. Our final calculationsfor the molecular-formation rates as functions of temper-ature therefore include contributions from about 500individual resonances.

The matrix element of the transition is written by VPas

2}.= f dRd'rdp y/hR) yfi)

'References 3 and 4. For a readily accessible review, see Bracciand Fiorentini, Ref. 4.

where ¥(/•,/?) are the wave functions of the internalcoordinates of the mesosystem tu + d and where i|/(p) arethat of the motion of the mesosystem with respect to thespectator nucleus (see Fig. 1). The /u + d collision time (atthermal energies) is estimated to be ~10~15 s, whichmeans that whereas the collision is sudden for the Z>2

(DT) molecule, it is adiabatic for the electrons. Hence noelectron excitation takes place during the "compound-molecule" formation. However, it is important that thenext stage, deexcitation of the compound molecule byAuger emission, is much more probable than dissocia-tion.

For the wave function V;(P)> VP simply use theground-state wave function of the target Z>2 molecuie (forK. = 0 and vibrational v{= 0):

yo(p)

An obvious generalization is to replace

with

Fig. 1.Vectors involved in the molecular-formation calcu-lation: r goes from the midpoint of R to (i, p fromthe dtfi cm. (marked 1) to the spectator d, and R\el

goes from the cm. of the tp, (marked 2) to that ofthe D2 (marked 3). The overall cm. is marked 4.

January-December 1983 PROGRESS AT LAMPF 9 7Los Alamos Mtr/omf Laboratory

However, it is also necessary to include a factor toexpress the motion of the /u atom and the Dt moleculewith respect to the overall center of mass (cm.). Thisimplies the factor exp(«>. Rttl), which introduces thedependence on the orbital angular momentum L; here/? isthe cm. momentum (Fig. 1). Because cf the small size ofthe /u atom, interaction takes place when rjl« p. Then^«i =* IP. where i\ - If 2 for D2,3/5 for Dr . Thus the VPexpression is replaced by

0

(0

The

/ K, £±1 KfK

\ 0 0 0 / etc.

are 3-/ coefficients, and the second term in the { } isabsent for L = 0. (The ±1 arises from the J= 1 of theloosely bound dtp state.) The factor

,s J

replaces the vibrational matrix element /„ of VP. Since thevibrational motion is of rather small amplitude aroundthe equilibrium value p 0 ^ 1.4 a0 (Rsf. 8), for a roughapproximation we can replace p with p0 in the argumentof the spherical Bessel function JL, and therefore get

The interaction Hamiltonian is approximated by

3- p- 3 :

m=—1

where 2 is the dipole moment of the dtp system.6 Theangular factors are now separated so that the angularintegrals can be performed and the results expressed interms of 3-/ coefficients.7 Taking the absolute square ofT~ and averaging over M( and summing over Mr, we findthe factor

where, as in VP,

For p-*0, only the S wave survives andy0 -*• 1; thenfor JKT;.=0, only Kj- = I is possible and F-* / ' . Thus

F{KX, Kt) = (2K(+ (2L + 1)

o

L-l

o / \ o o o ;J

L-l

(2)

is precisely the factor that corrects the VP result for theincoming orbital angular momentum and K{ > 0. Orbitalangular momentum L > 0 obviously allows a muchgreater variety of Kf values, not just Kf=Kt± 1, andtherefore greatly increases the number of resonancescontributing to molecular formation, For any fixed col-lision energy, however, the centrifugal barrier factor

J'1(T\PP0) will limit the number of partial waves contribut-ing to the sum in Eq. (2).

The incoming tfi atom can be in the singlet (S = 0) ortriplet (5 = I) spin state. Because the deuteron has spin 1,

9 8 PROGMEHATIAMPFLot Minos NuionH Ltboruory

the singlet tp can only give the 5 = 1 , dtp mesomolecule,whereas triplet tp can give rise to S = 0, 1, or 2. The dtphyperfine splittings have been calculated by Bakalov

al.9 For our purposes, we can ignore the energy" Splitting between the three hyperfine states formed from

triplet tp; then the hyperfine shifts mean that the effectivedtp binding energy is decreased by 38 meV for singlet tp

t and increased by 13 meV for triplet tp.'. Consider collisions of singlet tp with D2 molecules.Angular momentur conservation requires thai the L = 0partial wave have K,=K/± 1; then the corresponding" < 2, Kj. states have energies below the initial-statethreshhold and hence cannot contribute to resonantmesomolecule formation. Thus only v > 3 formation canoccur, which (it turns out) requires at least 0.27 eV ininitial kinetic energy. Therefore L = 0 can contributesignificantly to the molecular-formation rate A.2u_d onlyat extremely high temperature (T).

In contrast, when L > 0 is permitted, K* can be aslarge as K. + L + I, adding a significant amount of rota-tional energy and thus moving several v = 2 levels abovethreshhold. In this way, K. —>• Kj- transitions of 2 ^ - 4 ,3 —»• 5, . . . (requiring L = 1), and 0 —>• 3, 1 —>• 4, . . .(requiring L = 2), etc., produce resonances at energies oftens of milli-electron-volts or less. These terms are domi-nant not only because the resonant energies are extremelylow, but also because I2 is significantly larger than I3

(Ref. 6).

These very low energy resonances produce a AS(u_d

that is very sensitive to the precise value of the dtpexcited-state binding energy. Changing this number bylOmeV, which is the present limit of accuracy of thecalculation,3 will drive several of the resonances belowthreshold or introduce new ones. The temperature de-pendence comes not only from the positions andstrengths of the resonances, which determine the con-tribution of different parts of the Maxwell-Boltzmanndistribution of initial tp energies6 (the tp is assumedthermalized), but also from the Boltzmann factor for theinitial molecular excitation.

The calculated temperature dependences of the fourmolecular-formation rates are shown in Fig. 2, includingfor A.dtJI_d the effect of varying the dtp binding energy.These results make use of the A.dt(t_d value co'mputed byVP for L = 0 and resonance energy 0.07 eV. For D2

collisions of singlet tp atoms, the v = 2 contribution isstrongly dominant, as stated above; the extreme sensitiv-ity to the dtp excited-state binding energy seen inFig. 2(b) and its qualitatively different behavior both:orae from the low-energy resonances (indicatedschematically). For triplet tp, an additional 51 MeV ofrotational excitation is needed for resonant formationwith v = 2; this requires a larger increase in rotationalargular momentum (for example, 2 —»• 6 rather than2 _ 4) and therefore larger L (L = 3 rather than L = 1),

3 -

"o— 2 -

- i

. . I I , .

-

•

/

" /

/

11 r-r-j-r-1 . -r~

y

1 1 1

O-d—-—-.

/

• ^ — .

^ ^ '

TTT

———

O-J^--

1-d

1 | IT

(a) ."

_ — — •

•

I -

200 400TEMPERATURE(K)

6 0 0 ZOO 400

TEMPERATURE (K)

Fig. 2.(a) The four molecular-formation rates, calculated for dtp binding energy 640 meV; 0-d indicates

*Vd , etc.(b) The variation of A5,u_d with binding energy, marked in milli-electron-volts. The variation withbinding energy of the other three molecular-formation rates is rather small. For 640-meV bindingenergy, the positions and approximate strengths of the important low-energy resonances are shown asvertical bars, with the Kf—>• Rvalues marked.

6 0 0

utry-Dacember 1963 PROGRESS AT LAMPF 9 9Los Alamos National Laboratory

For DT collisions, the greater reduced mass lowers thevibrational levels so that the v = 2 contribution is com-pletely negligible and only v = 3 is significant. Here themajority of important resonant contributions involve areduction in rotational energy. For <ftu-/, the vibrationalenergies and matrix elements are scaled from the dtfi-dvalues of VP using harmonic oscillator behavior.

To make contact with experiment, we must considerhow the four molecular formation rates contribute to theexperimentally determined (normalized) muon-cyclingrate Xc. Introducing the effective (singlet or triplet)molecular-formation rates, which depend on the atomicconcentrations Cd and C, (see Refs. 1 and 10),

is the d—*-t ground-state transfer rate. The branchingratio x is given by

x=- Cd)

Xl0 is the effective triplet-quenching rate, which hascontributions from both d and t collisions

4-X1 C! * 'Wo *-t

it can be seen that

idtct 4(3)

Pa is the probability for a ground-state </ji atom; becausetransfer to tritium can take place during the rfu deexcita-tion, this can be significantly less than Cd (Ref. 3). We usePA = Cd exp(-aC,) to express this effect. Furthermore, X.dt

The rate k[0 has been predicted to be very large:9 x 10s s~' (Ref. 11). If this is indeed the case, the secondterm of the right-hand side of Eq. (3) is always dominatedby either the first or third term, and only the singletmolecular-formation rates can be easily extracted fromexperiment.

We show in Fig. 3 the data of Jones et al.2 and two setsof calculated curves for XC(T). Although parameters togive good agreement for Ct= 10, 20, and either 50 or80% can readily be found (including increasing the rategiven by VP by an overall factor p), we have not beenable to fit all of the data simulaneously. Although ourexploration of the six-dimensional parameter space cer-tainly has not been exhaustive, we strongly suspect thatthis represents a real discrepancy. To pin down thesource of this discrepancy, we urge the experimenters to

I . , . , I / r i . i • • i i . , . I

2OO 400TEMPERATURE <K)

6 0 0

Fig. 3.Theoretical and measured cycling rates Xc for theCt values marked. The curves were calculated usingthe following parameter values.

Solid curves:Binding energy = 641 meV,

A.dt =2.8xlO's- 1 ,o = 2.0,

^ 0 = 5 x l 0 8 s - 1I

X},, =0, andp=2.5 .

Dashed curves:Binding energy = 628 meV,

Jldt =2.6xl0's" 1 ,a =3.3,

k% = 1.75 x IO! s \Xfo=O.and

P = 1.6.

1 0 0 PROGRESS AT LAMPfLos Alamos National Laboratory

measure as many of the various rates and parameters aspossible.

REFERENCES

1. S. E. Jones etal., Phys. Rev. Leu. 51, 1757-1760(1983).

2. Proceedings of the Third Int. Conf. on Emerging Nuclear EnergySystems, Helsinki, Finland, June 6-9, 1983, Atomkernenergie-Kerntechnik 43, No. 3 (1983).

3. L. I. Ponomarev, Proc. of the Third Int. Conf. on EmergingNuclear Energy Systems, Helsinki, Finland, June 6-9, 1983,Atomkernenergie-Kemtechnik 43, No. 3 (1983); Proc. of the10th European Conf. on Controlled Fusion and Plasma Physics(Moscow, 1981), Vol.11, p. 66; and S. I. Vinitsky and L. I.Ponomarev, Sov. J. Part. Nucl. 13, 557 (1982) |Fiz. Elem.Chastits At. Yadra 13, 1336 (1982)].

4. L. Bracci and G. Fiorentini, Phys. Rep. 86, 169 (1982).

5. S. S. Gcrshtein and L. I. Ponomarev, Phys. Lett. 72B, 80 (1977).

6. S. I. Vinilsky et al.. Sov. Phys.-JETP 47, 444 (1978) |Zh. Eksp.

Teor. Fiz. 74, 849 (1978)].

7. A. R. Edmonds, Anguhr Momentum in Quantum Mechanics(Princeton University Press, 1957).

8. D. Rapp. Quantum Mechanics (HoK. Rinehart, and Winston,New York. 1971).

9. D. D. Bakalov et al., Sov. Phys.-JETP 52.820 (1980) |Zh. Eksp.

Teor. Fiz. 79. 1629 (19«0)j.

10. S. S. Gershtein etal.. Sov. Phys.-JETP 51, 1053 (1980) |Zh.Eksp. Teor. Fiz. 78, 2099 (1980)].

11. A. V. Matveenko and L. 1. Ponomarev, Sov. Phys.-JETP 32, 871

(1971) [Zh. Eksp. Teor. Fiz. 59, 1593 (197O)|.

tntwy-Otcembw 19B3 IATUUMPFLot Altmot Nuioni Laboratory

161

Experimental Investigation of Muon-Catalyzed dtFusion

(Exp.727, Biomed)(Idaho National Engineering Lab., Los Alamos)Spokesman: S. E. Jones (Idaho Engineering Lab.)

Because the dimensions of a muonic-hydrogenmolecule are about 200 times smaller than those of anordinary hydrogen molecule, negative muohs stopped ina mixture of hydrogen isotopes can rapidly bring aboutfusion reactions. Muon-catalyzed fusion was first seen byAlvarez etal.1 in 1957 but had been predicted evenearlier by Frank and others.2

The recent revival of interest in the dd and dt reactionsis mainly due to the discovery of a resonant molecular-formation process that precedes the fusion reactions.3

For dt, this allows the formation of a loosely boundexcited state of the dt\n mesomolecule, with the releasedenergy going into vibration and rotation of the resultinglarge molecule (for which the dt[i is one nucleus) ratherthan electron emission (see Fig. 1). This resonant processis predicted to enhance the molecular-formation rate bytwo orders of magnitude and to induce a strong tempera-ture dependence. In dense dt mixtures this opens theinteresting possibility of a single negative muon catalyz-ing ~ 100 fusions.4"6

An experiment to measure the parameters governingmuon-catalyzed fusion in deuterium-tritium mixtures isbeing carried out at the Biomed channel. The processesinvolved are shown schematically in Fig. 2. Of the ratesdefined there, only the transfer rate Xdt and a lower limiton the molecular-formation rate \dtu had been determinedpreviously. We have now measured %it, kdltl as afunction of temperature in the range 100-540 K, thesticking probability cos, and the •'He scavengingparameters (see below). (The fusion rate X{ and the atomiccapture rate Xa are too fast to be measured.) Furthermore,we are also able to separate the two constituents of Kdttl:

(la)

(lb)+ DT-+[(dt\i)t2e-\* .

The apparatus is sketched in Fig. 3. The deuterium-tritium mixtures (0.45 and 0.60 of liquid-hydrogen den-sity) are contained in gold-lined stainless steel vessels thatcan be heated or cooled.9 Entering negative muons areregistered by a scintillator telescope, the 14-MeV fusion

Fig. 1.Resonant production of </lu molecules.

• Decay

Fig. 2.Muon catalysis in a mixture of deuterium andtritium.

Muon countir (1)

Electronditictor(1 of 3)

-Secondttycomainmtm

Fig. 3.Layout of the experiment.

neutrons by three liquid scintillators,1 and the muon-decayelectrons by the combination of plastic scintillationcounters plus the liquid scintillators. An accepted eventrequires, in sequence, (1) entry of a single muon, (2)

1 0 2 PROGRESS AT LAMPFLot Alamos National Laboratory

Janu*ry-Dtc*mt*r H

detection of one or more neutrons, and (3) detection ofthe muon-decay electron.

The times between neutron and e~ pulses followingnuon arrival are recorded. Neutron and y events in the

neutron detectors are distinguished by fast pulse-shapediscrimination. These methods reduce background toacceptable levels. The neutron detector efficiencies aredetermined using the Los Alamos Van de GraafF ac-celerator as a 14-MeV neutron source in conjunction withMonte Carlo calculations that incorporate geometricalacceptance.10 Overall neutron detection efficiency t is3.4 ± 0.4%.

For any set of conditions there are two basic quantitiesto be determined: «, the average number of neutronsproduced per muon stopped in the gas, and \a, the rateassociated with the time dependence of the appearance ofthe neutrons. The equations relating «, Ka, and the muon-cycling rate Ac to the fundamental rates can easily bededuced from some simple considerations. Because k{

and A., are very large,5 the cycling time (1 A c) of the muonis simply the sum of the time spent waiting to transferfrom d to t for that fraction captured in deuterium Cd,plus the time the ty atom waits for molecular formation.Therefore,

(2)

(By convention, the fundamental rites are normalized toliquid-hydrogen density, hence the density factor (j>, whichis the ratio of the actual number density to liquid-hydrogen density.) Rate Xn depends on all the processesthat remove muons from the cycle; for small 3He concen-trations,

(3)

where wHe is the probability for initial capture on 3Heplus the probability of transferring to 3He during themuonic-hydrogen cascade, and where kiHt and ^,He arethe rates for transfer from the ground state of the muonic-hydrogen atoms. Finally, as indicated by reactions ofEq. (1), there are two components of KdtM :

(4)

—. 1.4

O

1.0

0.8

0.6 -

moo

'355 0.4-n

0.2 -

II*

2 z S I

T5 1 iJtt

50% tritium

, 20% tritium "

T»O% tritium

I '0% tritium

200 400

Temperature (K)600

Fig. 4.Muon-cycle rate Xc normalized to liquid-hydrogen density as a function of temperature.

ftnutry-Dtcembtr tgS3

Our principal experimental results obtained so far aredisplayed in Figs. 4 and 5 and Table I; the error bars in

200 400

Temperature (K)600

Fig. 5.Mesomolecular formation rates as functions oftemperature.

MOOKMATLMM* 1 0 3LotAltmotNttorflLibontory

Table I. Parameters of Muon Catalysis in Deuterium-Tritium Mixtures.

Parameter

"•dtu

*>s

n

•Reference 7.

Theory

2 x 108 s"1

~108

0.86%0.91%

~11.5xl08s-1

5.6 x 108 s~'~102

Reference

85

11

121413135

Previous Experiment1

(2.9 ± 0.4) x 10" s-'>10* s"1

—

—...

This Experiment

(2.8±0.3)xl08s-»see Fig. 5

(0.77 ± 0.08)%

1 ± 1(2 ± 1) x 10s s-'(7 ± 2) x 108 s-!

90 ±10

the figures are statistical, whereas the errors quoted in thetable include systematic errors. Figure 4 shows the tem-perature dependence of Xc for four concentration ratios.Whereas the low C, data show no significant temperaturedependence, in agreement with the experiment ofBystritsky etal., the temperature dependence for thehigher tritium concentrations is quite striking. The lowtritium concentration data are flat because the cyclingtime is dominated by the d—>1 transfer time (l/CtA.dt).The rate Xdi (assumed to be independent of temperature)extracted from our data agrees very well with thatreported in Ref. 7 (see Table I).

Once Xit is determined, Xitu can be obtained usingEq. (2). From the concentration dependence of Eq. (4),the separate components of Xdtfl are found (Fig. 5). Bothof these components appear to be resonant. However,whereas A.dt«-t has the expected property of approachingzero as T—>• 0, the A.dt(1_d surprisingly appears to beconstant in the temperature range 100-400 K.

The experiment also determines the stickingprobability oos [see Eq. (3)]. The result for o>s

(0.77 ± 0.08)% is in fair agreement with the two calcula-tions.11' (High-Z contamination of our target gas,which could produce an artificially large value of <os, wascalculated to be less than 2 ppm and therefore negligible,but so far has not been measured.)

The final results concern the scavenging of muons by3He produced from tritium decay. The three contribu-tions to this scavenging have been separated roughly bytheir X.c and C t dependence [see Eq. (3)]; the results areshown in Table I. The X,dHe and \Ht values agree quitewell with the calculations of Aristov et al.,1 and the raHe

value is quite reasonable.

In summary, this first investigation of muon-catalyzedfusion in high-density dt mixtures has produced a numberof new results. Formation rates for tftu molecules havebeen observed to be large and dependent on temperature,and quite different for the two molecular specks involved(Z>2 and DT). The measured sticking probability cos isconsistent with calculation. The cycle rates and neutronyields demonstrate that a significant number of dt fusionsper muon can be realized. Indeed, our measurementsindicate that an average of 90 ± 10 fusions per muon willbe produced in an equimolar deuterium-tritium mixture atif = 1 and 540 K.

REFERENCES

1. L. W. Alvarez et al., Phys. Rev. 105, 1127 (1957).

2. F. C. Frank, Nature 160, 525 (1947); A. D. Sakharov, Report ofthe Physics Institute, Academy of Sc r ee s (1948); and Ya. B.Zeldovitch, Dokl. Akad. Nauk SSSR 95,493 (1954).

3. E. A. Vesman, Sov. Phys.-JETP Lett. 5, 113 (1967).

4. S. S. Gershtein and L. I. Ponomarev, Phys. Lett. 72B, 80(1977).

5. L. I. Ponomarev, Proc. of the 10th European Conf. on ControlledFusion and Plasma Physics (Moscow, 1981), Vol. II, p. 66.

6. L. I. Ponomarev, Proc. of the 6th Int. Conf. on Atomic Physics,R. Danberg, Ed. (Plenum Press, New York, 1978), p. 182.

7. V. M. Bystritsky et al., Sov. Phys.-JETP 53, 877 (1981).

8. S. S. Gershtein et al., Sov. Phys.-JETP 51, 1053 (1980).

9. A. J. Caffrey, S. E. Jones, and K. D. Watts, Bull. Am. Phys. Soc.28,646(1983).

1 0 4 PROGRESS AT LAMPFLos Alamos National Laboratory

January-Decambar 196.

10. N. R. Stanton, Ohio State Research Foundation report 12. L. Bracci and G. Fiorentini, Phys. Rep. 86, 169(1982).COO-1545-92 (1971); and A. J. Cafirey and S. E. Jones, to bepublished. 13. Yu. A. Aristov et al., Sov. J. Nucl. Phys. 33,564 (1981).

11. S. S. Gershtein et al., Sov. Phys.-JETP 53,872 (1981). 14. J. S. Cohen, R. L. Martin, and W. R. Wadt, Phys. Rev. A 2">,1821 (1983).

January-December 19B3 PftOOAESS Art-AMPF 1 0 5Los Alamot National Laboratory

Materials Science

Dilution Refrigerator for uSR Measurements(Exps. 499, 640, 771, SMC)(Los Alamos, Rice Univ., Univ. of California at River-side)Spokesman: D. Wayne Cooke (LosAlamos)

The potential of muon spin rotation (nSR) as acondensed matter probe has been well established. Re-cent experiments have shown that such phenomena asfluctuation dynamics near spin-glass transitiontemperatures and muon motion in noble metals, forexample, are amenable to study by muon-spin rotationand relaxation techniques. It is expected that potentiallyexciting physics occir-: at temperatures below 4K andthat future uSR expei ;.iisnts will thus require cryogenicapparatus that can attain temperatures in the millikelvinregion.

Accordingly, Group MP-3, assisted by Group P-10,has undertaken the task of designing and constructing a3He/4He dilution refrigerator suitable for use in uSRstudies. In addition to the temperature requirements, therefrigerator also must satisfy space requirements —namely, it must fit inside the existing uSR high-fieldHelmholtz coil.

Such a refrigerator has been designed and constructed,and initial testing has indicated the need for severalmodifications. During the past year these modificationshave been made and tested, and include

• an improved method of mounting the refrigerator sotnat thermal isolation between the 1 K cold plateand 4 K heat shield is assured;

• the installation of a larger diameter heat shield tominimize risk of thermal shorts between the mixingchamber and heat shield;

• the construction and installation of a new counter-flow heat exchanger that provides the proper pres-sure gradient between the still and mixing chamber;and

• an improved method of connecting the still andmixing chamber so that the thermal link between thetwo is minimized for temperatures below I K.

To date the minimum temperature attained by operat-ing in a continuous mode has been 235 mK. It is expectedthat replacement of a faulty *He dewar will lower thistemperature further to the design value of 50 mK. Thepresent experimental effort is directed toward designing asuitable target chamber and devising a sample tempera-

ture control scheme in anticipation of performing nSRexperiments with the dilution refrigerator.

Muon Longitudinal and Transverse RelaxationStudies in Systems with Random Exchange(Exp.499,SMC)(Rice Univ.; Los Alamos; UC, Riverside; Univ. ofLeiden, The Netherlands)Spokesmen: S. A. Dodds (Rice Univ.), R. H. Hejjher(Los Alamos), and D. E. MacLaughlin (UC, Riverside)

Silver-Manganese Spin Glasses

Progress has been made in understanding the fielddependence of zero- and longitudinal-field muon-spinrelaxation (uSR) in AgMn spin-glass alloys attemperatures well below the freezing or "glass" tempera-ture Tt (Ref. 1). These experiments provide a directmeasurement of spin-glass dynamics, which is quitedifferent in AgMn spin glasses than in their orderedcounterparts (ferromagnets, antiferromagnets). Inparticular, the local spin correlations die off as r"; that is,the correlations possess "long-time tails." This is incontrast to the behavior of correlations in comparablenonrandom systems, which typically decay with an ex-ponential time dependence. Recent theories, which useLangevin equations to represent the dynamics of the spinglass, also give this result, with v ~{, when applied to amean-field model of the spin-glass state.

Our results may be summarized as follows.1. Over a wide range of magnetic fields for

0.3 < T/Tt < 0.7, and for several manganese concentra-tions, the positive-muon (u+) spin-lattice relaxation rateh\ varies with effective applied field as H""1, withv =* 0.54 ± 0.05. On general grounds we expectAy oc /(«„), where /(©) is the noise spectrum of fluctuat-ing fields produced at u+ sites by manganese spins andwhere (oM is the u+ Larmor frequency. Thus the fielddependence of hi gives the functional form ofj(<o), if theexternal field (1) dominates o)H, and (2) does not affect thefunctional form of J(a) directly.

Static internal field distributions are known from uSRmeasurements in zero- and transverse-applied fields, socorrections can be made. Confirmation that the man-ganese-spin dynamics is indeed independent of appliedfield comes from 63Cu and 109Ag nuclear-magnetic-reso-nance experiments4 in CuMn and AgMn alloys forr « Tg, which directly demonstrate the absence of a field

1 0 6 PROGRESS AT LAMPPLos Alamos National Laboratory

Jtnutry-Otctmbtr 106

dependence oiJ(a)). Our data therefore provide the firstexperimental evidence that spin correlations decay; gebraicalJy and not exponentially in spin glasses below

'fr The observed value of v is within experimental errorof that obtained from dynamic theories.

'i. For T near Tt we obtain v =; 0.2, which is not inagreement with the dynamic theories. Here, however,J(«) may be directly affected by the applied field. Thedata are shown in Fig. 1.

3. A scaling law of the form

( I )

where x is the manganese concentration and/(«,v) is adimensionless function, is obeyed. This form is expectedfor dilute spin glasses, where the dipolar coupling scalesas x and spin-glass energies (and frequencies) scale as Tt

(Ref. 5).These results call for further theoretical work. It is

important to know, for example, how much intrinsic fielddependence of J(a>) is to be expected from current theory.The most fundamental question, perhaps, is whetherpower-law correlation decays can be obtained from morerealistic models than have been studied up to the presenttime.

Palladium Manganese

The Pd,_xMnx system has been widely studied, both asan example of a non-RKKY spin glass and as a diluteferromagnet. A competition between direct antifer-romagnetic couplings and long-range ferromagnetic cou-plings leads to a complicated phase diagram with aferromagnetic phase for x < 3 at.% and a spin-glassphase for x > 5 at.%. In addition, manganese inpalladium possesses a giant moment described by spin5 = f and effective g factor gelt~ 2.7. Both the x = 0.02ferromagnetic (Tc = 5.8 K) system and x = 0.07 spin-glass {Tg = 5 K) system have been studied using uSR as amicroscopic probe of magnetic ordering and dynamics.Measurements were carried out in zero applied field andwith both transverse- and longitudinal-applied fields. Thedata were analyzed using standard expressions for theuSR linewidths. The data analysis and samplecharacterization are described in Ref. 8 for PdMn(2 at.%) and in Ref. 9 for PdMn (7 at.%).

10' I0 2

SCALED FIELD H/Tg (Oe/K)

Fig. 1.Scaled isotherms of u* spin-lattice relaxation rateA.|, vs effective longitudinal field H for temperaturesbelow TK in Ag,.xMnx spin glasses,

Open symbols: x = 0.016,Half-filled symbols: x = 0.03,Filled symbols: x = 0.06.

Least squares fits to a power law are shown foreach scaled temperature T/Tf. Scaled widths &/TK

of the u+ dipolar field distributions for the variousmanganese concentrations are shown by arrows onthe horizontal axis.

Ferromagnetic PdMn (2 at.%)

It was determined that the transverse-field relaxation-rate data K^ were much larger than the longitudinal-fieldrates hi for nearly all temperatures and fields.Furthermore, measurements of muon diffusion inpalladium with gadolinium impurities indicate a negligible

Jawtry-Dacember 1983 PfKXMEMATLAMPF 1 0 7Lot Alums NUiorfl Ltbontory

muon diffusion rate below about 100 K. Thus the A.data reflect the distribution of quasi-static internal fields.

Walstedt and Walker (WW) have treated10 the prob-lem of local-field distributions at spin-probe sites in dilutemagnetic alloys and find a Lorentzian line shape with awidth A.j_ given by

' ! $z I -Nil (quasi-static limit)

<^z>ih (rapid limit)

where X^Q denotes the dilute-limit dipolar coupling andthe brackets refer to a thermal average of the Z compo-nent of spin 5. This can be generalized in cases where theimpurity spins possess randomly distributed values of<Sz>ttl, as discussed in Ref. 8.

In Fig. 2 wt compare our transverse-field relaxationrates A.j_ to the linewidth computed using the WWcoupling scheme. The quantity <Sz>lh is given by (1) auniform mean-field mode), and (2) the measuredmagnetization data of Star etal. We used gCfr=2because the induced conduction-electron polarizationcloud about the manganese spins is comparable to theaverage manganese-manganese spacing, thus giving riseto a uniform magnetization density that does not con-tribute greatly to the spread in local fields sensed by themuon. For Tz 1-5 Tc both the mean-field model and themagnetization data give excellent fits to Jlj_. This is incontrast to the spin-glass PdMn (7 at.%) discussedbelow.

Below Tc, however, the homogeneous mean-fieldmodel overestimates both X± (Fig. 2) and the zero-fieldinhomogeneous linewidth a(T) (Fig. 3). These data there-fore are compared to the infinite-range mean-field Isingmodel of Sherrington and Kirkpatrick (SK). In spite ofa great deal of theoretical work, this is the only modelthat explicitly accounts for the disorder in a randommagnet. In the SK model, impurity spins (S. = ± 1) arecoupljd by random interactions with mean and variancegiven by Jo/N and J2/N, respectively. Here TV is thenumber of spins and/0 = kBTc. Figures 2 and 3 show thatthe SK model yields a better description of both the zero-and transverse-field ferromagnetic linewidths than doesthe mean-field model. The "shortfall" in uSR linewidthsin the ferromagnetic state is thus qualitatively explainedin the SK model by including antiferromagnetic coupling(/„//= 1.1).

10

1000

Fig. 2.Temperature and field dependence of the transverseu+ relaxation rate A-x (H,T) in Pd + 2.0 at.% Mn.

Circles: / /=200Oe,Upright triangles: H= 1 kOe,Inverted triangles: H= 5 kOe.

The dashed curves were obtained from suscep-tibility data. The solid curves are obtained from theuniform mean-field model. The inset shows thetemperature dependence of \± in the SK modelwith H = 5 kOe.

Dashed curve: /„ = 5.8 K, Jo/J= 1.1,Solid curve: Jo = 5.8 K, J = 0.

The muon spin-lattice relaxation rate .11 is shown inFig. 4. The data show a sharp cusp in the zero-field A.11 atT-Tc that is completely destroyed by a 5-kOe appliedfield. This cusp presumably is due to critical spin fluctua-tions; the broad temperature range is larger than usuallyobserved in ordered ferromagnets, however. Similar re-sults are seen in neutron-scattering data on ferromagneticPdMn.

Raman-magnon scattering ' can explain the order ofmagnitude of Xy well below Tc, as shown in Fig. 4. This isin contrast to spin-glass AgMn where the observed h\ atT~TJ2 are almost two orders of magnitude larger thanestimates obtained from simulated low-temperaturemagnon spectra. In ferromagnetic PdMn there appears to

1 0 8 PROGRESS AT LAMPFLos Alimot Nitioml Laboratory

Jtnutry-Dactmher 1XL

100T(K>

Fig. 3.Temperature dependence of the zero-field u+ quasi-static field distribution width a(T) (in frequencyunits) in Pd + 2.0 at.% Mn.

Solid curve:SK model with /„= 5.8 K, / o / /= 1.1,

Dashed curve:SK model, Jo = 5.8 K, Jo/J= 1.5,

Dash-dot curve:Homogeneous mean-field model, S = | .

1 2 3 4 5 6 7

Fig. 4.Temperature dependence of the n+ spin-lattice re-laxation rate in Pd + 2.0 at.% at zero field (circles)and 5 kOe (triangles). The curves are predictions ofthe two magnon (Ramon) scattering mechanism(see text).

Solid curve:Anisotropy energy h<oA = 0.3 A:B Tc.

Dashed curve:

be no additional relaxation mechanism caused by therandom nature of the spin system.

Spin-Glass PdMn (7 at.%)

The main goal of this is to measure the temperatureand field dependence of both the quasi-static local-fielddistribution at the muon site and the muon's dynamicspin-lattice relaxation. Theories of linewidths and relaxa-tion mechanisms in dilute alloys have been used to inferfeatures of the impurity spin configuration. Comparisonswith ferromagnetic PdMn (2 at.%), discussed above, areuseful to show how the difference in magnetic orderingbrought about by a change in concentration influencesmicroscopic properties.

Figure 5 shows measured transverse-field exponentialrelaxation rates A.j_ for applied fields of 200 G, 1 kG, and5 kG. Measured spin-lattice relaxation rates (discussedbelow) indicate that the nonsecular contribution to Xj_ issmall. Thus the rates shown in Fig. 5 represent only thequasi-static field distribution in PdMn (7 at.%).

The observed paramagnetic susceptibility in a PdMn(5-at.%) sample is well described by a g= 2, S = § Curie

January-Dacomber 1983

law for T > 3 Tt and low field.14 Using this Curie law for<Sz>th in Eq. (2) gives the lines shown in Fig. 5. At lowtemperatures, we simulate the spin-glass state by assum-ing spins to be quasi-static and equally distributed amongthe 25 + 1 Ms states in calculating the order parameter< 15Z | >lh. Equation (2) then gives the high-field frozen-spin linewidth (*.±)froien = 57.1 us"1. A concentration of7 at.% is not ordinarily considered to be in the dilutelimit, so we have calculated a polycrystalline-averagedline shape numerically; the result differs in width from theWW result by no more than 7%.

The discrepancy in Fig. 5 between the X± data and theWW prediction using a Curie law well above Tt is notunderstood. Similar data on the disordered ferromagnetPdMn (2 at.%) show very good agreement with the WWresult. Since our numerical work indicates that the WWresult should still be valid at this higher concentration, weconclude that the observed discrepancy is due to the spin-glass ordering and is present for T well above Tt.Transverse-field uSR results in spin-glass AgMn show anincrease above the WW result, however, to at least 10 Tt.

PfKXMEMATLAMPF 1 0 9Los Alamot Nation! Laboratory

POfc • i . . , „ • !

10

0.K)

0,01

(3kG) -

1.0i I f t I I f l l f * j l f I I

100T (K)

Fig. 5.Temperature and fleld dependence of the transversemuon relaxation rate A L in PdMn (7 at.%).

Circles: 200 G,Triangles: 1 kG,Squares: 5 kG.

The solid lines are from Eq. (2) using a Curie law

for <S7>; (Kl )r is the frozen-spin rate.

The zero-field muon-rclaxation function allows aseparation between the quasi-static field distribution ofwidth a(T) and relaxation from dynamic spin-latticerelaxation (rate An). In zero-applied field the WW result isno longer valid, however, because all three components ofthe local-field distribution contribute to the muon relaxa-tion. Including this effect, one obtains the zero-fieldfrozen-spin linewidth a0 = 85 us"' for PdMn (7 at.%).The temperature dependence of a{T), normalized by a0,shows a temperature dependence similar to ferromagneticPdMn (2 at.%), as shown in Fig. 6. Thus the developmentof a static field distribution is independent of the charac-ter of the magnetic ordering.

oo

p

1.0

o.e

0.6

0.4

0.2

n

• i i i

Q

Q

i i i i

i

-

-

o8i

0.2 0.4 0.6 0.8 1.0 1.2T/T, c,g

Fig. 6.Reduced temperature dependence of the zero-foldquasi-static field distribution width a(T), nor-malized to the theoretical zero-field frozen rate aa.

Open circles:

PdMn (2 at.%), a0 = 28 jis"1, Tc = 5.8 K.Filled circles:

PdMn (7 at.%), aa = 85 us ' J , = 5K .

Figure 7 presents measured muon-spin-latticc relaxa-tion rates in zero and applied longitudinal fields; aboveand below TK. Above 7", the relaxation was fit to the"root exponential" form7 appropriate for rapidly fluctuat-ing (paramagnetic) spins in a dilute alloy. Fits of the datato a simple exponential form for G,(t) yield a similar %l

value, so that we have not explicitly demonstrated theroot exponential form. Below TH we expect that fluctua-tions will remain rapid, since this has been observed byHSR in spin-glass AgMn (Ref. 7). Thus a root exponentialdecay of (he dynamical component of the relaxationfunction was used to fit the low-temperature data for An.

The peak in the zero-field spin-lattice relaxation rate at1\ is interpreted as being due to a change in the powerspectrum of manganese spin fluctuations near the glasstransition. Note that a relaxation mechanism is stilleffective near TK in an applied field of 5 kG, whereas inferromagnetic PdMn (2 at.%) an applied field of 5 kGcompletely suppresses the fluctuation-induced relaxation.

At temperatures well below Tj,, spin-lattice relaxationpresumably is due to spin wave-like excitations of theground state.17 Walker and Walstedt18 have computedthe spectrum of excitation frequencies numerically for a

1 1 0 PROGRESS AT LAMPFLos Altmo* NMOMl UborUory

\

Fig. 7.Temperature and field dependence of the muon-spin lattice relaxation rate in spin-glass PdMn(7 at.%).

Circles: Zero field,Triangles 200 G,Squares: 5 kG.

Fitting functions used arc described in Ref. 7.

realistic model of a ground state of a CuMn spin glass.These excitations are localized (nonpropagating) modesof the linearized equations of motion. A similar calcula-tion19 for spin-glass PdMn (10 at.%) has shown a morecomplicated three-peak structure for the excitation spec-trum, with the mean spectral weight at a frequency~5 x 1O'J s~'. Because these fluctuations are much toofast to cause depolarization through the dipolar interac-tion in the lifetime of the muon, the observed relaxationmust be due to some other (other than WW) lowerfrequency component of the excitation spectrum.

Recent analytic theories of spin-wave excitations inspin glasses predict that small k magnons can propagatethrough the system with a dispersion relation linear in k(Ref. 20). Further evidence for propagating modes hasbeen seen in recent computer simulations.21 These excita-tions are at frequencies lower than the localized modesand may be responsible for the relaxation observed at lowtemperatures. Future zero-field uSR studies in spinglasses at lower temperatures may provide useful data on

, relaxation for comparison with these theories.

JanuaryDecamhto 1983

In conclusion, the transverse-field relaxation rate Xj_ inPdMn (7 at.%) is not proportional to the observed Curielaw magnetization for temperatures as high as 100 K^20 r , ) , where the onset of muon diffusion makes inter-pretation of \± difficult. This result is especially surpris-ing because \± in ferromagnetic PdMn (2 at.%) isproportional to a Curie-Weiss magnetization over a widetemperature range, indicating that the observed reductionin A.j_ below the Curie law prediction may be a high-temperature precursor of the spin-glass phase. We knowof no satisfactory explanation for this effect nor for theincrease in A. above the measured magnetization in spin-glass AgMn (1.6 at.%).

In zero field we observe the onset of a quasi-static fielddistribution below Tt with a similar temperature de-pendence to that observed in PdMn (2 at.%). Spin-latticerelaxation near TK shows a strong cusp, indicating achange in the spectrum of manganese-spin fluctuations.These fluctuations continue to induce relaxation in a largeapplied field, in contrast to PdMn (2 at.%).

REFERENCES

1. D. E. MncLaughlin, I.. C. Gupta. D. W. Cooke, R. H. HefTner,M. Leon, and M. E. Schillaci, Phys. Rev. Lett. 51.927 (1983).

2. S.-K. Ma, Modern Theory of Critical Phenomena (Benjamin,Rending, Massachusetts. 1976). pp. 442-444.

3. H. Sompolinsky ami A. Zippclius, P!. /a. Rev. Lett. 47. 359(1981); Phys. Rev. I] 25, 6860 (1982); and J. Phys. C 40, L1059(1982).

4. H. Alloiil, S. Murayama. and M. Chapellier, J. Magn. Magn.Mater. 31-34, 1353(1983).

5. J. Sonic-tic and R. Tournier, J. Phys. (Paris) Colloq. 32, C1-172(1971).

6. H. A. Zweers and G. J. van den Berg, J. Phys. F 5, 555 (1975);and B. R. Coles, H. Jnmicson, R. H. Taylor, and A. Tari, J. Phys.F 5, 565(1975).

7. R. H. Mcflher, M. Leon, M. E. Schillaci, D. E. MucLaughlin, andS. A. Dodds, J. Appl. Pliys. 53. 2174 (1982).

8. S. A. Dodds, G. A. Gist, D. K. Macl.aughlin, R. H. HclTner, M.Leon, M. H. Schillaci, G. J. Nicuwcnliuys, and J. A. Mydosh,Phys. Rev. i) 28. f.209 (1983).

9. R. II. Hcflncr, M. Leon, M. If. Schillaci, S. A. Dodds, G. A. Gist,D. E. MiicLnuglilin, J. A. Myuosh, and G. J. Nicuwenhuys, inProe. of tile 29lh Magnetism and Magnetic Materials Conf.,Pittsburgh. Pennsylvania. 198.1, to be published in i. Appl. Phys.

PROGRESS AT UMff 1 1 1Lea Alamos NUIontl Liboruory

i

10. R. E. Walstedt and L. R. Walker, Phyi. Rev. B 9,4587 (1974).

11. W. M. Star, S. Foner, and E. J. McNiff, Phys. Rev. D 12, 2690

(1975).

12. D. Sherrington and S. Kirkpatrick, Phys. Rev. Lett. 35, 1792(1975); and S. Kirkpatrick and O. Sherrington, Phys. Rev. B 17,4384 (1978).

13. E. A. Turov and M. P. Petrov, Nuclear Magnetic Resonance In

Ferro- and Ar.tiferromagnets (Halsted Press, New York, 1972),p. 93.

14. B. R. Coles, H. Jamieson, R. H. Taylor, and A. Tari, J. Phys. F 5,565 (1975).

15. J. A. Brown, R. H. Heffner, T. A. Kitchens, M. Leon, C. E. Olsen,

M. E. Schillaci, S. A. Dodds, and D. E. MacLaughlin, J. Appl.

Phys. 52, 1766(1981).

16. A. T. Fiory, Hyperfine Interactions 8, 777 (1981).

17. D. Beeman and P. Pincus, Phys. Rev. 166,359 (1968); and A. H.

Mitchell, J. Chem. Phys. z7, 17 (1957).

18. L. R. Walker and R. E. Walstedl, Phys. Rev. B 22, 3816 (1980).

19. W. Y. Ching, D. L. Huber, and B. H. Verbeek, J. Appl. Phys. 50,

1715 (1979).

20. B. I. Halperin and W. M. Saslow, Phys. Rev. B 16, 2154(1977);W. M. Saslow, Phys. Rev. B 22, 1174 (1980); K. H. Fischer, Z.Phys. B 39, 37 (1980); and S. E. Barnes, J. Phys. F II, L249(1981).

21. D. L. Huber, W. Y. Ching, and M. Fibich, J. Phys. C 12, 3535

(1979).

Fusion Materials Neutron Irradiations(Exp. 545, Radiation Effects Facility)(Los Alamos, Arizona State Univ.)Spokesman: R. D. Brown (Los Alamos)

Toroids wound from strips of the soft magnetic alloysMumetal (crystalline) and 26O5S-3 (amorphous) wereneutron irradiated at the LAMPF Radiation-Effects Fa-cility. The initial magnetic permeability values for bothmaterials decreased during irradiation. The permeabilityof the Mumetal decreased more rapidly than that for theamorphous alloy, resulting in the 260SS-3 having thehigher permeability for neutron fluences exceeding about3 x 1021 n/m2. At the beginning of the irradiation the

Mumetal had permeability of 23 000 and the 2605S 3had permeability of 5000. Four months later, afterirradiation to 2 x 10" n/m2, the penneabiiity of theMumetal approached unity, whereas that for the 2605S-3was about 2000.

We have reported similar results for a comparativeirradiation of Permalloy and the amorphous alloy2605S-3 (Ref. I). For both the crystalline Mumetal andthe amorphous 26O5S-3, the drop in permeability wasvery rapid initially, followed by a slow decrease thatappeared to continue to the maximum fluence.

A quantitative analysis of the permeability decaycurves was made using the direct spectrum analysismethod, which is capable of determining a good approx-imation of the spectrum of relaxation constants for aprocess involving first-order kinetics, without requiringinitial assumptions as to the nature of the spectrum.Analysis of our data in terms of a relaxation fluence(analogous to a relaxation time) showed that both theMumetal and the amorphous 2605S-3 alloy exhibitedvirtually identical spectra. Each spectrum consisted oftwo discrete peaks, one centered at a fluence of about1 x 1021 n/m2 and the second at a fluence of about4 x 1022 n/m2. The two widely separated peaks provideevidence for the permeability decay occurring in twostages, each associated with a particular mechanism.

Our interpretation of the data3 assumes that the firststage is governed by short-range ordering because ofexcess point defects introduced during the irradiation,whereas the second stage is dependent on agglomerationsof these point defects, such as dislocation loops and voidsthat pin the magnetic domain walls. The finding that therelaxation fluences are virtually identical for thecrystalline Mumetal and the amorphous 2605S-3 wassurprising. Although it was not totally unexpected thatdefect agglomerates could pin domain walls, the presenceor absence of short-range ordering in amorphous alloyshas been the subject of controversy.

Further work is planned to obtain more information onthese stages observed during irradiation. The effects ofthe initial heat treatment on the permeability of several26OS amorphous alloys will be studied. This alloy systemmay be suitable, because of its relative stability underirradiation, as a replacement for the present Mumetaltoroids used upstream of the beam slop, where radiationdamage results in a rapid decay in permeability, requiringfrequent replacement.

112 MOORESS AT LAMPFLos Alamos National laboratory

January Otcmmtm IM3

REFERENCES

R. D. Brown, i. R. Cost, and J. T. Stanley, "Effects of NeutronIrradiation on Magnetic Permeability of Amorphous andCrystalline Magnetic Alloys," to be published in J. Appl. Phys.,Suppl. Part 2 (March 1984).

2. J. R . C o s l J . Appl. Phi s. 54, 2137(1983).

3. R. D. Brown, J. R. Cost, and J. T. Stanley, "Irradiation-InducedDecay of Magnetic Permeability of Metglas 26O5S-3 andMumetiil," submitted to J. Nucl. Mater.

MUOIJ Spin Rotation (uSR) Studies of DiluteMagnetic Alloys(Exp. 571 , SMC)

(Los Alamos, Rice Univ., Univ. of California at River-side, Sandia National Lab.)Spokesmen: S. A. Dodds (Rice Univ.) andR. H. Heffner

and M. E. Schillaci (Las A lamos)

Experiment;!! Program

Experiment 571 is designed to measure muon diffusionin fee materials other than copper and aluminum. Theresulting diffusion data will provide a basis for under-standing the apparently anomalous motion of muons incopper, aluminum, and bee materials. In addition, knowl-edge of muon mobility is needed to properly interpret

data from the other muon-spin-rotation (|iSR) experi-ments being undertaken by our group.

Our muon-diffusion measurements have exploited theimpurity-doping technique first applied' to uSR atLAMPF. As noted in the previous report,2 we haveextensive data on the field and temperature dependence ofthe iniion depolarization rate in silver, gold, andpalladium doped with gadolinium, erbium, and man-ganese. We have extracted the muon-diffusion rate frqmthese data with a model that treats the muon hopping,muon-impurity interaction, and impurity spin-flip timerather simply. '" This model gives a reasonable accountof the observed temperature dependence in the systemsstudied, but it is not able to account for the magnetic-fielddependence of the depolarization rate, as shown by (hedashed lines in Fig. 1.

Several features of the simple model have been examined to determine the cause of the problem. We havebeen able to show that the muon-impurity interaction isweak enough that "strong-collision" effects as seen inNMR are unimportant here. We have also shown thatthe effective correlation time approximation used in ourmodel yields the same results as a near-exact treatment ofthe combined muon hopping and impurity spin flipping,at least in the parameter region of interest.

Our next approach was to examine the effect of host ormuon-induced electric fields on the impurity relaxation.The simplest case an axial field gradient, improves theagreement between the model and the data considerably,as shown by the solid lines in Fig. 1.

0.5-

1 °< I

i 1 • 1

AgGd (340)T=325KHi

AuGd (350)T=I4OK

H*. , ,

1 1 -

s -

(a )

( c )

1 1

i l l r

AgErOOO)T = 325 KHi

j , ^ AuGd (350!

. . i I . I i ~

i

(b)

..i

( d )

i

0 . 5 -

0 1 2 3 4 5 0 ! 2 3 4 5

H (kOe)

tnmry December 1983

Fig. I.Magnetic-field dependence of inuon depolarizationrates for the alloys listed. Rare-earth concentra-tions are in parts per million (atomic). Data areshown for both transverse (NJ) and longitudinal(//|,) applied fields. The curves are fits to the twomodels described in the text.

PROGRESS AT LAMPFLos Alamot NUIoool LtbaKory

113

At the temperatures of interest, all of the crystal-fieldlevels are populated, so the cubic fields of the host mustbe considered together with the axial field due to themuon. We have reformulated a theory6 for spin dynamicsof a multilevel system and have carried out numericalcalculations for erbium [/=(15/2)J in silver and gold. Tothe best of our knowledge, this is the first calculation thattreats a high-spin system in an unsymmetric electric-fieldenvironment with arbitrary applied magnetic field. Pre-liminary results show that the muon-induced axial fieldhas a profound effect on the erbium fluctuation rate thatleads to an enhanced depolarization rate for the muon.Yet to be done is incorporating this model into ourhopping model, so that muon diffusion and muon-ioninteraction are treated together.

Theory: Calculator! of Muon Polarization FunctionP. F. Meier (Univ. of Zurich) and M. E. Schillaci (LosAlamos)

The spin dynamics of a muon localized at an interstitialsite interacting with nearest neighbor nuclear spins isbeing investigated. Kubo and Toyabe studied the spin-relaxation process in zero or weak external magnetic fieldby approximating the influence of the surrounding nu-clear spins by a random local field.

For a static muon in zero external field the muonpolarization decreases from its initial value of unity,passes through a minimum, and smoothly reaches a valueof one-third asymptotically with time. Recently, Celioand Meier8'9 reported on exact numerical calculations forN = 4 nuclear spins with angular momentum J--\ andJ= 1, and for N=6 with J={- Both dipolar andquadrupoiar interactions with the muon were incuded.Their principal result is that the muon polarizationfunction continues to oscillate with time, contrary to thesmooth, asymptotic behavior predicted by the Kubo-Toyabe theory.

The critical limitations in these investigations are thetime and memory required to diagonalize very largeHamiltonian matrices. Using a Cray-1 computer at LosAlamos, we were able to study N= 4 nuclear spins with/ = § , which corresponds, for example, to a muonlocalized in a tetrahedral site in copper. Dipolar andquadrupoiar interactions between the nuclei and themuon were included, and applied fields in transverse andlongitudinal orientations, as well as zero field, were

treated. Including isotope effects (for example, copper)and internuclear dipolar interactions had little effect onthe results.

Recently, Holzschuh and Meier10 gave an analyticzero-field approximation for J=\ and N = 4,6,8 cor-responding to tetrahedral, octahedral, and cubic arrange-ments, respectively. For J=\, N=4, their solution is ingood agreement with our exact numerical result. Also,they find that with increasing N the oscillations of themuon polarization function are reduced and the mini-mum is shifted to shorter times.

We have started numerical calculations for N=%,J ~\ and have begun preparations for N=6, J=l,corresponding to cubic and octahedral arrangements,respectively. The dimension of the state space is given by2(2J+ 1)N; consequently, we are nearing the 4xlO2

word capacity of our largest Cray-1. In some cases,group-theoretical reduction techniques can be applied toreduce the maximum dimension; however, for zero ex-ternal field, the approximation scheme given in Ref. 10 isbetter suited for studying larger systems (for example, theeffects of next-nearest neighbor nuclear spins).

REFERENCES

1. J. A. Brown, R. H. Hefiher, R. L. Iluuon, S. Kohn, M. Leon, C.E. Olson, M. E. Schillaci, S. A. Dodds, T. L. Estle, D. A.Vanderwater, P. M. Richards, and O. D. McMasters, Phys. Rev.Lett. 47, 261 (1981).

2. "Progress at LAMPF, January-December 1982," J. C. AUred,Ed., Los Alamos National Laboratory report LA-9709-PR(March 1983), p. 70.

3. M. E. Schillaci, R. L. Hutson, R. H. Heffner, M. Leon, S. A.Dodds, and T. L. Estle, Hyperfine Interactions 8, 663 (1981).

4. S. P. Vernon, P. Thayamballi, R. D. Hogs-, D. Hone, and V.

Jaccarino, Phys. Rev. B 24.3756 (1981)

5. M. E. Schillaci, R. H. Hefrher, R. L. Hutson, M. Leon, D. W.Cooke, S. A. Dodds, P. M. Richards, D. E. MacLaughlin, and C.Hockema, Proc. of the Third Int. Conf. on Muon Spin Rotation,Tokyo, Japan, April 1983 (to appear in Hyperfine Interactions).

6. K. W. Becker, P. W. Fulde, and J. Keller, Z. Phys. B 28,9 (1977).

7. R. K ubo and T. Toyabe, in Magnetic Resonance and Relaxation,R. Blinc, Ed. (North-Holland, Amsterdam, 1966).

8. M. Celio and P. F. Meier, Phys. Rev. B 27, 1908 (1983).

114 PflOOBESS AT LAMPFLos Altmos NUiontl Lmbontory

J*nu*ry-D*cvnb»r 1S83

9. M. Celio and P. F. Meier, "Exact Calculation of the MuonPolarization Function," Yamada Conference on Muon SpinRotation and Associated Problems, Shimoda, Japan, April 1983(to be published in Hyperfine Interactions).

10. E. Holzschuh and P. F. Meier, "Zero-Field Spin Relaxation ofPositive Muons," University of Zurich preprint (1983).

Muon-Spin-Rotation Study on Muon Bonding andMotion in Select Magnetic Oxides(Exp. 639, SMC)[Los Alamos; Texas Tech Univ.; Univ. of Wyoming;Atomic Energy Research Establishment (AERE),Harwell, United Kingdom; Technical Univ., Eindhoven(NL)]Spokesmen: C. Boekema (Texas Tech Univ.), D. W.Cooke (Los Alamos), and A. B. Denison (Univ. ofWyoming)

Muon-spin-rotation (uSR) studies on select magneticoxides are nearing completion. Detailed knowledge andbetter understanding of muon behavior, especially bond-ing and localization, have been obtained. ' These resultsare based primarily on work done at LAMPF, withcontributions from experiments at SIN to complete theoverall picture.

Our most recent efforts were directed to the sesquiox-ides, with emphasis on A12O3 and V2O3. In addition tothese experiments, efforts have been made to integrate theuSR data, taken on a larger set of (magnetic) oxides, intoa consistent model of the muon in oxides.

A12O3 (corundum) is a structure model for a setof magnetic oxides studied or currently under study[a-Fe2O3, Cr2O3, FeTiO3 (Ref. 3), and V2O3]. Thisdiamagnetic material has been examined with uSR to seeif the muon behaves in a similar manner in the non-magnetic host as it does in magnetic crystals of the samecorundum structure. This question carries two aspects:(1) do we see free muon-like behavior, or is muonium(also) formed, as has been reported earlier ; and (2) if a u-oxygen complex exists, what can we say about itsmobility in these materials, particularly at lowtemperatures?

In zero-field measurements recorded between 50 and200 K, a weak uSR signal is seen with an asymmetry of0.04 and a constant relaxation rate of 0.05 us""1. Thisweak signal could be identified as the " 1/3 component" ofmuon polarization, indicating strongly that the muon islocalized. Above 200 K the signal disappears because ofincreasing relaxation effects, probably muon diffusion;

below 50 K the signal strength increases as a result of anincreasing asymmetry. Because 27A1 nuclear momentswill fluctuate slower at decreasing temperatures, themuon polarization at short times (0.2-1.0 us) thereforewill increase.

Of special interest is the transverse field dependence ofthe relaxation rate (X) at 5 K, illustrated in Fig. 1; Xdecreases very rapidly by a factor of 2 for the first 100 Gof externally applied field, then at higher fields remainsconstant within experimental error. This figure may becompared with Fig. 2 of Ref. 4, where the longitudinalfield dependence of the muon polarization is depicted. Astriking similarity can be seen.

From these experimental data we estimate that theeffective local fields at the muon site are of the order of100 Oe and may be caused by the 27A1 nuclear momentsthrough superhyperfine effects. Here we assume that themuon is localized at low temperatures, as indicated byzero-field measurements and observed for similarly struc-tured magnetic oxides.

Vanadium oxide V2O3 also possesses the corundumstructure and is therefore isostructural with a-Fe2O3,FeTiOj, and Cr2O3, which have been recently reviewed.3

Of main interest is that a metal insulator (MI) as well as amagnetic transition occurs at 150 K. Below this tempera-ture, V2O3 is an insulator and is antiferromagnetic,whereas above the transition temperature it is conductingand paramagnetic.

Fig. 1.The muon-relaxation rate measured at 5 K for asingle refined crystal of a-A!2O3 as a function of atransverse externally applied field.

I nuary-December 1983 PMXMEM AT LAMPFLos Altmot Ntttoni Laboratory

115

300 400 500

T(K)

Fig. 2.The temperature dependences of the relaxation rate(k) in the temperature region (300-600 K) for themagnetic oxides. For comparison the data havebeen smoothed. Data are from Refs. 1, 2, and 8.The flattening of the X(r) curve above 500 K forthe orthoferrites is due to decreasing magnetization(Ref. 8).

Of additional interest in light of other oxides in-vestigated is the fact that the conduction in V2O3 isbandlike, whereas in Fe3O4 conduction is most likely dueto phonon-assisted electron hopping above the (Verwey)MI transition (the other oxides are insulating). Also,V2O3 is an end member of two most interesting mixedsesquioxide systems ( T i ^ V ^ O j and (V,_xCrx)2O3. Theformer is known because of remarkable spin-glassproperties, the latter, for interesting changes in conduc-tive and magnetic properties.

To date the temperature dependences of the uSRfrequency and relaxation rate (A.) have been traced.


Above the MI transition a strong uSR signal is seen at thefree muon frequency with a low Gaussian "K of 0.06 us~l.Most likely this Gaussian behavior indicates local dif-fusive behavior. Below the transition temperature astrong signal was seen in zero field at 15 MHz, cor-responding to a muon site with an internal field of1.1 kOe. Presently we are pursuing a study of the phasetransition in more detail and trying to determine themuon stop site from crystal-oriented transverse-fieldmeasurements.

A consistent picture of the muon behavior in (magnet-ic) oxides is developing, and a general model based on thecollective knowledge of the different oxides appears to beemerging. ' In this examination it is most helpful toconsider uSR results from the rare-earth orthoferrites.

Basically, it was found that in RFeO3 the muonlocalizes near oxygen and engages in a muon-oxygenbond. These results are in agreement with those obtainedearlier for a-Fe2O3, which showed for the first time thatmuon-oxygen bonding occurs in oxides and also thatlong-lived metastable muon states may be present in(magnetic) oxides well below room temperature.

If one compares the muon-relaxation rates as a func-tion of temperature for magnetically and structurallydifferent oxides (a-Fe2O3, Fe3O<, ErFeO3, and YFeO3),it can be seen (Fig. 2) that the X increase starts above360 K. These combined-relaxation data also suggest thatthe muon is behaving similarly in various magneticoxides.

Generally, at temperatures below 100K the muonappears to find itself in several nonequivalent magneticsites. As proposed by Stoneham, the muon is trapped ina metastable state longer-lived than the muon decay time.Going up in temperature, local diffusion sets in; above500 K, global diffusion through the whole lattice takesplace.

With the chemical and physical muon behavior becom-ing understood the muon can now be used as a bonajidemagnetic probe of the sample under investigation. Theobservation, for instance, of the anomalous behavior ofthe uSR frequency at 250 It in the Verwey transitiontemperature region is a good example. Moreover,preliminary uSR measurements on V2O3 point in thesame direction.

REFERENCES

i. C. Bockema, in the Proc. of the Yamada Conf. on Muon SpinRotation and Associated Problems, Shimoda, Japan, April 1983(to be published in Hyperfine Interactions).

January-Decernbtr 19BL

2. A. B. Deniion, Proc. of the 29th Annual Conf. on Magnetism andMagnetic Materials, Pittsburgh, Pennsylvania, November 1983.

. C. Boekema, A. B. Denison, K. J. Riiegg, J. Magn. Magn. Mat. 36,111(1983).

4. E. V. Minaichev et al., Sov. Phys.-JETP 31, 849 (1970).

5. J. M. Honig, J. Solid State Chem. 45, 1 (1982).

6. J. Dumas and C. Schlenker, J. Phys. C 12, 2381 (1979).

7. H. Kuwamuto et al., Phys. Rev. B 22,2626 (1980).

8. E. Holzschuh et ai., Phys. Rev. B 27, 5294 (1983).

9. A. Browne and A. M. Stoneham, J. Phys. C 15, 2709 (1982).

Effects of Superconductivity on Rare-Earth IonDynamics in (HoxLu,_x)Rh4B4

(Exp. 640, SMC)(Rice Univ., Los Alamos, and UC, Riverside)Spokesmen: S. A. Dodds (Rice Univ.), R. H. Heffher(Los Alamos), and D. E. MacLaughlin (Univ. of Califor-nia at Riverside)

Our previous JISR studies in the rare-earth rhodiumborides3'4 HoxLu,_xRh4B4, for x = 1.0,0.7,0.35, and 0.0,have revealed a sharp shoulder in the temperature de-pendence of the muon-spin-Iattice relaxation rate at thetemperature Ts corresponding to the onset of superconductivity. Here we report zero-field measurements inHo0 02Lu0 ,gRh4B4, which becomes superconducting atr s=11.3K.

Three distinct forms for the normalized muon-spin-relaxation function1'5 Gz(/) were observed in differenttemperature regimes (Fig. 1). At 50 K the Gz(0 wasfound to be well described by the static zero-field relaxa-tion function derived by Kubo and Toyabe, which isappropriate for a time-independent Gaussian distributionof local magnetic fields at u+ sites.

