storage ring compton light sources · 2010-09-09 · dfell, duke university 48th icfa future light...

48th ICFA Future Light Sources Workshop (FLS2010), SLACDFELL, Duke University Y. K. Wu

Work supported by U.S. Grant and Contract:

DOE DE-FG02-01ER41175 and AFOSR MFELFA9550-04-01-0086

Acknowledgment:

M. Busch, M. Emanian, J. Faircloth, S. Hartman, J. Li, S. Mikhailov, V. Popov, G. Swift, P. Wang, P. Wallace (DFELL)

M. Ahmed, T. Clegg, H. Gao, C. Howell, H. Karwowski, J. Kelley, A. Tonchev, W. Tornow, H. Weller (TUNL)

HIGS Collaborators

Y. K. Wu

DFELL, Triangle Universities Nuclear Laboratory

Department of Physics, Duke University

March 2, 2010

Storage Ring Compton Light Sources

Y. K. Wu

Outline

Compton Gamma-ray SourcesA brief historical overviewMajor Compton gamma-ray facilitiesNew projects

High Intensity Gamma-ray Source (HIGS)Accelerator facilityOperation modesBeam diagnosticsOptical resonator issuesHigh flux operation

Issues with Compton Light Sources: focus on Gamma-ray SourceAcceleratorsLaser beamsEnergy rangeImpacts on LS operation due to Compton gamma-ray source


History of Compton Light Sources

Early HistoryEarly 1920's, Arthur Compton, Discovery of Compton Effect

A. H. Compton, Bulletin Nat. Res. Council (U.S.) 20, 19 (1922); Phys. Rev. 21, 483 (1923)

1963, Milburn, and Arutyunian and Tumanian, first proposed γ-beam production via Compton back-scattering of photon with accelerator based high-energy electron beam

R. H. Milburn, Phys. Rev. Lett. 10, 75 (1963). F. R. Arutyunian and V. A. Tumanian, Phys. Lett. 4, 176 (1963).

1963 – 1965, the first Compton γ-ray beam experimental demonstrations,– Kulikov et al.with a 600 MeV synchrotron– Bemporad et al. with the 6.0 GeV Cambridge Electron Acclerator

O. F. Kulikov et al., Phys. Lett. 13, 344 (1964); C. Bemporad et al., Phys. Rev. B 138, 1546 (1965).

1967 – 1969, Ballam et al. with the 20 GeV Stanford linear Acclerator, first physics measurements using Compton γ-ray beam to study the photo-production cross section (~GeVs) with a hydrogen bubble chamber

J. J. Murray and P. R. Klein, SLAC Report No. SLAC-TN-67-19, unpublished (1967). J. Ballam et al., Phys. Rev. Lett. 23, 498 (1969).



Major Compton Gamma Source Facilities (1970's – 1990's)1978 – 1993, LADON, ADONE storage ring, Frascati, ItalyThe first γ-ray Compton light source facility for nuclear physics research, by colliding electron beam

(1.5 GeV) inside a laser cavity. It produced polarized γ-ray beams up to 80 MeV with an on-target flux of up to 5x10^5 s−1 for nuclear experiments.

L. Casano et al., Laser and Unconv. Opt. J. 55, 3 (1975).G. Matone et al., Lect. Notes Phys. 62, 3 (1977).L. Federici et al., Nuovo Cimento Lett. 27, 339 (1980).L. Federici et al., Nuovo Cimento B 59, 247 (1980).D. Babusci et al., Nucl. Instrum. Methods A 305, 19 (1991).

1987 – 2006, LEGS, NSLS x-ray ring, Brookhaven National Lab, USA. M. Sandorfi et al., IEEE Trans.NS-30, 3083 (1984).

1993 – persent, ROKK-1/ROKK-2/ROKK-1M, Budker Institute of Nuclear Physics, RussiaG. Ya. Kezerashvili et al., Nucl. Instrum. Methods A. 328, 506 (1993).G. Ya. Kezerashvili et al., AIP Conference Proceedings 343, 260 (1995).G. Ya. Kezerashvili et al., Nucl. Instrum. Methods B. 145, 40 (1998).

1995 – 2008, GRAAL, ESRF storage ring, ESRF, Grenoble, FranceA. A. Kazakov et al., JETP Lett. 40, 445 (1984).

1996 – present, HIγS, Duke FEL storage ring, Duke University, USV. N. Litvinenko et al., Phys. Lett. 78, 4569 (1997).

1998 – present, LEPS, Spring-8 storage ring, Spring-8, JapanT. Nakano et al., Nucl. Phys. A 629, 559c (1998). T. Nakano et al., Nucl. Phys. A 684, 71c (2001).



H.R. Weller et al. Progress in Particle and Nuclear Physics 62, p. 257-303 (2009).


