nuclear data measurements...sammy capture solve for k 1 @ 19.3 ev res @ 11.7 ev res @ 19.3 ev res...

nacThe Gaerttner LINAC Center

1

Overview Of

Experimental Nuclear Data Capabilities at RPI

Prof. Yaron DANON

Gaerttner LINAC Center Director

Nuclear Engineering Program Director

Rensselaer Polytechnic Institute, Troy, NY, 12180

Workshop for Applied Nuclear Data Activities (WANDA), January 22-24, 2019Elliott School of International affairs at the George Washington University


2

Outline

• The RPI Gaerttner LINAC Center

– Capabilities

• Examples

– U-235 fission and Capture

– Fe-56 and Fe-nat capture

– H2O transmission

– U-238, Be, Fe, scattering


3

Where is the RPI LINAC ?

• It is on the highest point in Troy, NY

LINAC

Flight Stations

NESOffices

RPI Campus


4

RPI LINAC History

• The RPI LINAC started operation in December 1961.

• Working “continuously” since.

Graduated over 180 students who utilized the LINAC as part of their graduate thesis research

Many years of accumulated experience

September 1997- LINAC was designated as Nuclear Historic Landmark by the American Nuclear Society

2014 - Started a major refurbishment and upgrade project


5

The RPI LINAC Facility

O FFICE

O FFICE

O FFICE

O FFICE

O FFICE

O FFICEO FFICEO FFICEO FFICE

SERVICE RO OM

BUTLER

BR

BR

SH OP A REA

BUILD IN G

HO T

LA BO RA TORY

D AR K

RO O MCO N TRO L

RO O M N EEP LA B

STO RA G E

RO O M

RO O M

TA RG ET

A CC ELERA TO R

RO O M

RO O M

MO DU LA TO R

N ICE

LA B

RO O M

TA RG ET

A CC ELERA TO R

RO O M

N

GAERTTNER LINAC LABORATORY

INSTITUTE

RENSSELAER POLYTECHNIC

N


INSTITUTE


HO T

RO O M

TA RG ET

A CC ELERA TO R

RO O M

N ICE

LA B

RO O M

TA RG ET

A CC ELERA TO R

RO O M

25-M ETE R

ST ATI ON

100-M ETE R 250-M ETE R

ST ATI ON

N


INSTITUTE


N


INSTITUTE


N


INSTITUTE


30 PO RT

ENERG Y

A NA LYZIN G

MA GN ET

He FLIG HT

PA TH

15-M ETE R

D ET EC TOR

TR AN SMI SSIO N

CA PTU RE

D ETECT OR

D ETECT OR

TRA N SMISSION

A UX ILLA RY

EQU IPMEN T

RO O M

Bent/Tilt

Focus

SPE CT ROM ETE R

LE AD SL OW IN G D OW N

EAS T

45-M ETE R

ST ATI ONST ATI ON

WEST

Neutron Production Target

Large Target Room

Detection Stations at:15m to 250m

Lead Slowing Down Spectrometer

Electron LINAC

New teaching Lab


6

Capability Matrix

KeV Neutron Scattering

In development

10-3 10-2 10-1 100 101 102 103 104 105 106 107

PAC

BBT/PAC C6D6 Capture Detector

ETT

LSDS fission sf / fragment dist.

PFNS

Fast/LiGlass ArrayBT

BBT/PACMultiplicity Detector

Fission

PAC 100m LiGlass Detector

Li-Glass Array

BBT

ETT

BT

BT

BBT

ETT

Scattering

Capture

Neutron Energy [eV]

Transmission

15m LiGlass Detector

25m/30m LiGlass Detector

250m EJ301

Multiplicity Detector


EJ301 Array

RPI LINAC - Nuclear Data Measurement Capabilities 2019

BBT/PAC/BBT

ETT

Targets

ETT- Enhanced Thermal Target PAC - PacMan Target

BBT - Bare Bounce Target PN - Photoneutron target

BT- Bare Target on Axis




Photoneutons

EJ301 ArrayLi-Glass ArrayPN Photoneutron target


7

Neutron Production TargetsEnhanced Thermal Target (ETT)Bare Bounce Target (BBT)