The measured width of the field distribution, about4 Oe, indicates that the ji+ spin relaxation is causedprimarily by u+ precession about the host nuclear dipolarfields. As the temperature is lowered, the form of Gz(i)changes, until at 15 K the relaxation function can beapproximated by a simple exponential GJ(t) = exp(-'Klt)(Fig. 1), where X, is the u+ spin-lattice relaxation rate. AtT < 11 K, the form of the relaxation function againchanges, exhibiting the two-component form shown inFig. 1 for T= 6 K. These data were fit with the function

3 6TIME (/is)

Fig. 1.Zero-field muon-spin-relaxation function Gz(t) atrepresentative temperatures in Ho002Lu09gRh4B4.The curves are fits to the appropriate functions asdiscussed in the text.

Git) = [ 1 - a] exp(-oO + a exp(-V) . (1)

with a » V One finds that(1) a is essentially independent of temperature, with an

average value of 11.5 ± 0.6 us"1;(2) a is about 0.6 at Z"= 11 K, and falls to one-third

for T<8K;and(3) ^j falls exponentially with decreasing tempera-

ture below Ts, with an activation energyA = 9.8 ± 1.3 K (Fig. 2).

From these results we conclude that the stochasticmotion of the Ho3+ moments becomes quasi-static below~ 11 K. The value of one-third for a at low temperaturesis itself indicative of a random, quasi-static field distribu-tion. ' ' Furthermore, the temperature independence ofa is evidence that the local field hh(t) reorients completelyin a time tm such that orm » 1, whence A2 = 2/(3Tm)(Refs. 5 and 6).

A two-component form for Gz(t) also can be due tolimited-amplitude fluctuations of hh(t) around a static orquasi-static average value, but in such a case o increasesmarkedly with decreasing temperature as the fluctuationamplitude decreases. This is not observed inHo002Lu098Rh4B4, and we conclude that hL(t) reorientscompletely below 8-10 K.

The value of o can be estimated using the formalism ofWalstedt and Walker8 for dipolar coupling and theholmium two-level Ising-like ground state discussed

anuary-December 7983 PROGRESS AT UMPFLos Alamos National Laboratory

117

10'X 50 20T(K)

I I" I

10'

10

10

Ho,Lu,.,Rh4B4

Te(x*0.7)

* • 0.02 0.7- / FULL ASYMMETRY o a

REDUCED ASYMMETRY • »

I01 0.2

I/KK'1)0.3

Fig. 2.Temperature dependence of the zero-field u+ spin-lattice relaxation rate in HoxLu,_xRh4B4, * = 0.02(circles and solid curves) and 0.7 (triangles anddashed curves).

Open symbols: relaxation rate of the full u+

asymmetry (relaxation rate XJ.Filled symbols: relaxation rate of the reduced-

asymmetry component of the u+ polarizationbelow ~11 K (relaxation rate >.2).

Superconducting [Ts) and ferromagnetic (Tc) tran-sition temperatures are indicated. The curves areguides to the eye.

below, with a magnetic dipole moment of ~10 uB (Ref. 9).For randomly oriented holmium moments this calcula-tion yields a = 6.7 us"1, which indicates a significantdipole coupling to the u+ and is consistent with identifi-cation of the two-component structure of Gt(t) withquasi-static inhomogeneous broadening.

Two basic processes, Korringa scattering of conduc-tion electrons1 and indirect exchange (RKKY) couplingbetween Ho3+ spins,11 should be important in dilutemagnetic alloys. For the Korringa mechanism the u+

spin-lattice relaxation rate X should be proportional to .v2

at high temperatures, whereas Xozx for the RKKYprocess. At 100 K our measured values of Kt for x > 0.3*are proportional to x2, which indicates that the Korrinj,mechanism is dominant in this temperature regime. The

^concentration dependence of Xt for x > 0.35 cannot be•determined in the temperature range 11 K < T < 50 Kpecause A.j is too large.

We have calculated crystalline-electric-field (CEF)energies and wave functions for rare-earth (RE) 3+ ionsin the RE Rh4B4 structure by diagonalizing the Hamilto-nian for 42/w point symmetry, using the crystal-fieldparameters of Dunlap and Niarchos.* For Ho3+ theground and first excited states are each doubly de-generate, with nearly pure | / z =±8> and |±7> wavefunctions, respectively. The first excited states occur at8 ~ 55 K. Allowed transitions from j ±8> to | *8> there-fore can occur only through small admixtures of differentJL eigenfunctions in the ground and excited states, whichare separated by at least 55 K. The slow Ho3+-momentfluctuations at low temperatures then can be accountedfor by a combination of the large ground-state isolationand the weakness of A/z = ± 1 transitions within theground-state doublet.

Below ~9 K the values of ^ for x = 0.02 and x = 0.7,shown in Fig. 2, are remarkably similar considering thelarge difference in holmium concentrations. This observa-tion can be understood if the dominant Ho3+-momentrelaxation mechanism is again Korringa scattering, as at100 K. At least one source of difference in the tempera-ture dependence of X2 between x = 0.02 and x = 0.7 is theonset of ferromagnetism below the Curie temperatureTc = 4.1 K at the latter concentration.

Below Ts the temperature dependence of \ forx = 0.02 indicates an activation energy A =t 10 K, whichis much smaller than the CEF ground-state isolation 8.Since A ~ 1.8 Ts, interpretation of A as a superconduct-ing gap parameter yields a value considerably smallerthan the BCS gap parameter ABCS = 3.5 Ts. Such aninterpretation is, however, speculative at this time, be-cause it is not. clear how the superconducting state couldreduce the activation energy for Ho3+ fluctuations to avalue much less than 6.

*See Ref. 12. The actusl parameters used vary somewhat fromthis reference, and were obtained from B. D. Dunlap, privatecommunication.

1 1 8 PROGRESS AT LAMPFLas Alamos Nalimal Laboratory

REFERENCES

1. C. Boekema, R. H. Heffher, R. L. Hulson, M. Leon, M. E.Schillaci, J. L. Smith, S. A. Dodds, and D. E. MacLaughlin, J.Appl. Phys. 53.2625(1982).

2. D. E. MacLaughlin, S. A. Dodds, C. Boekema, R. H. Hefflier, R.L. Hutson, M. Leon, M. E. Schillaci, and J. L. Smith, J. Magn.Magn. Mat. 31-34, 497 (1983).

3. B. T. Matthias, E. Corenzwit, J. M. Vandenberg, and E. Barz,Proc. Natl. Acad. Sci. USA 74, 1334(1977).

4. Proceedings of the Int. Conf. on Ternary Superconductors, G. K.Shenoy, B. D. Dunlap, and F. Y. Fradin, Eds. (North Holland,New York, 1981).

5. R. S. Hayano, Y. J. Uemura, J. Imazato, N. Nishida, T.Yamazaki, and R. Kubo, Phys. Rev. B 20,850 (1979).

6. R. K ubo and T. Toyabe, in Magnetic Resonance and Relaxation,R. Blinc, Ed. (North Holland, Amsterdam, 1967), p. 810.

7. R. H. Hefiher, M. Leon, M. E. Schillaci, D. E MacLaughlin, andS. A. Dodds. J. Appl. Phys. 53,2174 (1982).

8. R. E. Waist.ait and L. R. Walker, Phys. Rev. B 9,4857 (1974).

9. H. R. Ott, L. O. Woolf, M. B. Maples, and D. C. Johnson,J. Low Temp. Phys. 39, 383 (IJ.80).

10. H. Hasegawa, Prog. Theor. Phys. 21,483 (1959).

11. M. R. McHenry, B. G. Silbernagel, and J. H. Wernick, Phys. Rev.B 5, 2958(1972).

12. B. D. Dunlap and D. Niarchos, Solid State Commun. 44, 1577(1982).

itnutry-Decanber 7983 raOOMEWATLAMTF 1 1 9LotAHmot NttiontlLtborMory

Biomedical Research and Instrumentation

Instrumentation/ . D. Doss (Los Alamos)

Ophthalmology

This year has seen significant improvements in bothinstrumentation and treatment techniques in the thermo-keratoplasty program. This work involves using shaped rffields to thermally shrink the human cornea to alter shapeand improve vision. Because the work done in theprevious year to increase heat transfer at the cornealendothelium proved successful in animal experiments,human trials were resumed.

Introduction of a "triad" treatment, that is, threesymmetric applications around the pupil—have provedvery effective, both in shrinkage and, so far, in stability.Several patients have experienced dramatic clinicalbenefits, which will be observed for long-term stability.

A private corporation is seeking an exclusive license onthe two USDOE patents that cover this technology. Aversion of the ray-trace program LENS has been suppliedto the Doheny Eye Institute, University of SouthernCalifornia, where it is expected to be used to evaluateanimal experiments involving modification of the eye.

Kansas. The field-calculating software FIELD has beensupplied to the United States Environmental ProtectionAgency office in Las Vegas, Nevada. Work to developless expensive, more efficient rf sources for hypertherrrcontinues.

Microwave Dosimetry

. 2 ,Several passive resonant microwave dosimeters havebeen constructed and tested, in the frequency range from50 to 1000 MHz. Maximum useful sensitivity is about10 uW cm"2. A patent3 will be filed by the USDOE; two

• private companies are planning to develop the device forcommercial production.

Microsurgery

An applicator for microclips used in blood vesselsurgery has been developed, in collaboration with theUniversity of New Mexico (UNM) School of Medicine.Initial tests indicate that the device will enable moreeffective and rapid anastomoses (joining) of small bloodvessels. This work has implications for stroke victims,hand surgery, and a variety of related procedures. A jointUNM/USDOE patent is expected to be filed.

Hyperthermia

The hyperthermia unit loaned to China has been usedto treat seven cases of human brain cancer, with someevidence of beneficial effect in two of the three caseswhere the highest dose was applied. This program willcontinue, with treatment of 30 patients planned. Addi-tional instrumentation was supplied to China during1983, following the initial treatments.

A protocol for treatment of cervical intraepithelialneoplasia (CIN) has been approved and special elec-trodes have been designed for use at the University of

REFERENCES

1. C. J. Sternhagcn and J. D. Doss. "Combined Radiation Therapyand Localized Current Field Hyperthermia with a 13-MHz Ap-plicator in Head and Neck and Gynecological Cancer Therapy," inthe Proc. of the meeting of the Radiation Research Society, SanAntonio, Texas, February 28, 1983.

2. J. D. Doss, "Passive Dosimeters for rf and Microwave Fields,"

accepted for publication in Rev. Sci. Instrum.

3. J. D. Doss, "Multipolar Corneal-Shaping Electrode with FlexibleRemovable Skirt," l/.S. Patent No. 4,381,007, issued April 26,1983.


Jtnovy-O»cmnb*r IS

\Nuclear Chemistry

Time-of-Flight Isochronous (TOFi; Spectrometerbr the Mass Measurements of Nuclei Far fromStabilityD. J. Vieira, J. M. Wouter, G. W. Butler (Los Alamos),H. Wollnik (Univ. of Giessen), L. P. Remsberg(Brookhaven), and D. S. Brenner (Clark Univ.)

Introduction

In recent years there has been a rapid increase in ourknowledge of the atomic-mass surface far from the valleyof p stability. However, even with these advances thereremain more than 60 neutron-rich nuclei with A < 70 forwhich the only known information is that they are stablewith respect to neutron emission. Clearly, more detailedinformation about these nuclei is essential.

Especially important are the measurements of ground-state atomic masses, because the ground-state mass isone of the most fundamental properties of a nucleus. Acomparison of measured masses with those predicted byvarious mass models not only is a test of these models butis a serious test of our understanding of nuclear interac-tions in general.

Because the binding energy, and hence the mass, of anucleus is dependent on the exact details of the nuclearforce, its prediction requires an understanding of thesedetails. In a strong sense, an atomic-mass model includeseverything that we know about the nuclear force andnuclear interactions. A systematic study of accuratelydetermined masses encompassing a wide variety of nucleifar from p stability would provide a most challenging testof current atomic-mass theories and should yield newinsight into the nuclear structure of such exotic nuclei.

During discussions in 1979 with Hermann Wollnik ofthe University of Giessen concerning the limitations ofperforming direct mass measurements using a totalkinetic-energy, time-of-flight measurement technique, theidea of building a recoil time-of-flight spectrometer wasconceived and developed.3

Such a spectrometer, which we call the time-of-flightisochronous (TOFI) spectrometer, has vastly improvedthe ability to make direct mass measurements, overcom-ing to a large extent the limitations of the above ap-proach. Moreover, this new type of recoil spectrometerhas all the advantages of other direct mass measurementapproaches, but with the added features of being both fastand universal (that is, all reaction products with half-livesgreater than ~2 us could be studied). Thus, with the

development of the TOFI spectrometer, one expects forthe first time to be able to systematically and globallyinvestigate the entire nuclear-mass surface up to A = 70.

In this report we outline the basic features of the TOFIspectrometer and its associated transport line, discuss themass measurement capabilities of the system, highlightprogress during 1983, and review future plans.

TOFI Spectrometer

The basic principle of the TOFI spectrometer is that itis designed to be isochronous (the TOF is velocityindependent). This means that the measured transit timeof an ion through the system provides a precise measure-ment of the mass-to-charge ratio. Because charge is aquantized entity, only moderately accurate measure-ments (at the 1-2% level) of the energy and free-spacetime of flight, together with the known momentumacceptance of the spectrometer, are necessary to uniquelydefine the charge state. Having thus determined thecharge, the mass can be deduced from the mass-to-chargeratio as obtained from the measured transit time of theion through the spectrometer.

Another important feature of the spectrometer is that itcan be focused in both energy and angle, thus allowing along flight path (~13 m) with a relatively large solid angle(2.5 msr) and momentum acceptance (±2%). Because thespectrometer is nondispersive, there is no physicalseparation between different ions, allowing the simultane-ous measurement of many nuclei (especially importantare isobaric members with well-known masses that will beused as internal calibration points). Since approval of thefunding proposal to DOE, extensive work has gone intoimproving the design of the spectrometer, and during thelast year significant engineering progress has been made(see section under Progress in 1983 in this report, p. 123).Figure 1 shows a sketch of the current system, whichconsists of a transport line and the TOFI spectrometer.

Through discussions with Karl Brown of SLAC, animproved version of the TOFI spectrometer has beendeveloped that is optically superior to the original design.Applying Brown's ideas of an achromatic' system consist-ing of identical unit cells, the spectrometer is envisionedto consist of four integrated-function dipoles. Each dipolebends the beam by ~81° such that sufficient dispersion isproduced to make the overall sys.tem isochronous (that is,ions of higher momentum are made to follow a longerflight path than those with lower momentum so that allions take the same amount of time to traverse the

Janijsry-Dectmber 1983 PfiOQnESSATLAMPF


121

spectrometer). Edge angle focusing at the entrance andexit boundaries of the magnets is used to produce anintermediate image of the beam spot exactly at themidpoint of the system. Here the beam is dispersed and amomentum coUimator defines the momentum acceptanceof the spectrometer, after which the dispersion is removedby the last two dipoles.

The beauty of this system is its symmetry. Because ofthis symmetry, all first- and second-order geometricoptical terms are identically zero, and because the systemis made to be isochronous, all first- and second-orderachromatic optical terms are essentially zero. Beyondsecond order, the symmetry of the system ensures thathigher order terms should be small as well. This has beenconfirmed in RAYTRACE calculations performed byHarald Enge (MIT), who has consulted with us on theoptics of both the spectrometer and the transport line andwho has greatly assisted with the engineering and con-struction details. Thus, to the extent that the magnetsfollow design, no ray tracing of particle trajectoriesemploying position-sensitive detectors will be necessary,and the mass resolution will be limited only by the timingbetween the start and stop signals.

In summary, the important features of the spec-trometer are

(1) isochronicity;(2) 1:1 imaging, nondispersive at focus;(3) acceptance Ail - 2.5 msr, Ap = ±2.5%; and(4) resolution M/AM = 2000.

The first two features enable the time-of-flight techniqueto determine the mass of the ion, using small state-of-the-art timing counters to obtain the ultimate in mass resolu-tion while simultaneously maintaining a large solid angleand momentum acceptance. Incorporating all these fea-tures, this unique spectrometer will make possible a seriesof direct atomic-mass measurements involving a largenumber of previously unmeasured nuclei that lie far from(3 stability.

Transport Line

Another important development is the idea of movingthe spectrometer out of the LAMPF switchyard into amore accessible area with the reaction products beingtransported to the spectrometer via a secondary beamline. In the Thin Target Area there has always beenprovision for a 90° port and a pipe through theswitchyard wall that leads to the basement area of the hotcells. This location has recently been vacated with the

move of the machine shop to a new building. Workingaround the constraints of not disturbing the nuclearchemistry rabbit system and the hot water resin filters, wedeveloped the layout shown in Fig. 1 for a secondarbeam line connecting to the Thin Target Area scatteringchamber. The advantages cf incorporating such a trans-port line into the design include the ability to

(1) accept a larger phase space with better matching tothe spectrometer acceptance,

(2) use a dedicated start-time counter to sharpen time-of-flight resolution (and thus mass resolution) in-dependently of the primary beam timing,

(3) eliminate high-yield light ions before they enter thespectrometer, and

(4) work on the system during LAMPF beam opera-tion.

Mass Measurement Capabilities

The TOFI spectrometer will greatly advance directmeasurements of atomic masses of numerous light nucleithat lie far from stability. With a mass resolving power ofM/AM= 2000, an A= 40 reaction product would have alinewidth of ~19MeV (FWHM) and a centroid uncer-tainty of

o. =-2.35 \/N M

where N is the number of events in the mass line. Thiscentroid uncertainty, which represents the mass measure-ment accuracy, can be minimized by good mass resolu-tion and large sample size, both of which the TOFIspectrometer and high-intensity LAMPF beam canprovide.

In the above cjse with an accumulation of 10* events,a mass accuracy of 80 keV can be achieved. Systematicerrors, which also contribute to the overall uncertainty ofthe determination, are dramatically reduced (<;30 keV),as our technique would take advantage of the fact thatseveral members of an isobar (which are resolved in Z bya thin dE/dx detector) with accurately known masseswould be measured simultaneously at each mass position.Thus, mass measurement accuracies ranging from30 keV to 1 MeV are expected, depending on the produc-tion rates of these nuclei.


January-Dtctmbarise

800-MffPRO TOW BEAM

LAMPF SWITCHYARDFl.EL.69S7'

Fig. 1.Layout of the TOFI spectrometer and transport line.

Scaling from the neutron-rich isotopic yields that wehave observed in the nitrogen-through-chlorine region,6

we estimate that the TOFI spectrometer can measuresome 30 new or improved atomic masses with accuraciesof 100 keV or better together with some 15 additionalnew measurements with accuracies ranging between100 keV and 1 MeV. Outside this region, numerous massmeasurements of other neutron-rich nuclei in the argon-to-zinc region appear feasible, where adequate Z resolu-tion can still be obtained. Moreover, the masses of alimited number of neutron-deficient nuclei could also bemeasured.

In summary, the TOFI spectrometer will be able tomeasure the masses of from two to five new isotopes perelement from Z=l to Z~Z0. Development of such aspectrometer at LAMPF will provide a unique op-portunity to systematically study the atomic-mass sur-face throughout the light mass region. Such measure-ments will permit a critical test for a variety of atomic-mass models, sufficiently constraining these theories tosuch a degree that significant advances in our under-

standing of the light nuclear-mass surface can be ex-pected.

Progress in 1983

During the past year the TOFI spectrometer projecthas made significant progress in three major areas. First,detailed optical studies of the spectrometer and transportline have resulted in final designs. Second, the spec-trometer dipoles have been designed, modeled (using thePOISSON magnet code), and sent out for fabrication. Andthird, the first half of the transport line has been engi-neered and all four quadrupole triplets needed for the linehave been refurbished.

In addition, conceptual layouts and engineering detailsof various other components of the spectrometer andtransport line (magnet stands, vacuum tanks, collimators,control system, and beam boxes) have been developed.Finally, the room in which the spectrometer will residehas been prepared and fitted with water-cooling lines.

January-December 1983 PMXMEU AT LAMPFLOS Alnrnt NUiontl Ltoruory

123

These undertakings have been carried out with theassistance of several MP-Division groups. In particular,we would like to acknowledge Jim Sims, Don Clark, andJoe Van Dyke (MP-8); Jim Little and Del Kercher(MP-1); Ed Schneider and Harold Ferguson (MP-11);and Dick Werbeck (MP-7). We greatly appreciate thisessential LAMPF support.

Future Plans

During the 1984 winter/spring shutdown of LAMPF,the first of half of the transport line will be installed,which will enable the characterization and performanceoptimization of one of he key transport-line components:the mass-to-charge filter. Moreover, the first half of thetransport line will be used to test and develop newdetectors needed for the TOFI spectrometer. Finally,once this section of the transport line is operational, theremaining part of the transport line and the spectrometercan be assembled and tested independently of LAMPFbeam operations.

The spectrometer dipole components are scheduled fordelivery in early summer, at which time they will beassembled and the initial field mapping will take place.After one dipole has been thoroughly tested and op-timized, the other dipoles will be trimmed in like fashion.Configuration of the four dipoles into final spectrometer

form is planned for the fall when off-line testing usingalpha and fission sources will begin. After optimization ofthe spectrometer performance and the completion of thesecondary beam transport line in early 1985, the T O !spectrometer is scheduled to undertake its first on-lineexperiment.

REFERENCES

1. W. Benenson and J. Nolen, Eds., "Proceedings of the SixthInternational Atomic Mass Conference," East Lansing, Michigan.September 1979 (Plenum Press, New York. 1980).

2. "Proceedings of the Fourth International Conference on NucleiFar From Stability," Helsingor, Denmark, June 1981, CERNreport 81-09 (1981).

3. H. Wollnik and T. Matsuo, Int. J. Mass Spectrom. Ion Phys. 37,209 (1981); and J. M. Wouters, D. J. Vieira, H. Wollnik, H. A.Engc, S. B. Kowalski, and K. L. Brown, in preparation.

4. D. J. Vicira, G. W. Butler, L. P. Remsberg, A. M. Poskanzcr, andH. Wollnik, "LAMPF Timeof-Flight Magnetic Spectrometer forPrecision Mass Measurements of Very Neutron-Rich Light Nu-clei," in the INC-Division proposal to DOE, WPASFY84 (1980),pp. 41-73.

5. K. L. Brown, IEEE Trans. Nucl. Sci. NS-2f"., 3490 (1979); andStanford Linear Accelerator Center rcpor. SLAC-PUB-2257(1979).

6. G. W. Butler, D. G. Perry, L. P. Rcmsbcrg, A. M. Poskanzer. I. B.

Natowilz, a-d F. Plasil. Phys. Rev. Lett. 38, 1380(1977).

124 PflOGRESSATUMPFLos Alamos National Laboratory

January-DGCwnbtt 191

Helium-Jet Transport of Fission and Spallation Re-action ProductsIxp. 629, AB-Nucchem)

Kuos Alamos, Idaho National Engineering Lab., Univ. ofOklahoma)Spokesmen: M. E. Bunker and W. L. Talbert, Jr., (LosAlamos) and R. C. Greenwood (Idaho National Engi-neering Lab.)

Introduction

A unique opportunity exists at LAMPF for the pro-duction and study of nuclei far from stability. Theproperties of these highly unstable nuclei are of greatinterest to theorists, largely because they constitute animportant extension of the systematic base of data that isused to test nuclear models and thus to improve ourunderstanding of nuclear forces.

Approximately 3 years ago, advances in helium-jettechnology, especially the coupling of helium-jet systemsto isotope separators, suggested a relatively simplemethod of gaining access to the short-lived reactionproducts producible at LAMPF. The helium-jet tech-nique, as a method for transporting radioisotopes to anisotope separator, has three main advantages:

(1) it provides access to many isotopes of a number ofelements that cannot be efficiently extracted forstudy at any of the present or proposed on-linefacilities;

(2) it allows transport of recoil reaction products overdistances of many meters in fractions of a second,thus providing access to very short-lived activities;and

(3) it has a relatively low cost.Except for gaseous products, all elemental species are

transported efficiently with a helium-jet system, includingthe refractory metals such as zirconium, niobium,molybdenum, tcchnetium, palladium, ruthenium, andrhodium, in contrast, the relatively massive targets thatmust be used (because of low beam currents) at othermajor on-line separator facilities almost completely retainthe refractory-metal factionuclides, making these ac-tivities unavailable for study. Use of the thin targetsrequired in the helium-jet method requires a very largeincident beam current, of thy order of that available atLAMPF, to get a sufficient yield of individual radio-isotopes for detailed study.

The helium-jet technique involves stopping the atomsthat recoil from the thin targets in aerosol-loaded helium,with subsequent attachment of the radioisotopes to the

aerosol particles. The transport of the activity-laden gasfrom the target chamber to an evacuated collectionchamber or mass-separator ion source then takes placethrough a long, small-diameter capillary, at velocitiesapproaching sonic.

The separated ion beams extracted from the isotopeseparator would be directed to various experimentaldevices capable of determining basic nuclear propertiessuch as half-life, spin, nuclear moments, mass, andnuclear structure. The data acquired would have broadapplication to theories of nuclear matter and such relatedtopics as nucleosynthesis of the elements. Emphasisinitially would be on the study of short-lived, neutron-richfission products. Fission is the only way to reach veryneutron-rich nuclei, and among the refractory metalsalone it appears that we would have a good chance ofidentifying and making measurements on at least 150previously unobserved isotopes, a prospect that wouldinevitably attract a sizable international user group.

Our studies of helium-jet systems at LAMPF wereinitiated in FY 1981. These initial experiments, whichused a rather crude target chamber and activity collectionarrangement, yielded very promising results on the ac-tivity transport efficiency for both fission and spallationproducts. The experiments were carried out with littleflexibility; only one target chamber pressure was used,and the beam current and aerosol furnace temperaturewere not widely varied. Hence, additional experimentswere outlined to better investigate the influences of beam-current variations, aerosol furnace temperatures, andtarget chamber pressures. Since the first experimentsemployed only NaCI as the aerosol, it was also con-sidered important that another aerosol, namely PbClj, bestudied in the next set of experiments.

For the second set of experiments at LAMPF, a newtarget chamber design was needed to determine pressureeffects on transport efficiency and transport time. Withassistance from Los Alamos Technical Associates, a newconcept was developed that facilitated changes inchamber thickness for the pressures of interest (to keepthe chamber thickness approximately equal to the fission-product range in helium when different pressures wereused). Also, analytical calculations were made to predictthe transit times through the capillary.

The above preparations were accompanied by a seriesof discussions with MP-Division staff, which resulted inincluding a helium-jet target in the plans to reconstructthe beam-stop area of LAMPF and in providing space inthe LAMPF staging area for an on-line separator system.

muary-Decomber 1983 PROGRESS AT LAMPFLot Altmos Ntlionil LUxrttory

125

Experimental Results

Much of our experimental effort has been directedtoward (1) establishing whether a helium-jet system canbe operated successfully when an 800-MeV, ~750-uAproton beam is incident on the target chamber, and (2)establishing whether transport times of < 1 s for thereaction products can be achieved. Not until these ques-tions were satisfactorily resolved could we consider thatthe planned facility is viable.

Because of the great difficulty of using the main beam(Line A) for our feasibility experiments, we chose insteadto use the beam available in the Nuclear Chemistry caveon Line B, where the maximum beam current is onlyabout 6 uA. However, since the beam-current densitieson Lines A and B are comparable, many of the dataobtained on Line B should be representative of what wecan expect on Line A. In addition to the on-line LAMPFexperiments, we have conducted on-line experiments atthe Omega-West Reactor, as well as various bench-typeexperiments on helium-jet configurations, to study varia-tions in performance caused by changes in critical designand operating parameters.

The second set of LAMPF experiments was performedin November 1982. The operations staff provided anintense, steady, tightly focused beam, which in effectmade unnecessary the plans to continue these studieswith a future Line A experiment. The major results of theexperiments are summarized below.

The target chamber contained two 7.6-cm-diamdepleted-uranium foils, of thickness ~10 mg/cm2, situ-

ated facing each other across the chamber volume. At thecollection chamber, we used a moving tape collector torapidly transport collected samples of activity to a well-shielded Ge(Li) gamma-ray detector. The tape collectoiallowed us to observe short-lived activities, of half-life1-5 s. The observed counting rates of 23SV(p,f) productswere very high, and in the resulting spectra many of tiegamma-ray peaks could not be identified from previouslyreported studies. The transport efficiencies for all non-gaseous-element activities averaged about 60%,measured absolutely. At higher target chamber pressures(up to 600 kPa), the short-lived activity levels were muchhigher than those observed at 200 kPa, in keeping withfaster transport caused by higher flow rates.

Transit-time measurements were performed for vari-ous conditions, with the best result being 230 ms for atarget chamber pressure of 500 kPa. The data are shownin Fig. 1. The calculated prediction of this transit time fora capillary length of 22 m is 320 ms. Since the calculationis based on an average flow velocity in the capillary, theexperimental result illustrates that the aerosols are"herded" into the central part of the capillary during theflow, thus acquiring a larger-than-average flow velocity.The transit-time measurements provide convincingevidence that activities as short as 300 ms can be studiedwith the proposed helium-jet on-line mass-separator sys-tem.

The Line B current was varied over a range from 1.5 to6.1 uA. The transport efficiency did not vary over thisrange. Postexperiment scans of the beam-induced activityin the 238U target foils indicated that at the highest

Transit-Time Measurements at LAMPF

gjjj.

C

1000

800

800

700

500-

200

100

• • • * •%• • • •

• , • » V «,

delaytimt(054 •)

— 0Z3 • ExtendedCapillary

0 05 1 15

Fig. 1.Activity transit-time measurements atLAMPF. Beam is turned on at 0 s, and thetape transport delay is 0.54 s. In the targetchamber illustration, the beam spot is thehorizontal line across the circular target foil.

25 J 3.5 4 4.5 5 55 8Time (t)

1 2 6 PROGRESS AT LAMPFLos Alamos Nation*/ Laboratory

Jsnuvy-OKttnbv 1963

current, a beam-current density of 45 uA/cm2 had beenachieved, about twice that expected for Line A. We"onclude that the gas-transport system should functionatisfactorily in the intense Line A beam.

The highest target chamber pressures used (500 and600 kPa) resulted in capillary flow for which the Rey-nolds number exceeded conventional design limits (valueof 2200). However, the activity rate continued to increasewhen these pressures were used. The conclusion was thatany turbulence resulting from the flow did little to disturbthe transport of the heavy aerosols.

The temperature dependence of the amount of activitytransported verified that the activity attaches to theaerosols according to the total aerosol surface area,which had been indicated in unrelated studies at otherlaboratories for aerosols in the size range employed here(less than 0.1 um). Samples were collected for electronmicroscopy, and aerosol size distribution measurementswere made on activity-loaded aerosols. The PbCI2 aero-sols were seen to be chain-like aggregates with a largeresulting surface area.

The availability of a several-micro-amp beam onLine B is too rare to make systematic studies of designparameters to optimize the configuration of a Line Atarget chamber. We therefore have installed a neutronbeam shutter at the Omega-West Reactor to continuethese studies and to arrive at an optimum configurationregarding these questions;

1. What will be the effect of using multiple capillariesrather than only one?

2. What design of capillary and helium supply-lineplacement will result in the highest target-volumesweep rate?

3. W A h of the three candidate aerosol materials willpro|lde the highest transport efficiency—NaCI,KCI, or PbCl2?

The test target chamber has a number of possibleconfigurations for gas inlet and exit ports. Preliminaryresults indicate that, for a circular target chamber (suchas would be installed on Line A), a single capillary outletline, opposite from two inlet lines 90° apart, wouldprovide an optimum configuration. Multiple capillaryoutlets appear not to improve the flow characteristics, buttwo inlets provide improved performance over one orIhree inlets. PbCl2 appears to be the most efficient aerosolfor activity transport.

We have developed a series of figures showing thelimits of known properties for nuclei and graphicallydepicting the large regions of nuclei that are unknownand yet have half-lives larger than 300 ms, consistentwith the capabilities of the proposed helium-jet system.The illustrations for %ass and ground-state spin areshown in Figs. 2 and 3, in which some of the regions thatare available only with the use of a helium jet arehighlighted. The neutron-rich regions are accessible byfission of 238U, and the neutron-deficient regions areaccessible by use of appropriate spall ation targets.

The experimental results from the LAMPF experi-ments have been reported at APS meetings and at a

100

80-

60-

40-

20-

known m

300-ms limit(Takohashi et ol.)possible onlywith He jet

0 20 40 60 80 100 120 140 160 180

Fig. 2.Chart of nuclides showing limitof known masses and predicted300-ms half-life boundaries. Theshaded areas are some of theregions where a helium-jet/isotope-separator system canuniquely provide separatedisotopes for on-line study.

January-December 1983 PROGRESS AT LAMPF 1 2 7Los Alamos National Laboratory

100

80-

60-

40-

20-

known ground-state•pin parity

300-ms limit(lakahashi et al.)

--"• • • ' ' '

20 40 60 80 100N

120 140 160 180

Fig. 3.Chart of nuclides showing limit of known spin-parity assignments and predicted 300-ms half-lifeboundaries. The shaded areas are some of the regions where a helium-jet/isotope-separator systemcan uniquely provide separated isotopes for on-line study.

Nuclear Data Committee Specialists' Meeting on Yieldsand Decay Data for Fission Product Nuclides.4 At theThird LAMPF II Workshop, a presentation was made ofthe results of Exp. 629, and the merits of a helium-jetsystem at a thin target area at LAMPF II werediscussed.

We are confident that the results obtained in Exp. 629establish the feasibility of a helium-jet activity transportsystem at LAMPF, and no further beam requests arecontemplated. A proposal for funding a helium-jet cou-pled mass separator at LAMPF is in preparation and willbe submitted to the USDOE Division of High Energy andNuclear Physics in early 1984.

REFERENCES

1. W. L. Talbert, Jr., M. E. Bunker, B. J. Dropesky, J. W. Sterner, R.

C. Greenwood, R. J. Gehrke, and V. J. Novick, Bull. Am. Phys.

Soc. 26, 1156(1981).

2. W. L. Talbert, Jr., M. E. Bunker, J. W. Starner, S. C. Soderholm,V. J. Novick, and R. F. Petry, Bull. Am. Phys. Soc. 28,646 (1983).

3. W. L. Talbert, Jr., M. E. Bunker, J. W. Slarner, and M. E.Schaffner, Bull. Am. Phys. Soc. 28, 990(1983).

4. W. L. Talbert, Jr., M. E. Bi -.Ker. and J. W. Starner, in "Proceed-ings of the OECD/NEA Nuclear Data Committee Specialists'Meeting on Yields and Decay Data lor Fission Product Nuclides"(October 1983).

5. D. J. Vieira and W. L. Talbert, Jr., in "Proceedings of the Third

LAMPF II Workshop," Los Alamos National Laboratory report

LA-9933-C (1983), Vol. II, p. 886.

128 PROGRESS AT LAMPF£.05 Alamos National Laboratory

January-Dtcember 19B3

Radioisotope ProductionDavid C. Moody

During 1983 the1 Medical Radioisotopes ResearchGroup (INC-3) substantially increased the quantity ofradioisotopes made available to the nuclear medicinecommunity (22 Ci in 1982 vs 35 Ci in 1983). Thisincrease is tied directly to requests from the nuclearmedicine community in general, but also can be linked tomajor new emphases in our own radiopharmaceuticalsresearch program at Los Alamos, as well as new col-laborative research directions.

Isotope Production and Separation

Table I shows radioisotope shipments made during FY1983. Although this presents a reasonable summary ofour production and separation activities, two areas ofemphasis during 1983 warrant more detailed discussion(these are grouped under the principal isotopes involved,IMI and 67Cu, in the sections that follow).

Iodine-123/ . W. Barnes, M. A. Ott, K. E. Thomas, and P. M.Wanek

Current brain perfusion agents under developmentindicate a need for amounts of 123I that far surpass thepresent supply. To evaluate LAMPF as a potential newsource for this radioisotope, we have developed a batchprocess and are initiating the design and implementationof an on-line 123Xe recovery system that is expected tosubstantially increase the 123I yield and improve itsradionuclidic purity.

At LAMPF, 123I is produced through the decay of123Xe formed by spallation of cesium in CsCl. The batchprocess currently in use involves transferring of 123Xeafter irradiation to a generator where it is held for anappropriate decay period for the formation of 123I. Aproposed on-line process uses the same generator system,but differs from the currently used process in that thexenon is continuously transferred to the generator duringirradiation.

The development of a reliable target container and atrouble-free vacuum system for 123I production wasreported in the INC-Division Annual Report in 1982.Additional experiments were performed to demonstratethe maximum production capability of the batch process

at LAMPF. A target containing 175 g of CsCl wasirradiated for 4 h and subjected to a 4-h crow*h period.The quantity of I23I recovered, corrects ,<id-of-growth period, was 850 mCi with a 0.4% contaminationby 125I. The surface of the void above the salt was washedwith dilute NaOH to extract the 123I that resulted fromthe decay of 123Xe during irradiation. The resultantsolution contained 900 mCi of 123I, corrected to the end-of-growth period, with a 0.5% contamination by I2SI. The123I in this last solution represents a proof of principle forthe on-line process, but is not a usable product from thebatch method because it contains undesirable spallogeniciodine species that were extracted from the surface of thesolid CsCl block. However, the sum of the two solutions,1750 mCi of 1MI, represents a conservative approxima-tion of the 8-h production from the on-line operation.

Copper-67G. Bentky and W. Taylor

A new separation method for 67Cu has been developed,based on a novel electrochemical technique. The productfrom the separation is free from radioactive contami-nants, with the exception of 64Cu, and has minimalquantities of stable materials present as impurities.

The zinc oxide target is dissolved in 3Af sulfuric acid.Following dissolution of the target material, the solutionis transferred to an electrolytic cell that consists of aplatinum working electrode, a platinum counter electrodethat is isolated from the bulk of the solution by a glassfrit, and a silver/silver chloride reference electrode. Theelectrodes are connected to a potentiostat that maintainsa controlled potential at the working electrode. A poten-tial of-0.35 V (all potentials are vs Ag/AgCl) is appliedto the working electrode. This potential is sufficientlycathodic to result in the reduction of copper. Zinc, lead orcadmium (both of which are present in the zinc oxide asimpurities), or nuclides other than copper formed duringthe irradiation are not reduced at this potential.

Following deposition of the copper onto the platinumelectrode, the electrode is rinsed and the solution isreplaced with a clean 0.1M sulfuric acid solution. A +0.1 -V potential is applied to the working electrode and thecopper is stripped off the electrode into the solution. Thepotential of the working electrode is again changed to-0.35 V and the copper replated onto it. This secondplating operation affords additional decontamination ofthe copper from any zinc that is carried along with thecopper product. The sulfuric acid solution is replaced

luary-December 1983 PROGRESS AT LAMPF£.05 Atamos National Laboratory

129

Table I. Medical Radioisotope Shipments—FY 1983.

Isotope InstitutionNumber ofShipments

Amount(mCi)

26A1

"Br

77Br Estradiol

• 7Cu

5 'Fe

148Gd

68Ge

Oak Ridge National Laboratory, EPRITOTAL

George Washington UniversityJohns Hopkins Medical InstituteLos Alamos National Laboratory, Group INC-3Los Alamos National Laboratory, Group INC-7TRIUMF

University of New MexicoWashington University

TOTAL

University of MassachusettsNortheastern UniversityUniversity of New Mexico

TOTAL

California State University, FullertonColumbia UniversityHospital for Sick Children, Toronto, CanadaJohns Hopkins Medical InstituteLos Alamos National Laboratory, Group INC-3Los Alamos National Laboratory, Group LS-3Mayo Clinic

University of California, DavisTOTAL

Los Alamos National Laboratory, Group INC-11TOTAL

Lawrence Livermore National LaboratoryTOTAL

Brookhaven National LaboratoryMedical Research Council, Hammersmith Hospital, LondonMt. Sinai Medical Center, FloridaOak Ridge Associated UniversitiesOffice des Rayonnement Ionisant, FranceOak Ridge National Laboratory/DOEUniversity Hospital/The NetherlandsUniversity of ChicagoUniversity of Liege, BelgiumWashington University

TOTAL

11

448116226

2114

4142131521

22

22

121211121214

3

2

13

0.0040.004

624955963150511339443

52.631.36

56.96

0305

493148.42.43015

083806.8

0.00420.0042

10.810.8

10.12113112025354

25.415.06

357.58


Jtnuuy-Dtc*rnb»r1983

Table I. Cont.

Isotope InstitutionNumber ofShipments

Amount(mCi)

I 2 3 I

172Lu

m L u

86Rb

82.Sr

4Ti

127Xe

88y

Benedict NuclearMedi-Physics

TOTAL

VA Hospital, San DiegoTOTAL

Los Alamos National Laboratory, Group INC-11Los Alamos National Laboratory, Group INC-7

TOTAL

New England Nuclear, University of South CarolinaNew England NuclearUniversity of South Carolina

TOTAL

Medical Research Council, Hammersmith Hospital, LondonE. R, Squibb & SonsE. R. Squibb & Sons/Mt. Sinai and University of TexasE. R. Squibb & Sons/National Institutes of HealthE. R. Squibb & Sons/Sloan Kettering InstituteUniversity of California, Donner LaboratoryUniversity of Liege, Belgium

TOTAL

Los Alamos National Laboratory, Group INC-11TOTAL

Los Alamos National Laboratory, Group INC-DOTOTAL

California State University, NorthridgeLos Alamos National Laboratory, Group HSE-8Los Alamos National Laboratory, Group INC-11

TOTAL

Brookhaven National LaboratoryTOTAL

Hybritech Inc., San DiegoNew England NuclearVA Hospital, San Diego

TOTAL

Total Shipments: 117Total Curies Distributed:

24831

2

22

112

1113

451i24421

11

11

4116

55

121

3

1

6

2020

279

17.617.6

0.80.160.96

0.040.2360.040.316

550392340125310031432180

0.0100.010

0.0130.013

24.70.0670.1524.92

820820

10161036

35.03

luary-Dectmber 1983 PROGRESS AT LAMPF{.as Alamos National Laboratory

131

with a 2M HC1 solution and the copper is again removedfrom the electrode by applying an anodic potential. Thesolution is passed through an anion-exchange resin col-umn to remove any remaining zinc contamination. Quan-tities of 67Cu that have been recovered using this tech-nique have been as large as 5-6 Ci.

Radiopharmaceutical Labeling Research

Our radiopharmaceutical labeling program is madepossible by the availability of isotopes from LAMPF.These efforts continue to emphasize the use of silaneintermediates to achieve regiospecific labeling with "Brand I23I. This expertise in no-carrier-added radio-chemistry is currently being applied to monoclonal-antibody labeling for radioimmunoimaging and therapy.We are evaluating direct halogenation-coupling reactionsof small labeled precursors and complexing agents, suchas metallochelates. These areas are briefly outlinedbelow.

Radiohalogen Labeling: Brain and Heart AgentsD. S. Wilbur and Zitta V. Svitra

Brain. Amines play a major role in regulation of brainactivities. Although many molecules circulating in theblood cannot cross the blood-brain barrier, a variety ofamines can pass readily into the cerebral cavity. Theability of some amines to pass through the blood-brainbarrier makes these compounds attractive for radiolabel-ing. For example, an amine labeled with a gamma-emitting radionuclide might find wide use in single-photon-emission computed tomography (SPECT) forevaluation of the 400 000 hospitalized stroke patients inthis country. In addition to the benefits derived from themeasurement of cerebral blood flow, radiolabeled aminesmight be used to measure brain amine metabolism and toquantify amine protein receptors in different regions ofthe brain. Metabolism of amines and amine receptorconcentrations have been implicated in a number ofmental disorders, such as schizophrenia, manic-depress-ive psychoses, and parkinsonism.

Blau and Kung have studied several different amine-containing compounds that were able to cross the blood-

brain barrier.4"6 However, they found that only a few ofthe compounds stayed in the brain long enough to permitstudy of the regional blood flow. From their studies the;have postulated that the difference in the intracelluiarbrain pH (~7.0) and the blood pH (~7.4) is enough toretain some amines in the brain for extended periods oftime. In one study they were able to demonstrate that[ I23I|-iodoxyldiamine, 1, would stay in the brain for hours(T1/2 = 18 h), whereas [I25I]-iodobenzylamine, 2, cameout of the brain within minutes (Tl/2 = 15 min). Despitethe fact that I appeared to be a promising blood flowagent, the investigators chose to study other compoundsbecause the radiolabeling yields obtained for 1 were verypoor.

Our model compound studies using simple com-pounds similar to 1 and 2 had shown thataryltrimethylsilanes could be used to regiospeciflcallyintroduce radiobromine and radioiodine into suchmolecules. Therefore, a chemical study to investigate theuse of arylsilanes in radiolabeling 1 and a benzylaminesimilar to 2 was carried out (for specific details, see the1983 INC-Division Annual Report).

Another class of amines that is interesting with respectto brain studies is the phenethylamines. These com-pounds are congeners of the naturally occurringcatecholamine. dopamine. Changes r aubstituents on thephenethylamine backbone yield a variety of compoundsthat produce physiological responses from a light eu-phoria (caused, for example, by amphetamines) to hal-lucinations (for example, from mescaiine or the morepotent DOM). The interest in radiolabeling these com-pounds comes from the fact that they most likely interactwith dopaminergic or other catecholaminergic systems.Studies of the interactions may ultimately help delineatehow these systems work and thus how malfunctions ofthe systems might be treated.

Preliminary radiobromination studies of benzylaminesand phenethylamines demonstrate that the aryltri-methylsilane intermediates should work well for radio-halogenations of amines for brain studies. Collaborativestudies with C.-Y. Shuie and A. Wolf (Brookhaven) areunder way to determine if radiofluonnations might alsobe accomplished using arylsilanes. Applications ofaryltrimethylsilanes and pentafiuorosilicates in radio-halogenations will continue to be studied since the resultsthus far have been very encouraging.

1 3 2 PROGRESS AT LAMPF

Los Alamos National LaboratoryJanutry-Dtctmtm 196>

REFERENCES

1. H. Davson, "The Blood-Brain Barrier," J. Physiol. 225, 1-28. , (1976).

2. T. C. Hill, "Single-Photon Emission Computed Tomography toStudy Cerebral Function in Man," J. Nucl. Med. 21, 1197-1199(1980).

3. P. L. McGeer, J. C. Eccles, and E. G. McGee;, MolecularNeurobiulogy of the Mammalian Brain (Plenum Press, NewYork, 1978), Chap. 8, pp. 493-500.

4. K. M. Tramposch, H. F. Kung, and M. Blau, "RadioiodineLabeled Amines as Brain Imaging Agents," Applications ofNuclear and Radiochemistry, R. Lambrecht and N. Morcos, Eds.(Pergamon Press, New York, 1982).

5. H. F. Kung and M. Blau, "Regional Intracellular pH Shift: AProposed New Mechanism for Radiopharmaceutical Uptake inBrain and Other Tissues," J. Nucl. Med. 21, 147-152 (!98O).

6. H. F. Kung and M. Blau, "Synthesis of Selenium-75 LabeledTertiary Diamines: New Brain 'maging Agents," J. Med. Chem.23, 1127-1130(1980).

7. K. M. Tramposch, H. F. Kung, and M. Blau, "Synthesis andTissue Distribution Study of Iodine-Labeled Benzyl- andXylylamines," J. Med. Chem. 25, 870-873 (1982).

8. H. F. Kung, K. M. Tramposch, and M. Blau, "A New BrainPerfusion Agent: [I-123] HIPDM: N,N,N'Trimethyl-N'-[2-Hydroxy-3-Methyl-5-Iodobenzyl]-l,3-Propanediamine," J.Nucl. Med. 24, 66-72(1983).

9. D. S. Wilbur, K. W. Anderson, W. E. Stone, and H. A. O'Brien,Jr., "Radiohalogenation of Non-Activated Aromatic CompoundsVia Aryltrimethylsilyl Intermediates," J. Labelled Compd. Radio-pharm. 19, 1171-1188(1982).

10. D. S. Wilbur and Z. V. Svitra, "Organopentafluorosilicates:Reagents for Rapid and Efficient Incorporation of No-Carrier-Added Radiobromine and Radioiodine," J. Labelled Compd.Radiopharm. 20, 619-626(1983).

Heart. An accurate assessment of the extent of thedamage in myocardial infarcts or ischemia is criticallyimportant to heart patients. One method of evaluatingdamage to the myocardial tissue is to study the metabolicprocesses in that tissue. Because the major metabolicprocess in the heart is degradation of non-esterified fattyacids, it is not surprising that researchers from manydifferent groups have been exploring radiolabeled fattyacids as a noninvasive method for evaluating regionalmyocardial metabolism.

The radionuclide of choice for metabolic studies usinglabeled fatty acids is carbon,1 but as a positron emitter itsapplication is limited to only a few institutions. Radio-fluorinated fatty acids also have been studied, but thislabel has the same shortcoming. Radioiodine- and radio-bromine-labeled fatty acids have been studied as the bestalternatives.

Studies of radiolabeled fatty acids that encompassedmodifying the fatty acids chain length,4"6 degree ofunsaturation, and position of radiohalogenattachment4'8 have been carried out. Researchers havefound that long-chain fatty acids, 16-22 carbons inlength, are most effectively extracted, and unsaturationappears to be unimportant. The most important factorappears to be the position of the label within the molecule.Addition of bulky halogens to unsaturations within thefatty acid chain or halogenation at the carbon adjacent tothe carboxylic acid functionality has led to dramaticdecreases in the extraction from the blood. Contrary tothis, radiohalogen labeling at the carbon farthest from thecarboxylic acid functionality (r<> carbon) has shown littledifference in extraction from that of the |"Cl-labeled

3 9

analogs. '

Radiohalogen labeling, at the co carbon has beenaccomplished in high radiochemical yields by exchangereactions.9"1' Despite this fact, problems still exist for theco-radiohalogenated fatty acids. One of the problemsarises because haloacetic acids are produced asmetabolites of <B-radiohalogenated fatty acids and thesecompounds are extremely toxic substances. A solution tothis problem can be obtained by making a very highspecific-activity radiohalogen-labeled fatty acid. Un-fortunately, this is not readily accomplished throughexchange reactions. " A second problem arises be-cause co-radiohaJogenated fatty acids are not very stablein vitro or in vivo, which seriously affects the bloodactivity for imaging studies. Stabilization of the radio-halogen label has been accomplished by attaching theradiohalogens to phenyl or vinyl substituents on the cocarbon. Although there are some questions about usingthese agents to measure metabolism,14'15 a large efforthas been devoted to the synthesis and evaluation of thesecompounds.

The problems with obtaining high specific activities,long reaction times, and low radiochemical yields haveled to an investigation of organosilanes asintermediates20"22 to radiohalogen-labeled fatty acids.The investigation has been directed toward the synthesisof key precursor compounds that could be used to make

^.January-December 1983 PROGRESS AT i.*MPF

Los Alamos National Laboratory133

a series of co-silylated fatty acids. Several intermediatesnecessary to the synthesis of these precursor compoundshave been prepared. Synthesis procedures for convertingthese intermediates into the desired precursors and ul-timately into the co-silylated fatty acids are being de-veloped.

REFERENCES

1. E. S. Weiss, E. F. Hoffman, M.E. Phelps, M. J. Welch, P. D.Henry, M. M. Ter-Pogossian, and B. E. Sobel, "External Detect-ion and Visualization of Myocardial Ischemia with "C-SubstratesIn Vitro and In Vivo," Circ. Res. 39,24-3?. (1976).

2. E. J. Knust, M. Schiiller/and G. Stocklin, "Synthesis and QualityControl of Long-Chain "F-Fatty Acids," J. Labelled 'Compd.Radiopharm. 17, 353-363 (1979).

3. N. D. Poe, G. D. Robinson, and N. S. MacDonald, "MyocardialExtraction of Labeled Long-Cbain Fatty Acid Analogs," Proc.Soc. Exp. Biol. Med. 148,215-218 (1975).

4. H.-J. Machulla, G. Stocklin, C. Kupfernagel, C. Freundlieb, A.Hock, K. Vyska, and L. E. Feinendegen, "Comparative Evalua-tion of Fatty Acids Labeled with C-l 1, Cl-34m, Br-77, and 1-123for Metabolic Studies of the Myocardium: Concise Communica-tion," J. Nucl. Med. 19, 298-302 (1978).

5. C. A. Otto, L. E. Brown, D. M. Wieland, and W. H. Bierwaltes,"Radioiodinated Fatty Acids for Myocardial Imaging: Effects ofChain Length," J. Nucl. Med. 22,613-618 (1981).

6. E. J. Knust, C. Kupfernagel, and G. Stocklin, "Long-Chained'*F-Labe!ed Fatty Acids for the Study of MyocardialMetabolism; Odd-Even Effects," J. Labelled Compd. Radio-pharm. (Abstract) 16, 143-144(1978).

7. W. H. Beierwaltes, R. D. Ice, M. J. Shaw, and V. Y. Ryo,"Myocardial Uptake of Labeled Oleic and Linoleic Acids," J.Nucl. Med. 16,842-845(1975).

8. G. D. Robinson and A. W. Lee, "Radioiodinated Fatty Acids forHeart Imaging: Iodine Monochloride Addition Compared withIodine Replacement Labeling," J. Nucl. Med. 16, 17-21 (1975).

9. G. D. Robinson, "Synthesis of 123I- 16-Iodo-9-Hexadecanoic Acidand Derivatives for Use as Myocardial Perfusion ImagingAgents," Int. 3. Appl. Radiat. Isotop. 28, 149-156 (1977).

10. P. Laufer, H.-J. Machulla, H. Michael, H. H. Coenen, A. S. E!-Wetery, G. Kloster, and G. Stocklin, "Preparation of (0-ll3I-LabeIed Fatty Acids by '"I-For-Br Exchange: Comparisonof Three Methods," J. Labelled Compd. Radiopharm. 18,1205-1214 (1980).

11. H.-J. Machulla, K. Dutschka, and C. Astfalk, "ImprovedSynthesis of 17-l23I-Heptat'?canoic Acid for Routine Prep-aration," Radiochem. Radioaiml. Lett. 47, 189-192(1981).

12. H.-J. Machulla and K. Dutschka, "Iodination Methods forRoutine Preparation of 17-"3I-Heptadecanoic Acid and 15-("3I-Phenyl)Pentadecanoic Acid," J. RadioanaJ. Chem. 65,122-130(1981).

13. VI. Argentini, M. Zahner, and P. A. Schubiger, "Comparison ofSeveral Methods for the Synthesis of eo-Iodine-123-Hep-tadecanoic Arid." J Radioanal. Cheni. 65. 111-138(1981).

14. H.-J. Machulla, M. Marsmann, and K. Dutschka, "BiochemicalConcept and Synthesis of a Radioiodinated Phenylfatty Acid forIn Vivo Metabolic Studies of the Myocardium," Eur. J. Nucl.Med. 5, 171-173(1980).

15. H. H. Coenen, M.-F. Harmand.G. Kloster, and G. Stocklin," 15-(p-["Br]Bromophenyl)Pentadecanoic Acid: Pharmacokineticsand Potential as a Heart Agent," J. Nucl. Med. 22, 891-896(1981).

16. H.-J. Machulla, M. Marsmann, K. Litschka, and D. van Beun-ingen, "Radiopharmaceuticals. II. ?.3diobromination ofPhenylpentadecanoic Acid and Biodistribution in Mice," Radio-chem. Radioanal. Lett. 42, 243-250 (1980).

17. H.-J. Machulla, M. Marsmann, and K. Dutschka, "Synthesis ofRadioiodinated Phenylfatty Acids for Studying MyocardialMetabolism," J. Radioanal. Chem. 56, 253-261 (1980).

18. H.-J. Machulla, K. Dutschka, D. van Beuningen, and T. Chen,"Development of 15-(p-l!3I-Phenyl)Pentadecanoic Acid for InVivo Diagnosis of the Myocardium," J. Radioanal. Chem. 65,279-286 (1981).

19. G. W. Kabalka, S. A. R. Sastry, and K. Muralidhar, "Synthesisof Iodine-12S Labeled Aryl and Vinyl Iodides," J. LabelledCompd. Radiopharm. 19, 795-799(1982).

20. D. S. Wilbur, K. W. Anderson, W. E. Stone, and H. A. O'Brien,"Radiohalogenation of Non-Activated Aromatic Compounds ViaAryltrimethylsilyl Intermediates," J. Labelled Compd. Radio-pharm. 19, 1171-1188(1982).

21. D.S. Wilbur, W. E. Stone, and K. W. Anderson, "RegiospecificIncorporation of Bromine and Iodine into Phenols Using(Trimethylsilyl)-Phenol Derivatives," J. Org. Chem. 48,1542-1544 (1983).

22. D. S. Wilbur and Z. V. Svitra, "Organopentafluorosilicates:Reagents for Rapid and Efficient Incorporation of No-Carrier-Added Radiobromine and Radioiodine," J. Labelled Compd.Radiopharm. 20, 619-626 (1983).

134 PftOORESSATLAMPFLos Alums Nilonil LtborHory

J*nuiry-D»c*m>»r >ft

Monoclonal-Antibody Labeling: 1231,77Br, and 67CuR. S. Rogers, J. A. Mercer-Smith, and W.A. Taylor

Monoclonal antibodies are produced using thehybridoma technique developed by Kohler and Milsteinin which spleen cells from an immunized animal are fusedwith myeloma cells and the resulting hybrid cells arecloned. The explosive growth in this field is due to theutility of the resulting homogeneous antibodies. Labeledantibodies made to a specific tumor antigen may providea highly specific way of delivering radionuclides to atumor for diagnosis by radioimmunoassay or radioim-munoimaging and.for radioimmunotherapy. ' We areworking to develop chemical methods of labeling anti-bodies in high radiochemical yield with high specificactivity that result in biologically active antibodies formedical use. It is also important that the antibodies havegood in vivo stability. We are collaborating with S.DeNardo's group at the University of California, Davis.We will examine the labeling chemistry and they willprovide the monoclonal antibodies and do the biologicaltesting. We are interested in three approaches to theradiolabeling of antibodies: radiohalogenation, chelateconjugation, and linking of tagged organic molecules tothe proteins.

Methods for radioiodination have been used ex-tensively for many years and are well characterized. "' Ingeneral, electrophilic reagents are generated .in situthrough oxidation of iodide by chloramine-T, iodogen,enzymes, electrolysis, or iodine monochloride.8"10

Iodination occurs primarily on tyrosyl residues. Radio-chemical yields vary from 75 to 100%. Unfortunately,iodinated proteins are not extremely stable in vivo, liberat-ing free iodide on degradation. Though radioiodinatedproteins have been used widely, free iodide increasesbackground, thus limiting contrast in radioimmunoim ag-ing and increasing whole-body dose in radioim-munotherapy.

The bromine carbon bond is stronger than the iodinecarbon bond and should be more stable in vivo. Alsoimportant is the fact that bromine does not concentrate inthe thyroid. Radiobromination offers high lethality forradiotherapy of tumors because the Auger electronsproduced in the decay of 77Br deposit their energy over asmall distance.11 For these reasons radiobromination ofantibodies is of great interest.

The literature and our own preliminary work haveshown that for the most part methods developed foriodination are not applicable to bromination. Some meth-

ods for bromination have been published, but in generalthey suffer from low yields, harsh conditions, or lowavailability of starting materials.12"14 We have radio-iodinated a model protein, ovalbumin, and an ascitesmixture (the proteins isolated from the peritoneal cavityof a mouse in which a hybridoma is grown) in high yieldusing iodogen, enzymobeads (immobilized lactoperox-idase), and iodobeads (immobilized chloramine-T). How-ever, radiobromination with 77Br with these methods wasunsuccessful. We have been successful in brominatingovalbumin in a buffered system (pH = 6.8) in 20%radiochemical yield with rBr and sodium hypochlorite,although an excessive amount of protein degradation wasseen by high-performance liquid chromatography(HPLC). With 82Br of low specific activity and iodobeadsas oxidant, we found that some labeling had occurredwith no observable protein degradation.

Neither of these methods is useful as they stand, butthey suggest that two questions must be addressed: thefirst is the oxidation of radiobromide to an electrophilicform suitable for aromatic substitution, and the second isthe stability of the proteins in the presence of theoxidizing agent. Our experience with the labeling of smallmolecules and model systems will allow us to optimizeoxidation. " The denaturation of the antibodies maythen be addressed by sequestering the oxidizing agent,thereby preventing direct oxidation of the protein. Forexample, we are examining different methods of formingthe hypochlorite of a hydroxyl-containing resin withpores too small to allow the proteins to diffuse into theresin. We have found that t-butyl hypochlorite oxidizesradiobromide to bromine monochloride in solution, andwe hope to be able to form BrCl in the pores of the resinfrom the reaction of the resin hypochlorite and bromide(which would freely diffuse into the resin). The BrCl soformed would then be able to diffuse out of the resin toreact with the excluded protein. Our preliminary resultsusing a Sephadex resin are promising.

Conjugation of chelating agents with proteins is an-other important method of labeling.18"21 For this methoda ligand that has a high binding affinity for the nuclide ofchoice is derivatized to allow covalent bonding to theprotein. The activated ligand is then reacted with theprotein, linking the ligand and protein. Radiolabeling isaccomplished by adding the nuclide to the derivatizedprotein. This method is promising in that a number ofdifferent nuclides could be chelated by the same con-jugated protein, allowing optimization of decaycharacteristics for different purposes. We are studying

maty-December 1983 PROGRESS AT LAMWLosA!amo$NttiontlLMbontory

135

the binding properties of porphyrins for nuclides that weproduce, such as 67Cu and 6iZn, and we will then developmethods to conjugate the porphyrins and other chelatingligands to our antibodies.

In the area of 67Cu-metalloporphyrin research, initialstudies appear quite promising. Copper (II) mesotetra (4-carboxyphenyl) porphine (CuTCPP) was prepared fromCuCl2 and mesotetra (4-carboxyphenyl) porphine(H2TCPP). A study of the effect of solvent on themetallation reaction indicates that dimethylformamide(DMF) is by far the best solvent tested for this reaction.ZnTCPP was prepared from ZnCl2 and H2TCPP, sinceZn2+ is present in the 67Cu hot cell preparation and canreadily metall?-<.e H2TCPP under the same conditionsused for the copper metallation reaction. Conditions weredeveloped to separate H2TCPP, CuTCPP, and ZnTCPPby HPLC.

Once the methods of metallation and separation ofH2TCPP and CuTCPP were developed, carrier-addedradiolabeling of H2TCPP was performed. The 67Cu2+

usually is supplied in 2M HC1. The HCI presents aproblem because it protonates the pyrrole nitrogens of theporphyrin; this pyrrole protonation retards the metalla-tion reaction. Therefore, a series of 67Cu2+ solutions indifferent solvents was prepared. These solvents were usedto optimize the carrier-added metallation reaction. Neu-tralizing the HCI solution increased the radiolabelingyield from 61 to 76%, but the phosphate buffer was onlyslightly soluble in DMF. The best radiolabeling yield,93%, was obtained when the HCI solution was removedby evaporation and 67Cu2+ was redissolved in DMFbefore initiation of the chelation reaction. This yield wasobtained after 45 min of refluxing the porphyrin and67Cu2+. In the analogous no-carrier-added reaction, aradiolabeling yield of 76% was obtained. Two additionalporphyrin bands could be seen by HPLC and radio-HPLC under no-carrier-added conditions; these areunder study to determine their identity.

REFERENCES

1. G. Kohler and C. Milstein, "Continuous Culture of Fused CellsSecreting Antibody of Predefined Specificity," Nature 265, 495(1975).

2. D. E. Yelton and M. D. Scharff, "Monoclonal Antibodies:Powerful New Tool in Biology and Medicine," Ann. Rev.Biochem. 50, 657-680(1980).

3. V. R. McCready, "Tumour Localization," Br. Med. Bull. 36(3),209 (1980).

4. T. Ghose, A. Guclu, J. Tai, A. S. MacDonald, S. T. Norvell, andJ. A. Aquino, "Antibody as Carrier of " ' I in Cancer Diagnosisand Treatment," Cancer 36, 1648 (1975).

5. W. C. Eckelman, C. H. Paik, and R. C. Reba, "Radiolabelint,Antibodies," Cancer Res. 40, 3036-3042 (1980).

6. K. A. Krohn, K. C. Knight, J. F. Harwig, and M. 1. Welch,"Differences in the Sites of Iodonation of Proteins FollowingFour Methods of Radioiodination," Biochim. Biophys. Acta 490,497 (1977).

7. L. R. Chervu and D. R. K. Mirty, "Radiolabeling of Antigens:Procedures and Assessment oi Properties," Semin. Nucl. Med.5(2), 157(1957).

8. K. A. Krohn. L. Sherman, and M. Welch, "Studies of Radio-iodinated Fibrinogen. I. Physicochemical Properties of the IC1,Chloramine-T, and Electrolytic Reaction Products," Biochim.Biophys. Acta 285, 404 (1972).

9. P. R. P. Salacinski, C. McLean, J. E. C. Sykes, V. V. Clements-Jones, and P. J. Lowcry, "Iodination of Proteins, Glycoproteins,and Peptides Using a Solid-Phase Oxidizing Agent, 1,3,4,6-Tetrachloro-3, 6-Diphenyl Glycoluril (Iodogen)," Anal. Biochem.117, 136(1981).

10. A. Sinti,., B. Lucka, and K. Russin, "Enzymatic Labeling ofCarcinoembryonic Antigen with Iodine-125," J. Labelled Compd.Radiopharm. 18(12), 1797(1981).

11. A. I. Kassis, S. J. Adelstein, C. Haydock, K. S. R. Sastry, K. D.McEIvany, and M. J. Welch, "Lethality of Auger Electrons fromthe Decay of Bromine-77 in the DNA of Mammalian Cells,"Radiat. Res. 90, 362 (1982).

12. L. Knight, K. A. Krohn, M, J- Welch, and B. Spomer, "LPH,"Br: A New Protein Label," in Radiopharmaceuticals, G.Subramanian, B. A. Rhodes. J. F. Cooper, and V. J. Sodd, Eds.(Soc. Nucl. Med., New York, 1975), pp. 149-154.

13. K. D. McEIvany, J. W. Barnes, ami M. J. Welch, "Characteriza-tion of Bromine-77-Labeled Proteins Prepared UsingMyeloperoxidase," Int. J. Appl. Radiat. Isotop. 31, 679 (1980):

14. G. Petzold and H. H. Coenen, "Chloramine-T for 'No-Carrier-Added' Labeling of Aromatic Biomolecules with Bromine-75,77,"J. Labelled Compd. Radiopharm. 18, 1319(1981).

15. D. S. Wilbur and K. W. Anderson, "Bromine Chloride from N-Chlorosuccinimide Oxidation of Bromide Ion. Electrophilic Addi-tion Reactions in Protic and Aprotic Solvents, "J. Org. Chem.47(2), 358 (1982).

16. D. S. Wilbur and H. A. O'Brien, "A-Ring Bromination ofEstradiol and i 7a-Ethynylestradiol with N-Chlorosuccinimideand Bromide Ion. Possible Evidence for Hybromite Inter-mediates," J. Org. Chem. 47(2), 359 (1982).


Jamury-Oectmtm 1

17. D. S. Wilbur, K. W. Anderson, W. E. Stone, and H. A. O'Brien,"Radiohalogenation of Non-Activated Aromatic Compounds ViaAryltrimethylsily) Intermediates." J. Labelled Compd. Radio-pharm. 19, 1171 (1982).

18. G. E. Krejcarek and K. L. Tucker, "Covalent Attachment ofChelating Groups to Macromolecules." Biochem. Biophys. Res.Commun. 77(2), 581 (1977).

19. M. W. Sundberg, C. F. Meares, D. A. Goodwin, and C. I.Diamanti, "Chelating Agents for the Binding of Metal Ions toMacromolecules," Nature 250, 587 (1974).

20. M. W. Sundberg, C. F. Meares, D. A. Goodwin, and C. I.Diamanti, "Selective Binding of Metal Ion to MacromoleculesUsing Bifunctional Analogs of EDTA," J. M^d. Chem. 17(12),1304 (1974).

21. C. F. Meares, D. A. Goodwin, C. S.-H. Leung, A. G. Girgis, D. J.Silvester, A. D. Nunn, and P. I. Lavender. "Covalent Attachmentof Metal Chelates to Proteins: The Stability In Vivo and In Vitroof the Conjugates of Albumin with a Chelate of Indium-Ill,"Proc. Nat. Acad. Sci. USA 73(11), 3803 (1976).

Group INC-3 Publications

.1. W. Barnes, M. A. Ott, P. M. Wanek, G. E. Bentley, K.E. Thomas, F. J. Steinkruger, and H. A. O'Brien, Jr.,"Iodine-123 Yields from 800-MeV Proton Irradiation ofCsCl Target," Proc. Thirtieth Annual Meeting of theSociety of Nuclear Medicine, St. Louis, Missouri, June7-10, 1983, J. Nucl. Med. (Abstract) 24, P24 (1983).

W. Cole, S. DeNardo, C. Meares, G. DeNardo, and H.O'Brien, "Development of Copper-67 Chelate Con-jugated Monoclonal Antibodies for Radioim-munotherapy." Proc. Thirtieth Annual Meeting of theSociety of Nuclear Medicine, St. Louis, Missouri, June7-10, 1983, J. Nucl. Med. (Abstract) 24, P30 (1983).

R. E. Gibson, W. C. Eckelman, B. Francis, H. A.O'Brien, J. K. Mazaitis, D. S. Wilbur, and R. C. Reba,"[77Br]-17-a-Bromoethynylestradiol: In Vivo and InVitro Characterization of an Estrogen Receptor Radio-tracer," Int. J. Nucl. Med. Biol. 9. 245-250(1982).

R. A. Goldstein, N. A. Mullani, D. J. Fisher, S. K.Marani, H. A. O'Brien, and K. L. Gould, "Quantificationof Regional Myocardial Flow with Rb-82 DespitePharmacologic Intervention," Proc. Thirtieth AnnualMeeting of the Society of Nuclear Medicine, St. Louis,

Missouri. June 7-10. 1983. J. Nuc!. Med. (Abstract) 24,P3OH983).

D. A. Miller, P. M. Grant. J. W. Barnes, G. E. Bentley,and H. A. O'Brien. Jr., "Research-Scale Experimentationon the Production and Purification of SpallogenicGermanium-68 at Los Alamos for Nuclear MedicineApplications," in Applications of Nuclear and Radio-chemistry, R. M. Lambrecht and N. Morcos, Eds.(Pergamon Press. NJW York, 1982), Chap. 4, pp. 37-44.

H. A. O'Brien, Jr., and P. M. Grant. "BiomedicalPositron Generators," in Applications of Nuclear andRadiochemistry, R. M. Larnbrecht and N. Morcos, Eds.(Pergamon Press, New York, 1982), Chap. 6, pp. 57-68.

A. P. Selwyn, R. M. Allan, A. L'Abbate, P. Horlock, P.Camici, J. Clark. H. A. O'Brien, Jr., and P. M. Grant,"Relation Between Regional Myocardial Uptake ofRubidium-82 and Pertusion: Absolute Reduction of Ca-tion Uptake in Ischemia." Am. J. Cardiol. 50, 112-121(1982).

D. S. Wilbur, K. W. Anderson, W. E. Stone, and H. A.O'Brien, Jr., "Radiohalogenation of Non-ActivatedAromatic Compounds Via Aryltrimethylsilyl Inter-mediates," J. Labelled Compd. Radiopharm. 19,1171-1186(1982).

D. S. Wilbur, W. E. Stone, and K. W. Anderson,"Regiospecific Incorporation of Bromine and Iodine intoPhenols Using Trimethylsilylphenol Derivatives," J. Org.Chem. 48, 1542-1544(1983).

D. S. Wilbur and Z. V. Svitra, "Organopen-tafluorosilicates: Reagents for Rapid and Efficient In-corporation of No-Carrier-Added Radiobromine andRadioiodine," J. Labelled Compd. Radiopharm. 20,619-626 (1983).

D. S. Wilbur, Z. V. Svitra, and H. A. O'Brien, Jr.,"Applications of Aryltrimethylsilanes in Radiobromina-tions," J. Nucl. Med. (Abstract) 24, P43 (1983).

!D. S. Wil6ur, Z. V. Svitra, and H. A. O'Brien, Jr.,"Applications of Aryltrimethylsilanes in Radiobromina-tions," Proc. Thirtieth Annual Meeting of the Society ofNuclear Medicine, St. Louis, Missouri, June 7-10, 1983,J. Nucl. Med. (Abstract) 24, P43 (1983).

tanuary-Decemter 1983 PROGRESS AT LAMPFLos Alums Nations! Laboratory

137

Papers Accepted for Publication

G. E. Bentley, F. J. Steinkruger, and P. M. Wanek,"Electrochemistry as a Basis for Radiochemical Gen-erator Systems," Proc. of the Symp. on New Radio-nuclide Generator Systems for Nuclear Medicine, 185thAmerican Chemical Society National Meeting, Seattle,Washington, March 20-25, 1983 (in press); Los AlamosNational Laboratory document LA-UR-83-898.

D. T. Cromer, R. R. Ryan, and D. S. Wilbur, "Structureof 1-H-Azepine- 2-1-5-Methoxime, C7H8N2O2," ActaCrystallogr. Sect. C (in press); Los Alamos NationalLaboratory document LA-UR-83-2303.

H. A. O'Brien, Jr., "Overview of Radionuclides Usefulfor Radioimmunoimaging and Current Status of Prepar-ing Radioiabeled Antibodies," in Radioimmunoimaging(Elsevier Biomedical Press, New York, in press); LosAlamos National Laboratory document LA-UR-83-154.

H. A. O'Brien, Jr., J. W. Barnes, G. E. Bentley, F. J.Steinkruger, K. E. Thomas, M. A. Ott, F. H. Seurer, andW. A. Taylor, "The Development of Short-Lived Radio-nuclides at Los Alamos," Proc. of the Int. Symp. on theDeveloping Role of Short-Lived Radionuclides in Nu-clear Medical Practice, Washington, DC, May 3-5,1982(in press); Los Alamos National Laboratory documentLA-UR-83-791.

F. J. Steinkruger, G. E. Bentley, H. A. O'Brien, Jr., M. A.Ott, F. H. Seurer, W. A. Taylor, and J. W. Barnes,"Production and Recovery of Large Quantities of Radio-nuclides for Nuclear Medicine Generator Systems,"Proc. of the Symp. on New Radionuclide GeneratorSystems for Nuclear Medicine, 185th American Chemi-cal Society National Meeting, Seattle, Washington,March 20-25, 1983 (in press); Los Alamos NationalLaboratory document LA-UR-83-835.

K. E. Thomas, "Recovery and Isolation of Curie Quan-tities of Hafnium and the Lanthanides from LAMPF-Irradiated Tantalum Targets," Radiochim. Acta (inpress); Los Alamos National Laboratory document LA-UR-83-579.

K. E. Thomas, "Proposal for the Production of Carrier-Free Osmium-191," Proc. of the Int. Conf. on SinglePhoton Ultra-Short-Lived Radionuclides, Pan AmericanHealth Organization, Washington, DC, May 9-10,1983;Los Alamos National Laboratory document LA-UR-83-1367 (in press).

K. E. Thomas and J. W. Barnes, "Large Scale Isolationof Strontium-82 for Generator Production," Proc. of theSymp. on New Radionuclide Generator Systems forNuclear Medicine, 185th American Chemical SocietyNational Meeting, Seattle, Washington, March 20-25,1983 (in press); Los Alamos National Laboratory docu-ment LA-UR-83-939.

D. S. Wilbur, Z. V. Svitra, R. S. Rogers, and W. E. Stone,"Radiohalogen Labeling Studies at Los Alamos," Proc.of the Int. Symp. on the Developing Role of Short-LivedRadionuclides in Nuclear Medical Practice, Washington,DC, May 3-5, 1982 (in press).

Papers Submitted for Publication

K. W. Thomas and the Los Alamos Medical Radio-isotopes Group, "Production of Microcurie Amounts ofCarrier-Free Aluminum-26," Los Alamos National Lab-oratory document LA-UR-83-1413 (submitted to Radio-chim. Acta).

D. S. Wilbur, "Structural Determinations of SomeChloroazepin-2,5-Diones Using a Lanthanide Shift Re-agent," Los Alamos National Laboratory document LA-UR-83-2233 (submitted as a Note to J. Org. Chem.).


Januvy-Dtctmbt )98

Theory

Spin Dependence of AW and AWn Reactions and theQuestion of Dibaryon Resonances*RichardR. Silbar (Los Alamos)

Abstract

Recent experiments on the spin dependence of thecoupled AW and NNn systems are reviewed and com-pared with theory. Conventional models involving theusual interactions of mesons and nucleons appear toexplain the rich spin dependence observed.

Introduction

The experimental information on spin dependence inthe coupled AW and AWTI systems for medium energieshas mushroomed in the past few years. The energiesinvolved run from pion-production threshold (around300-MeV incident nucleon laboratory energy) to about1500 MeV (where two-pion production becomes impor-tant).

At the same time theoretical models for the coupledAW and NJVn systems have undergone vigorous develop-ment. Both experiment and theory have been muchstimulated by the observation of relatively sharp energy-dependent structures.1 It was quickly recognized thatthese might be manifestations of new degrees of freedom,such as the dibaryon resonances suggested by the quarkbag model.2

This report summarizes recent experimental progressin this field** and discusses to what extent the new datarequire an interpretation of new quark substructures.

What is a Dibaryon Resonance?

A resonance is more than just a bump in a crosssection. The classic example of an elastic resonance isprovided by a Breit-Wigner amplitude

*To be published in Comments on Nuclear and ParticlePhysics 12(4), 177-189 (March 1984).••Experiments involving electromagnetic probes are not dis-cussed; references in this subfield may be traced, for example,from K. Baba et a!., Ref. 3.

2 ER-E-iT/2

where / denotes the partial-wave amplitude that is res-onating. Such a structure has a pole in the complexenergy plane at E = ER - iT/2, that is, "on the secondsheet." As the energy increases through ER, the complexamplitude Tt traces a counterclockwise path along acircle of radius | centered at +j, the so-called unitaritycircle. In this example without any background, thepartial-wave amplitude reaches the top of the circle (+i) atthe resonance energy ER and moves around into the lefthalf plane for energies above £ R . This counterclockwisemotion on an Argand diagram is typical of a resonance.However, a warning is definitely in order: such motionscan arise from other kinds of analytical structures, as wellas from resonance poles.

In the presence of inelasticity (that is, coupling to otheropen channels), the scattering amplitude becomes amatrix, and d resonance shows up as a pole in eachmatrix element. As the energy increases, the path tracedby the elastic amplitude T} is still counterclockwise, butthe conservation of probability (unitarity) constrains itonly to be somewhere within the unitarity circle.

At least two such counterclockwise looping behaviorsdeep inside the unitarity circle have been found in phase-shift analyses for AW elastic scattering. These occur inthe lD2 and 3F3 partial waves, the two prime candidatesfor dibaryon resonances. One needs a model to ex-trapolate the physical amplitude into the complex energyplane and search for resonance poles. There is an ex-tensive theoretical literature that deals with whether thelooping behavior is due to resonance poles (that is,dibaryons).* The issue is not settled, but it is clear fromsimple models that coupled-channel resonance poles cer-tainly can be present. On the other hand, the cut from theAW—•WA threshold also produces a resonance-likebehavior, and it could be the combined effect of poles andthe N& cut that causes the structures seen in the ob-servables.

The existence of dibaryons was first suggested in 1977by the energy-dependent structures found in spin-dependent total cross-section differences.6 These andother structures go hand in hand with inelasticity, whichin this energy region means single-pion production,

•Recent literature may be traced from W. M. Kloet and J. A.Tjon, Ref. 4.

lanuary-Decembsr 1983 PROGRESS AT LAMPFLos Alamo) Nation*! Laboratory

139

NN—*-NNn. If dibaryons are actually given by reso-nance poles, the next questions are: What is their origin?Can they be explained by conventional models of mesonsinteracting with nucleons? Or, does their existence implya new underlying hadronic structure, such as that as-sociated with quarks and color degrees of freedom?

Theoretical Framework

In the energy region under discussion, the standarddescription of the NN—>-NNn or nd—*-nd scatteringamplitudes uses the isobar model,7 as illustrated by thegraphs in Figs. l(a) and (b). Originally, the isobaramplitudes (the "blobs" in the figure) were simply fit tothe available data or calculated in the Born approxima-tion. Today, however, these amplitudes are calculated ina unified and unitary way. There are two approaches.

(1) The coupled two-body channel approach in-volves solving coupled scattering equations with tran-sition potentials between the AW, NA, and nd two-bo Jychannels. This method has been applied to calculateinelasticity parameters and phase shifts for AW scattering

a)

above the pion-production threshold**10 and spin ob-servables for the pp —*• dn reaction.11

b)

c)

d)

.TT

Fig. liFour Feynman graphs: (a) and (b) show graphs forthe isobar-model treatment of the AW -*• AWJI andnd —*• nd reactions, respectively, and (c) and (d)indicate explicit dibaryon-resonanee graphs.

140 PROGRESS AT LAMPF


(2) The three-body-equation approach has been th.most realistic path to the elastic scattering of pions bydeuterons, with important work being done by Rinat andThomas,12 Garcilazo,13 and the Lyon group.14 Gar-cilazo lias extended his calculations to the breakupprocess nd—*- nNN with good success. The other twogroups have emphasized the treatment of NN inter-mediate states, which is closely connected to an alterna-tive approach and which involves the truncation of anunderlying field theory to consider, at any given time,only two nucleons or two nucleons and a pion. Theoriginal work was by Afnan and Thomas. Later de-velopments vary in their details and philosophicalbasis. The major emphasis of Refs. 18-20 so far has beenon the pp—»• dn reaction, whereas the authors of Ref. 17have concentrated on calculating spin observables for thethree-body final state, AW-* AWn (Ref. 21).

All these models, two-body as well as three-body, areconventional in that they involve only the known mesonsand nucleons interacting in the usual way. If there areexplicit dibaryon resonances—that is, resonances notgenerated by the conventional meson-nucleon dynamics—these models must be supplemented by contributionsthat look like Figs. l(c) and (d). Incorporating suchgraphs without destroying the unitarity of the conven-tional models is slightly problematical. One way of doingthis has been discussed by Locher and co-workers. 2

Recent Experiments

It is convenient to discuss separately five kinds of spin-observable experiments: (1) nd elastic scattering, (2)pp —*• dn (and its inverse), (3) spin-dependent total crosssections, and (4) inclusive and (5) exclusive experimentson the NN—*- NNn reaction. Table I gives definitions forthese different spin observables.

(1) Elastic pion-deuteron scattering. Two differentspin observables are measured for this reaction. Thesharp angular oscillations in the vector polarization(iTn), found23 at TnM = 256 MeV, have beenparticularly suggestive of a 'G4 dibaryon resonance. Theextant (conventional) three-body calculations (see. forexample, Ref. 14) give rather smooth angular variationsfor iTn. By incorporating explicit dibaryon-resonance

January-December t98l

Table I. Definitions of Spin Observables.

ltd + nd:

Md=-l,O.i

V 0 ( M d )]Md=-l,0.1

The deuteron spin is quantized normal to the scattering plane.

Total Cross-Section Differences:

Initial nucleon spins are quantized in a direction transverse to the beam direction; AcL is definedl'kewise, but with spins quantized along the beam direction (longitudinal).

NN-^-NNn (or dn):

Initial nucleon spins are quantized normal to the reaction plane. Similar formulae define AhL, Ass, ALS,and ASL^AL.^ but with longitudinal and sideways quantization axes: likewise for spin-transferobservables Z>NN, KLL, etc., except that one spin is for an initial nucleon, the other for a final nucleon.

graphs, as in Fig. l(d), Locher et al. could predictoscillatory behavior very much like that observed.

Recently, however, Gibbs* noticed that the three-bodycalculations are quite sensitive to the small nN interac-tions that enter as input. The vector polarization isbasically an interference effect between the dominant P}3

nN interaction and the smaller contributions. Inparticular, the earlier three-body calculations used inputnN potentials, which were in fact unsupported by the nNexperimental data. Gibbs and Gibson have shown thata single-scattering-approximation calculation with nNinput directly related to the nN phase shifts can do areasonable job of reproducing the 256-MeV iTu angulardistribution, with the exception of a singularly negativedatum at 135°. That datum, in the meantime, has been

•Reference 24. A similar observation was evidently madeearlier by J. Arvieux and A. S. Rinat (unpublished).

anuary-December 1983

remeasured and was found to be positive.** Thus, on thewhole, the experimental data set for /71,,, over the wholeenergy range measured, now seems not to require (ex-plicit) dibaryon resonances.

The other spin observable of current interest in ltdscattering is the tensor polarization T20 of the recoildeuteron. Two groups have obtained very different ex-perimental results. The Argonne group25 finds T20's inagreement with conventional expectations—that is,predictions of the three-body models. In contrast, theETH group obtained data sufficiently oscillatory that,if correct, may demand an interpretation involving ex-plicit dibaryon resonances. In view of the present dis-crepancy in the T20 data, it is difficult at this time to drawany conclusions about the existence of dibaryon re-sonances.

••Private communication to W. R. Gibbs, spring 1983, fromDubach et al., authors of Ref. 21.

PROOAESS AT LAMPF

Los Alamos National laboratory141

(2) The reaction pp —*• dn and its inverse. Becausethe two-body final state is easier to deal with experimen-tally than the three-body state, there is already anextensive data set for this reaction from threshold toabove 1000 MeV. Three kinds of spin observables havebeen measured: polarization asymmetries, spin-spin cor-relations, and polarization transfers.27

The data, especially for the asymmetries AN, aresmoothly varying with energy and generally have verysmall error bars. At the moment, no conventional theoret-ical model 1-1 ' ° does a very good job. However, themodels do reproduce the general trends of the data. Tojudge from the differences among the various models,which are big compared with the experimental errors, it isreasonable to presume that a conventional model cansomeday fit this data set.

Incidentally, the spin-spin correlations ANN forpp -*• dn are large and negative, ANN a -0.8, a result thatcomes from conventional models quite easily since thereaction is dominated by NA intermediate states withorbital angular momenta L' = 0. These states areproduced in the initial NN state from the '.E>2 partialwave. Thus, the basic negativeness of Am is largelydetermined by nearly model-independent considerations(see definition, Table I).

(3) Spin-dependent total cross sections. It was theArgonnne ZGS measurements of the cross-section dif-ferences AoL and Ao r that created the great interest indibaryons. These quantities have since been remeasuredat all the meson factories. The sharp energy-dependentstructures in AoL and AoT have been confirmed, althoughthere is not yet complete agreement as to what themagnitudes of the cross-section differences are.

The peak in AoT and AoL at 550 MeV is related to theresonance-like structure of the 'Z>2 amplitude, whereasthe dip in AoL near 750 MeV is related to the iFi

amplitude (AoL contains contributions from the L=Jtriplet partial waves but AoT does not). From the point ofview of conventional models, these structures to a largeextent are due to the onset of the NN—* NA reaction as itopens up in the s and p waves of the NA state, respec-tively. However, none of the conventional models has asyet reproduced the details of the experimentally observedstructures. As an example, Fig. 2 compares the predic-tions of Ref. 28 with the data.

Conventional models also might be running intotrouble with the inelastic part of the longitudinal cross-section difference Ao^nel, which is negative (-3.5 ± 1 mb)at 800 MeV. 2 9 Three different conventional

0.4 06 08 10 12 14 16 18

E L (GeV)

Fig. 2.Experimental data for AoT and AoL (in millibarns),compared with the conventional model predictionof Ref. 28 (from which this figure was taken).

models17 '30 '31 give positive (^7-mb) predictions for thisquantity at that energy. Even the shape of the energydependence differs markedly between the models anddata. It should be pointed out that extracting Aci"el isdifficult, involving the difference of two large numbersobtained from two different experiments. The results ofRef. 29 should be checked.

The above remarks all refer to / = .' cross sections.Little is known about the / = 0 cross-section differences,although a flat AoL observed in pd interactions has beeninterpreted as requiring a XF3 "antidip" to compensate forthe }F3 dip a t 750 MeV.32 Such a structure, if it exists,would be very difficult to interpret in terms of conven-tional models.

(4) Inclusive NN —»• NNn reactions. In these reac-tions, typically, only one particle in the three-body finalstate is detected. Such experiments are more easilyperformed and more precise than exclusive experiments,which use detectors in coincidence to determine themomentum and direction of every final-state particle. Theresults of inclusive experiments measuring spin ob-servables are just now appearing in the literature.

One such experiment measures the analyzing powerAN in the reaction pp—>-pX (X=nn+ or pn°) at800 MeV. The prominent feature in the data is a sharprise to a value of 0.3 at the upper end of the outgoingproton momentum spectrum (Fig. 3). This feature can be



0.5 -

• . • . 1

- k'=800

. . . . i

11°MeV

QUOUHi*

1 1 f 1

1 . . . .

-

W

i . . . .

-0.5 -

-10 500 1000 1500

Pp.lab (MeV/c)

Fig. 3.Asymmetry for the inclusive reaction pp -*• pX,X=nn+ or pn°. Data are from Ref. 33 and thecurves are the unitary (solid) and Born approxima-tion (dashed) predictions from Ref. 34.

reproduced in a unitary model34 (the solid line in Fig. 3)but appears difficult to explain using a Born approxima-tion approach35 (dashed line). Spin observables such as-4N result from interference between different complexamplitudes and thus are sensitive to unitarization.

Another group has measured the polarization transfersKNN and KLL in the/>/>—»• TiX reaction, X =p7t+, again at800 MeV.36 There are as yet no unitary model predic-tions for these quantities, but a Born approximationcalculation35 fails to reproduce the features of the dataentirely. It will be interesting to see if unitarity alone cancure the disagreement.

(5) Exclusive NN —»• N N J I reactions. Until recently,kinematically complete information about this fundamen-tal pion-production process came mostly from a smallnumber of bubble chamber experiments performed in the1960s. The data base was therefore embarrassinglysmall. With the advent of meson factories, however, thereare now counter experiments that measure completekinematics for the reaction (although usually only for in-plane geometry). Two particles (at least) must bemeasured in coincidence to determine five kinematicalquantities: for example, pp, 9p, <t>p, 6,, and $„.


The first such experiment37 measured the polarizationasymmetry in pp -*pn+n at 800 MeV, and it establishedthe crucial importance of dealing with unitarity properly.As the first data were being processed, Umland, Duck,and Mutchler made Born approximation predictions ofAN as a function of the outgoing proton momentum forthe various angle pairs measured. Not surprisingly, sinceAN depends on the relative phases between complexamplitudes, the agreement with the data was quite poor*.They then tried including explicit dibaryon-resonancegraphs [Fig. l(c)|, fitting a free phase between thosegraphs and the usual isobar graphs [Fig. l(a)]. Theagreement with the experimental AN was much improved,but still not remarkably good.

Soon after this, Dubach et al.21 applied the unitarymodel of Ref. 17 to the problem, using the no-free-parameter version of the model based solely on one-pionexchange (OPE). These predictions, although still notagreeing very well with the data of Ref. 37, werequalitatively much more like the data than the Bornapproximation results. Considering the simple nature ofthe model (only OPE forces between tne nucleons andisobars, only P}3 and Pn nN input forces, etc.), one canbe optimistic that a more complete model eventuallymight be able to explain these data.

The asymmetry experiment37 also was able to recorddata at the same time for the reaction pp—*-ppn°. It iscurious that the predictions of the unitary model seemto fit these data much better than the data* for npn+. It isnot clear why this happens.

Another set of exclusive experiments measures spin-spin correlations ANN, ALL, etc., for the reactionpp ~* npn+ at three energies near 500 MeV39 and at 650and 800 MeV.40 The no-free-parameter OPE predic-tions of Ref. 21 are compared with preliminary data at500 MeV in Fig. 4. The agreement is quite good—that is,these data provide no surprises in comparison with aconventional model. All the spin-spin correlation coeffi-cients in Fig. 4 are large and negative, again reflecting thedominance of the AW('Z>2) —*• JVA(JS2) partial-waveamplitude.

The experiment on ^4NN and ALL at 650 and 800MeV has fewer data points (but smaller errors). Thesedata also are in agreement with the predictions of Ref. 21.At 800 MeV, ALL has become slightly positive, indicatinga cancellation between the 'D2 and 3F3 partial waves forthis quantity (see definition in Table I).

*G. S. Mutchler, private communication.

PROGRESS AT LAMPfLos Alamos Ntilontl Ltboritory

143

o.o

-01

-1.0

-l.i

-1.4

00

-0.2

-0 4

-OS

-0 8

-I 0

-1.2

-I 4

IrfcLJ

o e

o «

o z

oo

oo- 0 2

- 0 «

- 0 6

300 400 S00 100 400 $00

Pp.lab (MeV/c)

Fig. 4.Spin-spin correlation coefficients for j5p —> «pn+ at500 MeV. Data are from Ref. 39 and the curveswere calculated as in Ref. 21. This figure is acorrected version of one appearing in Ref. 39.

It is curious that in both experiments (and in thecalculations) the beam and target particle asymmetriesfor a given angle pair are approximately equal andopposite in sign. There is no evident simple reason forihis. (Identical-particle symmetry gives exact equalitiesbetween different angle pairs.)

A third kind of experiment involves the measurementof the polarization transfer coefficient DNN, for thereaction pp-+npn+ at 800 MeV.41 The one data pointmeasured (right at the peak of the A++ resonance) is alsoin good agreement with the prediction of Ref. 21. Thedifferential cross-section data elsewhere indicate the pres-ence of a strong final-state interaction between the outgo-ing nucleons. One naturally wonders how well the unitarymodels (which generally do not contain such interactionsin their input) will compare with a more extensive DNN

data set.

Conclusions

In general, we have seen that conventional models ofmesons and nucleons, so far, are able to explain a

substantial amount of new experimental data on the richspin dependence of the coupled AW and NNn interac-tions. Not all predictions agree perfectly, but that is to beexpected at this stage. It seems a little peculiar that thegross quantities (total cross-section differences) areharder to understand in this picture than the detailed ones(exclusive cross sections). Nonetheless, the major point tobe emphasized is that there is no obvious need at this timeto invoke new quark substructures to explain the presentdata.

So where, then, are the effects of the quarks and gluonsin the A = 2 interacting systems to be seen? It may simplybe that the present round of experiments is not verysensitive to quark degrees of freedom.42 To find out whatexperiments are sensitive, perhaps of this type or perhapsof some totally different kind, will probably require a lotmore experimental and theoretical work.

Acknowledgments

I wish to thank the many experimentalists who havediscussed with me their data, often while still preliminary.My colleagues J. Dubach and W. M. Kloet have con-tributed greatly to my understanding of the theory, and T.S. Bhatia urged me to write this summary of the rapidlychanging experimental situation.

This work was supported by the USDOE.

REFERENCES

1. A. Yokosawa, Phys. Rep. 64, 47 (1980); and D. V. Bugg, Nucl.Phys. A 374, 95c (1982).

2. A. Aerts et al., Phys. Rev. Lett. 40, 1543 (1978).

3. K. Baba et al.. Phys. Rev. C (July 1983).

4. R. A. Arndt, phase-shift analysis WI82 (winter 1982).

5. W. M. Kloet and J. A. Tjon, Nucl. Phys. A 392,271 (1983).

6. K. Hidaka et al., Phys. Lett. 70B, 479 (1977).

7. S. J. Lindenbaum and R. M. Sternheimer, Phys. Rev. 105, 1874(1957); and 123, 333 (1961).

8. A. M. Green, J. A. Niskanen, and M. E. Sainio, J. Phys. G (Nucl.Phys.) 4. 1055 (1978).

9. E. t. Lomon, Phys. Rev. D 26, 576 (19821.


10. E. E. van Faassen and J. A. Tjon, Phys. Lett. 120B, 39 (1983);and Phys. Rev. C (August 1983).

.: J. A. Niskanen, Santa Fe Polarization Conf., AIP Conf. Proc. 69,62 (1981).

12. A. S. Rinat and A. W. Thomas, Nucl. Phys. A 282, 365, (1977);and A. S. Rinat, Y. Starkand, and E. Hammel, Nucl. Phys. A 364,486 (1981).

13. H. Garcilazo, Phys. Rev. Lett. 45, 780 (1980).

14. C. Fayard, G. H. Lamot, and T. Mizutani, Phys. Rev. Lett. 45,524 (1980).

15. H. Garcilazo, Phys. Rev. Lett. 48, 577 (1982).

16. I. R. Afnan and A. W. Thomas, Phys. Rev. C 10, 109 (1974).

17. W. M. Kloet and R. R. Silbar, Nucl. Phys. A 338, 281 and 317(1980); and A 364, 346(1981).

18. B. Blankleider and I. R. Afnan, Phys. Rev. C 24, 1572 (1981).

19. M. Betz and T.-S. H. Lee, Phys. Rev. C 23, 375 (1981).

20. A. S. Rinat, Nucl. Phys. A 397, 381 (1983).

21. J. Dubach et al., Phys. Lett. 106B, 29 (1981); and J. Phys. G(Nucl. Phys.) 8, 475(1982).

22. K. Kubodera et al., J. Phys. G (Nucl. Phys.) 6, 171 (1980).

23. J. Bolger et al., Phys. Rev. Lett. 46, 167 (1981); and 484, 1667(1982).

24. W. R. Gibbs, invited talk, Baltimore APS Meeting, April 1983,Los Alamos National Laboratory preprint LA-UR-83-245(1983).

25. R. J. Holt et al., Phys. Rev. Lett. 47, 472 (1981).

26. W. Griiebler et al., Phys. Rev. Lett. 49,444 (1982).

27. P. Walden el al., Phys. Lett. 81B, 156 (1979); E. Aprile et al.,Nucl. Phys. A 335, 245 (1980); R. Bertini et al-, "High EnergySpin Physics," AIP Conf. Proc. 95, 231 (1982); A. Sana et al.,submitted to Phys. Lett. B; M. D. Corcoran et al., Phys. Lett.120B, 309 (1983); and W. B. Tippens et al., to be published.

28. T.-S. H. Lee. Argonne preprint (June 5983).

29. I. P. Auer et al., Argonne preprint ANL-HEP-PR-83-27 (July1983).

30. A. S. Rinat and R. S. Bhalerao, Weizmann preprint WIS-82 155(1982).

31. A. Konig and P. Kroll, Nucl. Phys. A 356, 345 (1981).

32. I. P. Auer et al., Phys. Rev. Lett. 46, 1177 (1981).

33. J. A. McGill et al., submitted to Phys. Lett. B, July 1983.

34. R. R. Silbar et al., contribution to the Few-Body Conf.,Karlsruhe, Germany, August 1983.

35. B. J. VerWest, Phys. Lett. 83B, 161 (1979).

36. G. Glass et al., Phys. Lett. B (to be published).

37. A. D. Hancock et al., Phys. Rev. C 27, 2742 (1983).

38. E. 'A. Umland, I. M. Duck, and G. S. Mutchler, Santa FePolarization Conf., AIP Proc. Conf. 69, i72 (1981).

39. R. Shypit et al., Phys. Lett. I24B, 314 (1983).

40. T. S. Bhatia et al., Phys. Rev. C (to be published).

41. B. E. Bonner et al., contribution to the Few-Body Conf.,Karlsruhe, Germany, August 1983.

42. P. J. Mulders, Phys. Rev. D 25. 1269 (1982).

muaiy-Decemtw 7983 PROGRESS AT LAMPFl o t AHmos NHiorml Libomory

145

Medium-Energy Probes and the Interacting BosonModel/ . N. Ginocchio (Los Alamos)

Introduction

In medium and heavy nuclei far from closed shells, thenumber of shell-model degrees of freedom in the low-lying spectrum of nuclei becomes enormous. For exam-ple, the number of shell-model / " = 2+ states with onlythe valence nucleons active for l i4Sm is of the order of10". Hence, spherical shell-model calculations of thesenuclei are impossible. The collective model of Bohr andMottelson can explain spectroscopic properties of themost interesting collective states for nuclei that have avery stable equilibrium deformation, but most nuclei donot have a stable equilibrium deformation. Such nucleiare called transitional nuclei. The series of samariumisotopes from l4*Sm to 154Sm, for example, fall into thiscategory.

Recently the interacting boson model (IBM) of thenucleus,' which is an approximation to the shell model,has been able to describe these transitional nuclei. Thismodel has three basic assumptions. One is that the low-lying spectra of nuclei are composed primarily of collec-tive pairs of valence nucleons coupled to angular momen-tum 0 and 2 moving about a spherical doubly magic core.The second is that these collective monopole and quadru-pole nucleon pairs are approximated as bosons. And the

third assumption is that the effect of the Pauli principleand other degrees of freedom, such as excitations of otherpairs and excitations of the core, are assumed to be takeinto account through a renormalized effective boso.Hamiltonian and transition operators.

There are two versions of the IBM. The originalversion, called 1BM-1, does not distinguish betweenneutrons and protons. This version has had phenomeno-logical success in many regions of the periodic table, andcan be related to the geometrical Bohr-Mottelson model.'In Fig. 1 we show a comparison of the spectrum of 168Erproduced by IBM-1 along with the spectrum seen in («,y)experiments.3 These experiments measure not only theground state band but the sidebands as well. The IBM-1with three parameters gives a remarkable reproduction ofthis pattern of excited states, as well as reproducingtransition rates.3

The second version, called IBM-2, distinguishes be-tween neutrons and protons. This model has been used tostudy a number of different types of nuclei. A fewexamples are the samarium and thorium isotopes,4 thepalladium isotopes,5 xenon, barium, and cesiumisotopes,6 platinum and osmium isotopes,7 and the tung-sten isotopes.

Although IBM-1 is relatively simple, IBM-2 isnecessary to develop a deep understanding of nuclei forseveral reasons. First, we have learned through phenome-nological studies of the shell model that the effectiveinteraction between like nucleons inside the nucleus is

2.0-

Fig. I.The experimental and IBM-for 16lEr from Ref. 3.

spectrum

UJ

5

oXUi

ao<-

—s'.f2*

EXPERIMENT

~ja')

- 8 *

0*

?*»

8*

6*

K0*

0>

INTERACTING BOSON MODEL

146 PROGRESS AT LAMPf

Los Alamos National LaboratoryJanuary-December 198.

dominated by the pairing interaction and tends to makenuclei spherical. On the other hand, the effective neutron-

roton interaction is dominated by a quadrupole interac-M and produces nuclear deformation. Furthermore,

IBM-2 has additional states that can be excited that arenot in the IBM-! space.

The states in IBM-2 that correspond to those in IBM-1are the ones most symmetric in the neutron-protondegrees of freedom. However, the less symmetric statesalso may occur in the low-lying spectrum. The combineduse of medium-energy electrons, pions, and protons cansort out the nature of the neutron and proton excitationsin nuclei. Finally, the parameters of IBM-2 may bederived from an underlying fermion many-body system.

Here we review some of these aspects of the IBM,particularly as they apply to medium-energy scattering.

The Boson Hamiltonian

The boson Hamiltonian reflects the properties of theeffective nucleon-nucleon interaction mentioned above:

(1)

where v refers to neutron bosons and n refers to protonbosons. The operators Nv and Nx count the number ofneutron and proton quadrupole bosons, respectively,

where d =(-\)md and s+(s) creates (destroys) a mono-pole pair. The quadrupole transition operator is

= v,n (2)

where dma(dma) creates (destroys) a quadrupole boson;m=2, 1, 0, - 1 , -2; and o = n or v. The energies ea are theexcitation energies of the quadrupole boson with respectto the monopole boson. This part of the Hamiltonianreflects pairing between like nucleons. The second partreflects the quadrupole interaction between neutrons andprotons. The operator Qma is the quadrupole operatorand is given by

(3)

= Vrr=rt.t*

(4)

where ca is the boson effective charge.The quadrupole operator in Eq. (3) has two parts. The

first changes a monopole boson into a quadrupole boson,and the second reorients the quadrupole boson. Theattractive (K > 0) quadrupole interaction reflects the neu-tron-proton quadrupole interaction, with the monopole-changing component producing deformed nuclei. Hence,the pairing interaction and the quadrupole interactioncompete with each other. As neutrons are added to agiven nucleus, the role of the proton-neutron interactionbecomes more important and mixes more quadrupolebosons into the low-lying spectrum, inducing deforma-tion.

The samarium isotopes illustrate this effect very well.The isotope I44Sm is semimagic, having the neutron shellsclosed at magic number 82 and having no valenceneutrons. The excitation energy of the first Jn = 2+ is1660 keV. As neutrons are added, the number of interac-tions between valence neutrons and protons increases,resulting in a decrease of the Jn = 2+ excitation energy to73 keV in l58Sm.

Figure 2 shows this dramatic drop in excitation energy.Furthermore, since the pairing interaction favors pairs ofprotons coupled to angular momentum 0, or monopolepairs, the lowest / " = 4+ state in l44Sm is primarilycomposed of monopole proton pairs, with one paircoupled toJn = 4+.

However, the IBM does not have such a state in itsspace. The only way to produce a / = 4+ in the IBMspace is to have two quadrupole pairs couple to angularmomentum / * = 4+. Such a state has two broken mono-pole pairs; hence in a semimagic nucleus these will liehigher in energy than the one broken-pair state. However,the implicit assumption in the IBM is that the quadrupoleinteraction lowers the energy of the state with the quadru-pole pairs more than that of the states with pairs withhigher angular momentum.

In Fig. 2, calculated results are shown that illustratethis point. A schematic fermion model was used that hasan 5O8 dynamical symmetry,9 but otherwise has manyfeatures in common with the IBM-2. With only three

luary-December 1983 PROGRESS AT LAMPfLos Albmos National Laboratory

147

IFig. 2.

Excitation energy for some low-lying states in thesamarium isotopes vs mass number. The solid linesare calculated (Ref. 9), the symbols are empirical.

156

parameters, the dramatic decrease in energy for the yrastlevels is reproduced for the isotopes l48l56Sm. However,for the lighter isotopes the calculated levels with J > 2 risemuch higher than the measured excitation energy.

As suggested in the previous paragraphs, the expla-nation for this is that for the isotopes with neutronnumber close to magic, the pairing interaction favorsstates with the fewest broken pairs. Hence the JK = 4+

state, for example, with one Jn = 4+ pair, will lie lower inenergy than the Jn = 44 state with two quadrupole pairs.Thus the Jn = 4+ state in the IBM space, which must haveat least two quadrupole pairs, will rise in energy as thenucleus becomes more nearly singly magic. Investiga-tions are under way to determine whether medium-energy scattering to high momentum transfer can helpsort out these different parts of the nuclear wave functionand thereby test this basic premise of the IBM.

The first Jn = 1+ state that is predicted bj- this model isalso plotted in Fig. 2, although experimentally no suchstate has yet been detected. This state is of special interestbecause within IBM-1 it cannot exist. This follows fromthe fact that identical quadrupole bosons cannot coupleto angular momentum Jn = 1+, which is obvious for twoquadrupole bosons, but it turns out to be true no matterwhat the number of identical quadrupote bosons. How-ever, for nuclei with neutron and proton quadrupolebosons that are active, such a state is possible. For M4Sm,which has only valence protons, we see that this statedoes not exist, but as neutrons are added, this stateappears at about 3 MeV in excitation energy. This energyprediction is a by-product of the model. Recently such aJK = 1+ state has been observed in electron scattering inthe neighboring '"Gd nucleus at an excitation energy ofabout 3 MeV.' ' These types of neutron-proton excita-tions are of interest to probe further.


J»nutry-D*c*mbw 1SB

Microscopic Basis of IBM

As we stated in the Introduction, the IBM is anpproximation to the nuclear shell model. How, then, do

we produce a boson Hamiltor.tan and transitionoperators from a fermion Hamiltonian and transitionoperators?

This question is actually an old one in nuclear physicsand was originally stimulated by the quadrupole vibratormodel. However, there has not been a satisfactory resolu-tion of this problem. The most difficult point is todetermine the coordinate-space wave function of themonopole and quadrupole bosons. The reason for thedifficulty is that this wave function varies with massnumber because the renormalization effects due to thePauli principle and the excluded pair and core excitationsvary with mass number.

For nuclei near closed shells there has been somesuccess. The procedure here is to diagonalize the shell-model Hamiltonian in the two-nucleon space and to takeas the collective monopole and quadrupole pair thelowest Jn = 0+ and 2+ pairs. The boson Hamiltonian andtransition operators are then determined by calculatingmatrix elements of the fermion Hamiltonian and tran-sition operators in the si:bspace of fermion states withonly monopole and quadrupole pairs. These matrix ele-ments are then equated to the corresponding bosonmatrix elements. Since a transition operator is at most aone-boson operator, only the matrix elements wiji atmost one quadrupole pair need be mapped, whereas forthe Hamiltonian, only the matrix elements with at mosttwo quadrupole pairs need to be mapped. This

method is called the OAI method, using the initials of theoriginal authors " (the first initial belongs to TakaharuOtsuka. at present a postdoctoral fellow in T-5, whocontinues to pursue the microscopic understanding of theIBM).

For highly deformed nuclei there also has been somesuccess. In this case the collective pair is determined bya Hartree-Fock-Bolgolubov minimization of the fermionHamiltonian. Because the nucleus is deformed, this pairwill be an admixture of different angular momenta. About90% of the pair is made up or a J* = 0T and J" = 2* pair,with the remaining 10% being a / * = 4+ pair. Thematrix elements between many collective fermion pairsare then set equal to the matrix elements between manycollective bosons, with the collective boson having thesame angular-momentum composition as the collectivefermion pair. The effects of the J n = 4+ boson, or g boson,are removed by renormalizing the resulting boson Hamil-tonian and transition operators.

Using this procedure, the parameters of the bosonHamiltonian [Eq. (1)| and transition operator |Eq. (4)]are determined for the nucleus I58Gd (Ref. 15). Themicroscopic results are given in Table I. Phenomenologi-cal parameters determined by fitting spectra and tran-sition rates of l58Gd are listed in the fourth column. Wesee that agreement between the microscopic and phenom-enologically determined parameters is very good. The lastcolumn gives the parameters determined by the OAImethod, valid near spherical nuclei but invalid for adeformed nucleus like l58Gd. In fact, the parametersderived by the OAI method do not produce a stableequilibrium deformation because the absolute magnitudesof x, and x,. <""e too small. The third column gives the

Table I. Parameters in the Boson Quadrupole Interaction and in the BosonE2 Operator for 158Gd. The second column shows calculationsobtained using the mapping method described in the text withrenormalization resulting from the elimination of the g boson; theunrenormalized result is shown in the next column in parentheses.Parameters obtained by a phenomenological calculation and thoseby the OAI method are also shown (from Ref. 15).

Parameter

K (MeV)

X,Xv^(e-fm2)e?,(e-fm2)

MicroscopicCalculation

0.094-0.86-1.1812.010.0

UnrenormalizedResult

(0.12)(-0.80)(-1.03)(10.6)(6.7)

PhenomenologicalParameters

0.08- 0.09-0.8 ~ -0.9-1.1 —1.2

12 ~ 1412~ 14

OAIMethod

0.190.04

-0.5514.38.4

nuary-December 1983 PROGRESS AT LAMPFI os Alamos National Laboratory

149

results before renormalization. In each case the re-normalization improves agreement, but is not too large acorrection—less than 35% for all parameters.

The difficult task is to handle the transitional nuclei,those between spherical and deformed. The search for aunified mapping procedure continues.

Transition Densities

The range of momentum transfer involved in medium-energy electron and proton scattering provides a tool forprobing the nuclear transition density. Within the IBM,the quadrupole transition density operator is a generaliza-tion of the transition operator given in Eq. (4):

valence protons. Furthermore, since it is singly magic, theground state is primarily monopole bosons. Hence thematrix element of (d*d ) n> to the first Jn = 2* stale wi"vanish. Therefore the transition density will depepredominantly on an(r). Consequently, this function can 'be determined phenomenologically. Likewise, a^r) canbe determined from the transition density for 144,Sn,4.

Because 'jjjBa,, has both valence neutrons andprotons, it is more complicated than either 138Ba or U4Sn,but the wave functions have been determined in IBM-2(Ref. 6). To determine the transition density for 134Ba, weneed to know Po(r). It turns out, however, that the matrixelements of (d*d )<2) between Ot and 2\ u '% or lessof the matrix element of s d + d s between these two

17 m mstates. Hence the transition density will not be sensitive

(5)

The boson wave transition densities aa{r) and Po(/-) can bedetermined phenomenologically or from a microscopictheory.

Recently the 0* —*• 2\ transition densities forl3,4Ba7g, ' j 'Ba^, and '^Sn74 were measured in elec-tron scattering. The nucleus 'seBaB2 has a closedneutron shell, hence the density is due primarily to the

Ignoring p a , we can determine the transition density ofl34Ba from the phenomenologically determined aa and theIBM-2 wave functions. Of course we must assume thatthe structure of the monopole and quadrupole pair doesnot change appreciably between 138Ba (I24Sn) and l34Ba.In Fig. 3 the empirical transition density is given I j thehatched line, where the hatches measure the uncertaintyin experimental analysis. The solid line is the IBM-2transition density, determined by combining the phenom-enologically determined ao 's and the IBM-2 wave func-tions. On the surface the measured and IBM-2 transitiondensities overlap and are undistinguishable.17

0.04 -

-o.oi -

r (Im)

Fig. 3.The transition density p{r) for the 0+ -+ 2\ transition in U4Ba. The hatched line is the empiricaltransition density, the solid line is the phenomenological IBM-2 density, and the dashed line is themicroscopic IBM 2 density, as explained in the text.


January-Decambv 19>,

In the interior region there seems to be some disagree-ment. However, since the phenomenologically de-•ermined ao(r) is less certain in the interior, the extent of

il disagreement is unclear. Further, since the IBM-2' transitior density becomes small for r •» 3.5 fm, the

neglected effects such as (3CT and renormalization of aa

may be important. Although not shown on the curve, theTassie transition density extends further out on thesurface, in disagreement with the empirical transitiondensity.

The functions aa(r) can be determined microscopicallyas well. The structure of the monopole pair has beendetermined from a BCS calculation for both I24Sn and17!lBa within one major shell using harmonic oscillatorwave functions. The quadrupole pair is determined byoperating on the monopole pair with the (fermion) quad-rupole operator.17 The result is given by the dashed linein Fig. 3. The microscopic result is shifted to a lowerradius than that of the empirical transition density(hatched iine). However, core polarization was neglectedin the microscopic transition density; this could reducethe wiggles. Improved calculations are under way inwhich core polarization and more realistic single-nucleonwave functions can be included in the microscopic trans-ition density.*

Glauber Approximation and IBM

Because the interaction of electrons with nuclei isweak, medium-energy electron scattering can be ana-lyzed using the distorted-wave Born approximation(DWBA). For hadronic probes this is not necessarily thecase. For 800-MeV protons, multiple scattering is impor-tant at high momentum transfer. ' One approach fortaking multiple scattering into account is to solve a set ofcoupled-channel equations.1 Another approach is tocalculate the transition matrix to all orders in the Glauberapproximation.20 Although the physics content of thesetwo approaches is similar, the Glauber approximation

I Q

gives more insight and is numerically simpler.For a strongly deformed nucleus such as !54Sm, the

Bohr-Motteison model can be used to evaluate theGlauber transition matrix to all orders.19 In Fig. 4 theresults of this calculation are shown for 800-MeV protonelastic and inelastic scattering from 1}4Sm (solid line) and

L ' ' • • ] ' •-' ' | ' • ' ' I ' ' ' ' I

10

I 0

O.I

1 • ' • I • • ' i I i i i

05 10 15 20 25

q (fm"1)

Fig. 4.The differential cross section vs momentum trans-fer for 800-MeV proton elastic and inelastic scatter-ing from l54Sm. The dots are the data (Ref. 18), thesolid line is the Glauber approximation using adeformed density (Ref. i9), and the dashed line isthe distorted-wave approximation to the elasticscattering.

*T. Otsuka, private communication.

myDecember 1983 PMXMEStATLAMI* 1 5 1Los Alimoi Niiontl Libortiory

I ft

are compared to the experimental data. The agreementis very good. The dashed line shows the DWBA predic-tion for elastic scattering. One sees the inadequacy of theDWBA in reproducing the phase and amplitudes of thedifferential cross section at high momentum transfer.

Recently we have realized that the Glauber approx-imation can be combined with the IBM such that thetransition matrix can be evaluated to all orders in closedform.1 This combination arises from the fact that theGlauber transition operator is a linear rotation in the IBMspace. For example, if the incoming projectile has aquadrupole interaction with the target, the Glauber tran-sition matrix for scattering a projectile with momentumk to A?" with resulting momentum transfer,

r rdr

dz

(8a)

(8b)

where/, is the forward-scattering amplitude of the projec-tile and proton (a = n) or neutron (0 = v); gc is thequadrupole coupling strength between the projectile andtarget nuc.'eon; C^\b) is the projectile unit sphericaltensor of rank t,

= k'-k , (6a)

, (6b)

where

UJ1 ~e Mfl

and the reduced transition matrix is

(6c)

ji L> (6d)

In the above, f and / label the final and initial states,respectively. Denoting the positon of the incoming pro-jectile as r, the two-dimensional impact radius 6 is

r = 5 + kz (7)

where k is the unit vector of the projectile momentum.Within an optical-model approximation, the Glauberphases are

1/2

(9)

and pa(r) is the proton (o = n) or neutron (o = i>) matterdensity.

Because the operator in the matrix clement | Eq. (6d)| isan exponential function of the boson quadrupole operator[Eq. (3)|, this operator has the oiTect of rotating thebosons in the initial nuclear wave function into those ofthe final nuclear wave function. For the example of aquadrupole vibrator, this transition matrix from theground state can be simply derive^.10

The ground state of the quadrupole vibrator is a bosoncondensate of N monopole bosons, where ./V is one-halfthe number of valence nuclcons. Excited states arelabeled by the number n of quadrupole bosons, or"phonons," with the energy of the states increasingapproximately linearly with n. For a given n (here is amultiple! of states, with the quantum number x designat-ing the number of quadrupole bosons not coupled, inpairs, to angular momentum 0, the quantum number «A

designating the number of quadrupole bosons coupled intriplets to angular momentum 0, and of course theangular momentum J and i(s projection M. The allowedvalues of these quantum numbers arc

= /J , w - 2 and finally lo rO , (!0a)

and for each t the allowed angular momenta and ;»A arcdetermined by all possibilities of partitioning x.

152 PROGRESS AT LAMPFLot Altmos Nulontl Labowory

January December rr

(!0b)

where n s and \ are integers. Then the allowed J are

, 2A.-2 . 2 X - 3 A. . (10c)

The reduced Iransition matrix for scattering from theiniiial ground state (n = T = «A = 7 = Af = 0) to an excitedfinal state with quantum numbers n, T, » v J, M is

Table H.

T

01223333

Coefficients A^n , for the Low-est

*\

00000001

Values

J

02246430

oft. A

A

]

I- |1 /7 |" :

(9/351"1

|3/771"J

-(1/7)| 6/51"1

0- | l / 1 0 5 | " :

(N

/V! (2T+3) ! ! "I "

-M)K"+T+3)!!(M-T)!!J

transfer the higher order multiple scattering makes asubstantial difference even in the clastic channel,particularly in the phase relationship between maximaand minima.

where Axn j is a constant that is independent of theGiaubcr phase f „. The functions W, X are

'X,,

X. - i-««>

(12a)

(12b)

and

Xu (12c)

The cocillcients Axn j are given in Table II for (he lowestvalues of x.

In Fig. 5 an example of the elastic differential crosssection for the scattering of 800-McV protons from avibralional nucleus is shown as a function of (he momen-tum transfer. The solid line is the differential cross sectiongiven by the transition matrix of Rt|. (11), which includesall the multiple scattering. The dashed line does notinclude the multiple scattering but is the DWBA elasticdifferential cross section. We sec that for high momentum

January Oacowbor 10Htl

0.5 l.O 1.5 2.0 2.5 3.0 3.5 4 0 4.5 5.0

q Cm"1)

Fig. 5.The differential cross section vs momentum trans-fer for 800 MeV proton scattering from a typicalquadrupolc vibrator in (he Glauber approximation(Kef. 10). The dashed line is the distorted waveapproximation (o the elastic scattering.

PROGRESS AT LAMPF 1 5 3Los Alitmun Nuinrml Ltborttoiy

Summary

Because medium-energy. projectiles can probe the

nucleus at high momentum transfer, detailed information

about static and transition densities can be determined.

The IBM gives a framework to study these derived

densities both phenomenologically and microscopically.

Of particular interest is the transition from spherical to

deformed nuclei. Furthermore, because of the algebraic

nature of the IBM, multiple scattering in the Glauber

approximation, which becomes important at high

momentum transfer, can be treated exactly to all orders.

Also, because medium-energy probes have varieties of

electromagnetic and hadronic charge, the neutron and

proton static and transition densities can be disentangled.

These neutron and proton degrees of freedom can be

analyzed in IBM-2.

Although in this review we have restricted ourselves to

even-even nuclei, odd nuclei can be studied in a similar

manner in the interacting boson-fermion model.21

REFERENCES

1. A. Arima and F. Iachello, Ann. Rev. Nucl. Part. Sci. 31, 75(1981).

2. 3. N. Ginocchio and M. W. Kirson, Nucl. Phys. A 350, 31 (1980).

3. D. D. Warner, R. F. Casten, and W. F. Davidson, Phys. Rev. C24,1713(1981).

4. O. Scholten, "A Phenomenological Study of Even-Even Nuclei inthe Neutron-Proton IBM," in Interacting Bosons in Nuclei, P.lachello, Ed. (Plenum Press, New York, 1979), pp. 17-35.

5. P. van Isacker and G. Paddu, Nucl. Phys. A 348, 125 (1980).

6. G. Paddu, O. Scholten, and T. Otsuka, Nucl. Phys. A 348, 109(H80).

7. R. Bijker, A. E. L. Dieperink. O. Scholten, and R. SpanhofT. Nucl.Phys. A 344, 207(1980).

8. B. R. Barrett and P. D. Duval, "Recent IBM-2 Calculations," inInteracting Bose-Fermi Systems in Nuclei, F. lachello, Ed.(Plenum Press, New York, 1981), pp. 47-52.

9. A. Arima, i. Ginocchio, and N. Yoshida, Nucl. Phys. A 384,112(1982).

10. J. N. Ginocchio, in the Proc. of the Workshop on NuclearCollective States, Suzhow University, China, L. M. Yang, G. O.Zhou, S. S. Wu, Z. Q. Zhou, and D. H. Feng, Eds., (1983); LosAlamos National Laboratory document LA-UR-83-3638; and tobe published in a special issue of Nucl. Phys. A (1984).

11. A. Richter, in the Proc. of the Int. Conf. on Nuclear Physics,Florence, Italy (1983), Vol. 2.

12. T. Otsuka, A. Arima, and F. lachello, Nucl. Phys. A 309, 1(1978).

13. T. Otsuka, Phys. Rev. Lett. 46. 710(1981).

14. S. Pittel, P. D. Duval, and B. R. Barrett, Ann. Phys. 144. 168(1982).

15. T. Otsuka, Los Alamos National Laboratory document LA-UR-83-1744, to be published in Phys. Lett. (1984).

16. T. Otsuka, A. Arima, and N. Yoshinaga, Phys. Rev. Lett. 48,387(1982).

17. T. Otsuka, K. Mori, Y. Mizuno, T. Terasawa, and Y. Torizuka."Test of the Interacting Boson Model by Inelastic ElectronScattering for the 2* State of I3<Ba," to be published in Phys. Lett.(1984).

18. M. L. Barlett, J. A. McGill, L. Ray, M. M. Barlett, G. W.HofTman, N. M. Hintz, G. S. Kyie, M. A. Franey, and G.Blanpied, Phys. Rev. C 22, 1168 (1980).

19. R. D. Amado, J. A. McNeil, and D. A. Sparrow, Phys. Rev. C 25.13 (1982).

20. R. J. Glauber, "High-Energy Collision Theory," in Lectures inTheoretical Physics, Vol. 1, W. E. Brittin and L. G. Dunham,Eds. (Interscience Publishers, Inc., New York, 1959), pp.315-414.

21. F. lachello, "Present Status of the Interacting Boson-FermionModel." in Interacting Bose-Fermi Systems in Nuclei, F. lachello,Ed. (Plenum Press, New York, 1981), pp. 273-283.


Januiry-Dxtmotc 1983

Implications of Using Approximate Chiral-Dynamics nN —• nm\ Amplitude in the CalculationofA(n,2n) Cross SectionsR. S. Bhalerao andL.-C. Liu (Los Alamos)

We have completed a study of the relative importanceof the diagrams contributing to the nN—* nnN reactionin the framework of the Weinberg effective Lagrangiantheory. Various approximate schemes in the recent litera-ture used to calculate the nN^-nnN amplitude and thusthe A(K,2K) cross sections have been found to be inade-quate. Besides the total cross sections, we have studiedfor the first time the angular correlations of the outgoingpions and the energy spectrum of the outgoing nucleon inthe nN—>- nzN reaction. A brief description of thisinvestigation, which we think is of vital importance fortheoretical interpretation of the A(n,2n) experimentsplanned at LAMPF, is given here. (Details can be foundin a paper, with the same title as this experiment, to besubmitted to Phys. Rev. C.)