C-Shaped target


8

Detectors

Transmission

Capture/multiplicity

ScatteringPFNS @ 30m

15m- 30m


9

Current Activity

• Time of flight measurements– Resonance Region

• Capture (0.01 eV – 2 keV)• Transmission (0.001 eV – 100 keV)• Capture to fission ratio (alpha)• keV capture detector• Neutron scattering (E<0.5 MeV)

– High energy (0.4-20 MeV)• Scattering (30 m flight path)• Transmission (100 m and 250 m flight path)• Prompt Fission Neutron Spectra• Photoneutron spectra

– High accuracy total cross section measurements using a filtered beam

• Lead Slowing Down Spectrometer– Simultaneous measurement of fission cross sections and fission fragment mass and energy distributions using the

RPI lead slowing down spectrometer– Measurements of energy dependent (n,p) and (n,a) cross sections of nanogram quantities of short-lived isotopes.

(collaboration with LANL).– Capture cross section measurements

• Other– Research on medical isotope production– Thermal scattering (S(a,b)) measurements (at SNS in ORNL)


10

Resonance Region


11

Resonance Region Detectors

Li-Glass Detector at 25m2 cm B4C Liner (98.4 atom% 10B)

Sample

~20 liter of NaI(Tl)Li-Glass Detector at 100m

C6D6 Detector at 45m


12

235U Capture & Fission Yield Data

• Challenges:• Normalization• False capture due to neutron scattering

Normalize experimental fission yield to a resonance

Use two equations for predominantly capture and fission resonances

Solve the two equations for k2 and k3

► Need 2 resonances with known parameters ◄

f

ENDF

f YkY 1

86.0

f

ENDF YkkYkY 222 132

63.0

f

f

ENDF YkkYkY 111 132

0.00

0.05

0.10

0.15

0.20

0.25

0.30

10 15 20 25 30 35 40 45 500.00

0.05

0.10

0.15

0.20

0.25

0.30

Yie

ld

RPI Capture

Sammy CaptureNormalization

Yie

ldf

Neutron Energy [eV]

RPI Fission

Sammy Fission

600 700 800 900 10000.00

0.01

0.02

0.03

0.00

0.01

0.02

0.03

Yie

ldf

Neutron Energy [eV]

RPI Fission

Sammy Fission

Yie

ld

RPI Capture

Sammy Capture

Solve for k1 @ 19.3 eV res

@ 19.3 eV res@ 11.7 eV res

63.0

f

• Provided data to address WPEC subgroup 29 report “Uranium-235 Capture Cross-section in the keV to MeV Energy

Region”

• The data were used in the U-235 CIELO evaluation which was adopted to ENDF-8.0


13

0.005

0.01

0.1

0.2

100 10000.005

0.01

0.1

0.2

Y

Capture

RPI - Experiment

ENDF/B-7.0

JENDL4

SAMMY ENDF7 Capture

Yf

Energy [eV]

Fission

RPI - Experiment

ENDF/B-7.0

JENDL4

SAMMY ENDF7 Fission

Comparing 235U Fission and Capture with Evaluations

• Fission is in excellent agreement with evaluations

• Capture data has up to 8% multiple scattering that must be taken into account during the analysis

• Capture error is about 8%

• 0.4-1 keV capture data is closer to ENDF/B-7.0

• 1-2 keV ENDF/B7.0 too high JENDL 4.0 too low.

• E>1 keV data is slightly higher than evaluations but within errors


14

500 1000 1500 2000 25000.005

0.010

0.015

0.020

0.025

0.030

Y

Energy [eV]

RPI - Experiment

JENDL4+MS

SAMMY ENDF7 Capture

END of RRR

in ENDF/B7.0

Comparing 235U Fission and Capture with Evaluations

• Fission is in excellent agreement with evaluations

• Capture data has up to 8% multiple scattering that must be taken into account during the analysis

• Capture error is about 8%

• 0.4-1 keV capture data is closer to ENDF/B-7.0

• 1-2 keV ENDF/B7.0 too high JENDL 4.0 too low.