For definiteness, we consider the reaction

procedure to calculate A{n,2n) cross sections up to

t (G)+P(P/) (1)

with the four-momenta of the respective particles writtenin parentheses. The invariant amplitude T for this reac-tion, which can be calculated using Weinberg's effectiveLagrangianIi2 in the lowest order perturbation theory,and has the form

T= Tfl> + Tl2) T'K)(2)

T1" is composed of the pion-pole term and the contactterm. Tm and T(3) are the so-called two- and three-pointdiagrams with one- and two-nucleon propagators, respec-tively. r<K) is the anomalous magnetic-moment term.Various approximations to the above amplitude havebeen proposed in the literature. We describe them brieflyin the following paragraphs.

Olsson and Turner2 (OT) have neglected the contribu-tions of T(3) and Tm and have calculated Tw and Ti2) inthe threshold approximation defined by qt = q2 = (mT,d),

N,o), Q = Qthr, and p^p^v T n e v h a v e m a d e

is approximation also in the invariant phase space andhave calculated nN—*• TZKN cross sections up to7; =300 MeV.

Rockmore4 (Rl) has neglected Tm, Ta\ and TK) andhas calculated T(i) and the invariant phase space in thethreshold approximation defined above. He has used this

thi

Recently, Rockmore5 (R2) has neglected Ti2>, Til\T(K), and the contact term in Tn\ made the thresholdapproximation, and thus calculated A(n,2n) cross sec-tions up to Tn = 280 MeV.

Eisenberg and Cohen6 (EC) retained the contributionsof 7 l l ) and Ta\ made the threshold approximation, andused the center-of-mass amplitude in the laboratoryframe to calculate the A(n,2n) cross sections.

In spite of the diversity of these approximations, wenote that as soon as the threshold approximation isinvoked, the amplitude T becomes independent of theenergy and momentum of the particles in the final state.As a consequence, these different approximate calcula-tions differ from each other and from the phase spaceonly by constant multiplicative factors. That is to say,they all have the same energy and angular dependence asthat predicted by the phase space.

Figures 1 and 2 show the relative importance of thevarious terms in Eq. (2), with and without the thresholdapproximation. It is evident from Fig. 1 that even atTn = J90 MeV the contact term and r(2) are far fromnegligible with respect to the pion-pole term. r(3), how-ever, is relatively less important until rn~240MeV;r(K) is negligible over the entire energy region considered.

It is clear from Fig. 2 that even in the near-thresholdregion there are sizable differences among the exact andthe approximate curves. The relatively close agreement ofthe curve labeled R2 with the low-energy data is some-what fortuitous in that this curve is based on the mostextreme of the approximations—that which neglects allbut the pion-pole term in Eq. (2).

The remaining curves tend to underestimate the exacttheoretical cross sections significantly. Considering thatthe exact theoretical cross sections in turn are muchsmaller than the experimental data, the approximateamplitudes for nN —*• nnN (except R2), when used in thecalculation of (n,2n) cross sections on nuclei, tend tounderestimate the A(n,2n) data, in some cases by anorder of magnitude. Results in Refs. 4-6 should be viewedin light of these remarks. (Incidentally, our remark aboveconcerning the essential phase-space nature of the calcu-lations in Refs. 2 and 4-6 is borne out by Fig. 2.)

It has been suggested in Ref. 6 that the existence ofpion condensation precursor phenomena would enhancethe A(n,2n) cross sections considerably above whatwould be observed otherwise, and that such an enhance-ment could provide partial evidence in support of such

January December 1983 PROGRESS AT LAMPFLos Alamos Nation*! Laboratory

155

REFERENCES 4. R. Rockmore, Phys. Rev. C 11, 1953 (1975).

1. S. Weinberg, Phys. Rev. Lett. 18, 188 (1967). 5. R. Rockmore, Phys. Rev. C 27, .150(1983).

2. M. G. Olsson and L. Turner, Phys. Rev. Lett. 20, 1127 (1968). 6 . J. M. Eisenberg, Phys. Lett. 93B. 12 (1980); J. Cohen and J. M.

Eisenberg, Nucl. Phys. A 395, 389 (1983), and Nuovo Cimento3. R. A. Arndt et al., Phys. Rev. D 20, 651 (1979). 7 6 A , 488 (1983); and J. Cohen, J. Phys. G 9. 621 (1983).

7. C. W. Bjork et al., Phys. Rev. Lett. 44, 62 (1980).

1 5 8 PROGRESS AT LAMPF January-December 1983Los Alamos National Laboratory

Report of the T-5 Theoretical GroupT. Goldman (Los Alamos)

This is a brief summary of some of the T-5 researchactivities relevant to LAMPF and LAMPF II. Becausethis report is included in a basically experimental docu-ment, items of a primarily technical nature have beenomitted.

While continuing their research role, T-5 staff mem-bers have invested a substantial amount of time and effortto further the LAMPF II project, including preparing forand running conferences and workshops, reporting atplenary sessions, and contributing to and editing theresulting proceedings. Major efforts included the Theoret-ical Symposium on Intense Medium-Energy Sources ofStrangeness at the University of California, Santa Cruz,and the Third LAMPF II Workshop at Los Alamos.Material in the Santa Cruz1 and Los Alamos Proceed-ings is not repeated here. In addition, T-5 stalY membershave argued the physics justification for LAMPF II inpublic forums and in the L.AMPF II proposal.

Research Related to LAMPF

We have made several developments in the codePIPROD. Motivated by the imminence of a number ofexperiments at LAMPF and elsewhere, we have extendedPIPROD to calculate spin-transfer coefficients (Wolfen-stein parameters, DLL, etc.) that measure the dependenceof the NN —•• NNn reaction on the spin directions of oneinitial and one final nucleon. We have numerically inte-grated exclusive cross-section predictions from PIPROD toproduce inclusive cross sections and spin observables.Our parameter-free prediction (using only one-pion-ex-change forces) for the polarized beam asymmetry in thereaction p+p—*p'-rX is in good agreement with arecent HRS experiment. Our preliminary results on thespin-transfer coefficients forp+p-^n+X, however, donot agree so well with another recent experiment. This isperhaps an indication that a dibaryon resonance canshow up in this particular spin observable but not inothers.

We have also employed PIPROD to calculate the rela-tive absorption rates of pions on a pair of (free) nucleons,using a relativistic isobar model for the coupled NN andNNn systems that respects two- and three-body unitarity.In contrast with an earlier calculation that only con-sidered NA intermediate states, we found that much of

the absorption takes place through an intermediate stateinvolving a nucleon and a (nonresonant) interacting pion-nucleon pair with the same quantum numbers as thenucleon. Moreover, this effect was able, for the first time,to explain qualitatively the order-of-magnitude changes inthe proton-proton to proton-neutron suppression as theincident pion energy increases from zero (capture at rest)to above the A resonance. In general, for the inversereaction AW —>- NNn, this mechanism is rather unimpor-tant compared with the NA state. Thus, the experimentalinvestigation of two-nucleon pion absorption in lightnuclei may clarify details of the weaker nN interactions.Much of our NNn work is summarized in the precedingreport in this section by R. Silbar.

Configuration-space, local-potential Faddeev calcula-tions were extended to the Coulomb problem of elasticscattering of protons by deuterons at zero incidentenergy. We found that the spin-doublet scattering lengtha^ was approximately zero. This differs substantiallyfrom (I) the accepted experimental value, (2) theoreticalestimates using approximation schemes to combineCoulomb effects with known neutron-deuteronamplitudes to obtain df, and (3) intuitive estimatesbased on the established linear relationship between thetriton binding energy and the neutron-deuteron doubletscattering length. (The fact that the binding energy of 3Heis smaller than that of 3H led people to expect that a^would be larger than a"d^0.1 fm.) However, thequalitative features of the Coulomb correction to thedoublet scattering length are analogous to Coulombcorrections in the two-body scattering problem when thescattering length is small (as for pion-nucleon scattering).Thus, although novel, the results of our Faddeev calcula-tions are a posteriori quite understandable.

Eikonal expansions were developed for the amplitudesin the scattering of Dirac particles (protons) by centralscalar and vector potentials, and for the correspondingSchrodinger case with central and spin-orbit potentials.The eikonal phases were calculated through second-ordercorrections. Our motivation was to correlate the Diracand Schrodinger approaches to proton-nucleus scatter-ing, to develop systematically a practical formalism forcalculation, and to provide insight into the scatteringprocess. Recently, the Dirac phenomenology approach tooptical potentials has given a more economical descrip-tion of spin-dependent observables in medium-energyproton-nucleus scattering than the usual Schrodingerapproach. Our analysis elucidates the simple physicalreasons for this.


159

The jt°—•:ji±e decays were investigated and an ex-perimental upper limit of

2 T(no-*al[)

< 7 x 10~8(90% confidence level)

was deduced from available data. We also considered theexisting constraints on the underlying muon-number-violating interaction. We found that the present ex-perimental information on u~ —»• e~ conversion in sulfurimplies an upper bound on the individual n" —• u1^branching ratios of about 10"15.

Research Relevant to LAMPF II

Study of K+ -nucleus elastic scattering has been pursued.Comparison with the available data on 12C and 40Cashows no conflicts with the scattering theory. We con-clude that the goal of precision measurements of thenuclear density, as seen by a K+, can be achieved as soonas accurate data on the fundamental iif+-nucleon systemcan be obtained.

A new investigation of the A lifetime in nuclear matterhas been completed. The free decay A —*• nN is severelyinhibited in nuclt' because of Pauli blocking of thenucleon, and the weak nonleptonic transition AN —*• AWdominates the decay process. The long-standing dis-crepancy between the calculation of Adams( r n n / r f r e e = 0.06) and the single experimental value for16O, which was determined by only 22 events(rn m /r f r e e = 3 ± 1), has been resolved; an incorrect cou-pling constant was used in the earlier theoretical in-vestigation. Including model estimates of the effects ofshort-range correlations, tensor forces, and heavy-mesonexchange in the weak interaction (in addition to one-pionexchange), and allowing for uncertainties in the variouscoupling constants and the vertex form factors, weestimate the ratio by Iog10(rnm/r frw) = 0 ± 0.3.

Detailed studies of the muon-number-violating decaymodes of hyperons were carried out, both in a phenome-nological framework and in considering some possiblesources of muon-number violation. We find thatbranching ratios as large as 10"6 cannot be excluded byavailable data and that they are consistent with someextensions of the three-generation minimal (standard)

electroweak model. However, such branching ratios re-quire the muon-number-violating interaction to be of avery special structure.

The experimental limit of dB% 6 x 10~2S e-cm for theelectric-dipole moment of the neutron has ruled out someof the many theories proposed to explain the CP andT violation observed in kaon decays. We have demon-strated that many-body effects can lead to large enhance-ments of nuclear electric-dipole moments, which in cer-tain cases fully compensate for the effects of atomicshielding; thus, the latter need no longer limit measure-ments of the proton electric-dipole moment dv. Therecent development of experimental techniques tomeasure atomic-dipole moments at levels well below thelimit on dn leads us to conclude that comparable stringentnew limits on both dn and dp may be obtained withsignificant implications for predictions in the kaon sys-tem.

Anyone wishing further information on these subjectsmay contact Group T-5 members J. L. Friar, W. R.Gibbs, B. F. Gibson (Group Leader), J. N. Ginocchio, T.Goldman, W. C. Haxton, L. Heller, P. Herczeg, R. R.Silbar, or G. J. Stephenson, Jr. (Acting P-3 GroupLeader).

REFERENCES

1. T. Goldman, H. E. Haber, and H. F.-W. Sadrozinski, Eds., IntenseMedium-Energy Sources of Strangeness, University of California,Santa Cruz. 1983. A1P. Conf. Proc. No. 102, Particles and FieldsSubseries No. 31 (American Institute of Physics, New York,1983).

2. "Proceedings of the Third LAMPF II Workshop," Vols. I and II,Los Alamos National Laboratory report LA-9933-C (1983).

Group T-5 Publications

J. L. Friar, B. F. Gibson, and G. L. Payne, "Three-Nucleon Forces and Meson-Exchange Currents in theTrinucleon," Comments Nucl. Part. Phys. 11, 51 (1983).

J. L. Friar, "Classification of Exchange Currents," Phys.Rev. C 27,2078(1983).

J. L. Friar and E. L. Tomusiak, "Threshold PionPhotoproduction from the Trinucleon," Phys. Lett. I22B,11(1983).


J. L. Friar and B. H. J. McKellar, "Pion ExchangeContributions to the Lobashov Experiment," Phys. Lett.123B, 284(1983).

J. L. Friar, S. Fallieros, E. L. Tomusiak, D. Skopik, andE. G. Fuller, "Electric Polarizability of the Deuteron,"Phys. Rev. C 27, 1364-1366 (1983).

J. L. Friar, "Three-Body Forces," Indiana UniversityCyclotron Facility (IUCF) Workshop on the InteractionBetween Medium-Energy Nucleons in Nuclei—1982, H.O. Meyer, Ed., AIP Conf. Proc. 97, 378 (1983).

J. L. Friar, B. F. Gibson, and G. L. Payne, "The Proton-Deuteron Scattering Length," Phys. Lett. 124B, 287(1983).

B. F. Gibson, C. B. Dover, G. Bhamati, and D. R.Lehman, "Binding Energy Estimates for Charmed Few-Body Systems," Phys. Rev. C 27, 2085 (1983).

B. F. Gibson, W. M. Kloet, G. J. Stephenson, Jr., and E.M. Henley, "Parity Nonconserving Asymmetry in Neu-tron-Deuteron and Proton-Deuteron Scattering," Phys.Rev. C 27,2529(1983).

J. L. Friar, B. F. Gibson, and G. L. Payne, "Configura-tion-Space Faddeev Calculations: VI. Triton WaveFunction," Z. Phys. A 312, 169 (1983).

J. L. Friar, B. F. Gibson, and G. L. Payne, "Configura-tion-Space Faddeev Calculations: pd s-Wave ScatteringLength," Phys. Rev. C 28, 983 (1983).

B. F. Gibson and D. R. Lehman, "Structure of the3H —>• nd (d*) Vertices," Los Alamos National Labora-tory document LA-UR-83-2960 (to be published in Phys.Rev. C).

W. C. Haxton and E. M. Henley, "Enhanced T-Nonconserving Nuclear Moments," Phys. Rev. Lett. 51,1937(1983).

W. C. Haxton, "Double Beta Decay," Comments Nucl.Part. Phys. 11,41 (1983).

W. C. Haxton, "Double Beta Decay," in the McGraw-Hill 1984 Yearbook of Science and Technology.

E. G. Adelberger, W. C. Haxton, M. M. Hindi, C. D.Hoyle, and R. D. Von Lintig, "The Beta Decays of l8Neand "Ne and their Relation to Parity Mixing in 18F and19F," Phys. Rev. C 27, 2833 (1983).

G. A. Cowan, M. Goldhaber, and W. C. Haxton, "ARadiochemical Test of Double Beta Decay," Phys. Rev.C 28,467(1983).

W. C. Haxton and G. J. Stephenson, Jr., "A Comment on'Nilsson-Pairing Model for Double Beta Decay,'" Phys.Rev. C 28,458(1983).

W. C. Haxton et al, "Neutron and Proton TransitionMatrix Elements for 90Zr from a Microscopic Analysis of0.8-GeV Proton Inelastic Scattering," Phys. Rev. C 28,294(1983).

P. Herczeg and T. Oka, "Study of Muon-Number-Violating Hyperon Decays" (to be published in Phys.Rev. D, February 1984).

P. Herczeg and C. M. Hoffman, "Study of n0-*^Decays" (submitted to Phys. Rev. D).

Dean Preston and T. Goldman, "The Strangeness-Conserving Effective Weak Interaction in the QuarkBasis," Nucl. Phys. B 217, 31 (1983).

T. Goldman and Dean Preston. "A Quark Model Calcu-lation of the Weak Parity-Violating Asymmetry in High-Energy Proton-Nucleon Scattering," Nucl. Phys. B 217,61(1983).

R. R. Silbar and E. Piasetzky, "Isospin Dependence ofPion Absorption on Nucleon Pairs," Los Alamos Na-tional Laboratory document LA-UR-83-1883 (to bepublished in Phys. Rev. C).

R. R. Silbar and E. Piasetzky, "Ratio of Pion-InducedNucleon Removal Cross Section Involving Charge Ex-change," Phys. Rev. C 27, 894 (1983).

T. S. Bhatia, J. G. J. Boissevain, J. J. Jarmer, J. E.Simmons, G. Glass, J. C. Hiebert, R. A. Kenefick, L. C.Northcliffe, W. B. Tippens. R. R. Silbar, W. M. Kloet,and J. Dubach, "Analyzing Powers and Spin Correla-tions ANN and ALL for pp —*• npn+ at 650 and 800 MeV"(to be published in Phys. Rev. C).


161

J. N. Ginocchio, "A Class of Exactly Solvable Potentials:[. One-Dimensional Schrodinger Equation" (to be pub-lished in Ann. Phys. 152, 1984).

J. N. Ginocchio, "An SOt Model of Collectivity inNuclei," in Bosons in Nuclei, D. H. Feng, M. Vallieres,and S. P. Hel, Eds. (World Scientific Publishers Press,Singapore, 1984).

W. R. Gibbs, J. Kogut, M. Stone, H. W. Wyld, J.Shigemitsu, S. H. Shanker, and D. K. Sinclair, "Decon-finement and Chiral Symmetry Restoration at FiniteTemperatures in SU(2) and SU{3) Gauge Theories,"Phys. Rev. Lett. 50, 393 (1983).

W. R. Gibbs, "Analytic Structure of the p-NucleusOptical Potential." Phys. Rev. C 27, 408 (1983).

W. R. Gibbs and W. B. Kaufmann, "Nuclear MediumEffects in Pion Elastic Scattering and Charge Exchange,"Los Alamos National Laboratory document LA-UR-83-736 (Phys. Rev. C, in press).

B. F. Gibson, "Hyperon and Hypernuclear Physics withIntense Beams," in Intenze Medium Energy Sources ofStrangeness, T. Goldman, H. E. Haber, and H. F.-W.Sadrozinski. Eds.. AIP Conf. Proc. 102,43 (1983).

B. F. Gibson, "Electromagnetic and Weak Interactions inFew Nucleon Systems," in the Proc. of the 10th Int.Conf. on Few-Body Problems in Physics, Karlsruhe.Germany, August 21-27. 1983.

M. M. Nieto, W. C. Haxton, C. M. Hoffman. E. W. Kolb,V. D. Sandberg, and J. W. Toevs, Eds., Science Under-ground, AIP Conf. Proc. No. 96 (American Institute ofPhysics, New York, 1983).

T. Goldman, H. E. Haber, and H. F.-W. Sadrozinski,Eds., Intense Medium Energy Sources of Strangeness,University of California, Santa Cruz, 1983, AIP Conf.Proc. No. 102, Particles and Fields Subseries No. 31(American Institute of Physics, New York, 1983).


Jwiuaiy-Oecwnbar 1983

MP-Division Publications; Papers Submitted forPublication and Papers Presented

S. Adachi and N. Auerbach. "Widths of IsovectorMonopolc Resonances." Phys. Lett. 13IB. 11 (1983),Los Alamos National Laboratory document LA-UR-83-1811

L. Agnew, D. Grisham, R. J. Macek, VV. F. Sommer. andR. D. Werbeck, "Design Features and Performance ofthe LAMPF High-Intensity Beam Area," presented atICANS VII meeting. Chalk River Nuclear Laboratories,Ontario, Canada, September 12-16. 1983. Los AlamosNational Laboratory documenl LA-UR-83-2693.

J. F. Amann. R. J. Macek, T. W. L. Sanford, H. A.Thiessen, O. van Dyck. et al., "Measurement of Produc-tion Cross Sections for Negative Pions, Kaons, andProtons at 10. 18, and 24 GeV," Los Alamos NationalLaboratory report LA-9486-MS (1982).

G. Anderson, M. Oothoudt, J. Amann, and T.Kozlowski, "Dynamic Parameter Array System," IEEETrans. Nucl. Sci. NS-30, 3975 (1983).

I. P. Alter. W. R. Ditzler, D. Hill, K. Imai, H. Spinka, R.Stanck, K. Toshioka, D. Underwood, R. Wagner, A.Yokosawa, E. W. Hoffman, J. J. Jarmer, G. R. Burleson,W. B. Cottingame. S. J. Greene, and S. Stuart, "Measureof AaL and DLl = (L,L;O,O) in Proton-Proton ScatteringBetween ?00 and 800 MeV." submitted to Phys. Rev.,Los Alamos National Laboratory document LA-UR-83-3612.

N. Auerbach, "Coulomb Effects in Nuclear Structure,"Phys. Rep. 98, 273 (1983), Los Alamos National Labo-ratory document LA-UR-83-535

N. Auerbach, J. D. Bowman, M. A. Franey, and W. G.Love, "(p,«) and (n,p) Reactions as Probes of IsovectorGiant Monopole Resonances," Phys. Rev. C 28, 280(1983).

N. Auerbach and A. Klein, "Excitation of Giant ElectricIsovector Resonances in Pion Charge Exchange Reac-tions," Phys. Rev. C 28, 2075 (1983), Los AlamosNational Laboratory document LA-UR-1810(l983).

N. Aucrbach and A. Klein. "Excitation of Giant Re-sonances in the Ca Isotopes in (n*.rr°) Reactions." to bepublished in Nucl. Phys. A, Los Alamos National Labo-ratory documenl LA-UR-83-2978.

N. Aucrbach and A. Klein. "The Structure of IsovectorSpin Excitations in Nuclei." submitted to Phys. Rev. C.Los Alamos National Laboratory document LA-UR-83-2943.

H. W. Baer. J. A. Bistirlich. K. M. Crowe. W. Dahme. C.Joseph. J. P. Perroud. M. Lebrun, C. J. MartolT, U.Straumann. and P. Truol, "Study of the 7 = 2 States in A- 14 Nuclei with the 14C(jT.y)I4B Reaction." submittedto Phys. Rev. C. Los Alamos National Laboratory docu-ment LA-UR-83-170.

H. W. Baer. J. A. Bistirlich. K. M. Crowe. W. Dahme, C.Joseph, J. P. Perroud. M. Lebrun, "Isovector A/2 StateObserved in the I 4 C(JT,Y) Reaction." Phys. Rev. C 28,761 (1983).

R. D. Bolton, R. D. Carlini, M. D. Cooper. J. S. Frank,V. E. Hart. H. S. Matis. R. E. Mischke. V. D. bandberg,and U. Sennhauser, "A Stereo. Cylindrical DriftChamber for Muon Decay Experiments at LAMPF."presented at the Wire Chamber Conf., Vienna. Austria,February 15-18, 1983; Nucl. Instrum. Methods 217, 173(J983); Los Alamos National Laboratory document LA-UR-83-796.

R. L. Boudrie, "Spectrometers at LAMPF," invited talkat Magnetic Spectrometer Workshop, College of Williamand Mary, Williamsburg, Virginia, October 10-!2. 1983,Los Alamos National Laboratory document LA-UR-83-3294

J. D. Bowman and M. D. Cooper, "Pion Charge Ex-change and Nuclear Structure," submitted to Commentson Nucl. Part. Phys., Los Alamos National Laboratorydocument LA-UR-83-3097.

D. J. Brenner and M. Zaider. "The Applications of TrackCalculations to Radiobiology. II. Calculations of Micu-dostmetric Quantities," Rad. Res. 98 (in press), LosAlamos National Laboratory document LA-UR-83-809


163

D. J. Brenner and M. Zaider, "Soft X Rays as a Tool toInvestigate Radiation-Sensitive Sites in MammalianCells," presented at Conf. on Advances in Soft X-RayScience and Technology, Brookhaven National Labora-tory, Long Island, New York, October 17-19, 1983; LosAlamos National Laboratory document LA-UR-S3-3156

R. D. Brown, J. R. Cost, and J. T. Stanley, "Effects ofNeutron Irradiation on Magnetic Permeability ofAmorphous and Crystalline Magnetic Alloys," presentedat the 29th Ann. Conf. on Magnetism and MagneticMaterials, Pittsburgh, Pennsylvania, November 1983; tobe published in J. Appi. Phys. Magnetism and MagneticMaterials Conf., 1983, Los Alamos National Laboratorydocument LA-UR-83-2718.

R. D. Brown and D. L. Grisham, "Graphite Targets atLAMPF," presented at the 1983 Particle AcceleratorConf., Santa Fe, New Mexico, March 21-23, 1983; IEEETrans. Nucl. Sci. NS-30, 2801 (1983); Los AlamosNational Laboratory document LA-UR-83-956.

S. K. Brown, "The Use of a Commercial Data BaseManagement System in the LAMPF Control System,"presented at the 1983 Particle Accelerator Conf., SantaFe, New Mexico, March 21-23, 1983, IEEE Trans. Nucl.Sci. NS-30, 2302(1983).

R. D. Carlini, H. A. Thiessen, and J. M. Potter, "A High-er Perpendicular Biased Ferrite-Tuned Cavity,"presented at the 12th Int. Conf. on High-Energy Ac-celerators, Fermi National Accelerator Laboratory,Batavia, Illinois, August 1983; Los Alamos NationalLaboratory document LA-UR-83-2445 and LA-9946-MS(1983).

R. D. Carlini and G. J. Stephenson, "On thp. Feasibility ofPerforming Neutrino Experiments at an Intense Sourceof Strangeness," presented at the Conf. on Intense Me-dium Energy Sources of Strangeness, University of Cali-fornia, Santa Cruz, March 1983, AIP Conf. Proc. No.102, Particle and Field Subseries No. 31, pp. 170-180;Los Alamos National Laboratory document LA-UR-83-1788.

E. P. Chamberlin, J. F. Benage, Jr., and H. E. Williams,"Developing a 500-eV Proton Beam," presented at the1983 Polarized Ion Workshop, Vancouver, B.C., May23-28, 1983 (American Institute of Physics) and to bepublished in its Proceedings; Lei Alamos National Labo-ratory document LA-UR-83-1466

E. P. Colton, "Beam Transfer and Extraction at LAMPFII," presented at the 12th Int. Conf. on High-EnergyAccelerators, Fermi National Accelerator Laboratory,August 1983, and to be published in its Proceedings; LosAlamos National Laboratory report LA-9878-MS(1983).

E. P. Colton, "4-GeV Preaccelerator for LAMPF H,"Los Alamos National Laboratory report LA-9889-MS(1983).

I. P. Auer, E. Colton, W. R. Ditzler, D. Hill, R. Miller, H.Spinka, G. Theodosiou, J. J. Tavernier, N. Tamura, K.Toshioka, D. Underwood, R. Wagner, A. Yokosawa, P.Kroll, and W. Jauch, "Measurement of Spin Parametersfor a Decisive Clarification of the Structure Observed inthe p-p System,"Phys. Rev. Lett. 51, 1411 (1983).

E. P. Colton, "Simulation of Betatron-SynchrotronCoupling," Los Alamos National Laboratory reportLA-9901-MS(1983).

E. P. Colton, "SSC rf Design Example," presented at theSSC Workshop, University of Michigan, Ann Arbor,Michigan, December 12-17, 1983, to be published in theProceedings; Los Alamos National Laboratory docu-ment LA-UR-84-327 (in press).

E. P. Colton, "A Staged Approach for LAMPF II," LosAlamos National Laboratory report LA-9946-MS(1983).

J. K. Cortey and S. C. Schaller, "Particle AcceleratorControl and Data Acquisition in the Context of VAX-VMS," presented at the Digital Equipment ComputerUsers Society Symp., Las Vegas, Nevada, October23-28, 1983, to be published in the Proceedings; LosAlamos National Laboratory document LA-UR-83-3444.


JanuaryDecemtm 1983

J. F. Dicello, C. W. McCabe. J. D. Doss, and M. Paciotti."The Relative Efficiency of Soft-Error Induction in 4KStatic RAMs by Muons and Pions." IEEE Trans. Nucl.Sci. NS-30. 4613 (1983).

J. B. Donahue, "Power Deposition of LAMPF ProtonBeam in Various Materials," Group MP-7 TechnicalNote 9MP-7-TN-14, October 1980, Los Alamos Na-tional Laboratory document LA-UR-83-2769.

J. D. Doss, "Passive Dosimeters for rf and MicrowaveFields," Rev. Sci. Instrum. (in press); Los Alamos Na-tional Laboratory document LA-UR-83-2333

L. M. Earley, H. A. Thiessen, R. Carlini, and J. M.Potter. "A High-Q Ferrite-Tuned Cavity," presented atthe 1983 Particle Accelerator Conf., Santa Fe, NewMexico, March 21-23, 1983. IEEE Trans. Nucl. Sci.NS-30, 3469 (1983). Los Alamos National Laboratoryreport LA-9823-MS (1983).

R. A. Fisher, M. M. Nieto, and V. D. Sandberg, "Non-existence of the Naive Generalization of Many-PhotonCoherent States," submitted to Phys. Rev.; Los AlamosNational Laboratory document LA-UR-84-21.

D. L. Grisham and J. E. Lambert, "Applying AcceleratorRemote Technology to Fusion Devices," presented at theAmerican Nuclear Society annual meeting, Detroit.Michigan, June 12-15, 1983; Los Alamos National Lab-oratory document LA-UR-83-1558.

D. L. Grisham and J. E. Lambert, "Human FactorsConsiderations in the Monitor System," presented at theAmerican Nuclear Society annual meeting. Detroit,Michigan, June 12-15, 1983; Los Alamos National Lab-oratory document LA-UR-83-I559.

D. L. Grisham and J. E. Lambert, "Monitor 1983,"presented at the Particle Accelerator Conf., Santa Fe,New Mexico, March 21-23, 1983, IEEE Trans. Nucl. Sci.NS-30, 2267 (1983), Los Alamos National Laboratorydocument LA-UR-83-955.

D. L. Grisham and J. E. Lambert, "Remote Handling atLAMPF," presented at the ICANS VII meeting, ChalkRiver Nuclear Laboratories, Chalk River, Ontario, Can-ada, September 12-16, 1983; Los Alamos NationalLaboratory document LA-UR-83-2692.

D. L. Grisham and J. E. Lambert. "Remote HandlingExperience at LAMPF," to be presented at the AmericanCeramic Society meeting May 1984; Los Alamos Na-tional Laboratory document LA-UR-83-3613.

D. Grisham and J. Lambert, "Water-Cooled Target BoxDesign at LAMPF," presented at the Panicle Ac-celerator Conf.. Santa Fe, New Mexico, March 21-23,1983. IEEE Trans. Nucl. Sci. NS-30. 2270(1983), LosAlamos National Laboratory document LA-UR-83-954.

P. Herczeg and C. M. Hoffman, "Study of JT° -» u VDecays," submitted to Phys. Rev. D, Los Alamos Na-tional Laboratory document LA-UR-83-3573.

C. M. Hoffman, "LAMPF II." invited talk at the Theo-retical Symp. on Intense Medium-Energy Sources ofStrangeness, Univcrsityof California, Santa Cruz. Cali-fornia, March 1983, AIP Conf. Proc. No. 102, Particleand Field Subseries, No. 31; Los Alamos National Labo-ratory document LA-UR 83-795.

J. \V. Hurd, "Solution to the Transverse Phase Space-Time Dependence Problem with LAMPF's High-In-tensity H+ Beam," presented at the 1983 Particle Ac-celerator Conf.. Santa Fe. New Mexico, March 21-23,1983, IEEE Trans. Nucl. Sci. NS-30 No. 4 (1983), p.2487.

G. C. fdzorek and L. G. Atencio, "Fabrication of aHermetically Sealed Connector," Los Alamos NationalLaboratory report LA-9849-MS (1983).

T. Kozlowski, J. Amann, G. Anderson, R. Fioyd, J.Harrison, and M. Oothoudt, "Performance Results forthe New RSX-I1M Q System," IEEE Trans. Nuci. Sci.NS-30, 3998(1983).

R. W. Lourie, W. Bertozzi, T. N. Buti, J. M. Finn, F. W.Hersman, C. Hyde, J. Kelly, M. A. Kovash, S. Kowalski,M. V. Hynes, B. E. Norum, and B. L. Berman, "InelasticElectron Scattering from *Be," Phys. Rev. C 28, 489(1983).

R. J. Macek, D. L. Grisham. J. E. Lambert, and R.Werbeck, "Radiation-ResistantBeam-Line Componentsat LAMPF," presented at the ICANS VII Conf., ChalkRiver Nuclear Laboratories, Chalk River, Ontario, Can-ada. September 13-16, 1983, to be published in theProceedings; Los Alamos National Laboratory docu-ment LA-UR-83-2736.


Y. Mori, K. Ikegami, A. Takagi, Z. Igarashi. S.Fukumoto, W. Cornelius, and R. York, "OpticallyPumped Polarized H" Ion Source,"to be published in theProc. of the 3rd Symp. on the Production and Neutraliza-tion of the Negative Hydrogen Ions and Beams,Brooknavcn National Laboratory, Upton, New York,November 14 17, 1983.

M. Oothoudt and T. Kozlowski. "AI.I-CS: AssemblyLanguage Extensions and Control Structures," Proc.Digital Equipment Users Society (1982), p. 537; LosAlamos National Laboratory document LAUR-82-3334.

M. Oothoudt, J. Amann. R. Floyd, J. Harrison, and T.Kozlowski, "The Q Memory Resident HistogrammingSystem." IliliK Trans. Nucl. Sei. NS-30, 3838(1983).

G. C. Phillips, E. A. Umland, G. S. Mutchler, J. B.Roberts, M. Duong Van, J. A. Buchanan, J. B, Donahue,J. C. Allred, B. W. Noel. T. A. Mulcra, B. Aas. and B. W.Mayes, "A Novel Neutrino Detection System," to bepublished in Nucl. lustrum. Methods; Los Alamos Na-tional Laboratory document LA UR 83 2519

W. Reutcr. E. B. Shera. M. V. Hoelm, l;. \V. Hcrsman.T.Millman. J. M. Finn. C. Hyde-Wright, R. Lourie, H.Pugh, and W. llerto/./.i. "Nuclear Charge Densities in theTransition Region |c'2Os." to be published in Phys. Rev.Lett.; Los Alamos National Laboralory document I.A-UR 83-3313.

L. Rosen, "The Pros and Cons of a Nuclear Freeze."invited talk al Trinity on the Hill Episcopal Church, LosAlamos, New Mexico, March 15, 1983.

V. D. Sandberg, "An Heuristic Introduction to Gravita-tional Waves," Proe. Workshop on Science Under-ground. Los Alamos National Laboratory, Los Alamos,New Mexico, September 27-Octobcr I, 1982, Los Ala-mos National Laboratory document LA-UR-83-333.

G. H. Sanders, "The Imagery of Physics in Psychology:A Physicist's Reactions," presented at the Conf. onNuclear Reactions: A Three-Day Dialogue BetweenPhysicists and Psychologists, University of New Mexico.Albuquerque, New Mexico, November 1983, to be pub-lished in the Proceedings: Los Alamos National Labora-tory document LA-UR-83 744.

S. C. Schaller and P. A. Rose. "Data-Acquisition Soft-ware for the LAMPF Control System." presented at the1983 Particle Accelerator Conf.. Santa I c. New MexicoMarch 21-23, 1983: IEEE Trans. Nucl. Sci. NS 30. 2308(1983): Los Alamos National Laboratory document LA-UR-83-744.

P. Schuler. K. Hardt. C. Guniher. K. Frciiag. P. llcrzog.il. NicdeiweMberg. H. Reif. K. U. Shera. and M. V.llochi). "Experimental Investigation of Low-Lying Ex-cited States in -""HR." Z. Phys. A. 313. 305 (1983).

C. J. Sternhagen and J. D. Doss, "Combined RadiationTherapy and Localized Current Field Hyperthcrinia witha ].'• MHz Applicator in Head and Neck andGynecological Caiicrr Therapy," in the Proc. of themeeting of the Radiation Research Society. San Antonio.Texas. February 28. 1983.

R. R. Sievens. Jr.. and R. L. York. "A Cusped Field /•/Ion Source for I.AM Pi-'," presented at the 1983 ParticleAccelerator Conf., Santa Fe, New Mexico. March 2 I 23.1983, Los Alamos National Laboratory document LA-UR 83 815.

G. W. Swifi. A. Migliori. J. Whcatlev. C. R. Waller, andG. SIIH/.O, "Fabrication and Leak Tight Furnace Brazingof Intricate Objects." submitted to Rev. Sci. Instrum.;Los Alamos National Laboratory document LA-UR • 1.3-3455.

II. A. Thiessen and E. J. Schcidker,"Production ol'Pions,Kaons, and Muons by 16 GeV Protons." Los AlamosNational Laboralory report LA-9587-MS (1983).

H. A. Thiessen, "A Reference Design for LAMPF II."Proc. of the 12th Int. Conf. on High Energy Ac-celerators, Fermi National Accelerator Laboralory.August II 16, 1983; Los Alamos National Laboratorydocument LA UR-83-2426.

.). L. Warren and H. A. Thicssen. "Simulation of Trans-ilion Crossing in LAMPF II." Proc. of the 12th Int.Conf. on High-Energy Accelerators, Fermi NationalAccelerator Laboratory, August 11-16, 1983; Los Ala-mos National Laboralory document LA-UR-83-2367.

R. R. Wilson. "Acceleration in a Synchrotron by Harm-onic Hopping," Los Alamos National Laboratory reportLA-99O4-MS(I983).

166 PROGRESS AT LAMPFLot Alamos National Laboratory

A. Yaouanc. "Correlation Functions. GeneralizedSusceptibility, and uSR Spcctroseopy." submitted to J.'Miys, Lett., Los Alamos National Laboratory documentLA UR 83 664.

R. L. York and R. R. Stevens. J r . "A Cuspcd Field H

Ion Source for LAMPF," IEEE Trans. Nucl. Sci. NS-30,2704(1983).

R. L. York and R. R. Stevens. Jr.. "Development of aMuliicusp /•/ Ion Source for Accelerator Applications."to be published in the Proc. of the 3rd Int. Synip. on theProduction and Neutralization of Negative Ions amiBeams. Brookhavcn National Laboratory, Upton. New-York. November 14-17. 1983; Los Alamos NationalLaboratory document LA-UR-83-3273.

R. I.. York. R. R. Stevens. Jr.. K. N. Leung, and K. W.Ehlcis, "Extraction of / / Beams from a MagneticallyFiltered Multicusp Source." to IK- published in Kcv. Sci.lustrum., Los Alamos National Laboratory documentLA UR 83-3098.

L A M P F Experimental Program Reports and

Publications

(I-XP. 2) R. II. Jeppesen. M. J. Jakobson. M. D. Cooper.D. C. Mngcrinan. M. B. Johnson, R. P. Rcdwine, G. R.Burleson. K. F. Johnson. R. E. Marrs, H. O. Meyer. I.llalpern. atul L. D. Knutson, "Pion Nucleus ForwardScattering Amplitudes from Total Cross SectionMeasurements," Phys. Rev. C 27, 697 (1983).

(EXP. 9) K. G. Boyer. W. J. Braidiwaile. W. B. Col-lingamc. S. J. Greene. L. E. Smith, C. F. Moore, C. L.Morris, 11. A. Thicsscn, G. S. Ulanpied, G. R. Burleson, J.F. Davis, J. S. McCarthy, R. C. Minehart, and C. A.Goulding, "Pion Elastic and Inelastic Scattering from4».*j .« .«C a m u | j« F e « p h y s R c v c 2 9 i ,H 2(1984):Los

Alamos National Laboratory document LA-UR -82 -3171.

(EXPS. 9, 310, 401, 412, 448, 523, 680, 716) M. B.Johnson, "Recent Developments in the Understanding ofPion-Nuclcus Scattering," lectures presented at the 1983Int. Syrnp. on Nuclcon-Nuclcon Interaction and NuclearMany-Body Problems. Beijing. China. September 1983;Los Alamos National Laboratory document LA-UR-83-2851

(EXP. 12) C. Cunther. E. B. Shera. M. V. Hochn, H, D.Wohirahrt. R. J. Powers. Y. Tanaka. and A. R.Kunselmnn. "Muonic X Ray Study of ""Hi; and :uoHg."Phys. Rev. C 27,816(1983).

(EXP. 15) G. Paulctta. G. Adams. S. M. Haji-Sacid. G. J.Igo. J. B. McClelland, A. T. M. Wang, C. A. Whittcn. Jr.,A. Wriekat, M. M. Gaz/.aly, and N. Tanaka. "Dift'eren-tial Cross Section and Analyzing Powers for pp ElasticScattering at 1.46 GeV/c in the Coulomb-Nuclear Interference Region." Phys. Rcv. C 27. 282 (1983).

(EXP. 22) R. KunsehiKin. R. J. Powers, M. V. llochn.and E. B. Shera. "Piortie 3d — • 2/; X Ray Measurementsin '"•'•'••4Cr. "Se. "V. "Mn. and Fe." Niid. Phys. A 405.627(1983).

(EXP. 31) J. S. Frank, R. I... Barman. D. R. F. Cochrun.P. Nemethy. S. E. Willis. V. W. Hughes. R. P. Rcdwinc.J. Duclos. H. Kaspar, C. K. Hargrove, and U. Moscr."Reply to Direct Comparison Between the y-Ray Fluxesfrom Proton Beam Dumps at LAMPF and SIN." sub-mitted to Phys. Rev. D; Los Alamos National Labora-tory document LA UR 83 1345

(EXP. 32) W. K. McFarlane. L. B. Auerbach. F. C.Gaille, V. L. Highland. E. Jastrzcmn.ski. R. J. Macek. F.II. Cvcrna. C. M. Hoffman. G. E. llogan, R. E.Morg:<do, J. C. Pratt, and R. D. Werbeck. "New Meas-urement of the Rate for Pion Beta Decay." Phys. Rcv.Lett. 51. 249(1983).

(EXP. 87) J. Kiillne, R. C. Minehart. R. R. Whitney. R.L. Boiidiic. J. B. McClelland, and A. W. Stctz. "PionScattering and Absorption Contributions to ProtonEmission from Pion-Nuclcus Collisions at 7", =•= 50-295MeV." Phys. Rev. C 28. 304 (1983).

(EXP. 96) J. S. Frank, A. A. Browman. P. A. M. Grain.K. A. Klare. R. E. Misclikc. D. C. Moir. D. E. Naglc. R.H. Hell'ncr. J. M. Potter, R. P. Redwine, and M. A. Yatcs." M e a s u r e m e n t of L o w - E n e r g y E l a s t i cK'P Differential Cross Sections," Phys. Rcv. D 28, 1569(1983); Los Alamos National Laboratory document LA-UR 83 1490.

(EXPS. 120, 363) D. H . Fitzgerald. "nN Scattering atLAMPF: Baryon Spcctroscopy at 1200-1500 McV/c,"presented at the University of Colorado, April 25, 1983,Los Alamos National Laboratory document LA-UR 83 1179.

Jimmy-Otcmibtr IBM PROflfflm AT LAMP*I in Altmol Nttlantl Ltlxirwory

167

(EXPS. 120, 363) D. H. Fitzgerald, "JT.V Scattering aiLAMPF: Natural Baryon Spectroscopy ai 1200-1500MeV/cV presented at George Washington University,Washington, D C . March II , 1983; Los Alamos Na-tional 1.aboratory document LA-UR 83-635.

(EXP. 249) B. Hoistad. M. Gazzaly, B. Aas, G. Igo,,A.Rahbar. C. Whitten. G. S. Adf^ns, and R. Whitney,"3-4Hc(p,Ji')4l)Hej(.v Reactions at 800 MeV," Phys.Rev. C 29. 553(1984).

(EXP. 298) F. Jrom. G. J. Igo, J. B. McClelland, C. A.Whittcn, Jr., and M. Bleszynski, "Measurements ofSmall-Angle Elastic p d Scattering at 796 McV Using aRecoil Method," Phys. Rev. C 28, 2380(1983).

(EXP. 309) S. A. Wood, "An Experimental Study ofInclusive Pion Double Charge Exchange Reactions in theDelta Resonance Region," Ph.D. thesis, MassachusettsInstitute of Technology, Cambridge, Massachusetts,1983; Los Alamos National Laboratory reportLA-9932-T(l983).

(EXP. 333) M. J. Lcilch, R. L. Burman. R. Carlini, S.Dam, V. Sandberg, el al., "Pion-Nuclcu.s Elastic Scatter-ing at 80 MeV," Phys. Rev. C 29. 561 (1984); LosAlamos National Laboratory document LAUK -83-2569.

(EXP. 335) D. B. Laubacher, Y. T.-inaka, R. M. StefTen,E. B. Shera, and M. V. I lochn, "Muonic X Ray Measureinenl of the Monopoly and Quadrupole ChargeParameters of •"•»». 'J" .I" ."». '< '«CKI," Phys. Rev. C 27,1772(1983).

(EXP. 336) A. D. Hancock, R. VV. Mackenburg, K. V.I lungerford. 13. W. Mayes, L. S. Pinsky, J. C. Allred, T.M. Williams, S. D. Baker,.I. A. Buchanan. J. M. Clement,M. Copel, I. M. Duck, Ci. S. Mulchler, G. P. Pcpin, E. A.Umland, G. C. Phillips, M. W. McNaughlon, C. Hwang,and M. l-'uric, "Asymmetries and Cross Sections for theReaction p + p — p t n' + n at 800 MeV," Phys. Rev. C27,2742(1983).

(EXP. MS) C. .1. Marloff, J. A. Bistirlich, C. W.Clawson, K. M. Crowe, M. Kroike, J. P. Miller, S. S.Rosenblum, W. A. Zajc, II. W. Bacr, A. H. Wapstra. G.Strassner. and P. Trutil, "Spin-Flip Transitions in l1C ''*FProbed with the (n ,y) Reaction," Phys. Rev. C 27, 1621(1983).

(EXP. 357) J. D. Knight. C. J. Orlh. M. E. Schillaci, RA. Naumann. F. J. Hartmann. ami H. Schncuwly,"Target Density ElTects in Muonic-Atom Cascades."Phys. Rev. A 27. 2936 (1983).

(EXPS. 385, 563) M. L. Barlett, G. W. Hoffmann. J. A.McGiii. B. Hoistad. L. Ray. R. W. Fergcrson, E. C.Milner. J. A. Marshall, J. F. Amann, B. E. Bonncr, J. B.McClelland. G. S. Blanpied, and R. A. Arndt. "Forward-Angle Elastic and Quasi-elastic Proton Nucleon CrossSections and Analyzing Powers at 0.8 GcV," Phys. Rev.C 27.682(1983).

(EXP. 389) D. F. Geesaman. D. Kurath. G. C. Morrison,C. Olmer, B. Zeidinan. R. E. Anderson, R. L. Boudrie. H.A. TliJcsscn, G. S. Blanpied. G. R. Burleson, R. E. Segel,and L. W. Swcnson, "Inelastic Scattering of 162-MeVPious by UN." Phys. Rev. C 27. 1134 (1983); LosAlamos National Laboratory document LA-UR 82-3258.

(EXP. 390) S. M. Levenson, D. F. Geesaman, E. P.Colton, R. J. Holt, H. E. Jackson. J. P. Schiller. J. R.Specht. K. F. Slephcnson, B. Zeidman. R. E. Segel, P. A.M. Gram, and C. A. Goukling, "Inclusive Pion Scattering in the A( 1232) Region." Phys. Rev. C 28, 326 (1983).

(EXP. 400) R. Holton. R. Carlini, J. D. Bowman, M.Cooper, A. llallin. J. Frank, C. Hoffman, H. Matis. R.Mischke, D. Nagle, F. Mariam, V. Sandbcrg. U. Sen-nhauser, G. Sanders, R. Werbeck, R. Williams, R.Hofstadter, E. Hughes, S. Wilson, .1. R.,!ic, S. Wright, D.Grosnick, G. Hogan, V. Highland, and M. Van, "TheCrystal Box: Rare Decays of the Muon," presented at theBlacksburg, Virginia, Workshop on Low-Energy Tests ofConservation Laws in Particle Physics. September 11-15,1983; Los Alamos National Laboratory document LA-UR-K3-2908.

(EXP. 400) J. P. Sandoval, L. Bayliss. 7. Gordon, G.Hart. C. M. Hoffman. G. E. Hogan, V. I). Sanclberg, G.11. Sanders, and S. L. Wilson, "Alternatives to CoaxialCable for Delaying Analog and Digital Signals in aParticle Physics Experiment," Nucl. lustrum. Methods216, 171 (1983); Los Alamos National Laboratorydocument LA UR 83-967.


(EXP. 401) M. D. Cooper, H. W. Baer. R. D. Bollon. J.D. Bowman. F. H. Cverna. N. S. P. King, M. Leitch. J.Alster. A. Doron. A. Erell. M. A. Moinester, E. Black-more, and E. Siciliano. "Angular Distribution for"N(rr'.JT°)'-*O(g.s) at l\ ••••- 48 MeV," submitted to Phys.Rev. Lett.; Los Aiamos National Laboratory documentLA-UR 83 1030.

(EXP. 407) I"). J. Farnum. W. F. Soiiur.er, and O. T. Inal."A Study of Delects Produced in Tungsten by SCO MeVProtons Using Field Ion Microscopy," presented at theThird Topical Meeting on Fusion Reactor Materials.Albuquerque. Now Mexico, September 19-22. 1983, tobe published in J. Nucl. Mater.; Los Alamos NationalLaboratory document LA UR-83-2572.

(EXP. 407) W. F. Sommer. D. S. Phillips. W. V. Green.L. W. Hobbs, and C. A. Wert, "Proton IrradiationDamage in Cyclically Stressed Aluminum," J. Nucl.Mater. 114. 267(1983).

(EXPS. 412, 523, 827) N. Auerbach. M. li. Johnson. A.Klein, and H. R. Siciliano, "Nuclear Structure [-Heels inPion Single Charge Exchange," Phys. Rev. C 2*) 526(1984); Los Alamos National Laboratory document LAUR-83-2699.

(EXPS. 412, 607) A. l i F.rcll. J. Alster. J. Lichtenstadl.M. A. Moincstcr, .1. D. Bowman, M. D. Cooper, F. Irom.H. S. Matis, E. Piaset/.ky, U. Sennhauser, and Q. Ingram,"Properties of the Isoveclor Monopole and Other GiantResonances in I'ion Charge Exchange," submitted loPhys. Rev. Lett.; Los Alamos National Laboratorydocument LA-UR 84 599.

(EXP. 412) U. Sennhauser, li. Piasel/.ky, II. Baer, J. D.Bowman, M. D. Cooper, H. S. Matis, H. J. Ziock, J.Alster, A. F.rell, M. A. Moinester, and F, Irom, "lsobaricAnalog Stales in Pion Single Charge Exchange Reaclions On and Above the (},}) Resonance Fnergy," Phys,Rev. Lett. 51, 1324(1983).

(EXP. 452) S. Seestrom-Morris, C. L. Morris, R. L.Boudrie, H. A. Thies.cn, D. Dehnhard, and M. A.Franey, "Analysis of Elastic and Inelastic Scattering of162 MeV Pions from "C by an Optical Potential and aCollective Model," Phys. Rev. C 28. 1301 (1983); LosAlamos National Laboratory document LA-UR-83-452.

(IZXP. 479) D. L. Adams and M. Bleszynski. "On theRelevance of the Dirac Equation io the Scattering ofMedium-Energy Nucleons from Nuclei," submitted toPins, Lett.; Los Alamos National Laboratory documentLA UR S3 2749.

(EXP. 484) C. 1... Morris. S. J. Seestrom-Morris, P. A.Seidl, R. R. Kiziah, and S. J. Greene. "Pion Elastic andInelastic Scattering from " :Sm." Phys. Rev. C 28. 2165(1983); Los Alamos National Laboratory document LA-• UR-82-2542.

(l-.XP. 495) C. L. Morris. N. Tanaka, R. L. Boudrie, L.C. Bland. H. T. Fortune. R. Gilman, S. J. SeestromMorris. C. F. Moore, and D. Dehnhard. "Small AnglePion Inelastic Scattering from | :C at 162 MeV," sub-mitted to Phys. Rev. C; Los Alamos National Labora-tory document LA UR 84 Id.

(EXP. 498) I. P. Auer, W. R. Ditzler, D. Mill. K. lmai, H.Spinka. R. Stanek. K. Toshioka. D. Underwood. R,Wagner. A. Yokosawa, E. W. Hoffman. J. J. Jarmer. G.R. Burleson, W. B. Coltingame, S. J. Greene, and S.Stuart, "Measure of Ao, and C,, in Proton ProtonScattering Between 3iK) and 800 MeV," submitted toPhys. Rev. I.); Los Alamos National Laboratory doctimentLA UR-83 3612.

(EXP. 498) G. R. Burleson, W. B. Cottiugame, S. J.Greene, S. Stuart, E. W. Hoffman, J. J. Jarmer, I. P.Auer, W. R. Dit/ler. 1). Mill. K. Imai, H. Spinka, R.Stanek, K. Toshioka, 1). Underwood, R. Wagner, and A.Yokosawa, "C, , -- (/../.;(),()) Measurements and a Struc-ture Due to a / ' Partial Wave in the pp System," Nucl.Phys. B 213,365(1983).

(EXP. 517) W. B. Tippens, "Measurement o M N and ANN

for the Reaction pp —- tin' at Six F.nergies from 500 to800 MeV," Ph.D. thesis,Texas A&M University,CollegeStation, Texas, 1983; Los Alamos National Laboratoryreport LA 9909-T (1983).

(EXPS. 517, 518) T. S. Bhatia, J. G. J. Boissevain, J. J.Jarmer, K. R. Silbar, J. li. Simmons, G. Glass, J. C.Hiehert, R. A. Kenelkk. L. C. Northcliffe, W. B. Tip-pens, W. M. Kloet, and J. Duback, "Analyzing Powersand Sp»; Correlations A NN and// , , fwpp~* npn' at 650and 800 MeV," Phys. Rev. C 28, 2071 (1983).

JanuaryDucamtmt 1983 PROGRESS AT LAMPF 1 6 9Los Alamos National Laboratory

(EXP. 523) F. Irom, J. R. Comfort, R. Jeppcson, J. J.Kraushaar, R. A. Ristinen, W. Tew, J. L. Ullmann, H. W.Baer, J. D. Bowman, M. D. Cooper, A. Erell, M. A.Moinester, E. Piasetsky, U. Sennhauser, and E. R.Siciliano, "Pion Single Charge Exchange on I4C," Phys.Rev. C 28, 2568(1983).

(EXP. 545) R. D. Brown, J. R. Cost, and J, T. Stanley,"Effects of Neutron Irradiation on MagneticPermeability of Amorphous and Crystalline MagneticAlloys," presented at the 29th Ann. Conf. Magnetismand Magnetic Materials, Pittsburgh, Pennsylvania, November 8-11, 1983, to be published in J. Appl. Phys.; LosAlamos Nat ional Laboratory document LA-UR-83-2718.

(EXP. 558) P. A. Seidl, R. R. Kiziah, M. K. Brown, C. F.Moore, C. L. Morris, H. Baer, S. J. Greene, G. R.Burlcson, W. B. Cottingame, L. C. Bland, R. Gilman, andH. T. Fortune, "Observation of Analog and NonanalogTransitions in the Reaction 56Fe(n+,7t )sr'Ni," Phys. Rev.Lett. 50, 1106 (1983); Los Alamos National Laboratorydocument LA-UR-83-248.

(EXP. 558) P. A. Seidl, M. D. Brown, R. R. Kiziah, C. F.Moore, H. Baer, C. L. Morris, G. R. Burlcson, W. B.Couingame, S. J. Greene, L. C. Bland, R. Gilman, and II.T. Fortune, "Pion Double Charge F.xchangc on 7 ' - INuclei," .submitted to Phys. Rev. C; Los Alamos Na-tional Laboratory document LA-UR-84-17.

(EXP. 561) M. Blecher, K. Gotow, R. L. Burman, M. V.Hynes, M. J. Lcitch, N. S. Chant, L. Rccs, P. G. Roos, F.E. Bcrtrand, II. E. Gross, F. E. Ohcnshain, T. P. Sjorccn,G. S. Blanpied, B. M. Precdom, and B. G. Ritchie,"Isospin Effects in it' Elastic Scattering from "C, '3C,and I4C at 65 and 80 MeV," Phys. Rev. C 28, 2033(1983).

(EXP. 601,659) C. L. Morris, S. J. Seestrom-Morris, andL. C. Bland, "Excitation of Giant Resonances in PionInelastic Scattering," invited talk at the HESANS '83 Int.Symp., Orsay, France, September 5-8, 1983; Los Ala-mos National Laboratory document LA UR-83-3237.

(EXP. 606) M. O. Kaletka, "Core Excitation Effects inPion Double Charge Exchange," Ph.D. thesis, North-western University, Evanston, Illinois, 1983; Los AlamosNational Laboratory report LA-9947-T!

(EXP. 607) J. D. Bowman, H. W. Baer, M. D. Cooper,H. S. Matis, F. Irom, E. Piasetzky, U. Sennhauser, N. S.P. King, J. Alster, A. Erell, M. A. Moinestcr, J.Lichlenstadt, and C. H. Q. Ingram, "A Dependence ofthe Excitation Energy, Width, and Cross Section of theIsovector Monopole Resonance," presented at theHESANS '83 Int. Symp., Orsay, France, September 5-8,1983; Los Alamos National Laboratory document LA-UR-83-2924.

(EXP. 616) J. B. McClelland, J. M. Moss, B. Aas, A.Azizi, E. Blcszynski, M. Bleszynski, J. Gcaga, G. Igo, A.Rahbar, J. B. Wagner, G. S. Weston, C. Whitten, Jr., K.Jones, S. Nanda, M. Gazzaly, and N. Hintz, "CompleteMeasurement of Polarization Transfer Observables forthe nC{p,p')nC*r Phys. Rev. Lett. 52, 98 (1984); LosAlamos National Laboratory document LA-UR-83-3292.

(EXP. 625) J. L. Ullmann, J. J. Kraushaar, T. G.Mastcrson, R. J. Peterson, R. S. Raymond, R. A.Rislinen, N. S. P. King, R. L. Boudric, C. L. Morris, W.W. True, R. F.. Anderson, and F.. R. Siciliano, "Excitationof the Isoscakir Giant Quadrupole Resonance in ""Sn(n' . i t") ," Phys. Rev. Lett. 5J. 1038 (1983); Los AlamosNational Laboratory document LA-UR-83-2226.

(EXP. 627) R. A. Riskinen, A. M. Bernstein, B. Quinn, S.A. Wood, G. S. Blanpied, B. G. Rilchie, and V. R.Brown. "DWIA Predictions or (/>,/>') Data Using Elec-tromagnetieally Constrained Densities," Phys. Lett.13IB, 26(1983).

(EXP. 634) J. D. Bowman, R. Carlini, R. Damjanovich,R. W. Harper, R. E. Mischke, D. E. Nagle, R. Talaga,and V. Yuan, "Low-Noise lonization Chambers for Usein Transmission Measurements with Medium- and High-Energy Beams," Nucl. Instruin. Methods 216, 399(1983).

(EXP. 635) S. Tsu-hsun. B. E. Bonner. M. W.McNaughlon, O. B. van Dyck, G. S. Weston, B. Aas, E.Bles/.ynski, M. Bk'szynski, G. J. Igo, H. Ohnuma, D. J.Cremans, C. L. Hollas, K. H. McNaughton, P. J. Rilcy,R. F. Rodebaugh, S. Zu, and S. E. Turpin, "Measure-ments of the Spin-Rotation Parameters for p'd —* pelElastic Scattering at 496, 647, and 800 MeV," submittedto Phys. Rev. C; Los Alamos National Laboratorydocument LA-UR-83-3484.

1 7 0 PROGRESS AT LAMPI"Los Atamos National Laboratory

Jamaty-Dacambtr 1963

(EXP. 659) L. C. Bla.id. "Forward-Angle Pion InelasticScattering," Ph.D. thesis. University of Pennsylvania,Philadelphia, 1983; Los Alamos National Laboratoryreport LA-9960-T (1983).

(EXP. 659, 659U) L. C. Bland. R. Gilman, G. S.Stephans, G. P. Gilgoyle. H. T. Fortune, C. L. Morris, S.J. Seeslrom-Morris, S. J. Greene, P. A. Seidl, R. R.Kiziah. and C. F. Moore, "Forward-Peaked AngularDistributions Observed in (rt,n') on Light Nuclei," sub-mitted to Phys. Rev.; Los Ahmos National Laboratorydocument LA-UR 83 3086.

(EXP. 660) J. fi. McClelland, "Spin Excitation Studiesvia (/>,//) at the HRS," invited talk at the Int. Symp. onElectromagnetic Properties of Atomic Nuclei, Tokyo,Japan, November 9-12. 1983; Los Alamos NationalLaboratory document LA-UR 83 3236.

(EXP. 698) Y. Tanaka, R. M. StelYen, E. B. Shcra. W.Renter, M. V. Hoehn, and J. D. Zumbro, "Muonic X-Ray Study ot" 1MEu and "3f:u," to be published in Phys.Rev. C; Los Alamos National Laboratory document LA-UR 84 22.

(EXP. 698) Y. Tanaka. R. M. Sleflen. E. B. She/a, W.Reuler, M. V. Uoehn, and J. D. Zumbro, "PrecisionMuonic Atom Measurements of Nuclear QuadrupolcMoments and the Sternheimcr EITcct in Rare EarthAtoms," Phys. Rev. Lett. 51, i 633 (1983).

(EXP. 701) L. C. Bland, R. Oilman, M. Carchidi, K.Dhuga, C. L. Morris, fl. T. Fortune, S. J. Greene, P. A.Seidl, and C. F. Moore, "Systematics of Pion Double-Charge-Exchange Reactions on 7' - 0 Nuclei," Phys.Led. I28B, 157 (1983); Los Alamos National Labora-tory document LA-UR 83-1195.

(EXP. 705) R. R. Silbar and E. Piasetzky, "IsospinDependence of Pion Absorption on Nucleon Pairs," to bepublished in Phys. Rev. C; Los Alamos National Labora-tory document LA-UR-83-1883.

(EXP. 720) C. L. Morris. J. F. Amann, S. J. Seestrom-Morris. J. A. McGill, C. Glashausser, K. Jones, S.Nanda, M. Barlett. G. W. Hoffman. C. Milncr, C. F.Moore, J. R. Comfort, L. C. Bland, and R. Gilman,"Low-Momentum Delta Production in the "C(/),rf)'2C*Reaction." Phys. Lett. 123B, 37 (1983); Los AlamosNational Laboratory document LA UR-82-2877.

(EXP. 727) S. E. Jones. A. N. Anderson, A. J. CaiTrey, J.B. Walter, K. D. Watts, J. N. Bradbury, P. A. M. Gram.M. Leon. II. R. MaUrucl. and M. A. Paciotti, "Ex-perimental Invesligalioin of Muon-Catalyzed d-t Fu-sion." Phys. Rev. Lett. 51, 1757(1983).

(EXPS. 727, 745) M. A. Paciotti. J. N. Hradbn,y,and O.M. Rivera, "Muon Beams nl the LAMPF Biomedica!Channel," presented at ihe Particle Accelerator Conf.,Santa Fe, New Mexico. March 21-23, 1983, IEEE Trans.Nucl.Sei.NS-30. 235^(1983).

(EXP. 780) R. Gilman, II. T. Fortune, L. C. Bland, R. R.Kiziah, C. F. Moore, P. A. Seidl, C. L. Morris, and W. B.Cottingame, "Nonanalog (n ,rc') Double Charge Ex-change on '"O," submillcd to Phys. Rev. Lett.; LosAlamos National Laboratory document LA-UR-84-436.

(EXP. 783) E. Piasetzky, P. A. M. Gram, D. W.Mat-Arthur. G. A. Rebka, Jr., C. A. Bordner, S.Iloibraten, E. R. Kinney, J. I.. Matthews, S. A. Wood, D.Ashery, and J. Lichtenstadt,"Pion-lnduced Pion Produc-tion on the Deuteron." submitted to Phys. Rev. Lett.; LosAlamos National Laboratory document LA-UR-84-231.

1983 PflCXMEtt AT LMAff 1 7 1l.os Alamos NnliontlLtbcruoiy

IV. PROTON STORAGE RING CONSTRUCTION ANDRESEARCH PROGRAM DEVELOPMENT

OverviewC. D. Bowman

A world-class facility is under development on Line Dfor pulsed neutron and other research. The principalelements in this facility are the Proton Storage Ring(PSR) now under construction and the existing WeaponsNeutron Research (WNR) facility target and experimen-tal areas. The storage ring will convert the long LAMPFmacropulses into short, intense proton bursts for avariety of experimental programs. Two pulse structureswill be provided: the long-burst, low-frequency (LBLF)mode with 270-ns pulses at 12 Hz for an average currentof 100 uA, and the short-burst, high-frequency (SBHF)mode with 1-ns pulses at 720 Hz for an average currentof 12 uA.

The long-burst mode will be devoted primarily tocondensed matter research using pulsed neutron scatter-ing techniques and will be the major facility for this typeof pulsed neutron research in the United States. A Userprogram is being developed under the auspices of theDivision of Materials Science of the USDOE, whichshould grow to more than 100 Users annually when thePSR becomes operational. This User program began incalendar year J 983 with the availability of pulsed neu-trons produced by 5-fis bursts of LAMPF beam on thepresent WNR target-moderator system. More than 100visitors from 30 institutions participated in th.; pulsed-neutron planning and research in 1983.

Plans also were completed for a major increase inexperimental space around the WNR target area toaccommodate as many as 15 spectrometers for thisresearch. Funds were received in FY 1983 for a $2.7-miHion 3-year WNR program to upgrade the target areaand beam-transport system to handle the required currentand to improve the neutron-production target and shield-ing.

Research in the field of neutron-nuclear physics willreceive a major boost from the short, intense bursts ofneutrons produced from the PSR. the extension of usefulneutron energies up to several hundred MeV, and theabsence of an intense gamma flash associated with theneutron burst. Neutron physics experiments wereperformed this year at the WNR using sub-micro-amp

currents of LAMPF micropulses. Although these experi-ments are unsurpassed in intensity and resolution, orders-of-magnitude improvements will be possible when thePSR short-pulse mode becomes operational.

The low duty cycle and high-current capacity of thePSR almost certainly will be major advantages for low-energy neutrino research. In anticipation of such aprogram, a new beam line (Line E) has been assembledparallel to Line D and in the Line D channel, with apulsed magnet for multiplexing LAMPF beam betweenLines D and E. Neutrino experiments requiring an un-shared target will be conducted on this line using a targetand detector area now under construction.

The rapid progres.1- on the installation of Line E,carried out by a collaboration of Los Alamos GroupsP-3. P-9, P-14, and MP Division, the University of NewMexico, University of California at Riverside, and Tem-ple and Valparaiso Universities, should enable measure-ments on vu -nucleus charged-current cross sections dur-ing the summer of 1984. These data are crucial for thedesign of future detectors for use with any Los Alamosneutrino source. This measurement also will provide dataon possible vu —»• ve oscillations with a sensitivity ofabout 10~\ although this is far from the limit ultimatelyachievable at LAMPF.

The construction of the PSR is supported by Labora-tory Defense Program Funding. A substantial defenseresearch program will be conducted using the PSR andassociated facilities. On infrequent occasions, defense

The WNR/PSR facility, located south of the LAMPFswitchyard, accepts 800-MeV proton beam pulses from theLAMPF accelerator. Its design was accomplished in large part bythe Accelerator Technology (AT) Division of Los Alamos Na-tional Laboratory.

The research program at WNR/PSR is managed by thePhysics (P) Division at Los Alamos and is supported jointly byLaboratory internal funding and the Office of Energy Research ofthe USDOE. Researchers from P Division collaborate with otherLos Alamos staiT and outside Users in their experiments.

Progress at LAMPF thanks She management of P Division,especially Charles Bowman, for this section of reports on develop-ments and research at WNR/PSR.

1 7 2 PROGRESS AT LAMP*Los Alamos National Laboratory


programs will require the unshared use of the PSR. butthe typical defense experiment will only require the use ofone or more of the many neutron drift tubes that view acommon pulsed source of neutrons.

Participation in the PSR research programs is en-couraged. Interested individuals should contact RichardN. Silver for condensed matter physics, and Gerard J.Stephenson for neutron or neutrino physics.

PSR ConstructionG.A. Sawyer

The PSR is a major addition to the WNR facility atLAMPF. It will be a bunch compressor for the relativelylong linac macropulses from LAMPF, tailoring them intoshort, intense pulses ideally suited for neutron-scatteringresearch.

The PSR is located in a tunnel adjacent to, and belowthe level of, the existing beam line (Line D) that serves theWNR facility. A plan view of the ring and tunnel,showing component locations, is given in Fig. 1. Beamenters the ring from Line D; after accumulation, it returnsto Line D, through which it is transported to the WNRneutron-production target. Connections with Line D aremade by short, sloped, beam-transport channels. Locatedabove the ring tunnel and on top of a 4.9-m-thick earthshield are service and assembly buildings.

The ring operates in two accumulation modes, eachindependently optimized to provide the desired neutron-source pulse structure for nuclear physics and materialsresearch programs.

Operational characteristics of the two PSR storagemodes are summarized in Table I. In the short-bunchhigh-frequency (SBHF) mode, protons are accumulatedin six equally spaced I n s bunches during.each LAMPFmacropulse. The bunches are individually extracted by afast kicker during the 8.2-ms interval between injectionpulses. Because the linac macropulse frequency is120 Hz, this program produces an extraction rate of720 pps. For PSR injection, the final 108 us of eachmacropulse is modified by a chopper-buncher system inthe linac low-energy transport to form a sequence ofmicropulses spaced at 60-ns intervals. The ring circula-tion period is chosen so that this injected pulse train issynchronized with the six bunches already stored. Eachincoming micropulse, containing 3.3 x 108 protons,merges with a ring bunch; 300 micropulses are ac-cumulated in each ring bunch. The narrow bunch widthin this mode is maintained by a high-frequency buncherlocated in the ring.

In the long-bunch low-frequency (LBLF) mode, thering accumulates complete linac macropulses (5.2 x 10"protons) in a single 270-ns bunch. Each stored bunch isextracted after completion of the injection cycle, with amaximum delay of 4 ms. The cycle repetition rate is12-Hz peak current, assuming a parabolic longitudinalcharge distribution, is 46.3 A; average circulating currentis 100 uA. For injection, a slow-wave chopper in the linaclow-energy transport carves 90 ns out of each 360 nsthroughout the macropulse, permitting entering pulses tobe overlapped with those that are already stored in the360-ns circulation period. A first-harmonic buncherkeeps the 90-ns gap clear of protons to facilitate low-loss

HALO STRIPPER, /

BEAM FROM LAMPF

INJECTION LINE

EXTRACTION KICKERS

OCTUPOLESBEND MAGNET

503-MH; BUNCHER

BEAM TO WNR

EXTRACTION LINE

OCTUPOLES

TRANSVERSE DAMPERS

-DIAGNOSTICS

-TUNEUP BEAM STOP

2.8-MHi BUNCHER

Fig. I.Plan view of the Proton Storage Ring.

January-December 1983 PROGRESS AT LAMPF 1 7 3t os Alamos National Laboratory

Table I. PSR Operating-Mode Characteristics.

Short Bunch, High Frequency Long Bunch, Low Frequency

ParameterNumber of bunches in ringBunch length in ringBunch interval in ringBuncher frequencyProtons/bunch accumulatedAccumulated turnsInjection rateFilling timeExtraction ratePeak circulating current

Nuclear physics61 ns59.63 ns603.75 MHz1 x 10"300120 bursts/s108 ns720 pps24.0 uA

Materials science1270 ns—2.795 MHz5.2 x 10"210012 pps

750 (is12 pps100 uA

extraction. After accumulation is complete, the ring isemptied in a single turn by the fast-extraction kicker.

The PSR was authorized as a $21.8-million construc-tion project in FY 1981, and a staging building fordevelopment and assembly of equipment was built by theend of that year. Construction of the main-ring tunneland its associated equipment building started in May1982 and is now complete.

It was necessary to develop specialized equipmentsystems for the PSR, including an intense negative-ionsource, a beam chopper to provide the desired beam-bunch pattern, kicker magnets to deflect the beam intoand out of the ring, and beam bunchers to compress thebeam into well-defined short pulses. These developmentshave been under way for several years and satisfactorydesigns are proven for all systems. Final componentassembly is in progress.

Procurement of standard equipment, such as magnetsand vacuum components, is nearly complete and installa-tion in the ring has started.

First operation of the PSR is expected on schedule inthe spring of 1985. At first the beam current will be small,but as tuneup proceeds, the beam current will increaseand we expect to reach the 100-uA level at the end ofFY 1986.

WNR UpgradeR. Woods

The WNR upgrade will raise beam-handling capabilityto the 100-jiA level of the PSR design. The project

requires improvements to the proton beam-transport lineand the target-moderator-reflector (TMR) system.

To allow continuing hands-on maintenance of theproton beam-transport line under higher current condi-tions, beam losses must be kept low, requiring a largeraperture in the beam-transport system. The change fromH+ to H" and the revamping of the switchyard alsorequire reworking the beginning of Line D. There aretime-sharing modes in which some beam will be going tothe PSR and other beam pulses will be going either to theWNR or to the neutrino facility. A kicker magnet andstripper foil will be mounted in Line D to permit this timesharing.

The major thrust of the upgrade will be seen in theTMR. The increased current, from 10 to 100 uA, must bedissipated in the new design. We are also planning for adepleted uranium target and designing to permit theinstallation of a boosted target in the future.

The new concept for the TMR is shown in Fig. 2. Theconcept is a split target with a void between and mod-erators located around this void in an arrangementtermed the flux trap geometry. The neutron flight pathsthat view these moderators thus will not "see" theneutron target itself. This arrangement significantly re-duces the background of unwanted high-energy neutrons.

The existing WNR flight paths will view these mod-erators. The upper target will be provided with wingmoderators that can be viewed by future flight paths. Inthis design the target and moderators are surrounded by a1-mm-diam cylinder of material that reflects neutronsback into the moderators and also adds to the shielding.


January-Docembur 1983

UPPER TARGETWING MODERATORS

FLUX TRAPMODERATORS

LOWER TARGET

Fig. 2.New concept for target-moderator-reflector (TMR)system.

The installation of a depleted uranium target in thespring of 1985 will give a factor of ~2 in useful neutronproduction. A liquid-hydrogen moderator also will beinstalled at that time to provide a source of cold andultracold neutrons. A separate insertable target with littleor no moderation will be provided for higher energyneutron experiments.

The increased neutron flux resulting from these im-provements requires an additional 0.6 m of iron shieldingabove the WNR target for equipment protection; addi-tional shielding and a water-cooled beam stop also will beprovided below the WNR target.

Experimental Halls ExpansionH. Robinson

The original plan for the existing WNR experimentalhall did not contemplate the 100-fold increase in neutronsource capability made possible by the PSR. This greaterintensity and optimized pulse structure from the PSRtransforms the source into the most intense spallationneutron source in the nation, and perhaps in the world.These extraordinary capabilities have proved attractivenot only to the Los Alamos National Laboratory staff,but to a large contingent of researchers from universitiesand industry. Soon after the PSR becomes operational,the facility expects to host approximately 100 visitingexperimenters each year.

To provide an adequate experimental area to accom-modate the User community and permit the full use of theneutron source, construction funding of $15.7 million isrequested for FY 1985 to expand the present experimen-tal hall and support facility.

This funding will provide a 929-m2, prc-engineered,high-bay structure attached to the east side of the existinghall on the existing grade. The hall will be equipped withthe full complement of services required for six majorneutron-scattering spectrometers. A 186-nr pre-cngineered wing attached to this structure, shown inFig. 3, will house quiet rooms, set-up areas, and rest-room facilities.

In addition, a 1115-m2 reinforced concrete subterra-nean structure attached to the west side of the existinghall at the same floor elevation will be built. The comple-ment of mechanical and electrical services provided in theeast hali will be installed here for six more experiments.

A 745-m2, two-story, reinforced concrete and pre-engineered laboratory and support complex will adjointhe present control room and the west experimental hall.This building, shown in Fig. 4, will be equipped for officesand used for data collection and technician work space.

Modifications will be made to the existing hall to allowbetter access and control of experiments and to providepenetrations for additional neutron-beam tubes from thetarget crypt. The proposed project includes funding forthe construction of three new spectrometers especiallydesigned to make optimum use of the intense pulsed-neutron beam, plus funding for six additional data-collection computers and a hub computer for data analy-sis.

In summary, the combined floor space of the ex-perimental halls (2230 m2) will more than quadruple thespace available for the spectrometers and staging ofexperiments, thus assuring full use of the source for thenational neutron-scattering program. The 743 m2 of sup-port area on the west side will provide adequate room fordata collection and light technician service to ex-perimenters using this world-class facility.

Line E for Neutrino Physics

7". Dombeck and G. J. Slephenson, Jr.

The neutrino beam line designated Line E lies to thesouth of the LAMPF switchyard in the WNR complex,as shown schematically in Fig. 5. A kicker magnet was

PROGRESS AT LAMPFLos Alamos National Laboratory

175

Fig. 3.Lower level floor plu« for experimental halls.

inserted into Line D to divert LAMPF 800-MeV macro-pulses into Line E with current initially at ~20 uA,upgradable to perhaps 200 uA. The beam line consists offour quadrupole doublets, two bending dipoles, a graphitetarget, and a tungsten beam stop. The target station isfollowed by a 12-m-long, 4-m-diam pion-decay tunneland an iron-concrete shield approximately 9 m thick. Thedetector sits on a concrete pad beyond the iron shield in aconcrete blockhouse used for cosmic-ray attenuation.Biological shielding is provided by concrete and earthoverburden.

The target and beam-stop areas are water cooled anddesigned for remote handling. Iron shielding around thetarget allows manual maintenance to within a few feet ofthe target. The target is viewed by a beam pipe at 9° thatallows one to monitor the pion flux continuously duringthe run.

Engineering for the construction and beam-line com-ponents was performed by Los Alamos Groups ENG-2and P-12, construction was carried out by the ZiaCorporation, and alignment was done by the Antaresalignment crew (Group P-5). Beam-line magnets and

power supplies were provided by LAMPF. Various beamcomponents were fabricated or provided by universitygroups: vacuum pieces and electronics trailer (New Mex-ico State University); harp boxes (Temple University);target and computer (University of California, River-side); and pion monitor (UCLA). Shielding material wasprovided by LAMPF and P Division.

A number of features incorporated into Line E will beused in future beam lines. The kicker magnet, its powersupply, and the vacuum fan-out pipe will be duplicatedfor the PSR. The skew in Line E is a first at LAMPF andrequired a novel method of alignment, sighting along thebore tubes of the magnets. The harps for beam monitor-ing in Line E also are of a new design that will beduplicated for use in the PSR and other LAMPF beams.

The expected flux of muon neutrinos in the detector fora current of 20 uA is shown in Fig. 6. Provision has beenmade for a magnetic pion-focusing device that will beinserted just downstream of the target; it will enhance theneutrino flux by an order of magnitude. Flux calculationswere performed using two Monte Carlo programs basedon pion yields that were measured for carbon targets.

176 PROGRESS AT LAMPF



.J,. -«- I -•..

POfO£ni

J L .1 . / L

- I L.J

^isa lit. ?

_J

L_

• Z

Fig. 4.Upper level floor plan for experimental halls.

FUTURE PROTONSTORAGE RWG

IKON SHIELD

DETECTOR 7AD

Fig. 5.Layout of the WNR/PSR complex showing location of neutrino beam line (Line E), neutrino-production target, pion decay channel, shielding, and neutrino detector.

At the en< of 1983, the construction is approximately Publicationtwo-thirds complete. Beam-line magnet elements and avacuum system are installed and tested, and alignment is 1. P. Denes et al., Phys. Rev. C 27, 1339 (1983).complete, as are the wire connections. A test to transporta small proton current was successfully performed inJanuary 1984.

1 7 8 PROGRESS AT LAMPFLos Alamos Naliontl Laboratory

Jtnuary-Dtctmbtf 1163

NEUTRINO ENHOY SMCTflUM•t, Inltf •*•# fttulnn* IHli

Lo Plan 4«tr twfmBUON NIUTRINO

• ( I • *»> • 1.4 . i f . /em'

Fig. 6.Calculated neutrino energy spectrum. Calculated flux is for a bare target with 20-uA beam of 800-MeV protons.

Research Programs

WNR/PSR Neutron Scattering ResearchR. ,V. Silver, R. Alkire, G. Chrisioph, J. Eckert, J.Goldsione, A. Larson, R. Robinson, P. Seeger, P. Ver-gamini, and A. Williams

In 1983 the neutron-scattering group (P 8) announceda National User Program at the WNR/PSR facility. Thisannouncement formally opened the facility to the na-tional and international scientific communities in solid-state physics, chemistry, materials science, and biology.Proposals for the use of neutron-scattering instrumenta-tion are reviewed by a nationally appointed ProgramAdvisory Committee, which also reviews proposals forthe Intense Pulsed Neutron Source (IPNS) at theArgonne National Laboratory. Proposals are reviewedon the basis of scientific excellence and optimal use ofWNR/PSR characteristics.

The first two instruments in the formal User programare the Be-BeO Filter Difference Spectrometer (FDS) andthe Single-Crystal Diffractometer (SCD). The FDS,

shown in Fig. 7, is used for chemical spectroscopy,localized modes, and phonon density-of-state measure-ments. The FDS instrument is (he responsibility uf J.Eckert. The SCD, shown in Fig. 8, uses the Laue-TOFtechnique and is the responsibility of P. Vergamini. In1983, 24 proposals for experiments were received and 15were approved by the Program Advisory Committee.

In 1984 the Neutron Powder Diffractometer (NPD)will join the User program. The NPD is used for neutronpowder diffraction by the Rietveld profile-refinementtechnique. The scientist responsible for the NPD is G.Christoph.

In 1983 major progress was made in the constructionof neutron-scattering instrumentation. The present ar-rangement of instrumentation at the WNR is shown inFig. 9.

(I) The prototype FDS and SCD instruments werecompletely rebuilt into well-engineered instrumentssuitable for the National User Program. Thesemodifications greatly improved instrument per-formance and reliability.

Januan- December 1983 PROGRESS AT LAMPFLos Alamos NUiontl laboratory

179

•VACUUMCON1*INMENT(5)

SAMPLE

Fig. 7.Filter Difference Spectrometer.

PULStU SOURCE

GONIOMOEH

DEIECTOK

Fig. 8.Single-Crystal Diflractometer.

1 8 0 PROGRESS AT LAMPFCos Alamos National Laboratory

JvHjtry-Dtctmbtr 191

FP7

FP6

FP5-

/U.i

\

FP3

Fig. 9.WNR layout of instrumentation.

(2) A prototype Constant-Q Spectrometer (CQS)began operation. The CQS, shown in Fig. 10, willbe used to study elementary excitations, such asphonons and magnons in single-crystal samples.

(3) The nuclear-resonance-filter difference techniquefor electron-volt spectroscopy was extended tolow-Q measurements appropriate for the study ofmagnetic and electronic excitations. In a col-laboration with the Rutherford Appleton Labora-tory, a prototype low-Q electron-volt spectrometer(EVS) was constructed and brought into initialoperation at the WNR.

(4) An instrument optimized for low-angle diffractivescattering with epithermal neutrons at high in-tensities and low resolution is required for diffrac-tion of liquids and amorphous materials. Such aninstrument requires special attention to keep back-grounds low. A protoype diffractometer for liquid,

amorphous, and special-environment materials(LASED) built with these goals in mind beganoperation at the WNR.

(5) A new sample environment container was con-structed for the NPD, and additional detectorswere installed.

Some highlights of neutron-scattering research in 1983included the following.

• First Molecular Hydrogen ComplexP. Vergamini and A. Larson (P-8) and H.Wasserman and R. Ryan (INC-4)

The structure of the first complex that reversiblybinds molecular hydrogen was determined by single-crystal neutron diffraction at the WNR facility. Thisis an intermediate species in the catalysis of hydro-gen, a long-sought missing link. The structure isshown in Fig. 11.

Jinutry-Dtctmber 1983 PROGRESS AT LAMPf 1 8 1Los Alunot Nillontl LUmttory

5 S»UI>v£* Af»MT7Efl

D • UKE uPCf 'CC»O*»»C -KuTI'tPfOBO LCUJUA70ABS - BULK SM.ELO

[ . _

Fig. 10.Schematic of the Los Alamos Constant Q Spectrometer.

W H2(CO)3 (P ipr3)2

ORTEP PLOT OF THE STRUCTURE OF W H2(CO)3 (P

Fig. 11.Molecular hydrogen complex.

• H./fit-Pressure Structure ofR. A Ik ire, A. Larson, J. Schirber, and B. Morosin(Sandia National Labs.)

ReOj is an unusual material because it undergoesa "compressibility collapse" at high pressures with afactor of-10 decrease in compressibility abovelOkbar. The long sought structure of the high-pressure phase has finally yielded to a time-of-flightneutron-scattering experiment in which one can takeadvantage of the strong penetrating power of theneutron and its ability to Bragg scatter at fixedangles with a white neutron beam in a high-pressure(I D-kbar) cell using the SCD.

• Hydrogen Sites in PbO2 Battery Plate MaterialJ. Eckert, J. Golds tone, J. Jorgensen, andR. Varma(Argonne National Lab.)

The problem of hydrogen bonding in elec-trochemical cells is of immense practical interest.The strong penetrating power of the neutron, itssensitivity to hydrogen, and the high epithermal fluxof the WNR facility make it a very suitable probe foraddressing practical problems of this sort. Figure 12shows inelastic neutron spectra taken with the FilterDifference Spectrometer of PbO, before and after

1 8 2 PROGRESS AT LAMPF4.O9 Alamos National Laboratory

JanuaryOtcember 1983

PbOj-H(cycled 434 time*, not heated)

- PbO

absortodwattr

1

boundhydrogen

500 1000

cm- i

Fig. 12.Inelastic neutron spectra of lead dioxide PbO2 battery-plate material.

cycling. The spectra clearly show that the hydrogenintroduced in the cells appears as vibrational modesof water H2O and not as increased bound-hydrogenmodes.

• Octahedral-Site Occupancy in Rare-Earth HydridesJ. Goldstone, J. Eckert. G. Venturini, and P. Rich-ards (Sandia National Labs.)

In LaH,, CeH(, and other rare-earth hydrides, thehydrogen atoms primarily occupy tetrahedral sitesuntil x > 2 is reached, at which point octahedralsites begin to be filled. The relative occupancy ofthese sites can be determined by the differing vibra-tional modes in inelastic neutron scattering and bypowder diffraction. In YHS, octahedral sites werefound to be occupied before x = 2 composition was

reached, and the occupation of these sites increasedwith decreasing temperature, in contradiction toexpectations of increasing order at low tem-peratures. Experiments at the WNR using the FDSand NPD instruments showed that the "octahedral"sites were not quite octahedral as the temperaturedecreased, leading to an increased degeneracy thatcould explain the observed temperature dependence.

Other important activities in the neutron-scatteringgroup in 1983 included the following.

• Development qfa Proposal for the Expansion of theExperimental Halls at the WNR Facility. In ac-cordance with the recommendations of the DOEreview committees (Brinkman I and II, and Rowe), aproposal has been developed and submitted to the

JtnuwyDtcimbtr 1993 PMXMEUATLAMI*Los Altmot Nulontl Ltborntory

183

DOE for expansion of the experimental halls, com-puter support, and instrumentation in order for theWNR/PSR to serve as a national User facility. Thisproposal was submitted for FY 1985 funding.Workshops and Conferences. A workshop was heldin S^tember 1983 on "Frontiers in CondensedMatter Physics with the WNR/PSR Pulsed NeutronSource," chaired by R. Birgeneau of MIT. A mini-workshop was held in November on "BiologicalApplications of the WNR/PSR Facility." Planningwas carried out for a conference to be held inFebruary 1984 on "High Energy Excitations inCondensed Matter," and commitments were madeto sponsor an "International Conference on Neu-tron Scattering" in August 1985 in Santa Fe.

WNR/PSR Nuclear Science

Search for Resonance Structure in Few-Nucleon Sys-temsP. W. Lisowski and G. F. Auchampaugh (P-3); M.Moore and G. Morgan (PI 5); and R. Shamu (West-ern Michigan Univ.)

During the past few years, both experimental claimsand theoretical predictions for the existence of dibaryon

resonances have been made. The conventional mesonapproach interprets observed structure in the nucleon-nuclcon system as resulting from inelastic channels inVarious partial waves. A more exciting possibility is thatthe resonances may result from six-quark bound states.-In this mode) the nucleons are pictured as two bags ofquarks, with the resulting overlap producing a richdensity of dibaryon states. Before experiments performedat Los Alamos in 1982 and 1983. there was no un-disputed picture of the energy or width of the proposedresonances. In fact, searches at LAMPF and elsewherehad insufficient energy resolution to observe the narrowstructure predicted by some models.

A search for resonance structure in the nuclfon-nucleon system was completed by performing a high-resokition, high-precision tip total cross-section measure-ment over the entire range of interest. These data showedno evidence for narrow structure. A broad anomalypreviously seen in the np system, attributed to an / = 1,3/"j dibaryon resonance, was confirmed. An 1 = 0, lF3

state proposed by other authors was not observed. From200 to 700 MeV. our?data (Fig. 13) indicate that existingcross sections may be as much as 6% too low.

A second set of measurements searching for resonanceeffects in the nine-quark system nD was partially com-pleted in 1983. These data will provide accurate crosssections to test both the theory of binding effects in the

,5O_7OENERGY (MeV)

M° , '3°t PRESENT WORK\ BRADY ct al.

MEASDAY 3 PALMIERI• KEELER ( I 01.j DEVLIN t l o l .

ARNOT ISP82)

, 1 , 1 , 1 , 1 , 1 , 1 , 1300 400 S00 600 700 800 900 1000

ENERGY (M«V)

Fig. 13.Comparison of present results with selected high-accuracy np total cross-section data and with phase-shift predictions. The upper (lower) data correspond to the upper (lower) energy scale. Note that thecross-section scale for the upper data is a factor of 10 smaller than that for the lower data.

1 8 4 PHOOflESSATLAMPfLos Alamos N'tmnnlibotMtoiy

Jtnuvy-Dtctmbv 1983

dcutcron and charge symmetry effects in the threenucleon system.

RIIFRI ;NCI :

I. P. W. Liwmski. R. f:. Shiiinu. O I Auchanipnuph. N. S ('. King.

M. S. Monte. ,im! T S. Sinplclun. '"Scurcli for Resonance Structure

in the r.p Tola! Cross Section l i do* KiKI McV." Pin v Rc\. l.clt.

4». 255 i ISIK2*.

High-Resolution Nucleon Induced Charge ExchangeRe.'ction Studies at 800 MeVP. l.isowski (P-3); G. Morgan andX. King (PIS): andP. Craig, D. I And, R. Jeffcsen, J. Shepard, J. Ullman,and C. Zafiratos (Univ. of Colorado)

Nucleon-induccd charge-exchange reactions, at bom-barding energies of several hundred MeV have indicatedthat there are interesting but poorly understood processesinvolved. For example, in (p.n) reactions the strength ofGamow-Teller (GT) transitions may be computed from asimple sum rule. Recent data near 200 MeV indicate thaiapproximately 3*)% of the expected GT strength ismissing.

One exciting possibility is that the GT strength is"quenched'" because of appreciable delta-isobar, nucleon-hole (A-hole) components in the low-lying GT levels.Such a theory, if correct, would imply that nucleonexcitations such as the A. which have been considered tobe too high in energy to be of importance in the low-energy domain, must be considered. Alternative conven-tional nuclear-structure effects also have been proposedto account for the GT quenching effect. Our studies of(p,n) reactions at the WNR will permit a search for thetransfer of GT strength directly.

To study this and other aspects of nucleon-inducedcharge-exchange, we are using a 213-m-long 0° reactionangle flight path at the WNR. the only facility in theworld capable of neutron energy resolution sufficient topermit the observation of nuclear-structure effects at800 MeV. Preliminary results thus far obtained for (p,n)indicate that we can obtain information addressing fourareas of interest: (1) the excitation of discrete levelsleading to unique information on the isovector andisovector spin-flip parts of the effective AW interaction:(2) the nature of the Pauli-blocked quasi-elastic knock-onpeak; (3) the nature of the broad resonances associatedwith the A and the possible implications for A-holeconfigurations in nuclear spectra; and (4) the excitation

of charge-exchange analogs specifically using (n,p) reac-tions.

As an example of the above, we have compared ourspeetr.i lor '\*{p.n). shown m Fig. 14. with those available ai lower energies and have conclusively identifiedGT and l-'ermi transiti -< . thus greatly extending theenergy range over which these transitions have beenstudied.

To obtain angular distributions, we plan to install abeam swinger to change the angle of incidence of theproton beam and thereby obtain angular distributionsusing the existing equipment,

Neutron Induced y Ray ProcessesS. A. H'ender and C. /•". Auchainpaugh (P-3); L. R.Silsson (Tandvm Accelerator Lab., Uppsala, Sweden);and .V. R. Roberson (Triangle Universities NuclearLab., Duke Univ.)

Experiments that study y rays in the energy range from4 to 30 MeV produced by fast neutron induced reactionshave been hampered by low data acquisition rales, re-stricted neutron energy ranges, and high backgrounds.Typical systems fopstudying fast neutron-capture reac-tions, for example, have been located at Van dc Graaffaccelerators and have used large-volume Nal detectorswith massive active and passive shielding. These detectorsystems have been limited to one or two detectorsbecause of their large size and high costs. The neutronsources have been limited in their energy range andresolution because they usually relied on secondaryproduction targets [for example, the D(d,n) reaction withgas cells |.

During FY 1983 we developed a unique system tostudy high-energy y rays produced by neutron-inducedreactions. This system consists of five bismuth germanate(BGO) scintillators used in conjunction with a pulsedspallation neutron source at the WNR. The simultaneousacquisition of y-ray excitation functions and angulardistributions for incident neutrons in the energy rangefrom 1 to 200 MeV is possible with this system (a paperdescribing this method has been accepted for publicationin Nuclear Instruments and Methods). Figure 15 shows adiagram of the apparatus.

The physics program based on this system is beingformulated as the particular parameters and capabilitiesof the system are determined. The program presently


./VJLL.-.760 770 780

Tn(MeV)790 800

Fig. 14.An 800-MeV uC{p,n) TOF spectrum at 9 = 0° . Overall resolution is approximately 2.5 MeV(FWHM). Arrows indicate expected locations of peaks observed in the 160-MeV spectrum shown inthe inset. The smooth curves indicate best fits to the background and peaks.

-7.2 m

TO BEAM DUMP

Fig. 15.Experimental setup showing neutron collimators, shielding, and detector assembly.


Janutry-OtcinfriMi

consists of studying two broad areas: (1) inelastic neu-tron excitation of y rays from bound states using the(n,n') reaction, and (2) fast-neutron-capture reactions

•**• into the giant-resonance region of nuclei.In addition to these two programs we are also in-

vestigating the properties of the BGO detectors to op-timize their characteristics.

Inelastic y-Ray Production. As an initial test of thesystem, we measured the I2C(«n'y = 4.44-MeV) reactioncross section for incident neutron energies from threshold(4.9 MeV) to 100 MeV. This reaction previously has beenstudied up to 20 MeV. Figure 16 shows the results of ourmeasurements. These data represent approximately 13 hof beam time.

In this run we used only four BGO detectors at8llb = 55, 90, 125, and 140°. The data from these detect-ors were fitted to an expansion in Legendre polynomials,

do(Q)/dCl =A0 {1 + LakPk[cos (9)]} .

The a2 coefficient to the order of k = 2 as a function ofneutron energy agrees well with previous results, and isshown in Fig. 17. However, the data show the need forterms to the order of k = 4, consistent with the results ofthe l2C(p,p'y = 4.44-MeV) reaction. Because only fourdetectors were used and two of them were at symmetricangles, the errors in the Legendre coefficients are largewhen the expansion includes k = 4 terms; a remeasure-ment is planned.

Fast-Neutron Capture. For our first fast-neutron-cap-ture experiment we studied the 40Ca(w,y) reaction. Be-cause the cross section for this reaction in the giant-resonance region is only on the order of 10 ub, we used arelatively large sample of natural calcium (500 g, 7.6 cmlong by 7.6 cm diameter). Data were acquired for approx-imately 50 h. Preliminary analysis of the ground-state y-ray yield as a function of neutron energy, corrected forincident neutron flux and neutron energy bin size, is

12,!C(n,n'7=4.44 MeV)

inw

I id

c:

icT8"io""1

1 1 1 1 1 1 1

4*1CP- J i i i i i

En(MeV)

Fig. 16.The 90° differential cross section for the nC(n,n'y) = 4.44-MeV reaction as a function of neutron

energy.

^ Jtnutry-Dtcunber 1St3 mOODEMATLAMPF 1 8 7Lot Altmot Ntkxml Laboratory

12C(n,n>=4.44 MeV)1.500

-0.375 —

-0.750 -

-1.125 -

-1.500

4*10°NEUTRON ENERGY (MeV)

Fig. 17.The /42 Legendre polynomial coefficient for the 4.44-MeV y ray from the 12C(n,n'y) reaction. The plotcorresponds to fitting the data to Ao and A2 only.

shown in Fig. 18. The absolute cross section was ob-tained by normalizing to previous results. The maximumin the yield curve at Ea = 11 MeV corresponds to thepeak of the giant dipole resonance in 41Ca. The shape ofthis excitation function is in good agreement with previ-ous results.

BGO Detector Development. The use of BGO scin-tillators to detect high-energy y rays is a relatively recentdevelopment. We therefore have spent some time study-ing their characteristics and have considered methods toimprove their performance.

In a paper submitted to Nuclear Instruments andMethods, we report the measurement of absolute effi-ciency of a 7.6- by 7.6-cm BGO detector at 15 MeV. Weused the l2C(p,y0) reaction at Ep = 14.2 MeV and de-termined the efficiency to be (51 ± 4)%. We expect to

obtain response functions and efficiencies over the energyrange 1-30 MeV.

Planned Work. We plan to continue our study of the12C(n,w'y) reaction to improve the quality of the prelimi-nary data, and to study n B , which shows several isolatedresonances in the y-ray yield for the 2.0- and 4.4-MeVstates. In addition, we plan to measure the y-ray produc-tion cross section of 14N and I5N.

The fast-neutron-capture program will continue thestudy of the giant-resonance region of nuclei — inparticular, the search for the isovector E2 resonance in208Pb. In addition, we plan to search for giant resonancesbuilt on excited states in MC using the l3C(n,y) reactions.Such resonances previously have been seen in proton-capture studies. Visitors interested in participating in thisresearch are welcome.



40,Ca(n,7o)

. . . . . .1 L . . . . i . . . . i . . . \ h * . . . .5 10 15 20

NEUTRON ENERGY (MeV)25

Fig. 18.The 90° differential cross section for the 40Ca(«,y0) reaction as a function of incident neutron energy.

Fission Fragment Angular and Kinetic Distributionsfor Actinide NucleiG. F. Auchampaugh (P-3); M. S. Moore (P-15); C. E.Olsen (MST-13); C. Goulding (Q-2); N. W. Hill (OakRidge National Lab.); and R. White (Lawrence Liver-more National Lab.)

Angular, kinetic-energy, and mass distributions asfunctions of excitation energy play an important role inrevealing the physics of the fission process. Answers toquestions such as the importance of shell effects andangular momentum on the potential energy surface, thenature of vibration and complex structures associatedwith this surface, and the time scale and energy dissipa-tion mechanism in fission are all addressed by suchmeasurements. The paucity of high-quality data in thisarea opens a rich field of research in neutron physics.

During the past year we developed a double-volumeFrisch-grid ionization chamber that permits simultaneousmeasurements of the angular, kinetic-energy, and massdistributions of each fragment as a function of neutron

energy for low a-active targets. A detector with cathodefoils of 235-238U and 232Th was used to obtain data from0.8 to 20 MeV at the WNR facility. The 235U data havebeen examined in detail and show systematic effects thatare attributed to nonuniformity in the conductivity of thefoils and base-line shifts because of pulse pileup fromcharged particles in the neutron beam. Further develop-ment and measurements are planned.

On the Nature of the Coupling in Subthreshold Fissionof 238Np

G. F. Auchampaugh and J. D. Moses (P-3); M. S.Moore (P-15); R. O. Nelson (P-9); R. C. Extermann(P-3 Visiting Staff Member); C. E. Olsen (MST-13);and N. W. Hill andJ. A. Harvey (Oak Ridge NationalLab.)

Although intermediate structure in subthreshold fis-sion was first observed in the neutron-induced fission of237Np (Refs. I and 2), and the structure at 40 eV has been

January-December 1983 PROGRESS AT UUWPF 1 8 9Los Almmos National Laboratory

extensively studied,3'4 the nature of the coupling betweenthe first and second wells of the 23lNp fission barrierremains unknown.

Inspecc.on of high-resolution fission data4 reveals thatseveral levels are strongly enhanced in the fission chan-nel, so that the mixing between the class II level underly-ing the intermediate structure and the class I backgroundis neither extremely weak nor very strong. The mixingcan, however, be attributed to two very different physicalcauses, as discussed by Bj^rnholm and Lynn. In thesimplest case, the two classes of states may be weaklymixed because of a high intermediate barrier. Bj^rnholmand Lynn refer to this kind of mixing as moderately weakmixing to a narrow class II state. Alternatively, theclass II state may have a very large fission width thatleads to weak mixing because of rapid decay of theclass II state. This is known as very weak mixing to abroad class II state. The data for 237Np have not clearlydistinguished between these alternatives.

Our work was an attempt to resolve this question bymeasuring the fission and total cross sections with verygood energy resolution (1) to expose any underlyingbroad resonance near 40 eV, if possible; and (2) to obtaingood enough resonance parameters to permit detailedanalysis of the fine structure of the class II fissionresonances at 40 and 120 eV.

The total cross section was measured at the Oak RidgeElectron Linear Accelerator using a 78-m flight path and

metallic samples cooled to liquid-nitrogen temperature(~77 K) to reduce Doppler broadening. The fission crosssection was measured at the WNR using a 30-m flightpath and a unique cryogenic ionization chamber thatmaintained the samples at a temperature of 84 K. Bothexperiments were designed to achieve the higheststatistical accuracy and the smallest possible neutronresolution at the 40- and 120-eV class II states.

We attempted to determine the relative sizes of thecoupling and fission widths of the subthreshold res-onances in 23lNp by measuring and analyzing the fissionand total cross sections with great care and by analyzingthe resulting resonance parameters by a variety of tech-niques. We believe we succeeded to the extent that wecarried these techniques as far as they can reasonably betaken with current technology. We did not succeed inproviding a clear answer to the nature of the coupling in23SNp.

The multilevel analysis neither requires nor precludesthe presence of a broad resonance underlying the 40-eVstructure. The statistical analysis of the resonance-spac-ing distribution gives some indication that an anomalousintruder level is present at 40 eV, but the data also permitthe alternate hypothesis. We believe that this problem willnot be resolved by precise measurements of the typedescribed here, but by a more sensitive measurement of adifferent type that can be carried out at the WNR.

1 9 0 PROGRESS AT LAMPFLos Altmos National laboratory

Januty-Oacantbar 19*3

V. STATUS OF LAMPF II*

-••«-•

^ H . A. Thiessen(Los Alamos)

I will give you a report on progress since the beginningof the summer, including the physics that we iearned atthe July workshop. One way of organizing the physics wewould like tc do at LAMPF II is to order it by the neededenergy of the proton beam. This list is presented inTable I.

One of the stars of the LAMPF II program will bemuon-neutrino physics, which would be quite interestingif we had a 5-GeV proton beam. We could make a bettermuon factory than LAMPF, even with the 5-GeV beam.We would get variable-energy polarized protons, higherenergy pions, and most likely the nuclear chemists wouldsee the bulk of the changes in the reaction mechanismthat occur between 1 and 10 GeV in the first 5 GeV.

At 12 GeV we get kaon physics; charge-parity (CP)violation is one of the important things—the study of therare decays, the hypernuclei. We get kaon-nucleon scat-tering; we get a way to study the spectrum of thehadrons, some of which are missing, and the low-energyK-N scattering has lots of holes in the data. We get kaon-nucleus scattering, and we get more fiux of pions, muons,and neutrinos. If we get up to a 32-GeV class ofmachine, then we have a decent antiproton factory, weget much higher-energy kaons and pions, and we have a

Table I. Physics at Various Proton Energies.

5 GeV Neutrino physicsImproved muon physicsPolarized protonsHigh-energy pionsNuclear chemistry

10 GeV Kaon physics: charge-parity violationRare decaysHypernucleiKaon-nucleus scattering

More flux of pions and muons

30 GeV Antiproton physicsHigher energy ICsMore kaon flux

50 GeV Higher energy polarized PBetter antiproton beams

much higher flux of low-energy kaons than we wouldhave with lower-energy protons. And if we get aboveBrook haven, then we begin to get into new territory; wecould have a machine with the capability of the highest-energy polarized protons available anywhere, as well asimproved kaon and antiproton flux.

What I saw in the July Workshop was the bestworkshop ever held here on any subject. We brought insome new physics topics, including the high-pj exclusiveprocesses that Glynnis Farrar talked about. We hadsome fine talks on high-energy antiproton physics; highenergy means well above LEAR but nowhere near thecollider energies. We briefly discussed extending theenergy range of polarized protonSj and we talked aboutglueballs. We learned that the long lifetime of the Bmeson and the apparent large mass of the too quark maymake some huge differences in the details ot our write-upof the kaon decays, but they may in fact make it evenmore interesting.

You should receive the Proceedings of the ThirdLAMPF II Workshop about January 1. I would like tothank Tarlochan Bhatia (he managed to solicit from youevery talk save one, which was held up in the Frenchpostal strike) and the Proceedings production staff. It is abeautiful job—this is the best workshop we have everhad, and the best documented one.

At the end of the workshop, we were talking about a32-GeV machine, something like the biggest machine at12 kG that will fit on the mesa. This machine is shown inFig. I. It would be injected by H~ beam; it would betunneled under the existing machine and would have fourmajor experimental areas: a neutrino pulsed-muon areaand three slow-extractive beam areas with a thin targetupstream.

Our cost estimate for the 32-GeV machine was startedbefore the workshop, but the numbers came out later. Wehad a machine that cost about $130 million. We had astretcher that might cost half that, thus the total was $200million for the machine and stretcher. We had fourexperimental areas at about $50 million each, vvith beamsand detectors. So that gave us $400 million, and adding20% extra for contingencies raised the total to roughly

This report is excerpted from a presentation to the Seven-teenth LAMPF Users Group Inc., Meeting, November 7-8,1983. The full text is available in Los Alamos NationalLaboratory report LA-10080-C (1984).

JanufyDtcember 1983 PROWESS AT LAMPF 1 9 1Los Altmos Nation*/ LtxrUory

PROPOSED LAMPFII LAYOUTSLOW EXTRACTEO SEAMEXPERIMENTAL AREAS

LAMPF II ACCELERATORI STRETCHER

IRON SHIELO

OETECTOR

_ C-MUON AREA/PULSED MUON ft NEUTRINO I

-r—EXPERIMENTAL AREAS \

•..,* m wo JOO «oo

SCALE IN FEET

- r ^ ^D

N

PROTON ITOnAOP. RWO |MR|/WEAPONS NEUTRON RESEARCH (WNR)

COMPLEX %

24 JUNE IM3

Fig. 1.LAMPF II site layout

$500 million. We had a very expensive proposal as shownin Fig. I, and that did not include cooled antiprotons,which may cost, as a wild guess, another $100 million.

At the end of the summer, the system consisted of thefollowing: we had a 32-GeV accelerator and its stretcher,but we also had a booster. We did not know exactly whatenergy booster we wanted, and still do not, but theproposal included a booster, and because of a need forpolarized beam, it had a stretcher on the booster so theunused pulses of the booster could be used for variable-energy polarized proton beam. We have not carefullypriced this, but it costs about the same to build a 32-GeVmachine with a booster or without. The big machine getscheaper if we have a booster, but first we have to make upthe additional cost of the booster.

The last day of the workshop I talked about a stagedproposal; we would build the facility in several stages.The first stage, for example, might be just the injectionline in the neutrino area. The second stage might be abooster that could feed that neutrino area, and maybe itwould have one experimental area in addition, with thebooster set up so that the next stage, which would be a

1 9 2 PROGRESS AT LAMPF£.05 Atamos National Laboratory

higher energy machine, could use the same experimentalarea. And then we would add experimental areas andprobably add thc/j's last. So, the features were: we had abooster, we had a higher energy machine, we had severalexperimental areas, and we build them one at a time.

Just before the workshop, the news hit that the NuclearScience Advisory Committee group making a long-rangeplan decided that there should be a heavy-ion collider,and that such a collider represented a unique opportunityin the area of nuclear physics. And, given the constraintsof that report, it is not possible to have two expensivefacilities. And so LAMPF II was postponed for a verylong time. I see no way, as the committee is nowconstituted and the ground rules are now set up, to buildthe full facility, even in stages, because it is recognizedthat the whole accelerator is going to be very expensive inthe end, and what difference does it make if it is staged?

We must step back and ask, in some order, what doesthe country need? Let us say that it needs a next-generation e+e~ or u.+u.~ collider somewhere. It needs aDesertron. I think we need some kind of a factory forfixed-target physics that includes the physics we have

been talking about. We appear to need a heavy-ioncollider, and we are already committed to a 4-GeV'ectron machine.

At present, we are trying to come up with the minimumfactory that we could build here. It would be at least a 12-GeV, 100-ua kaon factory. We have several ideas forreducing the cost. We can reduce the energy, whichmeans reducing the counting rate, and thus it may bepossible to eliminate the stretcher. Eliminating thestretcher would dictate that the duty factor be one-thirdinstead of 1, but that goes with the counting rate, and so itis probably acceptable. And as you saw, if we had nomoney in the accelerator, it would still cost $200 millionfor the experimental areas, so we are thinking about waysto run with about half the number of beams talked aboutat the workshop. (I think we had 15 or 16 beams at theend of the workshop.) And we may be able to save somemoney by reconfiguring the existing experimental areas.

I remind you about the flux arguments. Figure 2 showsa plot (linear scale) of the kaon yield at fixed 1.4-GeV

UJ 8 -

(-cm CARBON TARGET

l.40-G«V/c SECONDARIES

SANFORD-WANG • KR

f PRESENT DATA

1 0 -

10 18 24

E PRIMARY (GeV)

Fig. 2.Energy dependence of production cross sections onI-cm carbon target normalized to 10-GeV crosssection.

secondary energy as a function of proton energy. Youcan see that there is no sharp structure in the regionproposed. The kaon yield is about 5 times more at24 GeV than at 10 GeV. so the first factor we have lost inlowering the energy is the beam power. And then maybeanother factor of 2 at most. It is a penalty we have to payif we lower the beam energy, but it is not a dramatic one.and there is no clear threshold in the region 10-24 GeVfor kaons. For p\s it is different. If we go down muchbelow 32 GeV, we lose fast on the p's.

Suppose we propose a 12-GeV machine like the oneshown in Fig. 3. It would have 10 times the flux of theexisting Brookhaven AGS slow extracted beam, 20 timesthe flux of kaons below 1 GeV, and of course atBrookhaven they have to divide the beam many ways.We have to divide the beam many ways: let us call thateven. So as a kaon factory, it is 20 Brookhavens. A 12-GeV machine is smaller, there may be a cheaper site, andwe have a way to do it with no interference with PSR.Figure 3 is a scheme in which we reconfigure Area A;that means at least a shutdown like the Great Shutdownfor Area A. And in that picture. Areas B and C arc noteasily used after we go to LAMPF II.

To see this concept in its simplest form, let us put a ringas shown, where it does not cross through the forest ofexisting buildings. It could be built at the same elevationas the present Imac, and it could be injected off thepresent Line B and rcinjected into ihe switchyard withminimum trouble. We could then reconfigure Area A tohave some very useful beams in it. Should we decide tohave a booster for such a machine, there is a naturallocation for it in (he present parking lot for Area B, andthere could be an experimental area for the booster.

Figure 4 is a blown-up drawing of Area A reconfiguredfor 12 GeV. It is conceptual only. The idea is to extractfrom the accelerator at one point and to provide, down asingle line, the capability of alternating pulses of a fast-extracted beam and a slow-extracted beam. On the slow-extracted pulses, which would have duty factor of aboutone-third, the beam would hit the first three targets.

The first target might be used for making a stoppingK' and K beam off th" me target, with a first magnetbeing a bending magnet common to both. This systemgives very clean beams, and it is clear that there is a needfor stopping A'1" beams and stopping K~ beams, both.When there are stopping beams, the energy is rarelyvaried. So this scheme might work for kaons even thoughthey arc coupled and even though it is an awkwardarrangement for muon beams at existing meson factories.

.anuary-December 1983 PROGRESS AT LAMPFLos Alamos National Laboratory

193

PROPOSED LAMPF I I LAYOUT

<-*••-

SCALE1 IN FLET

Fig. 3.A scheme for a 12-GeV machine.

The next target cell might include two medium-energybeams, and two examples might be an EPICS II and the1.8-GeV kaon beam. Anything could go there, but,looking at that target, they may have to be nonzero-degree beams independent of each other.

The third target cell would contain the high-energybeam. If the machine is only 12 GeV, then the beamwould be about a 6-GeV nJC,P beam and it could sharethat target with a K° beam. Bob Macek has suggestedputting a bending magnet right upstream of the target andaiming the proton beam toward the south side of thebuilding so that 0° for K°'s points into a useful ex-perimental area, and then bend it back to get onto thedump. There could be a muon beam produced at thisthick target. We would have the best duty factor and thebest muon rate. There could also be a test beam at thistarget. So for the slow-extracted beams, we would get anice set containing most of the secondary-beam physicsshown in the proposal.

Another idea for the fast-extracted beam is to let it goon down the same beam line, either with rotating targetswith holes, or the beam kicked around the upstream

targets, or slow and fast-extracted beam scheduled duringdifferent time periods. In any case, there is a fourthtarget, which is used as a neutrino target and a pulsed-muon target. For neutrinos, there is a horn with theexisting Line A as the decay region, putting the neutrinoarea downstream of the present beam stop. We mighteven be able to use the Biomed beam as a pulsed-muonbeam if we add a vacuum chamber. So we have beautifulneutrino physics, beautiful pulsed-muon physics, beaut-iful kaon physics up to 6 GeV, and somewhere else wherewe can get a not-too-expensive, low-energy, variable-energy polarized beam. If we choose to have no booster,we could put a jet target in Area B. Polarized protonexperiments could be done at variable energy by justwatching what happens as the circulating beam energychanges. The beam could be polarized; we will certainlydesign the accelerator for polarized protons.

What does this scenario cost? Table If shows theaccelerator cost estimate. We scaled the cost estimate wehad for the 32-GeV machine and came up with thefollowing set of numbers, which says that for about $60million, we could build such a machine. We made a guess,


January-Dacambar 196*

BE4M-

IsFig. 4.

A conception of Area A reconfigured for 12 GeV.

rejDSED LAMr nEXPE/i.VtNTAL A=£ASKl 11,111!/U i n Ml

Table II. Accelerator Cost Estimate, October 28,1983.

Accelerator

Buildings

Experimental-area modules

Magnets and power suppliesr.' systemDiagnostic and controlsVacuumExtraction systemsFast dampersInjectionFast abort and dumpCollimator systemBucket rotatorLAMPF injector modsInstallation

3 electromechanical equipment15OO-ft tunnel @ $2OOO/ftSupport lab

Office for 100 peopleControl building expansionRing entrance building

See Table IIITOTALContingency +20%

TOTAL (in 1984 dollars)

Dollars(in Millions)

S 15.813.612.06.02.01.51.41.01.01.00.37.5

$ 63.1

5.43.02.02.01.30.2

$ 13.9

68.0145.029.0

$174 x 106

not yet verified, that we really can have efficient slowextraction from single ring that goes along with a lowerintensity overall, a lower beam power overall. It mayhave a booster with a similar total cost. We have notproved that we can do it, but we are working on it.

The buildings are mostly mechanical equipment build-ings for this new ring. We are making very good use ofwhat we already have, so we need only a small number ofadditional buildings.

Table III shows the cost of the experimental area.Macek suggests reworking about two-thirds of the steeland concrete that we already have. We'a'dd 10 kilotons(kt) of new steel, some train—or canyon—fill (filling thetrains containing the secondary beam lines out to a

standardized cross section), and some new concrete. Thecosts for shielding, beam transport, etc., are shown. Thebiggest single item is the beams, seven beams guessed at$5 million apiece.

So we have a rather cost-effective experimental areawhere at least half of the funds go directly into things wewant, namely, into the beams. By using Area A, we saveshielding, beam transport, water, power, and buildings,and we can use the existing remote handling equipment;the final savings is over $30 million. The total cost,including a contingency in this year's dollars, is about$175 million, which is sufficiently close to Louis Rosen'sguideline of $150 million to meet his request.


Table III. LAMPF II Experimental Area Cost Estimates, October 28, 1983.

Dollars(in Millions)

Shielding installedCost

S18

(Kilotons

Reworked steelNew steelTrain fillNew concrete

Primary beam transportPrimary beam tunnel reworkTargets and target chambersRework beam-stop area andSecondary beam lines (7)Extend building

TOTAL

20104

10

Perton

$ 200800

1000200

Total(in Millions)

$ 4842

$18

(4 targets)neutrino-area construction

6145

352

$71

„ Jtwaiy-December 7983 PROGRESS AT LAMPFLos Mtmos Nuiontl LtborUory

197

VI. FACILITY AND EXPERIMENTAL DEVELOPMENT

The New Transition RegionA. A. Browman

with two high-current beams when the PSR comes on linein 1985. Thus, the decision was made to replace the TR.

Introduction

The first 100 MeV of energy gain at the LAMPFfacility is provided by an Alvarez-type accelerating

"structure operating at 201.25MHz. The remaining ac-celeration is provided by the side-coupled linac, whichoperates at 805 (=4x201.25) MHz. The transition re^.gion (TR) connects these two types of acceleratingstructures and provides proper phase-space adjustmentsof the 100-MeV beams so they can be acceleratedwithout loss in the side-coupled linac.

The original TR (Ref. 3) was unable to provide correctmatching of H+ and H" (P~) beams simultaneouslywithout causing unacceptable beam losses. When onlyone high-current beam was being run at a time, the TRcould be adjusted to handle it properly by allowing theother (low-current) beam to be not as well matched. Thenecessary "compromise tunes" were time consuming toachieve, and often did not result in very good beamquality for the low-current beams. In addition, the newProton Storage Ring (PSR) was designed to use high-current H~ beams, so LAMPF will be required to operate

Features of the TR

The most obvious requirement of the TR arises be-cause the operating frequency of the side-coupled linac isan even multiple (4) of that in the Alvarez linac. Thus, fordual-beam operation the phase of one of the beams mustbe changed relative to the other one by 180° (805 MHz)(see Fig. 1). In the TR this is achieved by separating thebeams and causing the paths followed by the two beamsto differ in length by 8 cm (nominally) before they arerecombined. Other functions that the TR must performare the correct steering and matching of both beams.Detailed descriptions of these requirements may be foundin Refs. 4 and 5.

Both the original and new TR are shown schematicallyin Fig. 2. In addition to the features described, the newTR includes larger apertures, additional diagnostics, a"straight-through" path, beam-path-length adjustment,quadrupole and steering magnets on all beam lines forindependent control of each beam, and a much neaterinstallation, as shown in Fig. 3. Considerable effort was

-201.25 MHz

Phase shift necessaryfor correct acceleration

Fig. 1.Representation of 201.25- and 805-MHz accelerating fields. The circles on the 201.25-MHz traceshow the approximate location of the different sign beam bunches. Note that the 805-MHz wavewould decelerate one bunch of particles if their phase were not shifted.

1 9 8 WKXJBEM AT LAMPFLos Altmos National Laboratory

Jtnjmry-CHcwnbtr IW,

SIDE-COUPLED

- LINAC

irnfsioE-]H\i COUPLEDjJliJLLINAC

s/BB'BEAM BOXBM-BENDING MAGNETBR • BUCKET ROTATORSM» STEERING MAGNETSV« SOLENOID VALVEQD« QUAO DOUBLET MAGNETQM«QUAD MAGNET

Fig. 2.Original TR (top) and new TR (bottom). The first module in the side-coupled linac was moved toobtain more room. Each beam line in the new TR has its independent quadrupole and steeringmagnets. Space was allowed for longitudinal matching (bucket rotator) in the new TR.

expended to make the TR installation as uncluttered andserviceable as possible (see Ref. 6 for a detailed descrip-tion of the mechanical fabrication of the TR, as well as alist of the drawings used in the TR construction).

To minimize beam loss in the side-coupled linac causedby "emittance growth" in the TR, field quality in themagnetic elements must be quite good. The magnets usedin the TR were extensively mapped and trimmed (seeRefs. 7 and 8 for a detailed report of the methods usedand the results obtained). The final TR design enabled asingle type of bending magnet, quadrupole magnet, andsteering magnet to be used. This approach allowed sparesfor all elements to be built and mapped during construc-tion o^ the TR.

Because the entire LAMPF facility would be renderedinoperable during the removal of the old TR and installa-tion of the new one, extensive planning was necessarybefore the work began. Most major components were

assembled and staged at the Equipment Test Laboratory(ETL) during production running and then moved to thebeam channel during the shutdown period. As a result,we were able to resume operation with a new working TRby the end of the same shutdown period that wasscheduled for experimental area maintenance and repairs.

Operation of the TR

Approximately 1 month was used to commission thenew TR. During this time beams were run through allthree beam lines, matched, steered, and checked for beamquality. A major effort was needed to get the diagnosticequipment checked out, but everything was working intime for production running.

By the end of 1983 we had run for several months withhigh-current H+ beam (up to 900 uA) and low-current

_ ^ jmiaryDtcember 1983 PROGRESS AT LAMPFLosAlmmot Ntliootl Ltbontory

199

Fig. 3.

Photograph of the new TR. Note success achieved in cleaning up the installation; maintenance isconsiderably easier.

polarized H~ beams. Beam quality is improved, tuning is

easier and faster, and the beams are stable.

At this time no changes to the TR have been necessary

and we believe the TR will satisfactorily handle the high-

current H~ beam when it becomes available in early

1985.

REFERENCES

1. D. A. Swenson, E. A. Knapp, J. M. Potter, and E. J. Schneider,"Stabilization of the Drift-Tube Linac by Operation in the it/2Cavity Mode," R. A. Mack, Ed., Sixth Int. Conf. on High-EnergyAccelerators, Cambridge, Massachusetts, September 11-15, 1967,Cambridge Electron Accelerator report CEAL-2000 (1967).pp. 167-173.

2. E. A. Knapp, "High-Energy Structures," in Linear Accelerators,P. O. LapostoUe and A. L. Septier, Eds. (North-Holland, Amster-dam, 1970), pp. 601-616.

3. D. A. Swenson, "The Transition Region," Los Alamos NationalLaboratory Group MP-3 document MP-3-75, February 24, 1969.

4. O. R. Sander, "LAMPF Transition Region," Los Alamos NationalLaboratory report LA-9315-MS (June 1982).

5. O. R. Sander, A. A. Browman, and E. D. Bush, "Redesign of theLAMPF Transition Region," in Proc. of the 1981 Particle Ac-celerator Conference, Washington, DC, IEEE Trans. Nucl. Sci.NS-28, 2914-2915 (1981).


Janutry-Oicvnbf 796.

6. E. D. Bush, Jr., J. D. F. Gallegos, R. Harrison, V. E. Hart, W. T.Hunter, S. E. Rislove, J. R. Sims, and W. J. Van Dyke. "LAMPF

^ Transition Region Mechanical Fabrication," to be available in aft Los Alamos National Laboratory LA-UR document.

7. A. A. Browman. "TR Bending Magnet Description," Los AlamosNational Laboratory Group MP-DO memo. August 18. 1983.

8. A. A. Browman, "TR II Quadrupole Magnets," Los Alamos

National Laboratory Group MP-DO memo, April 7, 1983.

New Experimental Staging Area

The Experimental Staging Area was completed and in use in September 1983. The primary purpose ofthis 9000-sq-ft facility is to provide an area for experimental teams to assemble and test their experimentsbefore installation in the experimental caves.

The facility is equipped with a 30-ton bridge crane and ample utilities for User requirements. Inaddition, an office is available, as well as power pedestals adjacent to the Staging Area to accommodatetrailers.

Fig. 1.New Experimental Staging Area.

nuary-Decamber 1963 PROGRESS AT LAMPF 2 0 1Los Atomos Nttionl Ltbomory

EPICS and HRS Data Systems

Group MP-10 spectrometer software has been rewrit-ten in the conversion from RSX-1 ID to -11M operatingsystems. In addition, some special features from the oldspectrometer software are now available in the newstandard Q program from MP-1. Improvements includecore histogram storage, easier implementation of datacuts, data reduction before taping, and batch replay onVAXes with spooled tapes.