• E>1 keV data is slightly higher than evaluations but within errors


15

Comparing 235U Fission and Capture

with ENDF-8.0

• ENDF 8.0 is a great improvement from ENDF 7.1

500 1000 1500 2000 2500 30001000.00

0.01

0.02

0.03

0.04

0.05 Experiment norm to ENDF 7.1

MCNP ENDF 7.1

Experiment norm to ENDF 8.0

MCNP ENDF 8.0

Captu

re Y

ield

Energy [eV]

500 1000 1500 2000 2500 30001000.00

0.01

0.02

0.03

0.04

0.05

0.06

0.07

0.08

0.09 Experiment norm to ENDF 7.1

MCNP ENDF 7.1

Experiment norm to ENDF 8.0

MCNP ENDF 8.0

Fis

sio

n Y

ield

Energy [eV]

Y. Danon, D. Williams, R. Bahran, E. Blain, B. McDermott, D. Barry, G. Leinweber, R. Block and M. Rapp,“Simultaneous Measurement of 235U Fission and Capture Cross Sections From 0.01 eV to 3 keV Using aGamma Multiplicity Detector”, Nuclear Science and Engineering, vol. 187, no. 3, pp. 291-301, 2017.


16

Fe and Fe-nat KeV Neutron Capturemid-energy capture detector system overview

• 4 C6D6 detector modules

manufactured by Eljen

Technology

• Low mass, low neutron

sensitivity design

• Located at 45m flight path in

newly constructed flight station

• Measurements made from 1 eV

to 1 MeV

• Requires a weighting function


17

• Possible unresolved or intermediate structure may account for higher data yields from 600-850 keV (self-shielding)

• ENDF/B VII.1 overcompensates with its background treatment, JEFF has no background treatment.

• Above 850 keV, the data agree with the 3 evaluations presented.

• ENDF 8.0 follows uses the IAEA evaluation for Fe-56

56Fe Results – MCNP Comparison

600 800 1000 1200 1400 1600 1800 20000.0000

0.0005

0.0010

600 800 1000 1200 1400 1600 1800 20000.0000

0.0005

0.0010

800 1000 1200 1400 1600 1800 20006000.0000

0.0005

0.0010

Ye

xp 56Fe

ENDF/B-VII.1

Ye

xp 56Fe

JEFF-3.2

Ye

xp

Energy [keV]

56Fe

IAEA

McDermott, Brian, Blain, Ezekiel, Thompson, Nicholas, Weltz, Adam, Youmans, Amanda, Danon, Yaron, Barry,Devin, Block, Robert, Daskalakis, Adam, Epping, Brian, Leinweber, Gregory and Rapp, Michael, “56Fe capture crosssection experiments at the RPI LINAC Center”, EPJ Web Conf., vol. 146, pp. 11038, 2017.


18

Lead Slowing Down Spectrometer


19

VacuumTi Window

ElectronBeam

He Filled Drift Section

Neutron Source(He cooled Ta Target)

LEAD

Crossed I beam + Li2CO3

180 cm

18

0 c

m

Fission Chamber

Flux Monitor

Flux Monitor

Flux Monitor

•Tantalum target in the center produces neutrons.

•Neutrons scatter elastically with the Pb.

•Neutrons can pass through the same position several times.

•About 103-104

times higher flux than an equivalent flight path TOF experiment (5.6m).