An array processor (a used AP-120B) has been ac-quired for EPICS and upgraded to be compatible with thetwo in place at the HRS, but software conversion toRSX-11M is still in progress. The HRS array*processorshave developed problems that have been difficult toresolve during production.

Other planned upgrades include the addition of aVAX-11/730 to replace the on-line PDP-11/45 at eitherHRS or EPICS, and higher density tape drives to reducethe number of tapes used by a factor of 3 or 4.

Instrumentation Technology Developments in MP-4Vernon Sandberg

The instrumentation developments in MP-4 during1983 have been to

• design a magnetic horn and pulser for a high fluxneutrino facility;

• develop a high-speed, high-voltage, variable-widthpulser for beam chopping;

• construct a CAMAC-controlled pulser monitor forthe flash chamber system used in Exp. 225;

• construct a computer-controlled test and repair sta-tion for the multiwire proportional chamber(MWPC) input electronics used in Exp. 225;

• design and fabricate the signal-processing elec-tronics for the drift chamber and the sodium iodidedetectors used in Exp. 400;

• develop and build a variety of control systems forExp. 634;

• upgrade the chamber wire-winding shop with newcontrollers; and

• provide miscellaneous support to LAMPF facilitiesand experiments.

A brief description and a few highlights of some of theseinstruments follows.

Portions of a design have been done for a neutrinohorn system. The system consists of a capacitor bank,horn, and silicon control rectifier (SCR) switches. The

capacitor bank energy is switched into the horn, whichacts as a resonating inductor. The current flow rechargesthe capacitors through a bridge rectifier circuit, thu-completing one-half of a sinusoidal cycle. The horn size2 m in diameter and 4 m in length; its capacitance isO.I F. The peak voltage is 500-800 V, and the peakcurrent is 300 kA.

A high-voltage pulser for the injector beam-choppersystem has been built. It produces a positive pulse ofadjustable amplitude from 1 to 15 kV, adjustable pulsewidth from 40 ns to oo, and rise and fall times of 20 nsacross a 1-Mft load shunted by 150 pF. The pulse is"flat" to within 5% of its peak voltage and recovers towithin ± 10 V of ground potential. The pulser is a hybridsystem composed of hard triode vacuum tubes, MOS-FET power transistors, bipolar microwave transistors,integrated circuits, and fiber optics systems. The pulser,which is mounted in a cylinder 1 m in diameter and 1.5 min length, will be installed in the injector area in 1984.

In support of Exp. 225 a system to monitor the high-voltage pulsers that drive the detector flash chambers hasbeen built. The monitor watches several key parametersin the flash chamber system (for example, the chargingvoltage and current, the trigger pulser waveform, and themain pulser waveform) and reports their status to theexperiment computer. When a major fault is detected(such as a capacitor failure), the monitor compares thepulser-system status with its past history and then takesappropriate action (such as disconnecting the high-volt-age charging power supply from the shorted capacitorbank). The monitor is fabricated with TTL logic andcommunicates with the experiment's computer throughCAMAC.

To facilitate testing and repair of the electronics used inthe cosmic-ray anticoincidence system for Exp. 225, wehave built a computer-controlled test station that tests thememory, logic, and shift registers of the input cards, thePAL layer logic, and the control-test cards. It is based ona Hewlett-Packard HP-85 portable computer and stan-dard CAMAC-control modules. Its software is veryflexible and can be easily adapted to changing require-ments encountered in diagnosing problems in the anti-coincidence system.

In support of Exp. 400, a system of amplifiers, analogdelay lines, and pulse-shaping circuits has been developedand fabricated. To run the Crystal Box detector at aninstantaneous muon stopping rate of 5-million muonstops per second, the sodium iodide signals must beclipped to reduce pileup and improve energy resolution.


January-December 1

The photomultiplier-tube base and amplifier systemused on the Crystal Box sodium iodide detectors clips the

vsignal (to a 100-ns-wide pulse) and then amplifies andjrther shapes the pulse leading edge with a pole-zero

filter. The processed signal is then split three ways andsent to a constant fraction discriminator, an analogsumming circuit, and into a 450-ns-wide bandwidth delayline, after which the analog signal is further split and sentto two parallel integrating analog-to-digital (ADC) chan-nels. Before clipping, the sodium iodide pulses have 250-ns decay time; after processing, the pulses are approx-imately square and 100 ns wide. This system has 432such amplifier cards and each card is independentlyaccessible.

Group MP-I Electronic Instrumentation and Com-puter Systems

Computer Maintenance Section

Since its inception 3 years ago, the MP-1 ComputerMaintenance (COMAINT) section has grown from six toits current staff of eight technicians. Meanwhile, themaintenance value of the equipment maintained by thesection has increased 60%. The increase in maintenanceefficiency is largely due to three factors: (1) replacementand/or redesign of older more troublesome hardware; (2)increased experience and training within the section; and

Martha Hoehn and Elvira Martinez working at a VAX-11/780 console.

•wary-December 1983 PROGRESS AT LAMPF 2 0 3


Sharon Lisowski and Mark Kaletka shelving magnetic tapes in the Data Analysis Center tape library.

(3) more efficient utilization of manpower by using splitshifts, with reduced on-call and overtime hours.

The COMAINT section is responsible for the mainte-nance of more than 50 computer systems and 200computer terminals at LAMPF. During operating cycles,the section is staffed from 7 a.m. to 12 p.m. midnight,Monday through Friday, with weekends and early morn-ings covered by assigned on-call duty. The section han-dles more than 100 trouble calls per month and countsmost of the personnel at LAMPF among its clientele.

Data Analysis Center (DAC)

The year 1983 brought several changes to the LAMPFData Analysis Center (DAC). In cooperation with theMedium-Energy Physics Theory Group (T-5), MP-1purchased and installed a new VAX-11/780 system(MPBGl), bringing the total number of VAX computersin the DAC to four. Delivered as part of this new systemwere two 125-in./s, 6250-bits/in. TU-78 tape drives, an


Januvy-Dtcember 7ft.

Tony Gonzaies making adjustments toMPSERF in the Data Analysis Center.

Andy Steck, Gerry Maestas, and Jim Santana performing routine maintenance on the Data AnalysisCenter computer MPSERF.

- muary-December 1983 PROGRESS AT LAMPFLos Alamos National Laboratory

205

Leon Guerin and Kelly Blount at the Computer Maintenance section repair facility.

Bob Critchfield inspecting a removable disk systemin the computer maintenance shop.



Bryan O'Malley and Boyd Cummings testingthe operation of a line printer.

HSC-50 disk and tape controller, four RA-81 Win-chester-type disk drives, and an RP-07 Winchester-typedisk drive.

The VAX systems are now connected to each other viaa CI-780 computer interconnect, a high-speed (70-mega-bit/s) bus link that replaces the slower DMR-32 hardwarefor network links. The CI-780 hardware also forms thebasis for a future VAX-cluster architecture, a closelycooperating network of VAX computers that sharescommon resources, such as disk storage, batch queues,and print queues. Because full software support for theVAX-cluster features is not available with the current(version 3.4) release of the VMS operating system, MP-1is acting as a test site for a pre-release of VMS ver-sion 4.0. The pre-release was installed on MPBG1 inDecember 1983 and will be extended to the other threeVAX systems during the early months of 1984. The testphase will run until the official release of VMS version 4.0in mid-1984.

The year also saw the completion of the LAMPFterminal network, with the Micom Micro-600 port selec-tor system becoming fully operational. All terminals

connected to the DAC are now routed through thissytem, which allows flexible terminal switching betweencomputers. The system is undergoing its first expansion,with equipment on order to service the new VAXMPBG1, provide additional terminals in the LaboratoryOffice Building, and possibly expand access to terminalsat the experimental areas.

A committee convened for 3 days during October1983 to consider long-range (5- to 10-year) computingneeds at LAMPF. This committee consisted of represen-tatives from MP Division and LAMPF Users, and waschaired by Martha Hoehn of MP-1. The committee heardpresentations on topics including parallel and front-endprocessing, computer networks, word processing, andnew central processing unit (CPU) standards, whileconsidering future directions for both data acquisitionand analysis at LAMPF. Presentations were made byspeakers from SLAC, Fermilab, and TRIUMF on thecomputer facilities and philosophies of those institutions.The final report of the committee should be available inearly 1984.

umuy-OKtmbw J9S3 PROCMEM AT LAMPF 2 0 7Lot A fwnos Nmtiorml Laboratory

Design for a Muon Channel Based on the ProtonStorage Ring

A muon channel using the proton beam from theLAMPF Proton Storage Ring (PSR) would providepulsed muon beams uniquely applicable to a wide class ofexperiments. Beam-optics studies led to a design for sucha PSR-based channel capable of providing either decaymuon beams, with momenta as high as 80 MeV/c, orsurface muon beams at 30 MeV/c.

The design incorporates a superconducting solenoid asa pion decay section for producing decay muons, andincludes an electrostatic chopper for short-pulse surfacemuon beams. The PSR is designed to run at 100 uA

average in the long-bunch mode at 12 Hz with 270-nsproton bunches or at JOJIA average in the short-bunchmode at 720 Hz with 1-ns pulses.

In the long-bunch mode, the chopper selects a smfinterval of the surface beam to produce intense 5- to 10-ns pulses of surface muons at 12 Hz. In the short-bunchmode of PSR operation, the surface beam will not bechopped; then the muon pulses are approximately 30 nswide at 720 Hz. In neither mode of PSR operation willthe higher momentum decay beams be chopped. Calcu-lated positive muon fluxes range from ~1 x 106/s forchopped long-bunch-mode surface beams to oS x 107/sfor long-bunch-mode decay beams.



VII. ACCELERATOR OPERATIONS

i . This report covers operating cycles 37 through 39. Theaccelerator was in operation from December 30, 1982through February 8, 2983, and again from August 1through December 1, 1983. Beams were provided forresearch for 136 days, and for facility development for11 days. A summary of information on beams providedfor research is given in Table I.

Machine operation continued lo be reliable and stable.The H+ beam intensity was increased to the 800- to 900-uA range for routine production, and the beam dutyfactor was increased to 10.5%.

As noted in LAMPF News in this report, the H+

average beam intensity reached and exceeded the designlevel of 1 mA for the first time on February 1. In a 3-h

demonstration run, 1.2 mA of 800-MeV beam was de-livered to Area A at 10.5% duty factor.

Installation of the new transition region between thedrift-tube and side-coupled linacs during the February-to-Juiy shutdown has made the machine-tuning task mucheasier. Dual-beam operation with no steering magnetsenergized in the 805-MHz linac has become routine.

A summary of unscheduled facility downtime duringresearch shifts is given in Table II. Because some of theoutages are concurrent, the total is greater than the beamdowntime.

Accelerator development efforts concentrated on mak-ing the new transition region operational and on improv-ing the H+ beam deflector in the low-energy transport.

Table I.

Number

H+

H"P-

H+

H"p -

H+

H~P~

H+

H", P"

Beam Statistics for Cycles

of experiments served

scheduled beam (h)scheduled beam (h)scheduled beam (h)

beam availability (%)beam availability (%)beam availability (%)

average current (uA)average current (^A)average current (nA)

beam duty factor (%)beam duty factor (%)

37 Through 39.

Cycle 37

33

860276588

898090

6251

~10

6-93-9

Cycle 38

33

884200

1356

808680

7702

- 1 0

6-93-9

Cycle 39

23

792

784

87

82

825

~10

7-10.53.5-10.5

January-December 1983 PflOCMESS AT LAMPF 2 0 9Los Alamos Nttiontl LtborHory

Table II. Unscheduled Machine Downtime from December 30, 1982 to December I,1983;

Category Downtime (h) Per Cent of Total

201-MHz amplifiers and transmission lines805-MHz amplifier systemsVacuum systemsMagnetsMagnet power suppliesInterlocksIon sources and Cockcroft-Walton hv suppliesCooling water systemsComputer control and data acquisitionProduction targetsMiscellaneous (utilities, ligtning)

TOTAL

8fi9669364816

1701823267

595

141612683

293441

2 1 0 PROGRESS AT LAMPF JanaryDmrnb* I9B3Los Alamos National Laboratory

CLINTON P. ANDERSON MESON PHYSICS FACILITY

MILESTONES

Official Ground BreakingSpinoff: Adoption of LAMPF Accelerating Structure for

X-Ray Therapy and Radiography Machines5-MeV Beam AchievedAdoption of a LAMPF-Standard Data-Acquisition System100-MeV Beam Achieved211-MeV Beam Achieved800-MeV Beam AchievedSpinofT: First Use of Electrosurgical Forceps in Open-Heart

Surgery (University of New Mexico)Discovery of 236Th (Experiment Zero)Dedication to Senator Clinton P. AndersonSpinoff: First Hyperthermic Treatment of Animal TumorsFirst H" Injector BeamFirst Simultaneous / /+ and H~ BeamsBeam to Area B

First Experiment (#56) Received BeamFirst Meson Production, Beam to Area ABeam to Area A-EastFirst Medical Radioisotope ShipmentUsable 100-uA Beam to SwitchyardPi-Mesic Atoms with "Ticklish" NucleiFirst Experimental Pion RadiotherapyFirst Tritium Experiment (80 000 Ci)Start of Great ShutdownNew Precise Measurements of Muonium Hyperfine-Structure

Interval and u+ Magnetic MomentQ Data-Acquisition Software OperationalSpinoff: First Use of 82Rb for Myocardial Imaging in Humans

(Donner Laboratory, Lawrence Berkeley Laboratory)Spinoff: First Hyperthermic Treatment of Human Cancer

(University of New Mexico)Accelerator Turn OnAcceptable Simultaneous 100-uA / /+ and 3-uA H~ Beams

to SwitchyardProduction Beam to Area BFirst Pions Through EPICS ChannelProduction Beam in Areas A and A-East:

End of Great ShutdownMuon-Spin-Rotation ProgramSpinofT: First Hyperthermic Treatment of "Cancer Eye" in

Cattle (Jicarilla Reservation)100-uA Production Beam in Area A

February 15, 1968

ca 1968June 10, 1970August 1970June 21, 1971August 27, 1971June 9, 1972

September 13, 1972September 25, 1972September 29, 1972October 1972March 28, 1973May 4, 1973July 15, 1973August 24, 1973August 26, 1973February 6, 1974July 30, 1974September 5, 1974October !3 , 1974October 21, 1974November 1974December 24, 1974

1975-77-80June 1975

June 1975

July 11, 1975August 1, 1975

September 14, 1975October 7, 1975March 18, 1976

April 5, 1976June 1976

June 3, 1976

August 1976

* January-December 1983 PROGRESS AT LAMPF 2 1 1Los Alamos Nallmel Liborttory

MILESTONES

(Continued)

Experiment in Atomic Physics (H~ + laser beam):Observation of Feshbach and Shape Resonances in H~

Double Charge Exchange in 16O: LEP ChannelStart Up of Isotope Production FacilityHRS Operation BeginsMaintenance by "Monitor" System of Remote HandlingProton Beam to WNRPolarized Proton Beam AvailableSpinoff: First Practical Applications Patent Licensed to

Private IndustryPion Radiotherapy with Curative IntentProton-Computed Tomography ProgramExperimental Results at Neutrino FacilityCloud and Surface Muon Beams: SMC ChannelEPICS Operation Begins300-uA Production Beam in Area AAT Division Establishedjt° Spectrometer Begins OperationOperation of Polarized-Proton TargetSuccessful Water-Cooled Graphite Production TargetSpinoff: First Thermal Modification of Human Cornea

(University of Oklahoma)600-uA Production Beam in Area ANew Limit on u —*• eyExperimental Measurement of the Strong-Interaction Shift

in the 2p-\s Transition for-Pionic HydrogenCommercial Production of RadioisotopesSpin Precessor Begins OperationData-Analysis Center OperationalVariable-Energy OperationSingle-Isobaric-Analog States in Heavy NucleiSpinoff: First Use of F2Rb for Brain Tumor Imaging in Humans

(Donner Laboratory, Lawrence Berkeley Laboratory)Production of Fast Muonium in VacuumDouble-Isobaric-Analog States in Heavy NucleiFocal-Plane Polarimeter Operational at HRSSafety Award to LAMPF Users Group, Inc., for Working

One Million Man-Hours Since 1975 Without aDisabling Injury

New Measurement of Pion Beta Decay —

Improved Test of Conserved Vector CurrentFirst Excitation of Giant Dipole Resonance by

Pion Single-Charge ExchangeFirst Excitation of Isovector Monopole Resonance in

120Sn and 90Zr by Pion Single-Charge Exchange

October 1976October 5. 1976October 15, 1976November 1976Fall 1976March 12, 1977April 1977

April 12, 1977May 1977June 1977July 1977July 1977August 1977Fall 1977January 1, 1978February 1978Spring 1978November 1978

July 11, 1979Novembei 1979December 1979

1980-81-82January 1980February 1980April 1980June 1980June 1980

September 1980Fall 1980October 1980October 1980

October 27, 1980

November 1980

March 1981

March 1981


January-Dacambar 1983

MILESTONES

(Continued)

Search for Critical Opalescence in "Ca September 1981Average Beam Current of LAMPF Accelerator Established

at75O»iA 1982Staging Area Constructed 1982Particle Separator Installed at Stopped Muon Channel 1982"Dia!-A-Spin" Capability on Line B Permits Different Spin

Orientations for HRS, Line B, and EPB Simultaneously 1982Time-Projection Chamber in Operation 1982Improved Test of Time-Reversal Invariance in

Strong Interactions January 1982Search for Parity Nonconservation inp-p Scattering November 1982d-t Fusion Catalyzed by Muons November 1982LAMPF Accelerator Produces Proton Beam of 1.2 mA February 7, 1983First Observation of vc-e~ Scattering October 1983

Jamary-Dtcimber 1983 PROGRESS AT UUHPF 2 1 3Los Alamos National Laboratory

APPENDIX A

EXPERIMENTS RUN IN 1983

Exp.No. Experiment Title Channel

BeamHow*

106 Proton-Induced Spallation Reactions Related AB-Nucchemto the Isotope Production Program at LAMPF

190 A Precision Measurement of then-mto LEPMass Difference

225 A Study of Neutrino-Electron Elastic Scattering

267 Preparation of Radioisotopes for Medicine and thePhysical Services Using the LAMPF Isotope ProouctionFacility

294 High-Energy Nuclear Reactions

308 An Attempt to Make Direct Atomic Mass Measure-ments in the Thin Target Area

392 A Measurement of the Triple-Scattering Parameters HRSD, R, A, R', and A' for Proton-Proton and Proton-Neutron Scattering at 800 MeV

400 Search for the Rare Decay u+ — e+e+e- SMC

449 Survey of the Single and Double Photodetachment SMCCross Section of the H- Ion from 14 to 21.8 eV

455 High-Precision Study of the u+ Decay Spectrum

465 Radiochemical Study of Pion Single Charge Exchange

470 Reactive Content of the Optical Potential

474 A Measurement of Spin-Dependent Effects inP + D Elastic and Inelastic Scattering

523 Studyof the 14C(T7+,TTO)14N Reaction

545 Fusion Materials Neutron Irradiatio: is. — A ParasiteExperiment

553 Study of Target Thickness Effects in the Cross-Section LEPMeasurement of the Pion Single-Charge-ExchangeReaction i3C(n+,n<>)i3N (g.s.) from 50 to 350 MeV

571 Muon Spin Rotation Studies of Dilute Magnetic SMCAlloys

587 Fundamental Experiments with Relativistic Hydrogen EPBAtoms: Exploratory Work

7.0

133.0

Neutrino Area

ISORAD

AB-Nucchem

Thin Target Area

692.0709.0

709.0692.0

16.0

70.0692.0

104.0

402.0329.0

112.0

P3

LEP

HRS

HRS

LEP

RADAMAGE-1

95.0

8.0

70.0

60.0

64.0

260.0

15.0

17.0

400.0



JmnutryDecembtr 1983


BeamHours

601 Determination of Isoscalar and Isovector Transition LEPRates for Low-Lying Collective States in *>Zr and2oepb by TT+ and n - Inelastic Scattering

626 Measurement of the Depolarization Parameters HRSDNN'. DLS'. and DSs- in Proton-Nucleus Scatteringat Very High Excitation Energies

635 Spin Measurements in pd Elastic Scattering

639 Muon-Spin-Rotation Study of Muon Bonding andMotion in Selected Magnetic Oxides

640 Transverse and Longitudinal Field uSR Measurementsin Selected Ternary Metallic Compounds

654 Measurement of the Spin-Rotation Parameter Q for800-MeV p -t 160, «°Ca, and aospb ElasticScattering

665 The Measurement of the Initial-State Spin-CorrelationParameters C|_L and CSL in n-p Elastic Scatteringat 500,650, and 800 MeV

675 Nuclear Distributions from the Study of the2p States of Pionic Atoms

681 Measurements of Large-Angle Pion-Nucleus Scatteringwith EPICS

685 Spin Correlations in the Reaction p (d ,d)p at 500 MeV

698 Ground-State Quadrupole Moments of DeformedNuclei

705 Study of Pion Absorption in 3He On and Above the P3

(3,3) Resonance

708 A Measurement of the Depolarization, the Polarization,and the Polarization Rotation Parameters and theAnalyzing Power for the Reaction pp — pn+n

709 Measurements of ANN. ASS, and ASL i n the Coulomb-Interference Region at 650 and 800 MeV

724 Measurement of the Lamb Shift in Muonium

727 Measurement of the Efficiency of Muon Catalysis inDeuterium-Tritium Mixtures at High Densities

728 Study of Pion Charge-Exchange Mechanisms byMeans of Activation Techniques

730 Pion Production in Pion-Nucleon and Pion-Nucleus P3Interactions

735 Pion-lnduced Emission of Light Nuclear Fragments LEP

741 Investigation of the Longitudinal-Spin Response of HRS2°flPb and Implications of Spin-Transfer Form Factorsfor Non-Nucleon Degrees of Freedom in Nuclei

414.0

154.0

EPB

SMC

SMC

HRS

AB-Nucchem

Biomed

EPICS

HRS

Biomed

166.0

44.0

102.0

153.0

727.0175.0

126.0

266.0

447.0

157.0

283.0

EPB

HRS

SMC

Biomed

P3

608.043.0

43.0

522.0

380.0

341.0

88.051.0


16.0

173.0

189.0

PftOQAEMATLAMPF 2 1 5{.osAfemot Nation* Laboratory


Biomed

EPICS

P3

ISORAD

BumHour*

284.0

357.0

641.0

570.0692.0

745 Hexadecapole Moments in Uranium: 233(j and *3«U

749 i6O(rr+,n-)i6Ne (g.s.) Angular-DistributionMeasurements at Tn = 120 MeV andV, = 200 MeV

750 Inclusive n+ and IT- Double Charge Exchange on "Heft

765 800-MeV Proton Irradiation of Materials for theSIN Beam Stop

780 A Study of the Double-Charge-Exchange Reactionsi4C(TT-,n+)i"Beand i

783 Pion-lnduced Pion Production on Deuterons

789 Two-Nucleon-Out Products Following the Absorption ofof 10-MeV n+ in

792 Measurement of Parity Violation in the p-p andp-Nucleon Total Cross Sections at 800 MeV

796 Core Excitation Effects in Pion Double Charge Exchange

798 Fission Induced by Energetic n* Particles

808 0° Excitation Functions for n - p — nt>n

EPICS

P3

LEP

EPB

EPICS

LEP

LEP

220.0

242.0

7.9

176.0351.0

328.0

61.0

71.0

2 1 6 MOGHESSATLAMPFLos Alamos National Laboratory

January-D»c*mb»r 1963

APPENDIX B

NEW PROPOSALS

ProposalNo. TiH* Spokesmen

M. CooperD. Fitzgerald

G. S. BlanpiedJ.-P. Egger

B. G. Ritchie

R. J. Peterson

J. J. KraushaarR. J. Peterson

M. BlecherM. Hynes

D. V. Bugg

R. D. Brown

A. AziziM. BleszynskiG. Igo

Institutions

Los AlamosLos Alamos

Univ. of South CarolinaUniv. of Neuchatel,Switzerland1

Univ. of Maryland

Univ. of Colorado

Univ. of ColoradoUniv. of Colorado

VPI and State Univ.Los Alamos

Queen Mary College,London

Los Alamos

UCLAUCLAUCLA

808 0° Excitation Function for i rp - • n°n

809 Study of <r,p and n\p Reactions with EPICS

810 Test Channel

811 Study of Unnatural-Parity States in Nuclei Using Low-Energy Pions

812 Back-Angle Charge Asymmetries for Elasticir-Deuteron Scattering

813 Pion Charge Asymmetries for "C at Low BeamEnergies on the LEP Spectrometer

814 n±-Nuclear Elastic Scattering from Nickel and TinIsotopes at Energies Between 30 and 80 MeV

815 Measurement of Am, ASI, and Au in pp -* pnn+ at 500,580, 650, 720, and 800 MeV

816 Radiation Effects on the Field Strength of Samarium-Cobalt Permanent Magnets

817 I. Elastic Scattering of Polarized Protons from 3H atIntermediate Energy

818 Proton-Deuteron Elastic Scattering at 800-MeV Two-and Three-Spin Observables

819 II. Elastic Scattering of Polarized Protons from 3H atIntermediate Energy

820 Pion-lnduced Pion Production on 3He

821 Pion Charge Exchange to Delta-Hole States ofComplex Nuclei

822 Inelastic n+ and n~ Scattering on "Ca at 50 and 75 MeV

823

G. Igo

Development of an {n,p) Reaction Capability at Area Bor Beam Line O

UCLA

A. AziziM. BleszynskiG. Igo

E. PiasetzkyP. A. M. GramG. A. Rebka, Jr.J. Lichtenstadt

R. J. Peterson

J. J. KraushaarJ. L. Ullmann

N. S. P. KingP. LisowskiJ. D. BowmanJ. Shepard

UCLAUCLAUCLA

Los AlamosLos AlamosUniv. of WyomingTel Aviv Univ.

Univ. of Colorado

Univ. of ColoradoUniv. of Colorado

Los AlamosLos AlamosLos AlamosUniv. of Colorado

'Jtnuary-Dtcimbtr 1863 PROGRESS AT LAMPF 2 1 7Lot Alums NMonl LabonKxy

ProposalHo. TUte SpoicoMnon

824 A Study of Low-Energy Pion Scattering as a Probe ofNuclear Magnetic Dipole Excitation

825 Investigation of the /VA Interaction Via n+o1-* pn+n

826 Isospin Dependence of Nonanalog Pion DoubleCharge Exchange

827 Study of Isobaric-Analog States in PionSingle-Charge-Exchange Reactions in the 300- to500-MeV Region

828 Total and Differential Cross Sections for n*d -> ppBelow 20 MeV

829 A Measurement of the Width and Position of the A**Resonance in *Li and 12C

830 The Reaction (ir.np) on 3He and 4He at Energies Abovethe (3,3) Resonance

831 The \n*,p[pp)] Reaction on Light Nuclei

832 Gamma-Ray Angular Correlation froml2C(p,p')"C*(15.11 MeV)

833 Continuation of the Investigation of Large-AnglePion-Nucleus Scattering

834 The Pion-Nucleus Interaction Studied with the At ->• 3dTransition of Rare-Earth Plonic Atoms

H. E. Jackson

G. S. Mutchler

C. L. MorrisC. Fred MooreR. Gilman

J. AlsterH. W. BaerE. PiasetzkyU. Sennhauser

K. GotowR. C. Minehart

K. Ziock

R. Minehart

C. F. PerdrisatR. Minehart

B. J. LiebC. F. PerdrisatH. 0 . Funsten

G. R. Burleson

Y. TanakaR. M. SteffenE. B. Shera

Argonne

Rice Univ.

Los AlamosUniv. of TexasUniv. of Pennsylvania

Tel Aviv Univ.Los AlamosLos AlamosLos Alamos Natl. Lab.

VPI and State Univ.Univ. of Virginia

Univ. of Virginia

Univ. of Virginia

College of William & MaryUniv. of Virginia

George Mason Univ.College of William & MaryCollege of William & Mary

New Mexico State Univ.

Purdue Univ.Purdue Univ.Los Alamos

835 Target Mass Dependence of the IsovectorContribution to the Giant Quadrupole Resonance

836 Energy Dependence of Pion Scattering to the GiantResonance Region of 2MPb

837 Measurement of Spin-Flip Cross Sections up to40-MeV Excitation in MNi and MZr

838 Pion-lnduced Pion Production on Nuclei at 400 MeV

839 Pion Inelastic Scattering from the 1* Doublet in "C

840 Inelastic Pion Scattering f rom "O at Tu = 120and 200 MeV

841 Forward-Angle Pion Inelastic Scattering on LightNuclei

842 MSR Shift and Relaxation Measurements in ItinerantMagnets

2 1 8 PROGRESS AT LAMPfLos Alunos Nation*! Lmbontory

S. J. Seestrom-Morris Univ. of Minnesota

S. J. Seestrom-Morris Univ. of Minnesota

C. GlashausserS. Nanda

M. J. LeitchE. Piasetzky

C. F. MooreC. L. Morris

L. C. BlandH. T. Fortune

L. C. BlandC. F. MooreH. T. Fortune

L. C. GuptaR. H. HeffnerD. E. MacLaughlin

Rutgers Univ.Rutgers Univ.


Univ. of TexasLos Alamos

Univ. of Texas, AustinUniv. of Pennsylvania

Univ. of Texas, AustinUniv. of Texas, AustinUniv. of Pennsylvania

Tata Inst., IndiaLos AlamosUniv. of Calif., Riverside

Jmnumry-Ometmbt 1t§i

XProposal

No. Titfc IntlHutiom

843 A Search for A33 Components of Ground-StateNuclear Wave Functions

844 Measurement of Am, A,t, and Alt for the Reactionpip —• p + n + TI* at 800 MeV

845 Plon Inelastic Scattering from 'Be

846 NW-* NAM: Cross Sections and Analyzing Powers forthe 800-MeV pp - * n*{np) and pn -* n-(pp) InclusiveReactions

847 A Precision Test of Nuclear Charge Symmetry

848 In-Flight Absorption of Low-Energy Negative Pions

849 A. Measurement of the Differential Cross Section forrr'p -f n°n at 0 and 180° in the Momentum Region471-687 MeV/cB. Test of Isospin Invariance in nW Scattering at 180° inthe Momentum Region 471-687 MeV/c

850 Study of the Mass and Energy Dependence of Low-Energy Plon Single Charge Exchange at 0°

651 Search for Recoil-Free A Production and High-SpinStates in the 2OtPb(p, f) IMPb Reaction at ED = 400 MeV

852 Measurements of (n=,n) Reactions on Nuclear Targetsto Study the Production and Interaction of n Mesonswith Nuclei

853 Measurement of Wolfenstein Parameters at 650 MeVand da/dQ at 500, 650, and 800 MeV for pd—*pdElastic Scattering

854 Muon Spin Research in Oxide Spin Glasses

855 Measurement of 2MPb-2O1Pb Ground-State NeutronDensity Difference

856 Comparison of Double Charge Exchange andInclusive Scattering in 3He

857 Inelastic Pion Scattering from "O at 7"n = 50 MeV

858 Additional Measurements of "O(n+, n-)"Ne(g.s.)

859 Study of the A Dependence of Inclusive Pion DoubleCharge Exchange in Nuclei

860 Inelastic n1 Scattering to Excited 0* States at EnergiesBetween 30 and 80 MeV

"' JtnutryCHctmbw 1963

C. L. MorrisC. F. Moore

G. PaulettaM. GazzalyN. Tanaka

J. J. Kelly

T. S. BhatiaG. Glass

T. S. BhatiaJ. C. Hiebert

Y. Ohkubo

D. H. FitzgeraldW. J. BriscoeM. E. Sadler

F. IromM. J. Leltch

N. M. Hintz

J. C. Peng

G. S. WestonG. J. Igo

C. BoekemaD. W. Cooke

N. Hintz

P. A. M. GramJ. L. MatthewsG. A. Rebka, Jr.

L. C. BlandC. F. Moore

H. T. FortuneR. Gilman

P. A. M. GramJ. L. MatthewsG. A. Rebka, Jr.

B. M. PreadomC. S. Whisnant

Los AlamosUniv. of Texas

UCLAUniv. of MinnesotaLos Alamos

Los Alamos

Texas A&M Univ.Texas A&M Univ.

Texas A&M Univ.Texas A&M Univ.

Los Alamos

Los AlamosGeorge Washington Univ.Abilene Christian Univ.


Univ. of Minnesota

Los Alamos

UCLAUCLA

Texas Tech Univ.Los Alamos

Univ. of Minnesota

Los AlamosMITUniv. of Wyoming

Univ. of Texas, AustinUniv. of Texas, Austin

Univ. of PennsylvaniaUniv. of Pennsylvania

Los AlamosMITUniv. of Wyoming

Univ. of South CarolinaUniv. of South Carolina

PMXMESSATLAMPFLos Alamos NUiontl laboratory

219

ProposalNo. Titte Spokesman

L. C. Northcliffe

S. K. NandaD. K. Dehnhard

A. SahaK. K. Seth

A. SahaK. K. Seth

B. AasM. BleszynskiG. Igo

R. HausammannJ. Donahue

A. SahaK. K. Seth

K. K. Seth

V. W. HughesA. BadertscherM. W. Gladisch

J. M.Wouters

B. J. LiebH. 0. Funsten

D. S. Brenner

E. B. SheraA. R. Kunselman

C. L. BlilieD. Dehnhard

InstihitioM

Texas A&M Univ.

Univ. of MinnesotaUniv. of Minnesota

Northwestern Univ.Northwestern Univ.


UCLAUCLAUCLA

Univ. of Calif., IrvineLos Alamos


Northwestern Univ.

Yale Univ.Yale Univ.Heidelberg Univ.

Los Alamos

George Mason Univ.College of William & Mary

Clark Univ.

Los AlamosUniv. of Wyoming

Univ. of MinnesotaUniv. of Minnesota

861 Measurements of the Spin-Correlation Parameter'We) forn-p Elastic Scattering at 800 MeV

862 Study of the M1 Transition in **Sr by the InelasticScattering of n* and rr

863 Study of Giant Resonances in the Palladium IsotopesVia Pion Scattering

864 Study of Deeply Bound Hole States in the Tin IsotopesVia the (p, d) Reaction

865 Spin-Rotation Measurement of 'He at 320, 500, and800 MeV

866 Neutrino Source Calibration

867 Measurement of Isovector Quadrupole TransitionDensities in the Palladium Isotopes

868 An Experimental Test of the A-Hole Model ofNonanaiog Double Charge Exchange

869 Higher Precision Measurement of the Lamb Shift inMuonium

870 Search for New Magic; Numbers: Direct MassMeasurements of the Neutron-Rich Isotopes withZ = 4to9

871 Coincident Nuclear y-Ray and Pionic X-Ray Study ofIT Absorption at Rest on "C

872 Direct Atomic Mass Measurements of Neutron-RichIsotopes in the Region Z= 13-17 Using theTime-of-Flight Isochronous Spectrometer

873 Pionic X-Ray Study of the Carbon Isotopes

874 Elastic Scattering of rt* from Deuterium in the Regionof the 3F3 Dibaryon Resonance


January-December T9K

APPENDIX C

ACTIVE AND COMPLETE EXPERIMENTS BY CHANNEL

BR NEUTRONS AND PROTONS

Exp.No. Titt* Spokesman

NORTHCLIFFESIMMONS

SIMMONS

SIMMONS

PtMMNO.*«Comp»«t«

1 •2 *

1 *

1 *2 *

BeamHours

0.00.0

996.8

343.4472.0

56 STUDY OF NEUTRON SPECTRUM FROM PROTON BOM-BARDMENT OF DEUTERIUM IN THE 300-600-MeV REGION

65 NEUTRON-PROTON POLARIZATION MEASUREMENTSUSING A POLARIZED TARGET — PHASE I: THEn-p POLARIZATION OBSERVABLE P(G)

66 NEUTRON-PROTON POLARIZATION MEASUREMENTSWITH A POLARIZED TARGET — PHASE II: THEn-p SPIN-CORRELATION OBSERVABLE CNN(9)

125 ELASTIC NEUTRON-PROTON BACK-ANGLE DIFFERENTIALCROSS-SECTION MEASUREMENTS 300-800 MeV

129 PION PRODUCTION IN NEUTRON-PROTON COLLISIONS

189 SEARCH FOR CONDENSED NUCLEAR STATES ANDSTUDY OF HIGH-q2 LOW-v NUCLEAR INTERACTIONS

193 MEASUREMENT OF SMALL-ANGLE NEUTRON ELASTICSCATTERING FROM PROTONS

205 (n,p) CHARGE-EXCHANGE AND NEUTRON-INDUCEDQUASI-FREE SCATTERING ON LIGHT NUCLEI

255 MEASUREMENT OF o(9) FOR n-p ELASTIC SCATTERINGAT 460 MeV

262 TEST OF ISOSPIN INVARIANCE IN THE REACTIONnp - dn°

263 MEASUREMENT OF THE ENERGY AND ANGULARVARIATION OF THE np CHARGE-EXCHANGE CROSSSECTION

264 MEASUREMENT OF THE ENERGY VARIATION OF THE ndELASTIC DIFFERENTIAL CROSS SECTION NEAR 180°

27S TEST OF CHARGE SYMMETRY IN nd AND pdSCATTERING

360 THE MEASUREMENT OF THE POLARIZATION TRANSFERCOEFFICIENTS D, AND At AT 800 MeV FOR THE REACTIONSd(p ,n 2p, 6Li(p,n)6Be, AND 9Be(p,n)9B

366 NONRESONANT PION PRODUCTION IN THE REACTIONnp — n~pp

DIETERLE

McFARLANE

RILEYSIMMONS

MAYESMUTCHLER

1 *

1 *

0.0

WOLFE

VAN DYCK

DIETERLEMcFARLANE

KENEFICKRILEY

NORTHCLIFFE

BONNER

BONNER

3ONNER

DIETERLE

1 *

1 •

1 *2 *

1 *

1 *

1 '

1 *

1 *

F S -

319.0

0.0

1091.10.0

38.5

5.0

304.8

237.1

473.1

101.0

493.5

427.7

"FEASIBILITY STUDY.

jMnuary-December 1983 PMXMEMATLAMPFLotAltmot Nutonal Laboriory

221

Exp.No. TiU*

r n l f f Plw>

Spokesman

GLASSSIMMONS

BONNER

BHATIASIMMONS

McNAUGHTONWILLARD

PHILLIPS

1 *2 *

1 *2 *

1 *

1 *

1 '

tote Hours

166.183.8

0.0223.6

785.0

860.2

1568.0

402 A MEASUREMENT OF THE POLARIZATION TRANSFERCOEFFICIENTS D,(0°) AND A{(0°) IN THE REACTIONp p - nX AT 800 MeV

403 A MEASUREMENT OF THE TRIPLE-SCATTERINGPARAMETER D, FOR THE CHARGE-EXCHANGE REGIONIN np SCATTERING

457 MEASUREMENT OF THE QUASI-FREE pn AND ppAND FREE pp ANALYZING POWERS. 500-800 MeV

492 POLARIMETER CALIBRATIONS AND SEARCH FORENERGY-DEPENDENT STRUCTURE IN pp ELASTICSCATTERING VIA CROSS SECTION, ANALYZING POWER,AND WOLFENSTEIN PARAMETER MEASUREMENTS

504 MEASUREMENT OF THE TOTAL CROSS-SECTIONDIFFERENCE FOR PROTON-PROTON AND PROTON-NEUTRON SCATTERING IN PURE TRANSVERSEINITIAL SPIN STATES IN THE 400-800-MeV REGION

505 MEASUREMENT OF THE TRANSVERSE SPIN-SPINASYMMETRY IN THE REACTION pp - d n + IN THE500-800-MeV REGION

517 POLARIZED BEAM AND TARGET EXPERIMENTS IN THEp-p SYSTEM: PHASE 1. AY AND Ayv FOR THEdn + CHANNEL AND AYY FOR THE ELASTIC CHANNELFROM 500 TO 800 MeV

518 POLARIZED BEAM AND TARGET EXPERIMENTS IN THEp-p SYSTEM: PHASE 2. MEASUREMENTS OF Azz AND Axz

FOR THE drr+ CHANNEL AND FOR THE ELASTIC CHANNELFROM 500 TO 800 MeV

589 FREE-FORWARD np ELASTIC-SCATTERING ANALYZING-POWER MEASUREMENTS AT 800 MeV

590 MEASUREMENT OF D(9) IN p-n AND n-p SCATTERINGAT 800 AND 650 MeV AND OTHER ENERGIES WITHASSOCIATED p-p MEASUREMENTS

664 THE MEASUREMENT OF THE POURIZATION TRANSFERCOEFFICIENTS A? AND D, AT 500,650, AND 800 MeVFOR THE REACTION d(p,n)2p

665 THE MEASUREMENT OF THE INITIAL-STATE SPIN-CORRELATION PARAMETERS CLL AND CSL

IN n-p ELASTIC SCATTERING AT 500,650, AND 800 MeV

683 MEASUREMENT OF AaL IN FREE NEUTRON-PROTONSCATTERING AT 500,650, AND 800 MeV

739 P-A FOR 800-MeV np SCATTERING: TEST OF TIME-REVERSAL INVARIANCE IN STRONG INTERACTIONS

770 THE MEASUREMENT OF np ELASTIC-SCATTERING SPIN-CORRELATION PARAMETERS WITH L- AND S-TYPE POLAR-IZED BEAM AND TARGET BETWEEN 500 AND 800 MeV

PHILLIPS

SIMMONSJARMERNORTHCLIFFE


GLASSNORTHCLIFFE

SIMMONSNORTHCLIFFE

GLASSSTANEK

BURLESONWAGNER

DITZLERSIMMONS

BHATIAKENEFICK

SPINKABURLESON

1 *2

1

1

1

12

1

1

FS

12

1

860.20.0

1294.9

1409.0

0.0

330.00.0

426.0

1258.0

0.0

0.00.0

0.0

2 2 2 PftOQAESSATLAMPfLos Alamos National Laboratory

Jmvy-Otcvnbtr 1St3

Exp.No. Title Spokesman

PhaMNo.• = Complete Houw

847 A PRECISION TEST OF NUCLEAR CHARGE SYMMETRY

861 MEASUREMENTS OF THE SPIN-CORRELATION PARAMETERANN(9) FOR np ELASTIC SCATTERING AT 800 MeV-

BHATIAHIEBERT

NORTHCLIFFE

0.0

0.0

AREA B NUCLEAR CHEMISTRY (AB-Nucchem)


Phase No.* = Complete

BeamHoura

103 SPALLATION YIELD DISTRIBUTIONS FROM PIONINTERACTIONS WITH COMPLEX NUCLEI

104 PROPOSAL FOR LAMPF EXPERIMENT: STUDIES OF THEPROTON- AND PION-INDUCED FISSION OF MEDIUM-MASS NUCLIDES

105 NUCLEAR SPECTROSCOPY STUDIES OF PROTON-INDUCEDSPALLATION PRODUCTS

106 PROTON-INDUCED SPALLATION REACTIONS RELATED TOTHE ISOTOPE-PRODUCTION PROGRAM AT LAMPF

118 FRAGMENT EMISSION FROM PION INTERACTIONS WITHCOMPLEX NUCLEI

119 CROSS SECTIONS OF SIMPLE NUCLEAR REACTIONSINDUCED BY n MESONS

123 NUCLEAR STRUCTURE EFFECTS IN PION-INDUCEDNUCLEAR REACTIONS

150 SEARCH FOR POLYNEUTRON SYSTEMS

169 PROTON IRRADIATIONS FOR PROJECT JUMper

HUD1S 2 * 0.4

PATE

BUNKER

O'BRIEN

PORILE

KAUFMAN

KAROL

TURKEVICH

ORTHSATTIZAHN

2 *

1 * -2 *

1 "2

1 *2

2 •

1 *2 *

*- C

M

1 *

0.05.0

10.058.6

0.746.1

0.00.0

15.2

0.01.0

0.014.2

0.0

243 RECOIL STUDIES OF DEEP SPALLATION AND FRAGMEN-TATION PRODUCTS FROM THE INTERACTION OF 800-MeVPROTONS WITH HEAVY ELEMENTS

282 MEASUREMENT OF CROSS SECTIONS FOR PROTON-INDUCED FORMATION OF SPALLATION PRODUCTSIN COPPER BY ACTIVATION ANALYSIS

294 HIGH-ENERGY NUCLEAR REACTIONS

301 IMPAIRMENT OF SUPERCONDUCTING CHARACTERISTICSBY PROTON IRRADIATION

349 NUCLEAR REACTIONS OF 127I WITH PIONS

407 THE EFFECT OF DISLOCATION VIBRATION ON VOIDGROWTH IN METALS DURING IRRADIATION

PORILE 1 •

DONNERT

KAROL

WILSON

123

1

1

PORILE

SOMMERPHILLIPS

55.8

0.61.50.1

134.2

185.0

3.6

516.20.0

JmoMryDtcumbe: f 983 MKXMEM AT LAMPF 2 2 3Lot Altmoa Nmtonal Laboratory

Exp.No. Titta Spofcownwi • - C o m p t f Hotiw

410 RADIATION EFFECTS IN AMORPHOUS MF.TALS DUE TO800-MeV PROTONS

424 PRELIMINARY EXPERIMENTS FOR DOUBLE CHARGEEXCHANGE AND ftj~ ,e+)SEARCHES

465 RADIOCHEMICAL STUDY OF PION SINGLE CHARGEEXCHANGE

579 A RADIOCHEMICAL STUDY OF NEUTRON-DEFICIENTPRODUCTS OF 238U FROM 500 MeV

603 SEARCH FOR DELTAS IN A COMPLEX NUCLEUSBY A RADIOCHEMICAL TECHNIQUE

610 USF OF LAMPF BEAM STOP TO OBTAIN M F e

629 FEASIBILITY OF HELIUM-JET TECHNIQUES FORSTUDYING SHORT-LIVED NUCLEI PRODUCED AT LAMPF

679 A RADIOCHEMICAL STUDY OF THE 209Bi(p,n°)z10Po,209Bi(p,n-xn)210-xAt,ANDZO9Bi(p,p2n-xn)il09->lAtPION PRODUCTION REACTIONS AT 500-800 MeV

690 SIMULATIONS OF COSMIC-RAY-PRODUCEDGAMMA RAYS FROM THICK TARGETS

728 STUDY OF PION CHARGE-EXCHANGE MECHANISMSBY MEANS OF ACTIVATION TECHNIQUES

762 COMPONENT IRRADIATION

789 TWO-NUCLEON-OUT PRODUCTS FOLLOWING THEABSORPTION OF 10-MeV n + in 26Mg AND 74Ge

COST 583.0

TURKEVICHWARREN

RUNDBERG

FAUBEL

TURKEVICH

HENNINGKUTSCHERA

GREENWOODBUNKERTALBERT, J.

DAURIAWARD

1 *

1 *

1

1 *2

1

1 *2

1

8.0

0.5

0.8

38.5234.0

0.0

47.5135.0

9.4

REEDY 0.0

GIESLER

HOLTKAMPJOSEPH

OHKUBO

1• 1

2

1

1

52.058.00.0

0.0

0.0

BIOMEDICAL PION AND MUON CHANNEL (BIOMED)

Exp.No. Ti«« Spc!c«*man

CARLSON

PHILLIPS

KLIGERMANKNAPP

KNOWLES

ZIOCK

Phase No.*=Compf«t«

1 •

1 *

1 *2 *3 *

1 *

1 *

B M mHours

75.0

0.0

0.00.00.0

8.0

0.0

44 RADIOBIOLOGY OF n " MESONS, A PRELIMINARY STUDY

84 QUALITY OF MESON RADIATION FIELDS

143 STUDY OF THE RADIOBIOLOGICAL PROPERTIES OFNEGATIVE PIONS

151 AN INVESTIGATION OF PION DOSIMETRY BY PASSIVEPARTICLE DETECTORS

167 HEAVY FRAGMENT FORMATION FOLLOWING THEABSORPTION OF n ~ IN 12C


Januvy-Dtcvrtbi 1983

Exp.No. Title Spotcinrn

PtMMNO.•=Compete

B M H I

Hours

171 STUDY OF NEGATIVE-PION BEAMS BY MEANS OFPLASTIC NUCLEAR TRACK DETECTORS

167 NUCLEAR GAMMA RAYS PRODUCED BY NEGATIVEP1ONS STOPPING IN CARBON, NITROGEN, OXYGEN,AND TISSUE

195 NUCLEAR RESONANCE EFFECT IN PIONIC ATOMS

196 A VISUALIZATION EXPERIMENT WITH CHARGEDPARTICLES

198 EFFECTS OF PIONS ON DNA OF NONDIVIDING CELLSYSTEMS

207 MEASUREMENT OF NEUTRON SPECTRUM AND INTENSITYRESULTING FROM IT" CAPTURE IN WATER PHANTOMAND HUMAN TISSUE

209 PION INTERACTIONS IN NUCLEAR EMULSIONS

212 COMPARATIVE EFFECTIVENESS OF NEGATIVE PIONSvs 2 K Cf IN A TUMOR-ANIMAL SYSTEM

215 VISUALIZATION OF STOPPING PION DISTRIBUTION

217 n" PRODUCTION CROSS SECTIONS

218 PION DOSIMETRY WITH NUCLEAR EMULSIONS ANDALANINE

235 RADIATION REPAIR OF NORMAL MAMMALIAN TISSUES

236 BIOLOGICAL EFFECTS OF NEGATIVE PIONS

239 STUDY OF 11C AND 13N PRODUCTION BY n"IRRADIATION OF CARBON, NITROGEN, OXYGEN, ANDTISSUE FOR RADIOTHERAPY MONITORING

242 SURVIVAL OF SYNCHRONIZED CULTURED HUMANKIDNEY T-1 CELLS EXPOSED TO STOPPING PIONSAND X RAYS AT VARIOUS TIMES AFTER MITOSIS

244 SYSTEMS DEVELOPMENT FOR EFFICIENT UTILIZATIONOF HIGH-PURITY GERMANIUM MOSAIC DETECTORSFOR TUMOR UTILIZATION

270 THERAPY BEAM DEVELOPMENT — BIOMEDICALCHANNELTUNING

271 THERAPY BEAM DEVELOPMENT — DOSIMETRY

272 THERAPY BEAM DEVELOPMENT — MICRODOSIMETRY

273 THERAPY BEAM DEVELOPMENT — LET MEASUREMENTS

274 PION RADIOBIOLOGY

mmiary-Dtcsmbar 1983

BENTON

BEIDY

TODD

BRILL 1 *

0.0

21.6

LEONREIDY

DANIELREIDY '

POWERS

BRADBURYALLRED

BRADBURYALLRED

MEWISSEN

PEREZ-MENDEZBRADBURY

PACIOTTI

KATZ

GILLETTE

RAJU

FRIEDLANDMAUSNER

1 •

2 *

1 •

1 •

1 •

1 *

1 *

1

1

1

1 '

1

1 *2 *

0.0155.2

0.0

0.0

0.0

0.0

0.0

172.1

5.9

0.0

68.4

556.0

55.08.0

105.5

0.0

PACIOTTI

SMITH

DICELLO

BUSH

1

1

1 *

1 •

1 *

992.8

3225.1

566.2

783.7

2910.0

PROGRESS AT LAMfF 2 2 5Los Altmos Nttiofml Ltborttory

Exp.No. TrUe Spokesman

BUSH

MAUSNER

DANIELLEON

LEONMAUSNER

PHILLIPSGOLDSTEIN

Phase No.'-Complete

1 *

1 *

1 *

1 •

1 *

BeamHours

7297.4

13.0

37.0

9.2

52.1

275 PION CLINICAL TRIALS

285 MIGRATION OF " C AND 13N RADIOACTIVITYPRODUCED IN VIVO BY n "

300 n " COULOMBCAPTUREANDrTTRANSFERINTISSUE, TISSUE-EQUIVALENT LIQUID, AND SIMPLECOMPOUNDS

304 STUDY OF THE AUGER PROCESS IN PIONIC ATOMS

380 RBE AND OER FOR NORMAL AND TUMOR TISSUES

384 BIOLOGICAL INTERCOMPARISON OF n ~ THERAPY BEAMSAT TRIUMF AND LAMPF USING MOUSE TESTES AS ABIOLOGICAL TEST SYSTEM

675 NUCLEAR DISTRIBUTIONS FROM THE STUDY OF THE 2PSTATES OF PIONIC ATOMS

698 GROUND-STATE QUADRUPOLE MOMENTS OF DEFORMEDNUCLEI

727 MEASUREMENT OF THE EFFICIENCY OF MUON CATALYSISIN DEUTERIUM-TRITIUM MIXTURES AT HIGHDENSITIES

732 HEAVY ELEMENT FISSION INDUCED BY ENERGETIC PIONS

745 HEXADECAPOLE MOMENTS IN URANIUM: 233U AND 234U

GERACI 23.7

KUNSELMAN

STEFFENSHERA

JONES

PETERSONRISTINEN

ZUMBROSHERA

1

1 *3

12

1 •2

14

126.0

305.00.0

919.0341.0

271.00.0

565.00.0

763 NATURE OF OXYGEN CONTAMINATION IN TITANIUM WITHSTOPPED MUONS

TAYLOR 259.0

787 MUON CHANNELING FOR SOLID-STATE PHYSICSINFORMATION

834 THE PION-NUCLEUS INTERACTION STUDIED WITH THE 4f - 3dTRANSITION OF RARE-EARTH PIONIC ATOMS

MAIERPACIOTTIFLIK

TANAKASTEFFENSHERA

0.0

0.0

BEAM STOP A RADIATION (BSA-RAD)


DUDZIAKGREENGIORGI

HILL

Phase No.*=Complete

1 *2 *

1 '2 *

BeamHours

0.01833.0

0.010.8

45 RADIATION-DAMAGE STUDIES — HIGH-TEMPERATUREREACTOR MATERIALS AND TYPE II SUPERCONDUCTORS

111 SEARCH FOR NEW NEUTRON-RICH NUCLIDES PRODUCEDBY FAST NEUTRONS

2 2 6 PROGRESS AT LAMPFLos Almmos Ntlionml Laboratory

Exp.No. Till*

PhmNo.Spofcwmwi Hours

113 RADIATION DAMAGE AND HELIUM EMBRiTTLEMENT IN MICHELELEVATED-TEMPERATURE REACTOR STRUCTURAL ALLOYS

161 THE MICRODISTRIBUTION OF THORIUM IN METEORITES

174 INVESTIGATION OF THE CHEMICAL REACTIONSOF ATOMIC 18F AS A MEANS FOR DIRECT SYNTHESISOF 18F-LABELED COMPOUNDS

326 ELECTRICAL COMPONENT RADIATION-EFFECTS STUDY

406 NEUTRON FLUX CHARACTERIZATION AT A-6 RADIATION- HARVEYEFFECTS FACILITY

415 TWO-NUCLEON-OUT PRODUCTS FROM STOPPED n - ORTHINTERACTIONS

467 IRRADIATIONS IN SUPPORT OF FERFICON STUDIES

542 FEASIBILITY STUDY: USING AN EXISTING NEUTRONBEAM PIPE AT LAMPF BEAM STOP FOR CRYSTALDIFFRACTION SPECTROMETER EXPERIMENTS

545 FUSION MATERIALS NEUTRON IRRADIATIONS —A PARASITE EXPERIMENT

554 IRRADIATION OF TECHNOLOGICALLY IMPORTANTMETALS WITH 800-MeV PROTONS USING THEISOTOPE PRODUCTION FACILITY AT LAMPF

560 STUDY OF NEUTRON-IRRADIATION-INDUCED GROWTH HARVEYOf METALS AT RADIATION-EFFECTS FACILITY

691 SIMULATION OF COSMIC-RAY PRODUCTION OF NUCLIDES REEDYBY SPALLATION-PRODUCED NEUTRONS

769 PROTON IRRADIATION EFFECTS ON CANDIDATE LOHMANNMATERIALS FOR THE GERMAN SPALLATION SOMMERNEUTRON SOURCE (SNQ)

816 RADIATION EFFECTS ON THE FIELD STRENGTH OF BROWNSAMARIUM-COBALT PERMANENT MAGNETS

1 •

0.0

BURNETT

ROWLANDMILLER

HARVEY

1

1 '2 *

11

11.7

0.07.0

179.9294.5

1306.3

0.0

GILMORE

LU

BROWN

BROWNCOST

1

1 •2

12

12

0.4

699.70.0

0.00.0

75.20.0

63.4

0.0

0.0

0.0

Exp.No. Title

EXTERNAL PROTON BEAM (EPB)

Spoketman

26 NEUTRON TIME-OF-FLIGHT EXPERIMENT AT BEAM STOP

27 p-p SPIN-CORRELATION EXPERIMENTS

42 BREAKUP OF FEW-NUCLEON SYSTEMS AND NUCLEI

81 STUDY OF N EUTRON-PROTON AND PROTON-PROTONCOINCIDENCE SPECTRA FROM p + d — n + p + p REACTION

PhaM No. (team* = Complat* H o w

VEESER

WILLARD

COLE

PHILLIPS

1 *

1 *2 *

1 •

1 *2 *

0.0

0.01141.8

530.8

0.0600.5

MwvyDKtmber 1983 PMOHEM AT LAMPF 2 2 7Lot Mvi.ot NMiontl Laboratory

Exp.No. THte Spokwwn

PhaMNo.Hours

128 WNR STORAGE RING STRIPPER EXPERIMENT

137 SEARCH FOR PARITY-VIOLATING CONTRIBUTIONTO SCATTERING OF HADRONS

153 INVESTIGATION OF NUCLEAR GAMMA RAYS RESULTINGFROM IN-FLIGHT PION AND PROTON REACTIONS

159 CHARGED-PARTICLE EMISSION IN PROTON-INDUCEDREACTIONS AS A FEASIBILITY STUDY IN THE USE OFINTRINISIC GERMANIUM DETECTORS WITH THEPRIMARY LAMK." BEAM

176 p-NUCLEUS TOTAL AND TOTAL REACTION CROSS-SECTION MEASUREMENTS

192 MEASUREMENT OF THE EMITTANCE GROWTH INH~ STRIPPING

194 p-p, D, R, AND A MEASUREMENTS

197 INVESTIGATION REACTION p + d — 3He + n°AT LAMPF ENERGIES

200 STUDY OF THE PHOTODETACHMENT SPECTRUM OFH ~ IN THE VICINITY OF 11 eV

219 DOUBLE PION PRODUCTION IN PROTON-PROTONSCATTERING

223 STUDIES OF THE (p.np) CHARGE-EXCHANGE REACTION

241 DIRECT LEPTON PRODUCTION AT LAMPF ENERGIES

278 STUDY OF REACTION MECHANISMS USING INTERNALCONVERSION TECHNIQUES

279 TEST OF CHARGE SYMMETRY IN nd AND pdSCATTERING

289 MEASUREMENT OF THE PHASE OF THE FORWARDNUCLEON-NUCLEON SPIN-INDEPENDENT ELASTIC-SCATTERING AMPLITUDE AT 800 MeV

323 STARK-EFFECT QUENCHING OF RESONANCES INTHE PHOTODISINTEGRATION OF THE H " ION

336 STUDY OF THE SPIN DEPENDENCE OF PROTON-PROTON PION-PRODUCTION REACTIONS

339 SURVEY OF PHOTODETACHMENT CROSS SECTIONOF H " FROM THRESHOLD TO 15 eV AND ITS DEPENDENCEUPON ELECTRIC FIELD

341 STUDY OF pd — drr+ n REACTION MECHANISMS

HAYWARD

NAGLEMISCHKEFRAUENFELDER

EISENSTEIN

EISENSTEIN

1 -

1 *2 *3 •

1 *

1 *

O.f

316.6363.4346.5

0.0

0.0

ANDERSON

HAYWARD

McNAUGHTON

HUNGERFORD

BRYANT

BEVINGTON

HOFFMANN

HOFFMANMISCHKE

HOFFMANNMOORE

DIETERLEMcFARLANE

WHITTEN

BRYANTGRAM

MUTCHLERPINSKY

BRYANTGRAM

PHILLIPS

1 •2 *

1 *

1 •2 *

1 •

1 *

1 *

FS*

1 *

1 •

FS*1 *

1 *

1 *

1 *2 *

1 *

1 *

0.0296.6

70.0

185.2498.5

363.0

128.8

422.0

66.3

531.2

53.0

67.00.0

354.6

350.6

419.4747.0

1363.1

229.0


Jtnmy-Dtctmbtr T4

Exp.NO.

392

449

Title

A MEASUREMENT OF THE TRIPLE-SCATTERING PARAMETERSD, R, A, R', AND A' FOR PROTON-PROTON AND PROTON-NEUTRON SCATTERING AT 800 MeV

SURVEY OF SINGLE AND DOUBLE PHOTODETACHMENTCROSS SECTION OF THE H~ ION FROM 14 TO 21.8 eV

Spokesman

HOFFMANNBONNER

BRYANTDONAHUE

PhaMNo.*=Complete

5 *

1 •2 '

BeamHows

87.0

570.7229.9

468 MECHANISMS OF LUMINESCENCE INDUCED BY PROTONS BECHERINCIDENT ON ULTRAVIOLET GRADE OPTICAL MATERIALS

492 POLARIMETER CALIBRATIONS AND SEARCH FORENERGY-DEPENDENT STRUCTURE IN pp ELASTICSCATTERING VIA CROSS SECTION, ANALYZING POWER,AND WOLFENSTEIN PARAMETER MEASUREMENTS

498 MEASUREMENTS OF LONGITUDINAL CROSS-SECTIONDIFFERENCE FOR LONGITUDINAL POLARIZED BEAMAND TARGETS (pp, pd, np)

512 PROTON-PROTON ELASTIC-SCATTERING MEASUREMENTSOF THE ASs(6), ALL(9), AND ASL(6) SPIN-CORRELATIONPARAMETERS AT 500,650, and 800 MeV

530 H - MAGNETIC STRIPPING RATES

586 A STUDY OF THE EFFECTS OF VERY STRONG ELECTRICFIELDS ON THE STRUCTURE OF THE H~ ION

587 FUNDAMENTAL EXPERIMENTS WITH RELATIVISTICHYDROGEN ATOMS: EXPLORATORY WORK

588 A SEARCH FOR LONG-LIVED STATES OF THE H " ION

591 AN INVESTIGATION OF INCLUSIVE ONE-PIONPRODUCTION IN PROTON-NUCLEUS COLLISIONS

592 AN INVESTIGATION OF TWO-PION PRODUCTIONAND CORRELATIONS IN PROTON-NUCLEUS COLLISIONSAT 800 MeV

633 MEASUREMENT OF p-p ELASTIC SCATTERING INTHE COULOMB INTERFERENCE REGION BETWEEN300 AND 800 MeV

634 MEASUREMENT OF PARITY VIOLATION IN THEp-NUCLEON TOTAL CROSS SECTIONS AT 800 MeV

635 SPIN MEASUREMENTS IN pd ELASTIC SCATTERING

636 A MEASUREMENT OF THE WOLFENSTEIN POLARIZATIONPARAMETERS DLL, DSL, KLL, AND KSL FOR p-p ELASTICSCATTERING

637 A MEASUREMENT OF THE VECTOR POLARIZATION BONNEROF THE DEUTERON IN THE REACTION pp — drt+

1 • 70.8

McNAUGHTONWILLARD

WAGNERBURLESON

GREENEIMAI

JASON

BRYANTGRAM

SMITHDONAHUE

CLARKBRYANT

DEVRIESDiGIACOMO

DEVRIESDiGIACOMO

PAULETTAIROM

CARLINITALAGAYUAN

BONNERIGOBLESZYNSKI

HOLLAS

1 *

1 *23

- N U- N U1 *

1 *

12

1 *2 *4

1

1 *2

1

1

1 •Q.