(60 cm from corner)

Lead Slowing-down Spectrometer at RPI

67 tons of Pb


20

10-1 100 101 102 103 104 5x104102

103

104

105

106

Ra

te [cp

s]

Energy [eV]

10 Mil Ta Sample

Simulation, ENDF/B-VII.1

Simulation, JEFF 3.2

Simulation, JENDL 4.0

Measurement

Sample impurities simulated with

ENDF/B-VII.1 libraries

102 103 104 5x1041.0x105

1.5x105

2.0x105

2.5x105

3.0x105

3.5x105

4.0x105

4.5x105

5.0x105

Ra

te [

cp

s]

Energy [eV]

10 Mil Ta Sample




Measurement

Detector 1

Results – Ta Capture• Good agreement up to 300 eV

– Some disagreement in the ENDF/B-VII unresolved resonance region

– RPI is Working on improving Ta RRR cross section in a project funded by NCSP

URR in ENDF

URR in JEFF and JENDL


21

102 103 104 5x104

106

105

2x106

Ra

te [cp

s]

Energy [eV]

0.6 mm Silver Sample




Measurement10-1 100 101 102 103 104 5x104

104

105

106

103

5x106

Ra

te [

cp

s]

Energy [eV]

0.6 mm Silver Sample




Measurement

Results – Ag Capture

• Large differences between

libraries above 1 keV160 170 180 190 200 210 220 230 240

0.0

2.0x102

4.0x102

6.0x102

8.0x102

1.0x103

1.2x103

Cro

ss S

ectio

n [

ba

rns]

Energy [eV]

107Ag Cross section

ENDF/B-VII.1

JEFF 3.2

JENDL 4.0


22

Fast Region


23

Collimation Collimation Collimation

Water

Cooled Ta

Target

SampleEJ-301 Liquid Scintillator

Modular Detector

99.93m

91 cm

60 cm

High Energy Transmission Experimental

Setup

Graphite Samples

33

13

7 5

Nominal thickness in cm


24

Zr Total Cross Section Measurements (0.5-20 MeV)

• Used low Hf (less than 100 ppm) Zr metal

• ENDF/B 6.8 seems like a better fit for E<16 MeV

• New partially resolved structure below 2.0 MeV

• Data can be used to improve the unresolved resonance region evaluation.

0.5 1.0 1.5 2.0 2.5 3.03

4

5

6

7

8

9

10

11

12

st [

ba

rn]

Energy [MeV]

RPI Experiment Arpil - May 2008

ENDF/B-6.8

ENDF/B-7.0

JEFF 3.1

JENDL 3.3

2 4 6 8 10 12 14 16 18 203.0

3.5

4.0

4.5

5.0

5.5

st [

barn

]

Energy [MeV]

RPI Experiment Arpil - May 2008

ENDF/B-6.8

ENDF/B-7.0

JEFF 3.1

JENDL 3.3


25

U-238, Fe, Be scattering


26

Elastic / Inelastic Neutron Scattering

• Important for neutron (and gamma) transport calculations

– Applications: criticality, reactors, shielding, oil well logging, SNM

detection, others…

• Quantities of interest

– Neutron cross section and angular distribution

– Gamma production from inelastic scattering and its angular distribution

– Neutron energy transfer (requires inelastic levels)

• Energy range of interest - from URR to fast

– In the RRR, resonance parameters can be used to calculate both cross

sections and angular distribution.

– URR sometimes difficult for model calculations experimental data is

needed.


27

Current Evaluated Scattering Data

• Hard to measure thus evaluate

– Large uncertainties

• Example: “well known” U-238

Elastic angular distribution En=0.9 MeV Notice ENDF-7.1 at back angles (n,inl) cross section

~10%ENDF-7.1 is very low


28

Scattering Detection System:

Experimental Setup

• Detector Array– Eight EJ301 Liquid Scintillation Detectors

– Eight A/D channels

– Pulse Shape discrimination in TOF

• Measures neutrons scattered from the sample at different angles

• Measured scattered neutron energy 0.5 MeV - 20 MeV

• Results are compared with a Monte Carlo simulation of the system

A. M. Daskalakis, E. J. Blain, B. J. McDermott, R. M. Bahran, Y. Danon, D. P. Barry, R. C. Block, M. J. Rapp, B. E. Epping and G. Leinweber, “Quasi-differential elastic and inelastic neutron scattering from iron in the MeV energy range”, Annals of Nuclear Energy, vol. 110, pp. 603 - 612, 2017.