12

1

0.0

1664.50.00.0

0.00.0

835.0

237.2

517.00.0

400.00.00.0

0.0

651.1243.0

4 o.o

0.0

299.2, i 471.0

i

507.7622.0

683.0

430.0

jnuary-Decembar 1983 PflOOIIESSATLAMPFLot Alamos NMional LtoorXory

229

Exp.No. TM* Spokesman

P I M M No.•=Complete Hours

708 A MEASUREMENT OF THE DEPOLARIZATION, THEPOLARIZATION, AND THE POLARIZATION ROTATIONPARAMETERS AND THE ANALYZING POWER FOR THEREACTION pp — pn+n

792 MEASUREMENT OF PARITY VIOLATION IN THE p-p ANDp-NUCLEON TOTAL CROSS SECTIONS AT 800 MeV

815 MEASUREMENT OF ANO, A S L , AND ALL IN pp — pnn +

• AT 500, 580, 650, 720, AND 800 MeV

817 ELASTIC SCATTERING OF POLARIZED PROTONS FROM 3HAT INTERMEDIATE ENERGY

818 PROTON-DEUTERON ELASTIC SCATTERING AT 800-MeVTWO- AND THREE-SPIN OBSERVABLES

832 GAMMA-RAY ANGULAR CORRELATION FROM 12C(p ,p')12C(15.11 MeV)

866 NEUTRINO SOURCE CALIBRATION

HOLLAS

YUAN

BUGG

BLESZYNSKIAZIZIIGO

IGO

LIEBPERDRISATFUNSTEN

HAUSAMMANNDONAHUE

651:0.0

527.0

0.0

0.0

0.0

0.0

0.0

ENERGETIC PION CHANNEL SPECTROMETER (EPICS)


Phase No.•-Complete

BeamHours

9 ELASTIC AND INELASTIC PION SCATTERING FROMCALCIUM ISOTOPES

13 STUDY OF n + -INDUCED DOUBLE-CHARGE-EXCHANGEREACTIONS

14 n + AND n~ ELASTIC AND INELASTIC SCATTERINGFROM 16O

18 SURVEY OF n SCATTERING BY COMPLEX NUCLEI

23 A SURVEY OF PION-NUCLEUS ELASTIC ANDINELASTIC SCATTERING AT 180 MeV

39 SEARCH FOR (n,p) REACTIONS WITH EPICS

74 STUDY OF PION-INDUCED DOUBLE-CHARGE-EXCHANGEREACTIONS ON LOW-Z ELEMENTS

87 n + AND n" SCATTERING FROM 3He AND <He

130 EPICS TUNEUP PROPOSAL: PION CARBONSCATTERING

133 PRELIMINARY PION-CHANNEUNG EXPERIMENTS

MCCARTHY

MORRIS

SETH

646.7

334.5

THIESSEN

ZEIDMAN

WHARTON

MACEKTHIESSEN

PEREZ-MENDEZSTETZ

MCCARTHY

THIESSEN

GEMMELL

1 *2 *

1 *2 *3 *

1 *

1 *

1 *

1 *

1 •2 *

1 *

798.8218.0

289.6198.464.3

300.5

295.5

346.0

358.1

221.0674.4

200.9

2 3 0 MMXMEMATLAMPFLo* Almot NMcrml Ltbmlory

Jmuvy-Otcwntw >A.

Exp.No.

156

229

246

265

310

317

325

342

Titto

SURVEY OF QUASI-ELASTIC PION SCATTERING

n + vs n~ INELASTIC EXCITATION OF LOW-LYINGCOLLECTIVE STATES IN N - 28 NUCLEI

246 STUDY OF THE (n~,n) AND (n.rrp) REACTIONS IN3,4iHe AND HEAVIER NUCLEI BY DETECTINGRECOILING TRITONS OR DEUTERONS

STUDIES OFn+ SCATTERING AT 50 MeVFROM LIGHT NUCLEI

STUDY OF PROMPT NUCLEAR DEEXCITATION GAMMARAYS FROM PION INTERACTIONS WITH 6'7U AND 12C

(n + ,n~) DOUBLE-CHARGE-EXCHANGE REACTIONSUSING CORE 2n TARGETS

INELASTIC PION SCATTERING TO THE 1 + STATESOF12C

PION AND MUON MULTIPLE COULOMB-SCATTERINGEXPERIMENT ON THE EPICS BEAM LINE

STUDY OF THE <TT+,p) REACTION IN 12C

368 INELASTIC PION SCATTERING TO THE 19.2 ± 0.3-MeVSTATE IN 12C

369 INELASTIC PION SCATTERING BY 170,18O, AND 19F

389 INELASTIC PION SCATTERING FROM LIGHT NUCLEI

391 INELASTIC n* SCATTERING ON 7Li

413 MASS MEASUREMENT OF Ne AND 48Ar BY THE(rr - , IT+ ) REACTION

419 n + vs n " INELASTIC EXCITATION OF SINGLE-PARTICLE AND CORE-COUPLED STATES IN M7Pb AND209Bi

442 STUDY OF THE INCLUSIVE PION DOUBLE-CHARGE-EXCHANGE REACTION

446 STUDY OF EO GIANT RESONANCES

448 STUDY OF TT+ DOUBLE-CHARGE-EXCHANGESCATTERING AT SMALL ANGLES ON VARIOUS NUCLEI

452 ELASTIC AND INELASTIC SCATTERING OF n*BY13C

456 THE (n,d) REACTION ON 12C AT 60 MeV

460 AN INVESTSGATION OF THE STABILITY OF 6H. 7H, AND9He BY (IT " ,n + ) REACTIONS

Spokesman

SWENSON

BRAITHWAITEMOORE

KALLNETHlESSEN

EISENSTEIN

MORRISBRAITHWAITE

BRAITHWAITEMORRIS

PETERSON

HANSON

MCCARTHY

KALLNE

PIMM NO.'-Comptete

1 •

1 •

1 •

1 •

1 *

1 *

1 *

1 *

1 *

mmmtm

DMMHKoura

190.0

281.8

943.9

564.0

319.0

265.2

246.5

69.7

151.2

MOORE

KALLNE

HALPERNEISENSTEINTHlESSEN

BURLESON

DEHNHARD 1 *

HOISTAD 1

SETH 1 •

246.5

DEHNHARD

MORRISONZEIDMAN

PETERSON

SETHNANN

BRAITHWAITEMORRISMOORE

1 *

1 *2 *3 *

1 •

1 *

1 •

318.1

685.00.0

132.0

201.7

0.0

25.3

124.7

0.0

399.7

219.5

0.0

444.7

ntOQMUATUMPF 2 3 1Lot Mvnot NtHcni Llborttory

Exp.No. THte Spokmnan

Phase No.*=Compt«t« Hours

463 COMPARATIVE STUDY OFTHE (n+ ,n~) AND(n" ,n+ ) REACTIONS ON 12C

478 IT* ELASTIC SCATTERING FROM DEUTERIUM

481 EXCITATION OF HIGH-SPIN STATES IN Tz - 0 s-dSHELL NUCLEI BY PION INELASTIC SCATTERING

484 INELASTIC PION SCATTERING FROM 148Sm AND 152Sm

495 ISOSPIN MIXING IN 12C

506 INELASTIC PION SCATTERING TO THE UNNATURALPARITY LEVELS IN 12C AND 6Li

510 ENERGY DEPENDENCE OF ELASTIC AND INELASTICSCATTERING OF n 1 BY 13C BETWEEN 116 AND 280 MeV

516 THE(n+,p)REACTION ON 1618O

522 EXCITATION OF GIANT RESONANCE STATES IN^ Z r AND 208Pb WITH 150-MeV PIONS

NANNSETH

539

546

549

550

558

565

570

572

573

577

581

SEARCH FOR PURE NEUTRON/PROTON TRANSITIONSINUC

INVESTIGATION OFTHE SPIN FORM FACTOR OFTRITIUM AND 3He

A STUDY OFTHE DCX REACTION MECHANISM —+ . n - ^ T i REACTION

EXCITED-STATE SPECTRA OF THE EXOTIC NUCLEI18C AND 26Ne BY (n~,n + ) DCX REACTIONS

MEASUREMENT OF (TT+,TT~ ) REACTIONS ON13MCAND26Mg

EXCITATION OF HIGH-SPIN PARTICLE-HOLE STATESIN^FeAND^Ni

INVESTIGATION OF THE STRUCTURE OF 16O WITHPION INELASTIC SCATTERING

A-DEPENDENCE OF THE (n+,n") REACTION ANDTHE WIDTH OF A DOUBLE ISOBARIC ANALOGSTATE IN HEAVY NUCLEI

PION SCATTERING FROM 24Mg AND 26Mg

MEASUREMENT OF ANGULAR DISTRIBUTIONS FOR16O(TT+,rr)16Ne

n * ELASTIC SCATTERING FROM DEUTERIUMAT 237 MeV

MASTERSON

GEESAMAN

MORRIS

MORRISBRAITHWAITE

COTTINGAMEBRAITHWAITE

DEHNHARD

ANDERSONHOISTAD

KINGANDERSONPETERSON

BAERHOLTKAMP

BRISCOENEFKENS

1 •

1 *

1 *

1 *

1 •

1 '2 *

1 *

1 *

1 •

FS1 •

SETH

SETH

1 *

444.7

148.3

134.7

70.7

424.1

0.0

61,1239.0

36.0

198.6

345.7

60.9240.0

349.3

0.0

BAERBURLESON

ZEIDMANGEESAMAN

HOLTKAMPFORTUNE

GREENEMOOREMORRIS

BLANPIED

GREENEFORTUNE

MASTERSONBOUDRIE

1 •

1 *

1 *

12

1

1 *

1 *2 *

432.0

209.0

325.0

0.00.0

159.0

237.0

193.0236.0

2 3 2 mOOOESSATLAMf>FLos Atunos NUiontl Latxnlory

Jvwary-DKWnbf 19*

Exp.No. Titt* Spokwman

PhataNo.•=Compt»t« Houw

597 THE STUDY OF BROAD-RANGE PION INELASTICSCAT lERING SPECTRA (WITH EMPHASIS ON THEEXCITATION OF THE GIANT MONOPOLE RESONANCE)

598 INELASTIC PION SCATTERING TO THE UNNATURALPARITY LEVELS IN 6Li

HALPERNEISENSTEIN

COTTINGAMEKIZIAH

190.0

332.0

601 DETERMINATION OF ISOSCALAR AND ISOVECTORTRANSITION RATES FOR LOW-LYING COLLECTIVESTATES IN ^Zr AND z08Pb BY TT+ ANDn~ INELASTIC SCATTERING

602 NEUTRON-PROTON COMPONENTS OF INELASTICTRANSITIONS IN PION SCATTERING ON 23Na AND25Mg

804 AN INVESTIGATION OF THE NEAR STABILITY OF 5H

605 A DIBARYON SEARCH AT EPICS

606 TESTS OF THE (N - Z) DEPENDENCE OF PIONDOUBLE CHARGE EXCHANGE

617 A STUDY OF THE (3/2,3/2) RESONANCE INLIGHT NUCLEI

619 INELASTIC PION SCATTERING TO 0 + AND 2 +

STATES IN 40Ca AND 42Ca

622 INVESTIGATION OF THE STRONG CANCELLATIONSOF NEUTRON-PROTON TRANSITION AMPLITUDES IN 14C

625 INELASTIC SCATTERING OF PIONS TO GIANTRESONANCES

HINTZ 0.0

HARVEYDEHNHARD

SETH

SETH

SETH

ZIOCK

MOOREFORTUNEMORRIS

HOLTKAMPBAER

KINGANDERSONPETERSON

1

1 '

1 "

1 *

1 *2 *

1 •

1 *

0.0

254.8

107.0

431.0

321.00.0

136.6

138.1

162.0

651 MEASUREMENT OF A LOWER LIMIT FOR THESUBTHRESHOLD PRODUCTION OF KAONS WITH800-MeV PROTONS

S57 INELASTIC n * SCATTERING FROM THE N = 28ISOTONES

659 SPIN-FLIP GIANT RESONANCE EXCITATION

661 GOOD-RESOLUTION STUDY OF 18O(TT,TT')

662 ELASTIC AND INELASTIC n~ AND n + SCATTERINGFROM 3 2S,3 1P AND ^Zr, 89Y

671 EXPERIMENTAL INVESTIGATIONS OF ISOVECTORPROPERTIES OF COLLECTIVE TRANSITIONS

672 STUDY OF GIANT RESONANCES IN 90Zr,116Sn,AND 208Pb WITH TT+ AND n~ INELASTIC SCATTERING

677 A DETERMINATION OF AS = 1 CONTRIBUTIONS ININELASTIC PION SCATTERING FROM ODD-A NUCLEI

' January-December 1983

MORRIS 0.0

SEIDLMOORE

BLANDMOORE

MORRISBLAND

KRAUSHAARPETERSON

SAHASETH

CAREYMOSS

HOLTKAMPFUNSTEN

1

1 *2 •

1

1

1

1 *

1

PROGRESS AT LAMPfLos Alamos NUiontl Ltborwtory

0.0

174.0108.0

0.0

0.0

271.0

233.0

0.0

233

Exp.No. Titlt Spokesman

DEHNHARDMORRIS

BURLESON

MORRISFORTUNE

COMFORT

HOLTKAMPSEESTROM-

MORRIS

SETH

BLANDMORRISGREENE

HARVEYFORTUNE

MOOREFORTUNE

KIZIAHCOTTINGAME

SEESTROM-MORRIS

BLANDFORTUNE

SEESTROM-MORRIS

BLAND

HOLTKAMPCOTTINGAME

HARVEYDEHNHARD

SEIDLBURLESON

SEIDLFORTUNEBAER

PtMMNO.

1 '

1

1 *

1

1 *

1 *2

1

1

1

1 •2

1

1 *

1 •

1

1

1

1

BeamHours

281.0

266.0

314.0

0.0

245.0

120.00.0

0.0

0.0

0.0

114.00.0

0.0

357.0

169.0

0.0

0.0

0.0

0.0

678 STUDY OF THE M1 TRANSITION IN 4*Ca BY INELASTICSCATTERING OF n + AND n "

681 MEASUREMENTS OF LARG<£-ANGLE PION-NUCLEUSSCATTERING WITH EPICS

701 PION DOUBLE CHARGE EXCHANGE ON SELF-CONJUGATE NUCLEI

702 NUCLEAR STRUCTURE EFFECTS IN PION SCATTERINGFROM92-100Mo

703 STUDY OF M4 STRENGTH IN 15N BY n + AND n "INELASTIC SCATTtiiING

716 PION DOUBLE CHARGE EXCHANGE ON HEAVY NUCLEI

717 PION SCATTERING TO COLLECTIVE STATES INSELENIUM ISOTOPES

723 MEASUREMENT OF THE NEUTRON AND PROTONCONTRIBUTIONS TO EXCITED STATES IN 39K BYn + ANDn~ INELASTIC SCATTERING

744 PION INELASTIC SCATTERING FROM 20Ne

746 PION INELASTIC SCATTERING FROM 6Li

748 MEASUREMENT OF (Mn/Mp)2 FOR2 + TRANSITIONS IN T = 1 NUCLEI

749 16O(n+,n"")16Ne (g.s.) ANGULAR DISTRIBUTIONMEASUREMENTS AT Tn = 120 MeV ANDTn = 200 MeV

755 MEASUREMENT OF M1 GIANT RESONANCESIN PION INELASTIC SCATTERING

756 n * INELASTIC SCATTERING FROM4He: AN EXAMINATION OF ISOSPIN-SYMMETRY BREAKING

772 NEUTRON-PROTON COMPOSITION OFTRANSITIONS IN Z3Na AND 25MgFROM INELASTIC SCATTERING OF n + AND n"

773 MEASUREMENTS OF (n+,n~) ANGULARDISTRIBUTIONS ON 56Fe AT 164AND 292 MeV

777 ANGULAR DISTRIBUTIONS FOR DCXON 14C AND 18O

234 PROGRESS AT LAMPFLos Alamos Nttiontl Ltboralory

JtnuKy-Otcvnbtr 19ti


DEHNHARDMORRIS

BAERSEIOLGILMAN

OEHNHARDSEESTROM-

MORR'S

ZEIDMANMORRISON

BLANDMOOREMORRIS

PtMMNO.*=Complete

1

1

1

1

1

BeamHours

0.0

220.0

0.0

0.0

0.0

778 CONTINUATION OF THE STUDY OF THE M1TRANSITION IN 48Ca BY THE INELASTICSCATTERING OF rt+ AND n "

780 A STUDY OF THE DOUBLE-CHARGE-EXCHANGEREACTIONS 14C(n",TT+)MBe AND18O(n-,!T+) l8C

782 ELASTIC SCATTERING OF n + AND n~ FROM3He AND <He BETWEEN 88.5 AND 194.3 MeV

791 ISOSCALAR QUENCHING IN THE EXCITATIONOF8~ STATES IN S2Cr

793 PION DOUBLE CHARGE EXCHANGE ONSELF-CONJUGATE NUCLEI (CONTINUED)

796 CORE EXCITATION EFFECTS IN PIONDOUBLE CHARGE EXCHANGE

797 THE STUDY OF GIANT RESONANCES AND LOW-LYINGCOLLECTIVE STATES IN Z r BY INELASTICTT~ AND IT + SCATTERING

800 INELASTIC PION SCATTERING FROM 22Ne

809 STUDY OF n ~ ,p AND n + ,p REACTIONS WITH EPICS

812 BACK-ANGLE CHARGE ASYMMETRIES FOR ELASTICIT DEUTERON SCATTERING

826 ISOSPIN DEPENDENCE OF NONANALOG PION DOUBLECHARGE EXCHANGE

833 CONTINUATION OF THE INVESTIGATION OF LARGE-ANGLEPION-NUCLEUS SCATTERING

835 TARGET MASS DEPEN DENCE OF THE ISOVECTORCONTRIBUTION TO THE GIANT QUADRUPOLE RESONANCE

836 ENERGY DEPENDENCE OF PION SCATTERING TO THEGIANT RESONANCE REGION OF ^ P b

839 PION INELASTIC SCATTERING FROM THE 1 + DOUBLET IN 12C

840 INELASTIC PION SCATTERING FROM 16O ATTn = 120 AND 200 MeV

841 FORWARD-ANGLE PION INELASTIC SCATTERING ONLIGHT NUCLEI

843 A SEARCH FOR A3.3 COMPONENTS OF GROUND-STATENUCLEAR WAVE FUNCTIONS

845 PION INELASTIC SCATTERING FROM 9Be


SETH

ULLMANNKING

FORTUNEMOORE

EGGERBLANPIED

PETERSON

MORRISMOOREGILMAN

BURLESON

SEESTROWI-MORRIS

SEESTROM-MORRIS

MOOREMORRIS

BLANDFORTUNE

BLANDMOOREFORTUNE

MORRISMOORE

1

1

1

1

1

1

1

1

1

1

1

1

KELLY 1

328.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

MtOMEMATLAMFF 2 3 5Lot Altmoi NW/WMf Lthoruory


FORTUNEGILMAN

NANDADEHNHARD

SAHASETH

Phase No.•"Complete

1

1

1

BeamHours

0.0

0.0

0.0

858 ADDITIONAL MEASUREMENTS OF 1 6O(n+ , r r)1 6Ne(g.s.)

862 STUDY OF THE M1 TRANSITION IN 88Sr BY THEINELASTIC SCATTERING OF n + AND n "

863 STUDY OF GIANT RESONANCES IN THE PALLADIUMISOTOPES VIA PION SCATTERING

868 AN EXPERIMENTAL TEST OF THE A-HOLE MODEL OFNONANALOG DOUBLE CHARGE EXCHANGE

874 ELASTIC SCATTERING OF n + FROM DEUTERIUM IN THEREGION OF THE 3 F 3 DIBARYON RESONANCE

SETH

BLILIEDEHNHARD

0.0

0.0

HIGH-RESOLUTION SPECTROMETER (HRS)


Phase No.•=Complete

BeamHours

4 LARGE ANGLE ELASTIC SCATTERING OF PROTONSFROM HELIUM AND QUASI-ELASTIC KNOCKOUT OFALPHA PARTICLES BY 800-MeV PROTONS

5 INELASTIC SCATTERING OF 800-MeV PROTONSFROM NUCLEI TO STUDY QUASI-FREE MODES

10 SEARCH FOR (p,TT) REACTIONS WITH HRS

15 ELASTIC SCATTERING AND TOTAL CROSS-SECTIONMEASUREMENTS OF PROTON ON HYDROGEN,DEUTERIUM, AND HELIUM

49 ELASTIC AND INELASTIC PROTON SCATTERINGFROM THE NICKEL ISOTOPES AND FROM 8gY

117 HIGH-RESOLUTION STUDY OF THE NEUTRONPICK-UP REACTION

138 INELASTIC PROTON SCATTERING AND EXCITATIONOF STATES OF INTERMEDIATE COLLECTIVITY INOPEN-SHELL NUCLEI

139 PRELIMINARY PROTON SCATTERING SURVEY WITHHRS

178 PROTON SCATTERING SURVEY ON s-d SHELLNUCLEI

183 PROTON SCATTERING SURVEY ON HEAVY DEFORMEDNUCLEI

IGO 1 * 458.0

CHRIENPALEVSKY

SPENCER

IGOTANAKA

1 *

1 '

1 *2 "3 '

532.7

167.9

0.075.0

249.0

PETERSON

IGO

McDANIELSSWENSON

SPENCERTANAKA

SPENCERHINT2

HINT2SPENCER

204 EXCITATION AND ASYMMETRY MEASUREMENT OFT = 1, IGOHIGH-SPIN, NONNORMAL-PARITY PARTICLE-HOLESTATE BY (p,p') SCATTERING IN THE INTERMEDIATE-ENERGY RANGE

223 STUDIES OF THE (p.np) CHARGE-EXCHANGE REACTION HOFFMANN

1 *

1 *

FS*

68.3

273.2

184.2

695.1

209.3

382.1

127.0

0.0


January-OecamtHr 19b

Exp.No. Till* Spokesman

SETHSPENCER

WHITTEN

FRANKEL

FRANKELFRATI

RICKEYSHEPARDPETERSON

HOFFMANN

FRANKEL

H1NTZ

I/VHITTEN

P I W M N O .•=Compt«W

1 *

1 •

1 •

1 *2

1 *

1 *2 '

1 *

1 "

1 *

Hour*

167.9

296.7

107.6

178.70.0

0.0

715.3245.6

209.8

209.3

204.8

233 SEARCH FOR DELTA CONFIGURATIONS IN NUCLEI

249 THE (p,n+) REACTION ON "He WITH 800-MeV PROTONS

256 p-NUCLEUS ELASTIC SCATTERING AT qz = 8 GeV2 INBe, C, AND THE STUDY OF p-NUCLEUS INTERACTIONSIN COBALT AND GOLD UP TO m* = q2/2v s 20

258 STUDY OF MECHANISMS FOR THE EJECTION OFHIGH-MOMENTUM PARTICLES FROM NUCLEI BYSTUDY OF THE COINCIDENCE SPECTRUM INp + a — (p,d,t) + (p,d,t) + X

261 INTERMEDIATE-ENERGY (p,d) REACTION MECHANISMSTUDIES

311 ELASTIC-SCATTERING SURVEY USING POLARIZEDPROTONS

346 STUDY OF HIGH-MOMENTUM COMPONENTS IN NUCLEIUSING A POLARIZED PROTON BEAM

347 SEARCH FOR ORBIT-FLIP STATES BY INELASTICPROTON SCATTERING

352 DETERMINATION OF NEUTRON-MASS DISTRIBUTIONFROM ELASTIC PROTON MEASUREMENTS[P(t) AND do/dt] ON ISOTOPES IN THE CALCIUMREGION

354 SCATTERING OF 800-MeV PROTONS FROM 12CAND 13C AT MOMENTUM TRANSFER >4 fm ~1

355 FURTHER ELASTIC SCATTERING CROSS SECTIONAND ANALYZING POWER MEASUREMENTS ON 208Pb

356

385

AND 116.124,Sn

ANALYZING POWER AND CROSS-SECTION MEASURE-MENTS FOR INELASTIC PROTON EXCITATION OF SIMPLESTATES

MEASUREMENT OF THE POLARIZED PROTONS +NEUTRONS ANALYZING POWER AY(6) FROMe c m 10-70°

386 TOTAL REACTION CROSS SECTIONS FOR p + NUCLEIAT800MeV

392 A MEASUREMENT OF THE TRIPLE-SCATTERINGPARAMETERS D, R, A, R', AND A' FOR PROTON-PROTONAND PROTON-NEUTRON SCATTERING AT 800 MeV

395 THE (p,n+) REACTION ON 16O AND 40Ca


BLANPIEO

HOFFMANN

GLASHAUSSERBAKERSCOTT

HOFFMANN

HOFFMANNBURLESONYOKOSAWA

HOFFMANNBONNER

BAUERHOISTADNANN

1 *

1 *2 *

1 *2 *

1 *

2 '

1 •2 *3 *4 *

1 *2 *3 *45 *

1 *

PROGRESS AT LAMPfLot Alarms National (.abortion

324.1

130.055.0

199.988.1

140.6

108.8

404.0113.5113.5

0.0

208.6491.0146.0

0.0104.0

195.8

237

No. TMuPIMM* NO.

Spoilsman

BERTRAND

HOISTADBAUERSETH

HINTZMOSS

SETHHOFFMANN

GLASHAUSSERMOSS

GLASHAUSSERMOSS

HOFFMANNSETH

—Comp*

1 *2 *

1 *

1 *

1 *

1 *

1 *

1 *

•to Hows

40.0144.0

271.7

247.0

283.2

181.0

148.9

0.0

399 EXCITATION OF GIANT MULTIPOLE RESONANCESBY 200-400-MeV PROTONS

405 THE (p,n~) REACTION ON 12C AND 13C

411 MEASUREMENT OF SPIN-FLIP PROBABILITIESIN PROTON INELASTIC SCATTERING AT 800 MeVAND SEARCH FOR COLLECTIVE SPIN-FLIP MODES,PRELIMINARY SURVEY

425 PROTON ELASTIC SCATTERING AT ~600 MeV BY40.48Ca w Z r A N D 2 0 » p b

431 CROSS SECTION AND ANALYZING POWER FORINELASTIC PROTON EXCITATION OF UNNATURAL PARITYSTATES IN 6Li, 12C, U N , AND 16O

432 CROSS SECTION FOR EXCITATION OF UNNATURALPARITY STATES IN 12C AT Ep < 800 MeV

433 ELASTIC SCATTERING DIFFERENTIAL CROSS SECTIONSAND ANALYZING POWERS FOR POLARIZED p + 4 ( M 8Ca,""Zr, AND 2 M Pb AT - 4 0 0 MeV

438 THE (p,d) REACTIONS ON 1 2 1 3 C, 7Li,1 6O,2 sMg, 28Si, AND 40Cu BETWEEN 650 AND 800 MeV

451 INELASTIC PROTON SCATTERING IN THE RANGE300 TO 500 MeV

462 ANALYZING POWER AND DIFFERENTIAL CROSSSECTIONS FOR THE REACTIONS p + p — d + n + ANDp + d — t + n + AT ~600 AND 400 MeV

470 REACTIVE CONTENT OF THE OPTICAL POTENTIAL

472 STUDY OF THE (p,d) REACTION ON ^ Z r ,U0Ce, AND 208Pb AT 800 MeV

473 STUDY OF GIANT MULTIPOLE RESONANCES WITH 800-MeVPROTONS

474 A MEASUREMENT OF SPIN-DEPENDENT EFFECTSIN p + d ELASTIC AND INELASTIC SCATTERING

475 SCATTERING OF 0.8-GeV PROTONS FROM 20NeAND22Me

476 THE ANALYZING POWER FOR POLARIZED PROTONS+ 2 4 2 6Mg AT500 AND 800 MeV

485 THE ENERGY DEPENDENCE IN THE (p.n*) REACTION

486 INELASTIC SCATTERING OF PROTONS POPULATINGTHE 4" (3.44-MeV) LEVEL OF 206Pb — A SEARCHFOR CRITICAL OPALESCENCE

2 3 8 PDOOHESSATLAMPFLo - Alamos National Laboratory

IGO 249.5

HINTZ

SETHNANN

BARLETTHOFFMANN

WHITTEN

MOSSADAMSCAREY

CORNELIUS

BLANPIED

BLANPIED

HOISTADSHEPARD

IGOGLASHAUSSERMOSS

12

1 *

1 *2 *

1 •

1 *2 '

1 *2 *

1 •2 *

1 '

1

1 *

221.30.0

118.0

247.583.0

79.5

110.8197.7

71.060.0

154.9133.0

147.6

0.0

65.6

Jammry-Otcunbf 1903

Exp.No. Spokesman

MOSS

SETH

FRANKEL

VAN DYCK

PtlMMNO.*=Compl«t«

1 *

1 •2 *34

1 *

1 *

BMfflHour*

63.9

178.0171.0

0.00.0

130.3

127.0

489 SEARCH FOR M1 GIANT RESONANCES IN THE (p,p')"*•* REACTION AT Ep = 800 MeV

508 DIBARYON RESONANCES IN PION PRODUCTION

519 STUDY OF THE REACTION p(pol) + d — (p,n) + XTO MEASURE THE ANALYZING POWER AND STRUCTUREFUNCTION FOR BACKWARD PARTICLES '

520 STUDY OF THE REACTIONp(POLARIZED) + 3 4 He — (p.d.n..) + XTO MEASURE THE ANALYZING POWER STRUCTUREFUNCTIONS FOR BACKWARDS PARTICLES

531 EXCITATION OF UNNATURAL PARITY STATES IN1 2CAT500MeV

532 MEASUREMENTS OF CROSS SECTIONS ANDANALYZING POWER IN THE (p,2p) REACTIONON DEUTERIUM

533 THE ASYMMETRY IN THE (p,n) REACTION ON6Li AT 800 MeV •.

535 A STUDY OF THE RELATION BETWEEN THE (p.d) AND(n,p) REACTION IN A PION EXCHANGE MODEL

538 ANALYZING POWER AND CROSS-SECTION MEASURE-MENTS OF THE 4He(p,d)3He REACTION

540 ELASTIC SCATTERING FROM LIGHT NUCLEI

556 A PROPOSAL TO STUDY THE (p,p') PROCESSLEADING TO n-ATOMIC STATES

563 p + p ELASTIC SCATTERING AT 800 AND 500 MeV

580 CROSS SECTIONS AND ANALYZING POWERS FORELASTIC AND INELASTIC SCATTERING OF 515-MeVPROTONS FROM 13C

583 MEASUREMENT OF CLL IN THE COULOMBINTERFERENCE REGION

585 MEASUREMENT OF p-p AND p-d ELASTIC SCATTERINGIN THE COULOMB INTERFERENCE REGION BETWEEN500 AND 800 MeV

616 MEASUREMENT OF THE WOLFENSTEIN PARAMETERSFOR THE 1 + STATES OF 12C

623 MEASUREMENT OF CROSS SECTION, ANALYZINGPOWER, AND DEPOLARIZATION PARAMETERS IN THE2SSi(p,p')28Si (6", T » 0 AND T = 1)REACTION AT 400 MaV

GLASHAUSSERMOSS

VAN DYCKL

HOISTADSETH

ANDERSONHOISTAD

SHEPARDKING

IGOBLESZYNSKI

BERTOZZI

HOFFMANN

SEESTROM-MORRIS

DEHNHARD

PAULETTAGAZZALY

PAULETTA

BLESZYNSKI •MCCLELLANDHINTZMOSS

GLASHAUSSER

1

1

1

1

1 *2

1 *

1 '

1 '

1

12

1 '

1 *2 *

1

101.3

0.0

0.0

0.0

43.00.0

0.0

52.6

143.3

43.6

0.00.0

106.0

324.40.0

0.0

JanutryDacembw 1983 PMXMESSATLAMW 2 3 9Lot Alamot HMion* Ltboruory


GLASHAUSSERMcGILL

HYNESBERNSTEIN

CAREYHINTZMCCLELLANDMOSS

BARLETTHOFFMANN

McGILLHOFFMANN

AASHYNES

PtMMNO.*=Comptet«

1 '

1 '

1 *23

1

1 *

1 '2 '

BmrniHours

208.0

64.0

133.076.00.0

0.0

151.3

20.0325.0

626 MEASUREMENT OF THE DEPOLARIZATION PARAMETERSD|W". DLS'. AND DSS 'IN PROTON-NUCLEUS SCATTERINGAT VERY HIGH EXCITATION ENERGIES

627 MEASUREMENT OF THE RELATIVE SIGN OF NEUTRONAND PROTON TRANSITION MATRIX ELEMENTS IN(p,p') REACTIONS

630 A STUDY OF PROTON INELASTIC SCATTERING AT0" AND A SEARCH FOR GIANT MONOPOLE AND GIANTMAGNETIC DIPOLE EXCITATIONS

632 CAN PROTON DENSITY DIFFERENCES BE EXTRACTEDFROM MEDIUM-ENERGY p-NUCLEUS ELASTIC-SCATTERINGDATA

642 REACTIVE CONTENT OF THE OPTICAL POTENTIAL —PHASE 2

643 STRUCTURE OF STATES IN THE OXYGEN ISOTOPESVIA MEASUREMENTS OF THE SPIN DEPOLARIZATIONAND SPIN-ROTATION OBSERVABLES

644 TESTS OF THE POLARIZATION-ANALYZING POWEREQUALITY IN ELASTIC SCATTERING OF INTERMEDIATE-ENERGY PROTONS FROM NUCLEI

IGO 0.0

649 ^ e l p . n * ) REACTION AT 650 MeV

654 MEASUREMENT OF THE SPIN-ROTATION PARAMETER QFOR 800-MeV p + 1 60,4 0Ca, AND 208PbELASTIC SCATTERING

658 STUDY OF THE SPIN-FLIP PROBABILITY FORELASTIC AND INELASTIC SCATTERING FROM ODD-MASS NUCLEI

660 MEASUREMENT OF POLARIZATION PARAMETERSFOR M1 TRANSITIONS IN THE " Z r f p . p ' ^ Z r * AND1l6Sn(p,p')116Sn" REACTIONS AT 500 MeV

663 ELASTIC SCATTERING OF POLARIZED PROTONS FROM3H AND 3He AT INTERMEDIATE ENERGIES

666 THE 12C(p,p'n)12C REACTION AND THESEARCH FOR COHERENT ISOBAR-HOLE RESONANCES

HOISTAD

HOFFMANN

SEESTROM-MORRIS

CAREYMOSSDEHNHARD

GLASHAUSSER

IGOBLESZYNSKI

GLASHAUSSERWHITTEN

1 '2

1 *

1

1

1 *

1

85.90.0

400.0

0.0

156.0

205.0

0.0

669 INVESTIGATION OF THE N = 28 NEUTRON SHELLCLOSURE BY ELASTIC SCATTERING OF 800-MeVPOLARIZED PROTONS

670 CONTINUATION OF GIANT RESONANCE STUDIESATTHEHRS

685 SPjN CORRELATIONS IN THE REACTIONp(d,d)p AT 500 MeV

2 4 0 PROGRESS AT LAMPFLos Altmos Nttiontl Ltbortlory

SHERA 0.0

MOSSCAREYADAMS

BLESZYNSKIIGO

1 *

12

116.0

447.00.0

Jvwwy-Oicvnbw 1983


PtMMNo.*=Complf Houf»

386 DETERMINATION OF NEUTRON TRANSITION DENSITIESIN 16O AND 208Pb BY INELASTIC SCATTERING OF-~400-MeV PROTONS

687 MEASUREMENT OF THE SPIN-ROTATION PARAMETERSIN 208Pb AND IN 40Ca AT 400 MeV

709 MEASUREMENTS OF ANN, A s s , AND ASL

IN THE COULOMB INTERFERENCE REGION AT 650 AND800 MeV

712 INELASTIC PROTON SCATTERING ON 48Ca AND50Ti — AN ATTEMPT TO IDENTIFY MESONIC EFFECTSAS THE CAUSE OF M1 QUENCHING

718 ENERGY DEPENDENCE OF THE TWO-NUCLEONEFFECTIVE INTERACTION

720 RECOILLESS DELTA PRODUCTION IN THE REACTION13C(p,d)12CA

722 MEASUREMENT OF CROSS SECTIONS AND ANALYZINGPOWERS FOR ELASTIC AND INELASTIC SCATTERING OF400-500-MeV PROTONS FROM 14C

736 STUDIES OF MULTIPLE-SCATTERINGTHEORY, THE EFFECTIVE INTERACTION ANDA-HOLE INTERMEDIATE STATES IN 300-MeVp-NUCLEUS ELASTIC SCATTERING

740 LARGE-ANGLE ELASTIC SCATTERING OFPROTONS FROM ^Z r AND ^ P b

741 INVESTIGATION OF THE LONGITUDINAL-SPINRESPONSE OF 208Pb AND IMPLICATIONSOF SPIN-TRANSFER FORM FACTORS FOR NONNUCLEONDEGREES OF FREEDOM IN NUCLEI

758 TO CATCH A DEMON...

760 PROTON ELASTIC SCATTERING ON 40Ca AND 208Pb

761 Q MEASUREMENTS AT 650 MeV ON 40Ca

766 ASYMMETRY MEASUREMENT OF THE p-9Be — dnXREACTION AT 800 MeV

768 DEVELOPMENT OF 0° CAPABILITIESAT THE HRS FACILITY

774 EXCITATION OF GIANT MULTIPOLERESONANCES IN sd-SHELL NUCLEI VIA MEDIUM-ENERGY PROTON INELASTIC SCATTERING

775 SEARCH FOIH M1 R ESONANCES IN H EAVYNUCLEI USING SMALL-ANGLE PROTON SCATTERING

HINTZ 1 * 105.0

AASIGO

GAZZALYPAULETTATANAKA

SEGELCOMFORT

KELLYHYNES

MORRISMcGILL

HARVEYSEESTROM-

MORRIS

HOFFMANN

AASBLESZYNSKIIGO

CAREYMCCLELLAND

SETH

HOFFMANN

IGO

HOISTAD

MCCLELLANDCAREYSEESTROM-

MORRIS

BERTRAND

MOSSHINTZ

1 *

12

1

1 '

1 *2 *

1

12

1

1 "

1

1 *

1 *2

1 *

1

1

1

134.0

0.0522.0

0.0

143.0

218.0140.0

0.0

0.00.0

0.0

189.0

0.0

44.0

65.00.0

89.0

0.0

0.0

0.0

i nuary-December 1983 PROGRESS AT LAMPFLot Alvnot Nuwml Laboratory

241

No. rm* SpokesmanPtMMNo. 6 M M•=Comptf HOOT

784 CROSS SECTION AND ANALYZING POWERMEASUREMENTS FOR THE (p,d) REACTIONS ON16O,S6Fe.ANDMZr

785 ELASTIC SCATTERING OF POLARIZED PROTONSFROM 3H AT INTERMEDIATE ENERGY

786 STUDY OF ISOSCALAR M(1) EXCITATIONSIN LIGHT NUCLEI BY PROTON INELASTICSCATTERING

790 I = 1 NN INELASTIC CROSS SECTIONS ANDAND FIRST MEASUREMENTS OF Tx FOR THEpp — d n + REACTION AT 800 AND 650 MeV

795 A PRECISION TEST OF CHARGEINDEPENDENCE

OHNUMAWHITTEN

AZIZIBLESZYNSKI

HINTZ

PAULETTAGAZZALYTANAKA

SETH

0.0

0.0

0.0

0.0

0.0

799 LARGE-MOMENTUM TRANSFER MEASUREMENTSOF Ay FOR 800-MeV p + 208Pb ELASTIC SCATTERING

801 A MEASUREMENT OF THE WOLFENSTEINPARAMETERS FOR ^Cafp .p ' ^Ca f i + , 10.2 MeV)

803 CROSS-SECTION AND ANALYZING-POWERMEASUREMENTS IN THE M1 ,M2 REGION IN w Zr ANDMSrAT318MeV

819 II. ELASTIC SCATTERING OF POLARIZED PROTONS FROM 3HAT INTERMEDIATE ENERGY

BLESZYNSKIWHITTEN

JONESMCCLELLANDIGOBLESZYNSKI

GLASHAUSSERMCCLELLANONANDA

AZIZIBLESZYNSKIIGO

0.0

0.0

0.0

0.0

837 MEASUREMENT OF SPIN-FLIP CROSS SECTIONS UP TO40-MeV EXCITATION IN MNi AND w Z r

844 MEASUREMENT OF ANN, Ass, AND ALS FOR THE REACTIONp p •— p + n + TT+ AT 800 MeV

GLASHAUSSERNANDA

PAULETTAGAZZALYTANAKA

0.0

0.0

846 NN — NNm CROSS SECTIONS AND ANALYZING POWERS BHATIAFOR THE 800-MeV p p — n+(np) AND pn — n - (pp) GUSSINCLUSIVE REACTIONS

851 SEARCH FOR RECOIL-FREE A PRODUCTION AND HIGH-SPIN HINTZSTATES IN THE ^Pbfp . tJ^Pb REACTION AT Ep =» 400 MeV

855 MEASUREMENT OF P b - ^ P b GROUND-STATE NEUTRON HINTZDENSITY DIFFERENCE

0.0

0.0

0.0

864 STUDY OF DEEPLY BOUND HOLE STATES IN THETIN ISOTOPES VIA THE (p ,d) REACTION

865 SPIN-ROTATION MEASUREMENT ON 4He AT 320, 500,AND 800 MeV

SAHASETH

AASBLESZYNSKIIGO

0.0

0.0

867 MEASUREMENT OF ISOVECTOR QUADRUPOLE TRANSITION SAHADENSITIES IN THE PALLADIUM ISOTOPES SETH

0.0

242 MOOflESSATLAMPFLot Mmtm Nttiontl Ltboriory

J*nutty-D»c*mbtr19».

ISOTOPE PRODUCTION AND RADIATION-EFFECTS FACILITY (ISORAD)

Exp.No. TW« Spokesman

184 PRODUCTION OF KSr O'BRIEN

210 ISOTOPE PRODUCTION FACILITY IRRADIATION O'BRIENVANADIUM, MOLYBDENUM, AND LANTHANUM TARGETS

211 NEUTRON IRRADIATION OF COPPER SINGLE CRYSTALS GREEN

267 PREPARATION OF RADIOISOTOPES FOR MEDICINE O'BRIENAND THE PHYSICAL SCIENCES USING THE LAMPFISOTOPE PRODUCTION FACILITY

407 THE EFFECT OF DISLOCATION VIBRATION ON VOID SOMMERGROWTH IN METALS DURING IRRADIATION PHILLIPS

725 THE EFFECT OF RARE-EARTH ADDITIONS ON DAVIDSONRADIATION DAMAGE IN ALLOY HT-9 (FERRITIC/MARTENSITIC) WECHSLERALLOY STEEL SOMMER

765 800-MeV PROTON IRRADIATION OF MATERIALS FOR THE BROWNSIN BEAM STOP

0.0

0.0

0.0

643.019889.3

709.0

0.0

0.0

692.00.0

570.0

Exp.No. Titt*

LOW-ENERGY PION (LEP)

SpokesmanPhaM No.*=Complete

2 *

1 *2 *3 •

1 *

1 *2 *

1 *

1 *2 *

1 *2 *

1 *2 '

BeamHours

663.4

0.0681.2268.2

195.0

0.00.0

297.5

0.0460.3

264.6707.4

0.087.5

2 TOTAL PION CROSS SECTIONS

25 PION DOUBLE-CHARGE-EXCHANGE REACTION

28 STUDIES OF THE n + ,n° REACTION

29 ELASTIC SCATTERING O F n + AND TT~ AT 10-30 MeV

35 CLUSTER EFFECTS IN NUCLEAR PION CAPTURE

50 RADIATIVE PION CAPTURE IN LIGHT NUCLEI

54 ELASTIC SCATTERING OF MESONS IN THE ENERGYRANGE 20-60 MeV

67 DEVELOPMENT OF PION BEAM-MONITORINGTECHNIQUES

79 CALIBRATION OF THE PION BEAM TRANSPORTSYSTEMS AND A PION BEAM MONITOR

96 SCATTERING OF 20-50-MeV IT * BY HYDROGENAND DEUTERIUM

102 EXCITATION FUNCTIONS AND ANGULAR DISTRIBU-TION RECOIL STUDIES OF SIMPLE PION-INDUCEDNUCLEAR REACTIONS

nuuyDecambv 1983

JAKOBSON

BURMAN

YAVIN

PREEDOM

ZIOCK

CROWEROWE

PREEDOM

DROPESKY

PHILLIPS

NAGLE

MARKOWITZ

12

0.0

0.0728.0

0.0

PIKXMCSSATLAMPF 2 4 3Lot Almot Ntkxnl Laboratory

Exp.No. Titto Spokesman

SEGEL

KUNSELMAN

KAROL

PREEDOM

BARNES

HIGHLANDMACEK

YAVINALSTER

FISHERMARSHAK

PhaMNo.'^Complete

1 •2 *

1 •

5 *

1 *'I '

1 *2 *3 '

1 *

1 *

1 •

Houra

0.0150.0

0.0

25.0

0.0260.0

0.0385.0

0.0

333.0

0.0

88.0

121 PION-INDUCED NUCLEAR REACTIONS

122 PIONIC ATOM X RAYS AND NUCLEAR DISTRIBUTIONS

123 NUCLEAR- STRUCTUhE EFFECTS IN PION-INDUCEDNUCLEAR REACTIONS

131 A STUDY OF THE n + + d — p + p REACTION AT PIONENERGIES 10-60 MeV

140 STUDY OF THE (n^d) REACTION WITH AN INTRINSICGERMANIUM DETECTOR

144 SEARCH FOR THE C-VIOLATING DECAY rr° + 3-y

162 STUDIES OF THE (n+,n°) REACTION ON LIGHTELEMENTS

164 PION TOTAL CROSS-SECTION MEASUREMENTS WITHAN ORIENTED 165Ho TARGF.T

170 STUDY OF REACTION '3C(rt+,nO)i3N(GROUND STATfc)

180 ELASTIC AND INELASTIC n+NUCLEUS SCATTERINGAT 25, 50, AND 75 MeV

181 MEASUREMENTS OF THE r T p — n°n ANGULARDISTRIBUTION AT LOW ENERGIES AND CALIBRATIONOF THE n° SPECTROMETER

190 A PRECISION MEASUREMENT OF THE n~ - n°MASS DIFFERENCE

191 n + NUCLEUS INELASTIC SCATTERING TO GIANTRESONANCES

209 PION INTERACTIONS IN.NUCLEAR EMULSIONS

ALSTER

EISENSTEIN

ALSTERBOWMAN

ZIOCK

1 * 0.0

0.0191.3

346.0859.2

133.0

HALPERN

BRADBURYALLRED

1 *2 *3 *4 *

1 *

0.0292.7484.4284.4

0.0

234 A STUDY OF THE INELASTIC PION SCATTERINGREACTION AT PION ENERGIES 10-100 MeV

247 DISTRIBUTION OF PRODUCTS FROM INTERACTIONSOF STOPPED TT" WITH SEVERAL MEDIUM- AND HEAVY-MASS NUCLEI

284 MEASUREMENT OF THE 3He(n",n°)3He ANGULARDISTRIBUTION

293 STUDY OF THE DOMINANT REACTION MODES FORPIONS INTERFACING WITH COMPLEX NUCLEI

295 STUDY OF THE PION-DEUTERON SINGLE-CHARGE-EXCHANGE REACTION d(n",n°)2n

GOTOW

ORTH

COOPERWHITNEY

SEGEL

BOWMANMOINESTER

436.3

35.659.5

209.00.0

151.0

75.8


Jtnutry December 1.06

Exp.No. Titto Spokesman

ZIOCK

JACKSON

WHARTON

SETHBURLESON

CHURCH

BERTRANDGOTOW

HALPERN

Pha*«No."=Compt«t*

1 "2 '3 *

1 •2 "3 "

1 •2 '3 •

1 *2 *

3 '4

1 •

1 *

B*MHHour*

0.0960.1

0.0

152.6290.9304.0

0.0338.1862.4

699.60.0

33.00.0

877.1

118.6

299 AN INVESTIGATION OF THE REACTION (n + ,n + + p)

303 A SURVEY OF PION SINGLE-CHARGE-EXCHANGESCATTERING USING BACK-ANGLE GAMMASPECTROSCOPY

315 HIGH-RESOLUTION STUDY OF THE (n r,2p) REACTION

316 n'NUCLEUS ELASTIC SCATTERING BETWEEN20 AND 50 MeV

320 A COMPARISON OF (n\xn) AND (n",xn)REACTIONS

322 SYSTEMATIC STUDY OF PION-IN ELASTICSCATTERING AT ENERGIES BELOW 100 MeV

324 PRECISION MEASUREMENT OF RATIOS OF CERTAINLIGHT ELEMENT PION EXCITATION FUNCTIONS

333 n±NUCLEAR ELASTIC SCATTERING AT ENERGIESBETWEEN 50 AND 100 MeV

GOTOW 1 •• 512.2

348 STUDY OF GIANT RESONANCES WITH RADIATIVEPION CAPTURE ON MEDIUM-Z NUCLEI AT LEP

349 NUCLEAR REACTIONS OF 127I WITH PIONS

350 STUDY OF PION-ABSORPTION MECHANISMS INNUCLEI

388 LOW-ENERGY PION ELASTIC SCATTERING FROMTHE PROTON AND DEUTERON AT 180°

CROWE

PORILE

SEGELSCHIFFER

HOLT

1 • 761.7

CM

C

O

1 "

1 *

25.028.0

225.8

392.2

393 ANGULAR DISTRIBUTION MEASUREMENTS OF THEPION SINGLE-CHARGE-EXCHANGE REACTION ON 13C

401 STUDY OF THE ISOBARIC ANALOG CHARGE-EXCHANGEREACTION 15N(TT+,n°)15O

412 SEARCH FOR ANALOG STATE TRANSITIONS IN(n+,n°) REACTIONS ON 7Li, 27AI, 93Zr, 120Sn, AND206Pb AND FOR COLLECTIVE ISOVECTOR STATES INTHE (n - ,n0) REACTION ON 93Zr

ALSTERMOINESTER

BOWMANCOOPER

BAERBOWMANCVERNA

1

1 *2

1 '2 *

279.8

357.10.0

270.6224.0

415 TWO-NUCLEON-OUT PRODUCTS FROM STOPPED n"INTERACTIONS

ORTH 1 * 121.6

416 STUDY OF FAST PION-INDUCED FISSION OF URANIUM

465 RADIOCHEMICAL STUDY OF PION SINGLE CHARGEEXCHANGE

483 MEASUREMENT OF THE ANGULAR DEPENDENCE OFTENSOR POLARIZATION IN THE ?H(n+ ,n+ )2H REACTION

. January-December 1983

DROPESKY

RUNDBERG

HOLT

3 *4 *

1 *2

1 *

PfKXMESSATLAMPFLot Altmos NUiontl Lttxxttory

15.011.0

46.061.4

478.3

245

Exp.No. Titl* Spokesman

REIDYLEON

GOODMANBAER

BAERBOWMANCVERNA

KINGMOINESTER

BAERBOWMAN

GUTBROD

PtWMNo.'-Complete

1 •

1 •33

1 *

1

1

1 *

BMMHours

202.8

103.4154.0

0.0

243.9

24 2

0.0

106.7

487 MEASUREMENT OF THE NUCLEAR RESONANCEEFFECT IN SOME PIONIC ATOMS

523 STUDY OF 14C(n+,n°)14N REACTION

524 STUDY OF THE ISOVECTOR TERMS IN n-NUCLEUSINTERACTIONS WITH (n+,n°) REACTIONS

4 0 4 2 4 4 * B 1 1 2 1 1 8 1 2 4

525 EXCITATION OF ISOVECTOR TRANSITIONS WITHPION SINGLE CHARGE EXCHANGE ON 12C

527 STUDY OF THE 10B(n-,n°)10B REACTION

536 EFFICIENCY MEASUREMENTS FOR n + IDENTIFICATIONIN THE PLASTIC BALL DETECTOR

541 A SEARCH FOR NUCLEAR CRITICAL OPALESCENCEUSING THE REACTION 40Ca(n+,2y)

543 A PRODUCT RECOIL STUDY OF THE ( i r ^ r^n) REACTION

544 SEARCH FOR A FAST FISSION PROCESS

553 STUDY OF TARGET THICKNESS EFFECTS IN THECROSS-SECTION MEASUREMENT OF THE PIONSINGLE-CHARGE-EXCHANGE REACTION"COT+Vyfy (g.s.) FROM 50 TO 350 MeV

557 EXPOSURE, IN A PARASITIC MODE, OF A 3-cm BY3-cm BY 1-cm STACK OF SOLID-TRACK DETECTORS TO An~ BEAM

561 n * -NUCLEAR ELASTIC SC/ TTERING AT ENERGIESBETWEEN 30 AND 80 MeV

567 A STUDY OF THE rr+ + d — p + p REACTION AT PIONENERGIES 5-200 MeV

576 STUDY OF THE (n+,2p) AND (n±,2p) REACTIONSON THE ISOTOPIC PAIRS 18O-18O AND*°Ca-«Ca

595 AN ON-LINE GAMMA-RAY STUDY OF PION-INDUCEDSINGLE-NUCLEON-REMOVAL REACTIONS ON 13C AND 46Ca

601 DETERMINATION OF ISOSCALAR AND ISOVECTOR TRANSITIONRATES FOR LOW-LYING COLLECTIVE STATES IN Z r and 208Pb BYn + AND IT" INELASTIC SCATTERING

607 STUDY OF ISOVECTOR GIANT RESONANCES WITHPION CHARGE EXCHANGE

COOPER

HINTZ

ALSTERBAERBOWMAN

773.7

CARETTO

WILHELMY

RUNDBERG

12

1 "2 *

1 •2 *3

7.851.5

48.076.0

69.014.0

100.0

COWSIK

BLECHEROBENSHAINHYNES

GOTOWMINEHARTRITCHIE

ROOSPREEDOMCHANT

ORTHVIEIRA

1 *

1 *2 *

1 *

1

1

0.0

241.0294.0

503.0

246.0

34.0

1 *2 '3

414.0

259.5774.0

0.0

2 4 6 PROGRESS AT LAMPFLos Alums Ntiontl LMborttory


Phase No. Beam•-Complete Houf»

J1 1 EXCITATION FUNCTIONS OF THE FOUR13OTe(TT±.n±n) REACTIONS

650

675

676

A SEARCH FOR NEUTRINO MIXING VIA NONEXPONENTIALn — uv DECAY

NUCLEAR DISTRIBUTIONS FROM THE STUDY OF THE2? STATES OF PIONIC ATOMS

STUDY OF PION ABSORPTION ON Ni ATTn = 160MeV

688 STUDY OF THE MASS AND ENERGY DEPENDENCEOF LOW-ENERGY PION SINGLE CHARGE EXCHANGE

732 HEAVY ELEMENT FISSION INDUCED BYENERGETIC PIONS

735 PION-INDUCED EMISSION OF LIGHT NUCLEARFRAGMENTS

738 ANALOG STATE CROSS SECTIONS OF THE92.96.iooMo(n+ n0) R E A C T | O N

767 IT* DEUTERON ELASTIC SCATTERING ^AT THREE ENERGIES BETWEEN 30 AND 80 MeV

776 STUDY OF THE 16O(n+,n°p) REACTION

789 TWO-N'JCLEON-OUT PRODUCTS FOLLOWING THE ABSORPTIONOF 10-MeV n + IN z6Mg AND 74Ge

794 n*-NUCLEAR ELASTIC SCATTERINGAT ENERGIES BETWEEN 30 AND 65 MeV

798 FISSION INDUCED BY ENERGETIC n*PARTICLES

808 0° EXCITATION FUNCTION FOR rT-p — rron

811 STUDY OF UNNATURAL-PARITY STATES IN NUCLEIUSING LOW-ENERGY PIONS

813 PION CHARGE ASYMMETRIES FOR I3C AT LOW BEAMENERGIES ON THE LEP SPECTROMETER

814 n±-NUCLEAR ELASTIC SCATTERING FROM NICKEL ANDTIN ISOTOPES AT ENERGIES BETWEEN 30 AND 80 MeV

822 INELASTIC n + AND n " SCATTERING ON 48CaAT 50 AND 75 MeV

824 A STUDY OF LOW-ENERGY PION SCATTERING AS A PROBEOF NUCLEAR MAGNETIC DIPOLE EXCITATION

jnuary-0ec«mber 1983

HOGAN

BOWMANMOINESTER

KUNSELMAN

CHANTREDWINEROOS

LEITCHCOOPER

PETERSONRISTINEN

KAUFMAN

COMFORT

GOTOW

GILADPIASETZKYALSTER

OHKUBO

BLECHERHYNESOBENSHAIN

HICKSPETERSONRISTINEN

COOPERFITZGERALD

RITCHIE

1 *

0.0

249.0

0.0

557.0

157.0

0.0

173.0

0.0

0.0

0.0

100.0

452.0

61.0

71.0

0.0

KRAUSHAARPETERSON

BLECHERHYNES

KRAUSHAAR

JACKSON

1

1

1

1

PMXMEMATLAMPFLot Mmmot NMtonal Laboratory

0.0

0.0

0.0

0.0

247


Phase No. B«am* =° C o m p l f Hour»

828 TOTAL AND DIFFERENTIAL CROSS SECTIONS FORn + — p p BELOW 20 MeV

829 A MEASUREMENT OF THE WIDTH AND POSITION OF THEA + + RESONANCE IN 6Li AND 1ZC

848 IN-FLIGHT ABSORPTION OF LOW-ENERGY NEGATIVE PIONS

850 STUDY OF THE MASS AND ENERGY DEPENDENCE OFLOW-ENERGY PION SINGLE CHARGE EXCHANGE AT 0°

857 INELASTIC PION SCATTERING FROM 16O AT Tn - 50 MeV

860 INELASTIC n ± SCATTERING TO EXCITED 0° STATES ATENERGIES BETWEEN 30 AND 80 MeV

871 COINCIDENT NUCLEAR y-RAY AND PIONIC X-RAYSTUDY OF n ABSORPTION AT REST ON 12C

GOTOWMINEHARTRITCHIE

ZIOCK

OHKUBO

IROMLEITCH

BLANDMOORE

PREEDOMWHISNANT

LIEBFUNSTEN

0.