A.M. Daskalakis, R.M. Bahran, E.J. Blain, B.J. McDermott, S. Piela, Y. Danon, D.P. Barry, G. Leinweber, R.C. Block, M.J. Rapp, R. Capote, A. Trkov, “Quasi-differential neutron scattering from 238U from 0.5 to 20 MeV”, Annals of Nuclear Energy, Volume 73, Pages 455-464, November 2014.

D. P. Barry, G. Leinweber, R. C. Block, and T. J. Donovan, Y. Danon, F. J. Saglime, A. M. Daskalakis, M. J. Rapp, and R. M. Bahran, “Quasi-differential Neutron Scattering in Zirconium from 0.5 MeV to 20 MeV”, Nuclear Science and Engineering, 174, 188–201, (2013).

F.J. Saglime, Y. Danon, R.C. Block, M.J. Rapp, R.M. Bahran, G. Leinweber, D.P. Barry and N.J. Drindak, “A system for differential neutron scattering experiments in the energy range from 0.5 to 20 MeV”, Nuclear Instruments and Methods in Physics Research Section A, 620, Issues 2-3, Pages 401-409, (2010)

238U Sample

EJ-301 Detectors


29

238U Scattering at 153 deg• Graphite experiment shows good

agreement with the simulations,

• 238U shows differences near 1 MeV

• Newer IAEA evaluation provides the best

fit

• ENDF/B-VII.1 needs improvement

500 800 1200 1600 2000 2400 2800 31280

1000

2000

3000

4000

50000.10.51251020

Detector 3

153o

Week 2

Energy [MeV]

Co

un

ts

Time of Flight [ns]

Uranium Data

ENDF/B-VII.1

JEFF-3.2

JENDL-4.0

IAEA-ib34

800 1200 1600 2000 2400 2800500 31280

2000

4000

6000

8000

10000

12000

140000.10.51251020

Energy [MeV]

Co

un

ts

Time of Flight [ns]

Graphite Data

MCNP Results

153 deg


30

Fe Scattering Measurement - Setup

The neutron beam diameter is smaller than the sample size.

EJ-301 Liquid Scintillator Neutron Detectors

Fe SampleDimensions 77.0 x 152.6 x 32.2 mm

Evacuated Flight Tube


31

Iron Scattering

• Measured the total scattering and compared with detailed simulation

• Method was verified with graphite

Resonance Region


32

NatFe Elastic/Inelastic Scattering – example data

1550 1600 1650 1700 1750 1800 1850 19000

500

1000

1500

2000

2500

3000

350011.41.51.61.71.81.92

Detector 2

77o

Week 2

Energy [MeV]

Co

un

ts

Time of Flight [ns]

Nat

Fe Data (MWD)

ENDF/B-VII.1

JEFF-3.2

JENDL-4.0

• The JENDL-4.0 evaluation overestimated the elastic signal at 77°

• It seems that the I/E ratio for JENDL is low because the elastic scattering is too

high.

1.4 1.6 1.8 2.00.0

0.4

0.8

1.2

1.6

I/E Ratio JEFF-3.2

I/E Ratio ENDF/B-VII.1

I/E Ratio JENDL-4.0Nat

Fe Ratio (Measured)

I/E

Ratio

Incident Neutron Energy [MeV]

Detector 2 at 77o

Elastic Scattering


33

Experimental Setup at LANL

• Motivation U-235 and Pu-239

• Relatively simple experiments

• Benchmark the simulation physics and

nuclear data.


34

Preliminary Results – 235U and 239Pu at 60 deg• 49.5 g of U enriched to 93% 235U,

• 24g of 239Pu

239Pu 235U

Graphite


35

Preliminary Results – 235U and 239Pu at 150 deg• Similar results at back scattering angles, possible issues with both 235U and 239Pu

239Pu 235U

Graphite


36

For a full list of publications visit: http://www.rpi.edu/~danony

nuclear data measurements...sammy capture solve for k 1 @ 19.3 ev res @ 11.7 ev res @ 19.3 ev res...

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