0.0

1

1

1

1

0.0

0.0

0.0

0.0

0.0

LINE B (LB)

Exp.No. Titla Spokesman

Phase No. Beam'=Complete Houra

179 DIFFERENTIAL PRODUCTION CROSS SECTIONS OFMULTIPLY CHARGED FRAGMENTS IN PROTON- ANDPION-INDUCED SPALLATION OF LIGHT NUCLEI

BOWMAN 1 " 1341.4

LINE X BEAM STOP (LX-BS)

Exp.No. Titla Spokesman

Phase No.*=Complete

BeamHours

184 PRODUCTION OF B2Sr O'BRIEN 0.0

NEUTRINO AREA (Neutrino-A)


NEMETHY

CHENREINES

CHEN

Phase No.*=• Complete

1 *2 •

1 '2 •

11

BeamHoura

6713.21097.4

0.01132.0

709.03213.0

31 A NEUTRINO EXPERIMENT TO TEST MUON CONSERVATION

148 NEUTRINO-ELECTRON ELASTIC SCATTERING AT LAMPF(A FEASIBILITY STUDY)

225 A STUDY OF NEUTRINO-ELECTRON ELASTIC SCATTERING

254 FEASIBILITY STUDY FOR THE MEASUREMENT OF THEINELASTIC NEUTRINO-SCATTERING CROSS SECTIONSIN39K

FIREMAN 1026.0

2 4 8 PROGRESS AT LAMPFLos Alimoi Natlonil Ltbormory

Jinutry-Doctmbw I

Exp.No. Titt*

636 A SEARCH FOR OSCILLATIONS USING MUON-NEUTRINOS

645 A SEARCH FOR NEUTRINO OSCILLATIONS AT LAMPF

647 A NEUTRON OSCILLATION EXPERIMENT AT LAMPF

708 A MEASUREMENT OF THE DEPOLARIZATION, THEPOLARIZATION, AND THE POLARIZATION ROTATIONPARAMETERS AND THE ANALYZING POWERFOR THE REACTION pp — pn + n

764 SEARCH OF NEUTRINO OSCILLATIONS ANDMEASUREMENT OF CROSS SECTIONS USING ALIQUID SCINTILLATOR DETECTOR IN A MUON-NEUTRINO BEAM AT THE LINE D STUB

823 DEVELOPMENT OF AN (n,p) REACTION CAPABILITY ATAREA B OR BEAM LINE D

Spokesman

DOMBECK

LINGROMANOWSKI

ELLIS

HOLLAS

Phat* No.' Comptota

1

12

1

3

BeamHour*

0.0

0.00.0

0.0

0.0

DOMBECKKRIJSE

KINGLISOWSKIBOWMANSHEPARD

0.0

0.0

PROTON IRRADIATION PORT (PIP)

Exp.No. Ti l l * Spokesman

Phase No. Beam•-Complete Hours

298 MEASUREMENT OF LIGHT OUTPUT vs ENERGY FORVARIOUS SCINTILLATORS

302 800-MeV PROTON IRRADIATION OF AN ALUMINUMSAMPLE

327 PIP, PROTON IRRADIATION PORT

SELOVE

GREEN

WILSON

1 •

1 '

0.0

326.6

16.9

PION PARTICLE PHYSICS (P3)

Exp.No. Tltta Spokesman

McFARLANEMACEK

MINEHART

NEFKENSFITZGERALD

DROPESKY

PHILLIPS

Phase No."-Complete

1 •2 *

1 *

1 •

1 •

2 •

3

1 •

BeamHours

0.01092.2

0.0

0.0

0.0220.2

6.3

n n

32 PRECISION MEASUREMENT OF THE PROCESSES

34 ELASTIC SCATTERING OF n 1 ON DEUTERONS

58 MEASUREMENT OF n " + p — y + n

67 DEVELOPMENT OF PION BEAM-MONITORINGTECHNIQUES

79 CALIBRATION OF THE PION BEAM TRANSPORTSYSTEMS AND A PION BEAM MONITOR

PROGRESS AT LAMPF 2 4 9Los Alamos National Laboratory

No. TMI* Spofc Horn

80 FORWARD ELASTIC SCATTERING OF n + AND n" FROM12C.l3C,16O.40Ca,AND20iPto

82 INVESTIGATION OF PION-INDUCED REACTIONS ONLIGHT ELEMENTS WITH THREE PARTICLES IN THEFINAL STATE

PHILLIPS

PHILLIPS

1 *2 *

1 •

0.0528.8

425.3

90 A TEST OF THE REVERSAL INVARIANCE IN SINQLE-PIONPHOTOPRODUCTION THROUGH A STUDY OF RECIPROCITYIN THE REACTIONS n~3He * yT AND n + T u

99 MEASUREMENT OF THE CROSS SECTION FORn " + p — n" + n + + n WITH A MAGNETICSPECTROMETER

102 EXCITATION FUNCTIONS AND ANGULAR DISTRIBU-TION RECOIL STUDIES OF SIMPLE PION-INDUCEONUCLEAR REACTIONS

SHERMANSHIVELYGLOCHSSPENCERWADLINGERNEFKENS

REBKAGRAM

MARKOWIT2

0.0806.9

0.0646.0

0.0

103 SPALLATION YIELD DISTRIBUTIONS FOR PIONINTERACTIONS WITH COMPLEX NUCLEI

104 PROPOSAL FOR LAMPF EXPERIMENT: STUDIES OFTHE PROTON- AND PION-INDUCED FISSION OFMEDIUM-MASS NUCLIDES

118 FRAGMENT EMISSION FROM PION INTERACTIONSWITH COMPLEX NUCLEI

119 CROSS SECTIONS OF SIMPLE NUCLEAR REACTIONSINDUCED BY n MESONS

120 MEASUREMENT OF THE POLARIZATION ASYMMETRYAND THE DIFFERENTIAL CROSS SECTION OF PION-NUCLEON CHARGE EXCHANGE FROM 160 TO 500 MeV

121 PION-INDUCED NUCLEAR REACTIONS

123 NUCLEAR STRUCTURE EFFECTS IN PION-INDUCEDNUCLEAR REACTIONS

144 SEARCH FOR THE C-VIOLATING DECAY n° -f- 3y

153 INVESTIGATION OF NUCLEAR GAMMA RAYS RESULTINGFROM IN-FLIGHT PION AND PROTON REACTIONS

154 ELASTIC SCATTERING OF IT + AND n ~ FROM THEHELIUM ISOTOPE

181 MEASUREMENTS OF THE n~p - - n°n ANGULARDISTRIBUTION AT LOW ENERGIES AND CALIBRATIONOF THE n° SPECTROMETER

HUDIS

PATE

PORILE

KAUFMAN

NEFKENSFITZGERALD

SEGEL

KAROL

HIGHLANDMACEK

EISENSTEIN

MINEHARTMCCARTHY

ALSTERBOWMAN

12

12

123

1 '2

1 '2 '3 '4 r

5

0.0295.7

0.0118.7

0.097.0

27.8186.8

870.290.3

1543.0

0.00.0

0.075.0

135.10.0

21.0

602.1

0.0

7.2316.0

204.3

2 5 0 HKXMEM AT LAMPFLot Mimes Nttlonil Liboruloiy

Jmnmy D*c»mb»r Itt

Exp.No. UN* Spofcomii

MMMNO.•-Complete How

! 95 NUCLEAR RESONANCE EFFECT IN P1ONIC ATOMS

201 THE n + d — 2d REACTION AT 100-500 MeV

214 PIONIC X-RAY ABSOLUTE YIELDS AS A FUNCTION OF Z

221 PRECISION MEASUREMENT OF THE DECAY RATEFOR THE DALITZ DECAY MODE OF THE n° MESON

222 MEASUREMENT OF THE DECAY RATE FOR n° — • + a "

247 DISTRIBUTION OF PRODUCTS FROM INTERACTIONSOF STOPPED n " WITH SEVERAL MEDIUM- AND HEAVY-MASS NUCLEI

248 STUDY OF THE (n.n), (n,A), (rt.BA), AND (n.n) REACTIONS IN3 4He AND *LI BY MEASURING RECOIL SPECTRA

283 CHARGED-PARTICLE EMISSION FOLLOWING | i " CAPTURE

286 PROTON AXIAL TOMOGRAPHY

304 STUDY OF THE AUGER PROCESS IN PIONIC ATOMS

309 INCLUSIVE n + AND n - DOUBLE CHARGE EXCHANGEON'«OAND«°C«

319 DETERMINING THE MECHANISM FOR MULTINUCLEONAND CLUSTER REMOVAL IN 200-MeV n NUCLEARINTERACTIONS

320 A COMPARISON OF (n+,xn) AND (n-,xn) REACTIONS

337 MEASUREMENT OF THE CROSS SECTION FORn-p — n-iT+n AT 200 AND 229 MeV

349 NUCLEAR REACTIONS OF 12?l WITH PIONS

058 ELASTIC SCATTERING OF PIONS FROM DFUTERIUM

363 MEASUREMENT OF n± + p ELASTIC SCATTERING

373 A COMPARISON OF RESIDUAL NUCLEI YIELDS FROMn - ABSORPTION IN i "Cd (GROUND STATE) AND ' «Cd(FIRST EXCITED STATE)

390 A STUDY OF INCLUSIVE INELASTIC PION SCATTERINGNEAR THE 6(3/2,3/2) RESONANCE

394 APPLICATION OF PROTON-COMPUTED TOMOGRAPHY

LEONREIDY

MINEHART

HARGROVELEON

HOFFMAN

REBKAGRAM

2 •

3 *

1 •

1 '

1 •

0.0163.1

338.0

199.1

351.5

MISCHKE

ORTH

KALLNEMCCARTHYGUGELOT

KRANESHARMA

HANSON

LEONMAUSNER

REBKA

UND

SHURCH

1 •

2 •

1 *

1 •

1 ••

1 •

1 •

1 "

1 *2 *

945.8

28.0

674.4

31.0

345.5

78.6

594.0

283.0

57.8170.1

999.8

PORILE

MINEHART

SADLERNEFKENS

REIDYLEON

JACKSON

1 *2 •3 '

1 •

1 •2 *

1 *

1 •

74.555.29.0

514.0

700.5844.5

94.1

453.0

HANSON 1 • 195.3

MKXMtMATLAMPFLOB Altmo* HMIontl LtboitKxy

251

Exp.No. Title Spokesman •Comp>«to Houf

396 COMPARISON OF MEASURED PIONIC-ATOM CASCADEINTENSITIES WITH THEORETICAL INTENSITIES OBTAINEDUSING PARAMETERS FROM MUONIC-ATOM STUDIES

400 SEARCH FOR THE RARE DECAY p*- — e+e +e~

404 A KINEMATICALLV COMPLETE STUDY OF THE(n.n'p) REACTION ON '60 ABOVE THE RESONANCEBY DETECTING PIONS AND PROTONS IN COINCIDENCE

416 STUDY OF FAST PION-INDUCED FISSION OFURANIUM

455 HIGH-PRECISION STUDY OF THE \i *• DECAY SPECTRUM

REIDY 110..

458

459

465

466

500

513

543

553

555

562

564

595

603

611

THE EXCITATION FUNCTION FOR THE SINGLE-CHARGE-EXCHANGE REACTION B5Cu(n ,nO)65Nj

CROSS-SECTION MEASUREMENTS OF THE"•N(n ' ,rtO)HO (g.s.) REACTION

RADIOCHEMICAL STUDY OF PION SINGLE CHARGEEXCHANGE

NUCLEAR CONFIGURATION OF INDIVIDUAL CORE-COUPLEDSTATES IN 209Bi FROM INELASTIC n * SCATTERING

FISSION FRAGMENT DISTRIBUTIONS IN FASTPION-INDUCED FISSION OF 238U

n ' QUASI-FREE SCATTERING FROM THE HELIUMISOTOPES

A PRODUCT RECOIL STUDY OF THE (n* .n'n) REACTION

STUDY OF TARGET THICKNESS EFFECTS IN THECROSS-SECTION MEASUREMENT OF THE PIONSINGLE-CHARGE-EXCHANGE REACTION'3C(rr i ,n")i3N (g.s.) FROM 50 TO 350 MeV

TOTAL CROSS-SECTION MEASUREMENTS OF THESINGLE-CHARGE-EXCHANGE REACTION'2C(n',nO)i2N(g.s.)

STUDY OF THE PION ABSORPTION MECHANISMTHROUGH THE A(n.p)X REACTION AT Tn <= 500 MeV

STUDY OF SMALL-ANGLF <He(n~ ,n t) REACTION

AIM ON-LINE y-RAY STUDY OF PION-INDUCEDSINGLE-NUCLEON-REMOVAL REACTIONS ON 13C

SEARCH FOR DELTAS IN A COMPLEX NUCLEUS BYA RADIOCHEMICAL TECHNIQUE

EXCITATION FUNCTIONS OF THE I-'OUR'30Te(nJ-,n±n) REACTIONS

HOFFMAN

HAMMSWENSON

DROPESKY

ANDERSONKINNISON

KAUFMAN

1 •

1 *

1 •2 •3 •4 •

12

1 •

156.8

401.5

141.017.026.20.0

1739.395.0

80.4

VIEIRA 96.0

RUNDBERG

FUNSTENPLENDL

RUNDBERG

MCCARTHYMINEHART

CARETTO

RUNDBERG

IMANISHIVIEIRA

JACKSONSCHIFFER

McKEOWN

ORTH

VIEIRA

TURKEVICH

1 •2

1 *

1 '2

1 '2 '

1

1 *2 *

1 •

1 '

1 •

1

2

99.1104.4

219.6

72.20.0

0.0557.7

96.5

61.337.5

139.0

428.0

435.5

89.0

13.0

HOGAN 8.5


January Dtctmbf I

Exp.No. T i l l . Spot(«tm»n

Ph«M No. BeamHOOT

617 A STUDY OF THE (3/2.3/2) RESONANCE IN LIGHTNUCLEI

628 STUDY OF THE (n,np) REACTION AND QUASI-FREESCATTERING IN''He

673 MEASUREMENTS OF THE ANGULAR DEPENDENCEOF TENSOR POLARIZATION IN THE 2H(n ' .rr + pHREACTION AT Tn - 180 AND 256 MeV

674 MEASUREMENTS OF PION-NUCLEUS ELASTIC ANDDoUBLE-CHARGE-EXCHANGE SCATTERING ATENERGIES ABOVE 300 MeV

682 SEARCH FOR DIBARYON RESONANCES IN THEHEACTION rrD -- pnn AT Pf1 - 200 TO 600 MeV/c

689 A. NEUTRON COUNTER CALIBRATION USING TAGGEDNEUTRONS FROM THF REACTION - ~d — nn.B. FEASIBILITY STUDY: MEASUREMENTS OF THE DIFFER-ENTIAL CROSS SECTION FOR - ~ d — nn TO TESTCHARGE SYMMETRY AND ISOSPIN INVARIANCE

705 STUDY OF PIOK ABSORPTION IN 3He ON AND ABOVETHE (3,3) RESONANCE

728 STUDY OF PION CHARGE-EXCHAMGE MECHANISMSBY MEANS OF ACTIVATION TECHNIQUES

730 PION PRODUCTION IN PION-NUCLEON AND PION-NUCLEUSINTERACTIONS

734 PION PRODUCTION IN PION-NUCLEUS COLLISIONS

750 INCLUSIVE n > AND n DOUBLE CHARGEEXCHANGE ON •'He

753 RECOILLESS A PRODUCTION IN THE RFACTION

783 PION-INDUCED PION PRODUCTION ON DEUTERONS

804 MEASUREMENT OF THE ASYMMETRY PARAMETERIN n - + p — Y + n USING A TRANSVERSEPOLARIZED TARGET

806 MEASUREMENT OF SPIN ROTATION PARAMETERS"A AND R" IN TT+p — n + p ANDn-p — rr-p

807 AN ABSOLUTE CALIBRATION OF A PROTONPOLARIMETER BETWEEN 90 AND 250 MeV

2IOCK

JACKSON

HOLT

BURLESONMORRIS

IMAIGREENE

NEFKENSFITZGERALD

ASHERY

1 '

0.0

0.0

634.0

0.0

0.0

332.0

283.0

GIESLER

SAGHAIPREEDOMDROPESKY

PIASETZKYDIGIACOMOLICHTENSTADT

GRAMMATTHEWSREBKA

AMANNMGHRISMcGILL

GRAMPiASETZKYREBKALICHTENSTADT

NEFKENS

NEFKENSBRISCOESADLER

BRISCOE

1

12

1

1

1

1

1

1

1

160.0

166.50.0

0.0

641.0

0.0

622.0

0.0

0.0

nn

January-December 1983 253Lot Alamos National Laboratory

Exp.NO. TW* Spokesman

PIASETZKYREBKAGRAMLICHTENSTADT

PETERSON

MUTCHLER

ALSTERBAERPIASETZKYSENNHAUSER

MINEHART

PERDRISATMINEHART

LEITCHPIASETZKY

FITZGERALDBRISCOESADLER

Phase No.'^Complete

1

1

1

1

1

1

1

1

DimHours

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

820 PION-INDUCED PION PRODUCTION ON 3He

821 PION CHARGE EXCHANGE TO DELTA-HOLE STATESOF COMPLEX NUCLEI

825 INVESTIGATION OF THE NA INTERACTION VIA n+d — pn+n

827 STUDY OF ISOBARIC-ANALOG STATES IN PIONSINGLE-CHARGE-EXCHANGE REACTIONS IN THE300- TO 500-MeV REGION

830 THE REACTION {n.np) ON 3He AND *He AT ENERGIESABOVE THE (3,3) RESONANCE

831 THE [n+,p(pp)] REACTION ON LIGHT NUCLEI

838 PION-INDUCED PION PRODUCTION ON NUCLEI AT 400 MeV

849 A. MEASUREMENT OF THE DIFFERENTIAL CROSS SECTIONON r t -p — n<>n AT 0° AND 180° IN THEMOMENTUM REGION 471-687 MeV/cB. TEST OF ISOSPIN INVARIANCE IN nN SCATTERINGAT 180° IN THE MOMENTUM REGION 471-687 MeV/c

852 MEASUREMENTS OF (n*,n) REACTIONS ON NUCLF.ARTARGETS TO STUDY THE PRODUCTION AND INTERACTIONOF n MESONS WITH NUCLEI

856 COMPARISON OF DOUBLE CHARGE EXCHANGE ANDINCLUSIVE SCATTERING IN 3He

859 STUDY OF THE A DEPENDENCE OF INCLUSIVEPION DOUBLE CHARGE EXCHANGE IN NUCLEI

PENG

GRAMMATTHEWSREBKA

GRAMMATTHEWSREBKA

0.0

0.0

0.0

Exp.No. Title

RADIATION DAMAGE A-1 (RADAMAGE-1)

SpokesmanPhase No. Beam

*=Complete Hours

302 800-MeV PROTON IRRADIATION OF AN ALUMINUM SAMPLE GREEN

545 FUSION MATERIALS NEUTRON IRRADIATIONS — BROWNA PARASITE EXPERIMENT

1 * 0.0

1 3821.8

254 PROGRESS AT LA MPFLos Alamos Nation*! Laboratory

J*nuvy-D*c*mb* 19t3

STOPPED MUON CHANNEL (SMC)

Exp.No. THto Spokesman

SHERA

POWERSKUNSELMAN

HUGHESCRANE

MALANIFY

KNIGHTSCHILLACI

CHANGKANE

PhawNo.'^Complete

1 •2 '

1 *2 *

1 *

1 *

1 *2 *

1 '

BeamHorn

0.0617.3

173.0141.9

0.0

119.3

0.0451.5

0.0

NUCLEAR-STRUCTURE PHYSICS USING STOPPED MUONS

12 MUONIC X RAYS AND NUCLEAR CHARGE DISTRIBUTIONS

37 ULTRA-HIGH-PRECISION MEASUREMENTS OF MUONIUMGROUND-STATE ENERGY LEVELS: HYPERFINE STRUCTUREINTERVAL AND MUON MAGNETIC MOMENT

51 TECHNIQUES FOR MATERIALS IDENTIFICATION ANDANALYSIS

60 CHEMICAL EFFECTS IN THE CAPTURE OF NEGATIVEMESONS IN MATTER

76 SEARCH FOR MUONIUM-ANTIMUONIUM TRANSITION

85 GAMMA-NEUTRINO CORRELATION AFTER NEGATIVE-MUON CAPTURE

100 TISSUE CHEMICAL ANALYSIS WITH MU-MESIC X RAYS

101 FEASIBILITY STUDIES: MEASUREMENT OF MUONICX RAYS AND NUCLEAR GAMMA RAYS WITH CRYSTALDIFFRACTION SPECTROMETERS AT LAMPF

122 PIONIC-ATOM X RAYS AND NUCLEAR DISTRIBUTIONS

142 NEGATIVE-MUON-INDUCED FISSION IN THE ACTINIDEELEMENTS

163 INVESTIGATION OF CHANGES IN CHARGEDISTRIBUTIONS FOR NUCLEI NEAR Z = 28 BYELECTRON SCATTERING AND MUONIC X RAYS

165 MUONIUM FORMATION IN HELIUM AND OTHERRARE GASES

166 MUONIC X RAYS AND NUCLEAR CHARGE DISTRIBUTIONSELECTRIC QUADRUPOLE MOMENTS OF 67Hoi«5 AND 73Tai»'

173 PHYSICS OF THE PION AND THE PIONIC ATOM

175 SEARCH FOR THE FORMATION OF MUONIC HELIUM

WELSH

HUTSON 1 *2 '

193.6

0.0167.0

BOEHMLU

KUNSELMAN

HUIZENGA

PERKINSSHERA

HUGHES

POWERS

BOEHMVOGEL

FS'

2 *

1 *2 *

1 *

1 •

1 '

1 •2 *

1O3.0

64.8

0.0520.3

0.0

0.0

0.0

600.9309.6

HUGHES 0.0

206 SEARCH FOR THE 2S METASTABLE STATE OFMUONIC HYDROGEN

213 MUON-TRANSFER STUDY

240 ISOTOPE AND ISOTONE SHIFTS IN THE1f7/2 SHELL

HUGHESEGAN

SHERASTEFFEN

SHERA

497.0

50.9

294.1

•WOOAESSATLAMPF 2 5 5Los Alamos National Lrtxxuory

Exp.No. TM»

266 TRAPPING OF POSITIVE MUONS AT DEFECTS INMETALS

268 MEASUREMENT OF THE GROUND-STATE HYPERFINESTRUCTURE INTERVAL OF THE MUONIC HELIUMATOM (aj i -e-)

276 PERTURBED CIRCULAR POLARIZATION OF MUONICXRAYS

Spokesman

GAUSTERHEFFNER

SOUDERHUGHES

YAMAZAKI •

PhM«No.*=-Comptarte

1 *2 *3 *

1 *

1 *2 *3 *

MamHours

223.0106.1

9.0

518.6

0.0183.0235.1

277 MUONIC X-RAY ANALYSIS OF CORE SAMPLES FROMOIL-BEARING FORMATIONS

ALLRED 33.0

283 CHARGED-PARTICLE EMISSION FOLLOWING \i~CAPTURE

KRANESHARMA

138.388.6

288 STUDIES OF \i- CAPTURE PROBABILITIES FORSOLID-STATE SOLUTIONS

NAUMANN 180.1

292 NEUTRON EMISSION FROM MUON-INDUCED REACTIONSON ACTINIDE ELEMENTS

297 A BICENTENNIAL PROPOSAL TO STUDY THE BEHAVIOROF POSITIVE MUONS IN SOLIDS

HUIZENGA

BROWN

196.2138.3

144.1137.147.1

328 MEASUREMENT OF THE DECAY RATE AND PARITY-VIOLATING ASYMMETRY FOR \i+ — e+y

330 FUNDAMENTAL MUONIC X-RAY MEASUREMENTS OFINTEREST TO MATERIALS ANALYSIS

331 FAST MUON REACTIONS WITH 12C, <8Ti, AND 58Ni

334 NUCLEAR CHARGE PARAMETERS OF 4iCa AND STABLECADMIUM AND TELLURIUM ISOTOPES

335 MONOPOLE AND QUADRUPOLE CHARGE DISTRIBUTIONSIN THE SAMARIUM AND GADOLINIUM ISOTOPES

BOWMANCOOPER ;:

HUTSONYATES-WILLIAMS

ORTH

SHERA :

SHERAYAMAZAKI

1 •

1 *2 *

1 *2 *

1 •2 *

1 *2 *3 *

1666.3

90.467.8

97.278.0

162.4170.3

298.765.0

0.0

344 HIGHER PRECISION MEASUREMENT OF MUONMAGNETIC MOMENT AND OF MUONIUM hfs INTERVAL

HUGHES 425.6

357 MUONIC X-RAY SPECTRA OF GASES: 1. DENSITY ANDADMIXTURE EFFECTS

KNIGHT 145.1

364 SEARCH FOR THE EXCITED 2S STATE OF MUONIUM

371 MUONIC X-RAY SPECTRA OF GASES: 2. CAPTUREPROBABILITIES IN MIXTURES

EGANDENISONHUGHES

HUTSON

535.8167.7

122.7

374 ( i - CAPTURE PROBABILITIES FOR SELECTED SOLIDBINARY COMPOUNDS

SCHILLACI 1 * 161.7


January-Decimber 19BJ

Exp.No. THte

PhasaNo.•~ Compete How*

375 MSR STUDY OF DIFFUSION IN METALS IN THEPRESENCE OF PARAMAGNETIC IONS

377 INVESTIGATION ON THE EFFECT OF GRAIN SIZE INMUON CAPTURE IN INHOMOGENEOUS SYSTEMS

382 A MSR INVESTIGATION OF THE EFFECTS OF IMPURITIESON THE TRAPPING AND DIFFUSION OF n+ PARTICLESIN bCC METALS

400 SEARCH FOR THE RARE-DECAY M+ — e+e+e-

408 MACROSCOPIC DIFFUSION STUDIES IN METALS

414 BONE CALCIUM ASSAY WITH MUONIC X RAYS —SIGNAL/NOISE AND REPRODUCIBILITY STUDIES

421 SENSITIVE SEARCH FOR p~ — e CONVERSION

427 MAGNET RESONANCE STUDIES OF M+-ELECTRONDEFECT COMPLEXES IN NONMETALS

436 NEGATIVE MUON SPIN ROTATION AND RELAXATIONIN MAGNETIC MATERIALS

444 SEARCH FOR THE DECAY n — ey

445 SEARCH FOR THE LEPTON-FLAVOR-VIOLATINGDECAY u+ —e+yy

449 SURVEY OF SINGLE AND DOUBLE PHOTODETACHMENTCROSS SECTION OF THE H " ION FROM 14 TO 21.8 eV

464 RADIATIVE MUON CAPTURE IN GASEOUS 3He

491 EXPERIMENTAL DETERMINATION OF THE STRONGINTERACTION SHIFT IN THE 2p-1 s TRANSITIONOF PIONIC DEUTERIUM AND HYDROGEN ATOMS

SCHILLACt

REIDY

KOSSLER

1 •2 *3 *

1 •

1 •

194/j287.0

28.0

111.4

HOFFMAN

HEFFNERLEON

HUTSONREIDY

SOUDERFRANKELHUGHES

ESTLE

YAMAZAKIHAYANO

BOWMANHOFSTADTER

MATISBOWMAN

BRYANTDONAHUE

ROBERTSMILLER

LEEFORSTER

12

1 *

1 •

1

1 "23

1 *

1

1

3

1

1 *2 *3 *4 *

651.41297.9

81.0

ti 2.6

42.0

253.3161.424.0

196.2

0.0

54.4

112.0

0.0

646.6376.1306.0

0.0

494 NUCLEAR CHARGE PARAMETERS OF THE STABLERUTHENIUM AND PALLADIUM ISOTOPES

499 MUON LONGITUDINAL AND TRANSVERSE RELAXATIONSTUDIES IN SPIN-GLASS SYSTEMS

517 POLARIZED BEAM AND TARGET EXPERIMENTSIN THE p-p SYSTEM: PHASE I. AY AND AYY FOR THEdn+ CHANNEL AND AyY FOR THE ELASTICCHANNEL FROM 500 TO 800 MeV

HOEHN 169.0

DODDSMacLAUGHLINHEFFNER


1 *234

2

329.6456.0

0.00.0

0.0

January-December 1983 PROOMtSATLAMPF 2 5 7Lot Alamos National Laboratory

Exp.NO. Tin*

PtWMNO.Hours

529 PART 1: MEASUREMENT OF THE RESIDUAL MUONPOLARIZATION IN 3He MUONIC ATOM (A FEASIBILITYTEST FOR PART 2). AND PART 2: ANGULAR CORRELATIONSIN THE CAPTURE OF POLARIZED MUONS IN GASEOUS 3He

547 SEARCH FOR FAST MUONIUM IN VACUUM

552 ULTRA-HIGH-PRECISION MEASUREMENTS ONMUONIUM

571 MUON-SPIN-ROTATION STUDIES OF DILUTEMAGNETIC ALLOYS

wuDUGANHUGHES

EGANHUGHESKANE

HUGHESEGAN

DODDSHEFFNERSCHILLACI

1 '2

1 '2 "3 *

1

12

136.0765.0

231.4144.0100.1

0.0

359.4110.0

594 PRECISION DETERMINATIONS OF SOME RELATIVEMUONIC COULOMB-CAPTURE RATIOS IN OXIDES OFDIFFERENT VALENCES

639 MUON-SPIN-ROTATION STUDY OF MUON BONDINGAND MOTION IN SELECT MAGNETIC OXIDES

640 TRANSVERSE AND LONGITUDINAL FIELD nSRMEASUREMENTS IN SELECTED TERNARY METALLICCOMPOUNCS

646 HYPERFINE STRUCTURE OF MUONIC 3He ANDMUONIC <He ATOMS

653 THE 241 Am AND 243Am MUONIC ATOM STUDIES

REIDY 93.0

BOEKEMADENISONCOOKE

DODDSHEFFNERMacLAUGHLIN

HUGHESEGAN

SHERAJOHNSONNAUMANN

12

1 *2

1 *2

1 *

144.044.0

246.0177.0

414.00.0

151.1

693 INVESTIGATION OF THE TWO-PHOTON DECAY RATE FROMTHE (|j4He) + STATE AS A FUNCTION OF PRESSURE

2S

698 GROUND-STATE QUADRUPOLE MOMENTS OF DEFORMEDNUCLEI,

724 MEASUREMENT OF THE LAMB SHIFT IN MUONIUM

726 SEARCH FOR THE C-NONINVARIANT DECAY nO —

727 MEASUREMENT OF THE EFFICIENCY OF MUONCATALYSIS IN DEUTERIUM-TRITIUM MIXTURES ATHIGH DENSITIES

742 SEARCH FOR THE NEGATIVE MUONIUM ION

745 HEXADECAPOLE MOMENTS IN URANIUM:2MUAND234U

763 NATURE OF OXYGEN CONTAMINATION INTITANIUM WITH STOPPED MUONS

REIDY 0.0

STEFFENSHERA

EGANGLADISCHHUGHES

HIGHLANDSANDERS

JONES

1 •2

1 *2 *

1

12

0.00.0

786.0380.0

0.0

0.00.0

EGANSOUDER

ZUMBROSHERA

TAYLOR

0.0

0.00.0

0.0

2 5 8 PftOOKMATLAMPFLos Alumt NUiontl Ltboftory

Jtnuty-Otctntf >W'

Exp.No. Tffl* Spokesman

COOKEHEFFNER

GUPTAHEFFNERMacLAUGHLIN

BOEKEMACOOKE

BADERTSCHERGLADISCHHUGHES

SHERAKUNSELMAN

PheeaNo.

1

1

1

1

1

•awnHours

0.0

0.0

0.0

0.0

0.0

771 MUON DIFFUSION IN (cc METALS

842 MSR SHIFT AND RELAXATION MEASUREMENTS INITINERANT MAGNETS

854 MUON-SPIN RESEARCH IN OXIDE SPIN GLASSES

869 HIGHER PRECISION MEASUREMENT OF THE LAMB SHIFTIN MUONIUM

873 PIONIC X-RAY STUDY OF THE CARBON ISOTOPES

SWITCHYARD LINE A BEAM STOP (LA-BS)

Exp.No. Titte Spokasman

PtMMNo.'•= Compete

BeamHours

105 NUCLEAR SPECTROSCOPY STUDIES OF PROTON-INDUCED SPALLATION PRODUCTS

BUNKER 0.0

118 FRAGMENT EMISSION FROM PION INTERACTIONSWITH COMPLEX NUCLEI

269 800-MEV PROTON IRRADIATION OF METAL SAMPLES

3B1 ALUMINA CERAMIC RADIATION EFFECTS STUDY

648 TEST OF EQUIPMENT FOR THE MEASUREMENT OFTHE I " FOR THE MAGNETIC MOMENT AT BNL

652 TESTS OF PROTOTYPE SEMICONDUCTOR DETECTORS

PORILE

GREEN

HARVEY

MILLER

SKUBIC

1 * 0.0

1 *

1 •

1

4.5

0.0

0.0

Exp.No. Title

THIN TARGET AREA (TTA)

SpokesmanPhase No.

'=ComplsteBeamHours

86 COUNTER EXPERIMENTS IN THE THIN TARGET AREA

308 AN ATTEMPT TO MAKE DIRECT ATOMIC MASSMEASUREMENTS IN THE THIN TARGET AREA

692 GERMANIUM-DETECTOR LOW-LEVEL RADIATION-DAMAGE EQUILIBRATION EXPERIMENT

752 TUNEUP OF THE TIME-OF-FLIGHT SPECTROMETERDIRECT ATOMIC MASS MEASUREMENTS

POSKANZER

BUTLERPOSKANZER

REEDY

VIEIRA

1 *2 *3 *

1 *2

0.0743.0

1128.0

7692.4762.0

00

0.0

Jmmty-Dtctmbv 1983 MKXMfMATUUWF 2 5 9Lot Mm* MMfonaf Ltxmory

Exp. H I M * No.No. TW tpok«»»wn •-CowpUX How

870 SEARCH FOR NEW MAGIC NUMBERS: DIRECT MASS WOUTERS 1 0.0MEASUREMENTS OF THE NEUTRON-RICH ISOTOPESWITH Z - 4-9

872 DIRECT ATOMIC MASS MEASUREMENTS OF NEUTRON- BRENNER 1 0.0RICH ISOTOPES IN THE REGION Z - 13-17 USINGTHE TIME-OF-FLIGHT ISOCHRONOUS SPECTROMETER

2 6 0 PHOORESSATUMPF Jtnuuy-Otcvnbv I9fLot Altmos National Ltboruory

APPENDIX D

ACTIVE SPOKESMEN, INSTITUTIONS, AND EXPERIMENTS

SPOKESMEN INSTITUTIONS EXPERIMENTS

ANDERSON. H. L.

ANDERSON. R. E.

BAER, H.W.

BARLETT. M. L.

BENTON. E. V.

BLANPIED, G. S.

BLESZYNSKI, M.

BOEKEMA, C.

BONNER, B. E.

BOWMAN, J. D.

BRADBURY, J. N.

BROWN, R. D.

BRYANT, H. C.

BUNKER, M. E.

BURLESON. G.R.

BURNETT, D. S.

BUTLER, G. W.

CARETTO, A. A.

CAREY, T. A.

CARLINI, R. D.

CHANT, N, S.

CHEN, H. H.

CLARK. D. A.

COOKE, D. W.

COOPER, M. D.

COST, J. R.

COTTINGAME, W. B.

DEHNHARD, D. K.

DENISON, A. B.

DEVRIES. R. M.

DIGIACOMO, N.

DODDS, S. A.

DOMBECK, T. W.

DONAHUE, J. B.

DUGAN, G.

EGAN, P. O.

ELLIS, R. J.

ESTLE, T. L.

FAUBEL, W.

FRANKEL, S.

GAZZALY, M. M.

GILMORE, J. S.

GLASHAUSSER, C.

GLASS, G.

GOODMAN, C. D.

GRAM. P. A .M.

LOS ALAMOS

UNIV. OF NORTH CAROLINA

LOS ALAMOS

UNIV. OF TEXAS. AUSTIN

UNIV. OF SAN FRANCISCO

UNIV. OF SOUTH CAROLINA

UCLA

TEXAS TECH UNIV.

LOS ALAMOS

LOS ALAMOS

LOS ALAMOS

LOS ALAMOS

UNIV. OF NEW MEXICO

LOS ALAMOS

NEW MEXICO STATE UNIV.

CALTECH

LOS ALAMOS

CARNEGIE-MELLON UNIV.

LOS ALAMOS

LOS ALAMOS

UNIV. OF MARYLAND

UNIV. OF CALIFORNIA, IRVINE

LOS ALAMOS

MEMPHIS STATE UNIV.

LOS ALAMOS

LOS ALAMOS

NEW MEXICO STATE UNIV.

UNIV. OF MINNESOTA

UNIV. OF WYOMING

LOS ALAMOS

LOS ALAMOS

RICE UNIV.

UNIV. OF MARYLAND

LOS ALAMOS

COLUMBIA UNIV.

YALE UNIV.

LOS ALAMOS

RICE UNIV.

KARLSRUHE

UNIV. OF PENNSYLVANIA

UNIV. OF MINNESOTA

LOS ALAMOS

RUTGERS UNIV.TEXAS A&M UNIV.INDIANA UNIV.LOS ALAMOS

455535523 527632171475 573635639635 637295 401 444 445 527215545 554586 588629498161308543630634576225588639401554598580 602639591 592591 592499 571 640638587529552 646647427579421583467531 623589523586

Jtnuary-Dacember 19B3 PIICXMCM AT LAMPF 2 6 1Los Alttnos National Laboratory


GREENE, S. J.GREENWOOD. R. C.HARVEY, A.HARVEY, C J.HEFFNER. R. H.HENNING.W.HINTZ. N. M.HOCHN, M. V.HOFFMAN, C. M.HOFFMANN, G. W.HOFSTADTER, R.HOGAN, J. J.HOISTAD, B.HOLLAS, C. L.HUGHES. V. W.IGO, G.J.IROM. F.JACKSON, H. E.JARMER.J.J.KAROL, P.J.KATZ. R.KING, N. S. P.KINNISON, W. W.KIZIAH.R. R.KUTSCHERA.W.LING.T.Y.LU, D. C.

MacLAUGHLIN. D. E.MATIS, H. S.MCCLELLAND, J. B.MICHEL, D.J.MILLER, J.MILLER. J. P.MOINESTER, M. A.MOORE, C. F.MORRIS. C. L.MOSS, J. M.NORTHCLIFFE, L. C.O'BRIEN, H. A.ORTH.C.J.PACIOTTI, M. A.PAULETTA, G.PEREZ-MENDEZ, V.PHILLIPS, D. S.POSKANZER, A. M.PREEDOM, B. M.RAJU, M. R.REIDY.J. J.ROBERTS, B. L.ROMANOWSKI, T.ROOS, P. G.

LOS ALAMOSIOAHO NATIONAL ENGINEERING LAB.LOS ALAMOSUNIV. OF TEXAS, AUSTINLOSALAMOSARGONNEUNIV. OF MINNESOTA

LOS ALAMOSLOS ALAMOSUNIV. OF TEXAS, AUSTINSTANFORD UNIV.McGILL UNIV.UNIV. OF TEXAS, AUSTINUNIV. OF TEXAS. AUSTINYALE UNIV.UCLAARIZONA STATE UNIV.ARGONNELOS ALAMOSCARNEGIE-MELLON UNIV.UNIV. OF NEBRASKALOSALAMOSLOS ALAMOSUNIV. OF TEXAS, AUSTINARGONNEOHIO STATE UNIV.YALE UNIV.

UNIV. OF CALIFORNIA, RIVERSIDELAWRENCE BERKELEYLOS ALAMOSNAVAL RESEARCH LAB.BOSTON UNIV.BOSTON UNIV.LOS ALAMOS/TEL AVIV UNIV.UNIV. OF TEXAS, AUSTINLOS ALAMOSLOS ALAMOSTEXAS A&M UNIV.LOS ALAMOSLOS ALAMOSLOS ALAMOSUCLALAWRENCE BERKELEYUNIV. OF ILLINOISLAWRENCE BERKELEYUNIV. OF SOUTH CAROLINALOS ALAMOSUNIV. OF MISSISSIPPIBOSTON UNIV.OHIO STATE UNIV.INDIANA UNIV. CYCLOTRON FACILITY

572629326 406560602499 571 640610601630494400632444611456485 533 535 649636421529552646

635644

633

628

518

294

218

525 536

455

598

610

645

542

499 640

445

630

113

648

464

295 525

572

572 651

531 630

518 589 590

106 267

595

217 270

583 633

215

407

308

576

236

187

464

645

576

262 PKOOAESSATLAMPfLos Mums NUIontl Ltbortory

JtnovyOtcwntm 19B3


RUNDBERG, R. S.SCHILLACi. M. E.SEESTROM-MORRIS. S. J.SETH. K. KSHEPARC. J. R.SIMMONS, J. E.SKUBIC, P.SMITH. A. R.SMITH, W. W.SOMMER, W. F.SOUDER. P. A.TALAGA, R. L.TALBERT, JR.. W. L.TURKEVICH. A. L.VAN DYCK, O. B.VIEIRA, 0. J.WAGNER, R.WU, C. S.YUAN, V.2I0CK, K. O. H.

LOS ALAMOSLOS ALAMOSUNIV. Of MINNESOTANORTHWESTERN UNIV.UNIV. OF COLORADOLOS ALAMOSUNIV. OF OKLAHOMAUNIV. OF NEW MEXICOUNIV. OF CONNECTICUTLOS ALAMOSYALE UNIV.UNIV. OF MARYLANDLOS ALAMOSUNIV. OF CHICAGOLOS ALAMOSLOS ALAMOSARGONNECOLUMBIA UNIV.UNIV. OF ILLINOISUNIV. OF VIRGINIA

465 553571580508 533 550485 538518590652271587407421634629603532595498529634190

MKXMEMATLAMPF 2 6 3Lot Mmmot Nmtontl Labontory

APPENDIX E

VISITORS TO L A M P F DURING THE PERIODJANUARY I - DECEMBER 31, 1983

Bjamo Aars UCLADaniel S. Acton Abilene Christian Univ.David L. Adarrm UCLAGary 0. Adami; . . Univ. of South CarolinaSloven 0. Adrian Abilono Christian Univ.Doijfjl/iti M. Aide Columbia Univ.Richard C. Allen UG, Irvine.lolii) C. Allrod Conuullrjnt, Now MexicoPeter W. I•'. Aloriw Unlv. of ColoradoJonrifi Ahitor Tel Aviv Univ.Aharon Arnittay Yale Univ.Adam W. Andoriion Yale Univ.Alan N, Anderson UiMl, IdahoBryon I). Andomon Kent Gtuto Univ.Daniel tl Andorwn UCLAKonrnrl A, Aniol , ITIIUMf-Hnrifi .lurfjon Arondd Catholic Univ.HlUiard A. Arndt Virginia Poly. InuL/Malo Univ.Daniel A-jtiory , . . , . . . I nl Aviv Univ.toonard l i . Aiiorltach lornplo Unlv.Nnllali AuwbaUi lol Aviv Unlv.David A. Axnu IIIIUMIAlirn/n A/l/l UCI.AAndrew I). Hach'if Indiana U/ilv.Murk O, llJK.hiniin Univ. ol TDXIIIIAndrddJi l(iuii)il'if,lmr Unlvol lluiiinUmtmrtl •) lintkii Aij)onrwtMitrlln I . lli'irldll . . Unlv, ol IoxnsIJavId I! Marlow . . . Mortliwotilom Unlv,Cliarloit A. Dfiriioijflornd hati'ialliKiK Unlv, nl NnwI'lififriim !i Uitnnr , , . . , . filMOtophfth ('* (1;ty11• ir> Dnlv id l-liiw MiixlcoI nnUituM I) ll<i(;r;lnitll , , . .Univ, of M|(;hl(j»nI, II, l)i»(/(»iruin . t'UnU) Univ. ol Now Yoik, 'ilony DrookMlcliitol f.i, Itiirloln Univ. ol 1'ninmylviinlnliniry I . llorifiiin I iiwronco l.ivnrtnoro l.rih,Hairnoiido P, M. Bnrtlnl c;i N, tioclayWilliam l.)nrto//l . , MITVlnod K. Hlmiiidwaj UC, Irvlfio(rirloclian IV Itlintln Irixnn AttM Unlv.Hani! f'JIchfiol Unlv. ol Wtiihlnfltonl<iftlloO, liland Unlv, of l«xa«fjnry .'». Dlanplnd . . Unlv, ol fioutti CarolinaMarvin Blnoli'tr Vlrfiinla I'oly, Iniil./.'ilaUi Univ.Manik IJI<m/yniikl UCLA

Ch.nios L. Blillo Univ, of MinnesotaCarolus Soekema Texas Tech Uiiiv".Joseph E. Bolgor Unlv. ol ToxnsJooH. Booth Abllono Christian Univ.Mir;tiool J, Gordon . . . Now Mexico Insi. of Mining Toch.Charlou A. Bordrtor Colorado CollageWilliam J, Briucoo . Qooro« Washington Univ.Mark D. Drown Unlv. of TitxasPaul A. Bruhwllor Univ. of VirginiaHoward C. Bryant Unlv. of Now MoxlcoWilliam J. Burger MITGooryo R, DurlOHon Now Mexico Stato Univ.Manilial! Btirm Unlv. ol TexasMary J, Burns Univ. of Mew MexicoKennolli B Buttorfield Univ ol New MexicoKaren I . Oyrum ArgonneAugutiline J, Caflrey LGAG, IdahoNicholas (>. Chanl - . . Unlv. ol MarylandHerbert H. Chen UC, IrvineHiian-Chlno, Chiung Intil, ol Iligli I netgy I'hys.Kalherlne W, 0. Choi , - . . . . , , louhilana.'ilate Unlv,fiheorghe Clangaiu . . . Boston Unlv /Univ. ol MarylandDavid A. Clatk Unlv. ot Mew MexicoNanr;e I , Collier! , UC, IrvineJoseph It. Coniloil Arizona fituto Unlvfiiturivliive II. Conitel . Cenlie Nat. de In lter;lier<;ho ,'!(.l,Doirmili; C Coiifjlantino Yale Univ.David C. Cook . . Univ. ol MlnntniOla(J. Wnyim Cooko MumfiUin f»(ril<» Unlv.William Collliiuarnn New Mexico Citato Unlv.tohn U, Coxe rentple Univ,Dtiviil •!, Cmhtfiui Abilene (Jhrliilian UnivUoiiiiii,), CrumaiiH Unlv, of Tnxai>Uenild 0. Croiitih UCI ADavid .I, Cunningham AhilnnoChriiitliinUniv..JaiiMiM A Dallon Abilene Christian Unlvfiourliiaukrtr Dan . , . , , . . .Univ. ol Virginia!)iinayana Datla l'eni|)lo Univ.Drirolhy It. Davidhon , . , Iowa Slain Unlv../Ohil K. Daylori Unlv. ol Cfjnne(j||r;ulDietrich Delinhard Unlv. ol MlnnenolaI'elnr I1, Denoii Unlv, ol New MexicoArthur U, Donl.'son , , . , . Univ of WyomingBialon A, Dnvolk Unlv. ol New Mexico3atliih Dhawan , , , Yale Univ.Kalvli ninghDhuga . Univ. ol I'ennriylvanla

2 6 4 PMOOBKN AT I.AMCion Alwtlint Nmlltitl*ltnll<il*t<nv

.lummy Dm'tmlmr l#*l

Byron D, Dielerlo Univ. ol Now MexicoW. Rodney DiUler Argonne'lanloy A Dodds Rice Univ.•eorgo W. Dodson MIT

Peter J. Doe UC, IrvineArgyrlos Doumus Texas A&M Univ.Mlnh V. Duong-Van Rico Univ.Morion Eckhause Coll. ot William & MaryPatrick O. E(jnn Lawronce Llv« more Lab.Andrew D. Elchon UCLAJuduh M. Eisonborn, Tol Aviv Univ.Mohammed l-madl-Babakl . George Washington Univ.Jon M, Engolago UCLAPeter A. J. Edgier! Univ. ol KolnAllot um l-roll Tel Aviv Univ.David J. f;mal Texas A&M Univ.Jor()t> A. riacalanto . Univ. ol South CarolinaMonouchohr f'arkhontleh MilDavid J. Farnuni . . . , Now Mexico IIIMI, of Mining lech.John A. Fauooll Unlv. ol OregonAll I a/oly , , Louisiana Quito Unlv,Raymond W. Rirgnrson Unlv. of Texasflrian I lick . . . . , , . Virginia Poly lm»l./Stale Univ.John M. Him . Ml IDavid H Under Ohio Htalti Univ.JJtovnn H. rifihnr Ohio !>lalo Unlv,Donald (1 Homing IRIUMIOoltlrlnd I Ilk . . Max Planck Inst.Cnilon A. I onltinla Now Mexico Mlalo Unlv.Irono I ftrstoi Unlv, of KolnH.'lorry I ortiino Unlv. ol Pennsylvanialiitnibard J I f)int;/tik Onollftch. liii Sohwoilonl,Mlchatil I ranny Univ. of MlnntmolaDan M. Iratioi Ulah fitaln Unlv.Hiiiifi I rauonltiklni . . , Unlv. ol IllinoisJiinaii J. I rondirian AroonnnWlllliiin ,'i I iDitniiin AiuonnnMlroohl I iijltiawa Unlv. ot MlnnoiiotaAvniluiiii Gal Uohiow Unlv.Mohryai K. fiaraknnl Unlv, ol Mlnn«nolaMOIJDII W. (iarnoll Mow MMXIOO HIIIIH Univ.Allxtil O (iiiy AhilonoOhrlHtinii UnlvM. Magely <ia//fily Unlv, o( MlniKiHOlaDonald I (iiMtHiiinan AigonnoDavid II. Clliililnk , , (oxaH MM Univ./Unlv, of MarylandMhalov (Iliad Mil(iorard P. Ullloyln Unlv, of PonnsylvanlaHonalil A. Cillnian Unlv, of Pttnimylvanlafirant A OIHI l'li<i« Unlv,Miohanl QlndiHiih Unlv, ol H«UI«llioruChariots (ilatihauHtior llntgoinUnlv,CitHMutt fHntiti TuxnftMM Unlv,Hoy J. Ctlauhtir , . , , . Harvard Unlv,A,:;, GoldhatKir . Htalo l/nlv. of Now York, Stony Iliook

Peggy A. Goldman Unlv. ol New MexicoDudley T. Qoodhead . . . Medical Res. Council, HarwellKa/uoGotow Virginia Poly. Insl./State Univ.Charles A, Goulding EG&G, Los AlamosScott C. Graessle Abilene Christian Unlv.Michael C. Green Argonne"Ray E. L. Graen Simon Fraser Univ.Steven J. Greene Now Mexico State Unlv.Chllton 0. Gregory Unlv, ol New MexicoDavid P, Groanlck Unlv. ol ChicagoFranz L. QroBS Coll. ot William a MaiyWill! Grilblttr Lab. Fur KurnphyslkLaxml Chand Gupta . Tata IriHt, ol fund Research, IndiaWilliam Huberichter ArgonneJtitlrey A. Hall , , Abllono ChrlHtlnn Univ,Hlsashl Haradfi Columbia Unlv.Serge Hurocho Unlv. ol ParisRonnie W. Harper Unlv, of IlllnolnMaroyo P. HanioQlon Unlv. ol Now MexicoIBanjamln L. Harris NorthwoHlem Ui\lv.Carol J. Harvoy , . , Unlv. ol Now Muxlco/Unlv. ol 1nxa:iH'lroml HiiNal HlroHhima Unlv,Rono Hautiainmann Unlv. of Gonevu/UC, IrvineJohn Walkor Htilrnatitoi , . , . . . . . Ohio Stuln Unlv,Dale J, HondeiMon AiQonne,lom> LUIH Hurnnnde/ Univ. of South CarolinaKenneth H. Hlckt* Unlv of ColoradoJohnC, Illtjberl Toxna AAM Univ.Virgil L Hluhland Temple Unlv,Danlnl A. Hill ArgonneMogul Hi. »till Unlv. ol Now MexicoNorton M. Hint/ Unlv. of Mlnnemitadm haul W. J. lloehlor Univ. ol KarlHiuhoOorald W lloflmann . . , Unlv. ot TexanJohn II, llofllo/or Argonne(iury I... llogan Temple Unlv,Sluliiui Holbralen , . , , . . MITDo llolwlad , , . , , . .Unlv. of loxawKarl I . llollnde Unlv. of lionnuharleH I,, Hollat* Univ, olllariy II, Holitleln Unlv, of MaHHJamoii A. Hull UCLAHoy J, Holl , ArgonneMaMtiliniii IIOMIII Hiroshima Univ.David Huang iori)|>ln Unlv.I:, llarrle llugheH Hlanlord Unlv.Vernon W. llughen , Yale Univ,Jon I). Kurd , Unlv, ol VirginiaOeorge ,1. Igo , UCLAC, H, OtiiMilIn Ingiam , (UNl:aiokh Iroin , , Arizona flinte Unlv,/Arl/ona filale Unlv,Dhlgerii Itiagawa KKK!:»ilgaru lahlmolo KliKVincent J««e«rlno , UC, SHII(H Bmhntn

iy iimtmuilm 1 265i« Altitun NMIim»l I alm

Harold E. Jackson ArgonneMark J. Jakobson Univ. of MontanaRandolph H. Jeppesen Univ. of MontanaRobert S. Johnson ArgonneWayne A. Johnson UC, IrvineGarth Jones TRIUMFKevin W. Jones UCLASteven E. Jones EG&G, IdahoWilliam P. Jones Indiana Univ.Richard J. Joseph U.S. Air Force AcademyDonald Joyce Coll. of William & MaryJan Kallne JET/Harvard SmithsonianJohn R. Kane Coll. of William & MaryJu Hwan Kang Univ. of New MexicoPaul J. Karol Carnegie-Mellon Univ.Thomas E. Kasprzyk ArgonneSheldon Kaufman ArgonneRobert A. Kenefick Texas A&M Univ.George J. Kim UCLAEdward R. Kinney MITLeonard S. Kisslinger Carnegie-Mellon Univ.Rex R. Kiziah Univ. of TexasTodd E. Kiziah Univ. of TexasHarrold B. Knowles Univ. of New MexicoJames N. Knudson Arizona State Univ.Lawrence J. Kocenko ArgonneDale S. Koetke Valparaiso Univ.Donald D. Koetke Valparaiso Univ.Donald K. Kohl Consultant, New MexicoNorman R. Kolb Valparaiso Univ.Kathryn L. Kolsky Carnegie-Mellon Univ.Ralph G. Korteling Simon Fraser Univ.Robert S. Kowalczyk ArgonneDaniel A. Krakauer Univ. of MarylandJack J. Kraushaar Univ. of ColoradoRaymond Kunselman Univ. of WyomingDieter Kurath ArgonnePeter H. Kutt Univ. of PennsylvaniaGary Kyle SINChris P. Leavitt Univ. of New MexicoSamuel M. Levenson Northwestern Univ.Jechiel Lichtenstadt Tel Aviv Univ.Roger L. Lichti Texas Tech Univ.Chung-Yi Lin Ohio State Univ.David A. Lind Univ. of Colorado'Richard A. Lindgren Univ. of MassachusettsTa-Yung Ling Ohio State Univ.Jerry E. Lisantti Univ. of OregonStanley Livingston Consultant, New MexicoEarle L. Lomon MITDavid Lopiano UCLADaniel C. J. Lu Yale Univ.Henry J. Lubatti Univ. of WashingtonDonald R. Machen Sci. Systems Int.

Douglas Maclaughlin UC, RiversideRichard Madey Kent State Univ.Kazushige Maeda Tohoku UnivHansjuerg Mahler UC, IrvintJill Ann Marshall Univ. of TexasRichard M. Marshall Univ. of VirginiaAkira Masaike KEKTerrence S. Mathis UNM Cancer CenterJune L. Matthews MITArthur B. Mcdonald Princeton Univ.James E. Mcdonough Temple Univ.John A. Mcgill Rutgers Univ.Carl Mchargue Oak RidgeRobert D. Mckeown CaltechKok-Heong Mcnaughton Univ. of TexasDaniel W. Miller Indiana Univ.Cas Milner Univ. of TexasRichard G. Milner CaltechRalph C. Minehart Univ. of VirginiaRicardo T. Miranda Ohio State Univ.Rachel E. Mischke Univ. of IllinoisChandrashekhar Mishra 'Jniv. of South CarolinaJoseph H. Mitchell Univ. of ColoradoJoseph W. Mitchell Ohio State Univ.Murray Moinester Tel Aviv Univ.Alireza Mokhtari UCLAC. Fred Moore Univ. of TexasC. Fred Moore Sr Univ. of TexasShaul Mordechai Univ. of PennsylvaniaWilliam G. Morterer Louisiana State Univ.Sanjoy Mukhopadhyay Northwestern Univ.Takemi Nakagawa Tohoku Univ.Sirish K. Nanda Rutgers Univ.James, J. Napolitano ArgonneSubrata Nath Texas A&M Univ.Robert A. Naumann Princeton Univ.B. M. K. Nefkens UCLATed E. Neil Abilene Christian Univ.Ronota A. Newberry Abilene Christian Univ.Charles Newsom UCLAFumitakaNishiyama Hiroshima Univ.LeeC. Northcliffe Texas A&M Univ.David S. Oakley Univ. of TexasYuji Ohashi UCLAHajimeOhnuma Tokyo Inst. of Tech.Pedro Oillataguerre UCLAAkira Okihana Kyoto Univ. of Educ.Glenn A. Olah Abilene Christian Univ.Hikonojo Orihara Tohoku Univ.Herbert Orth Univ. of HeidelbergGianni Pauletta UCLAJudith D. Pelzer Univ. of New MexicoBenjie M. Peterson Ohio State Univ.Roy J. Peterson Univ. of Colorado

2 6 6 PHOOMS«ATLAMPfLot Almmot NMlonml Ltboriory

Fred L. Petrovich Florida State Univ.^Alan Picklesimer Case Western Reserve Univ.

tandra Pillai Oregon State Univ.J*ichael E. Potter UC, IrvineDavid H. Potterveld CaltechBarry M. Preedom Univ. of South CarolinaArthur M. Rask ArgonneMohini W. Rawool New Mexico State Univ.GlenA.Rebka Univ. of WyomingRobert P. Redwine MITJames J. Reidy Univ. of MississippiLouis P. Remsberg BrookhavenJames H. Richardson Consultant, New MexicoKenneth P. Riley Univ. of TexasPeter J. RileyRobert A. Ristinen Univ. of ColoradoBarry G. Ritchie Univ. of MarylandMichael W. Ritter Vale Univ.Warren M. Roane Abilene Christian Univ.Donald A. Roberts Univ. of WyomingJohn P. Roberts Abilene Christian Univ.Raymond F. Rodebaugh Univ. of TexasUrs C. Rohrer SINSayed H. Rokni Utah State Univ.Joseph Rolfe Stanford Univ.Thomas A. Romanowski Ohio State Univ.Philip G. Roos Univ. of MarylandS. Peter Rosen Purdue Univ.Serge L. Rudaz Rice Univ.Michael E. Sadler Abilene Christian Univ.Arunava Saha Northwestern Univ.David P. Saunders Univ. of TexasJohn P. Schiffer ArgonneS. Seestrom-Morris Univ. of MinnesotaColin J. Seftor George Washington Univ.Ralph E. Segel Northwestern Univ.Peter A. Seidl Univ. of TexasRoger V. Servrancks Univ. of SaskatchewanKamal K. Seth Northwestern Univ.Stephen L. Shaffer Abilene Christian Univ.Tomikazu Shima ArgonneHajime ShimizuFrank T. Shively Lawrence Berkeley LaboratoryEdward R. Siciliano . Univ. of Georgia/Univ. of ColoradoRobert T. Siegel Coll. of William & MaryTerrence P. Sjoreen Oak RidgeDaniel M. Slate Univ. of New MexicoElton S. Smith Ohio State Univ.Kaleen J. Smith Abilene Christian Univ.L. Cole Smith Univ. of VirginiaRobert W. Smith Abilene Christian Univ.Winthrop W. Smith Univ. of ConnecticutW. Rodman Snythe Univ. of ColoradoDaniel I. Sober Catholic Univ.

James R. Specht ArgonneFranz Sperisen UCLABrian M. Spicer Univ. of MelbourneHarold M. Spinka ArgonneRobert W. StanekRolf M. Steffen Purdue Univ.George S. F. Stephans ArgonneEdward J. Stephanson Indiana Univ.Morton M. Sternheim Univ. of MassachusettsTsu-Hsun Sun Institute of Atomic Energy, PRCFrank Tabakin Univ. of PittsburghTerry N. Taddeucci Ohio Univ.Richard L. Talaga Univ. of MarylandYasutoshi Tanaka Purdue Univ.Peter C. Tandy Kent State Univ.Robert L. Tanner Consultant, New MexicoMorton F. Taragin George Washington Univ.Scott Taylor Abilene Christian Univ.Raphael M. Thaler Case Western Reserve Univ.Terry L. Thode UCLAT. Neil Thompson UC, IrvineMark Timko Ohio State Univ.W. Bradford Tippens Texas A&M Univ.Benjamin Titov UC, IrvineMichael J. Tobin Carnegie-Mellon Univ.Gerald E. Tripard Washington State Univ.Stephen E. Turpir Rice Univ.John L. Ullmann Univ. of ColoradoErnst Ungricht ArgonneAlbert Van Der Kogel UNM Cancer CenterKamran Vaziri Utah State Univ.Bruce J. Ver West Arco Oil/gas CompanyRoberta J. Wade Univ. of New MexicoRobert G. Wagner ArgonneJohn D. Walecka Stanford Univ.Robert L. Walker Consultant, New MexicoThad G.Walker Abilene Christian Univ.Stephen J. Wallace Univ. of MarylandRussell E. Walstedt . . . . Beli Laboratories/murray HillJohn B. Walter EG&G, IdahoAngel T. M. Wang UCLAJiunn-Ming Wang BrookhavenKeh-Chung Wang UC, IrvineZhao-Min Wang Univ. of MarylandCary M. Warren UC, RiversideJohn W. Watson Kent State Univ.Monroe S. Wechsler Iowa State Univ.Charles A. Wert Univ. of IllinoisChristopher Wesselborg Univ. of KolnGary S. Weston UCLAC. Steven Whisnant Univ. of South CarolinaD. Hywel White BrookhavenR.Roy Whitney Univ. of VirginiaCharles A. Whitten UCLA

PIKKMEMATLAMPF 2 6 7Los Alamos National Laboratory

Robert J. Why ley Coll. of William & MaryJay A. Wightman UCLABruce D. Wilkins ArgonneKentner B. Wilson Remotion Co.Robert R. Wilson Columbia Univ.Steven L. Wilson Stanford Univ.Andreas Wirzba . State Univ. of New York, Stony BrookStephen A. Wood Tel Aviv Univ./MITKim A. Woodle Yale Univ.H. G. Worstell Consultant, New MexicoBryan K. Wright Jniv. of VirginiaDennis H. Wright Virginia Poly. Inst./State Univ.S. Courtenay Wright Univ. of ChicagoShen-Wu Xu Univ. of Texas

Shuheng Yan Inst. of Atomic Energy, PRCMing-Jen Yang Univ. of ChicagoWilox Yang FermilfAlain J. Yaouanc CEN, Grenob.Akihiko Yokosawa ArgonneVincent Yuan Univ. of IllinoisLarry Zamick Rutgers Univ.Benjamin Zeidman ArgonneJohn J. Zimerle Ohio State Univ.Sandra R. Zink UNM Cancer CenterHans J. Ziock UCLAKlaus O. H. Ziock Univ. of VirginiaGisbert zu Putlitz Univ. of HeidelbergJohn D. Zumbro Princeton Univ.

2 6 8 PROGRESS AT LAMPfLos Alamos National Laboratory

JanutryDecemtar ( 9 8 -

INFORMATION FOR CONTRIBUTORS

Progress at LAMPF is the progress report of MP Division of Los Alamos National Laboratory. Inaddition it includes brief reports on research done at LAMPF by researchers from other institutions andLos Alamos National Laboratory divisions.

Progress at LAMPF is published annually on April 1. This schedule requires that manuscripts bereceived by January 1.

Published material is edited to the standards of the Style Manual of the American Institute of Physics.Papers are not refereed, hence presentation in this report does not constitute professional publication ofthe material nor does it preempt publication in other journals. Readers should recognize that resultsreported in Progress at LAMPF are sometimes preliminary or tentative and that authors should thereforebe consulted in the event that these results are cited.

Contributors can expedite the publication process by giving special care to the following specifics:

1. When possible, furnish computer files together with hardcopy of paper. Progress at LAMPF canaccept files from DEC computers and word processors, Wang, and IBM System 6.

2. Drawings and figures submitted should be of quality suitable for direct reproduction afterreduction to single-column width, 83 mm (3-1/4 in.).

3. Figure captions and table headings should be furnished.

4. References should be complete and accurate.

5. Abbreviations and acronyms should be avoided if possible (in figures and tables as well as text),and when used must be defined.

6. All numerical data should be given in SI units.

7. Authors are reminded that it helps the reader to have an introduction, which states the purpose(s)of the experiment, before presentation of the data.

Research reports should be brief but complete. A list of recent publications relating to the experiment, forseparate tabulation in this report, is much appreciated.

Contributors are encouraged to include as authors all participants in experiments so that they mayreceive credit for authorship and participation.

Questions and suggestions should be directed to John C. Allred, Los Alamos National Laboratory,MS H85O, Los Alamos, NM 87545.

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