New Compton Source Projects

A Few New Compton Source Projects in Planning and Development Shanghai Laser Electron Gamma Source (SLEGS), Shanghai Synchrotron Radiation Facility

(SSRF)– 3.5 GeV electron beam and a 500 W CO2 polarized laser– An energy up to 22 MeV and a flux of 109-10γ/s

Q. Y. Pan et al., Synchrotron Radiation News, Volume 22, Issue 3, p. 11 (2009).

Compton Gamma Source Project at MAX-lab– 3 GeV electron beam from the MAX IV storage ring to be built, up to 500 mA– An ultraviolet (UV) laser beam– The maximum gamma-ray energy around 500 MeV– A tagged flux as high as a few times 107 γ/s

L. Isaksson, MAX-lab, Lund, Sweden, private communication (2009).

Laser-Electron Photon 2 (LEPS2), Spring-8– For conducting research in the quark-nuclear physics– Higher intensity and higher maximum energy compared with LEPS– Expanded detector acceptance for a 4π γ-detector.

The LEPS2 website, www.hadron.jp; and the 2006 RCNP Annual Report, for example, www.rcnp.osaka-u.ac.jp/~annurep/2006/topics/yosoi.pd


Major Compton Gamma Source Facilities Around the World

HIGSLEGS

GRAAL

LADON

ROKK

LEPSSLEGS

MAX-Lab


A Storage Ring Compton Gamma Source

High Intensity Gamma-ray Source (HIGS)

at Duke University


HIGS AcceleratorsHigh Intensity Gamma-ray Source (HIGS) Accelerators

Recent Accelerator UpgradesNew lattice for OK-5 FELNew HOM-damped RF cavityNew OK-5 FEL with circular polarizationA New Booster synchrotron for top-off injection

Typical User Operation Modes

FEL: single-bunch, up to 95 mAHIGS: two-bunch, 80 - 110 mA


HIGS AcceleratorsOK-5 and OK-4 FELs (Since Aug. 2005)

OK-5 wigglers

OK-4 wigglers

OK-4 Planar wigglers

OK-5 helical wiggler, OK-5A

OK-5 helical wiggler, OK-5B

20.15 m

e-beam


HIGS ResearchOperation Principle of HIGS

52.8 m


HIGS ResearchOperation Modes of HIGS Operation Modes of HIGSQusi-CW operation vs PulsedHigh-flux vs high energy resolution

FWHM


HIGS ResearchHigh Energy-Resolution Operation

Asymmetric Bunch Pattern: one large (lasing) and one small (non-lasing)

Improving stability of gamma energy resolution and increase fluxDevelop a reliable way to measure bunch pattern, andAn automatic injection scheme to maintain charge distribution


Beam Diagnostics/FeedbackElectron/Photon Collision Angle Monitor


Beam Diagnostics/FeedbackBunch Length and FEL Spectrum Monitors

Beam DiagnosticsLive Spectrum Monitor

Live bunch length monitors

349 MeV, 27 mA


Beam Diagnostics/FeedbackBunch-by-bunch Longitudinal Feedback

Providing bunch-by-bunch damping of longitudinal instabilities

Part of Ph.D. thesis work of Wenzhong Wu

Commissioned for User Operation (Oct., 2008)

With .

iGp-64F Digital signalprocessing system

MILMEGA 200 WPower amplifier

LFB BPM

Pill-box cavity

Feed through

Nose cone

Beam pipe


Beam Diagnostics/FeedbackLFB Stabilizing Longitudinal Motion

Synchrotron sidebands LFB OFF574 MeV, 4-bunch, 15 mASynchrotron sidebands?

LFB ON574 MeV, 4-bunch, 15 mA

Part of Ph.D. thesis work of Wenzhong Wu


Beam Diagnostics/FeedbackIn-cavity Aperture System for High Current Operation

Electron Beam

Part of Ph.D. thesis work of Senlin HuangNIM A 606, p. 762 (2009).

WIG01 WIG02 WIG03 WIG03 Mirror

16.54 m6.72 m6.72 m6.72 m

22.29 mCollision

Point

Mirror

Lw = 4 m 4.58 m

Aperture


Beam Diagnostics/FeedbackCorrecting Mirror Deformation

45 MeV Setup with OK-5 FEL


HIGS SummaryStability of Gamma Operation in Electron Loss Mode

Current

Gamma flux

Current

Gamma flux

with closed apertures


High-Finesse FEL ResonatorHigh Reflectivity FEL Mirrors

780 nm MirrorsMinimal round-trip loss: ~ 0.107%Finesse @ Low power ~ 3,000

Effective: R ~ 99.95%

761 nm, Loss ~0.00107

Kicker firing



Mirror degradationCarbon deposition on the surface

Horizontal

Vertical

780 nm, CCV020, downstream cavity mirror, D=50 mm


Intracavity FEL Power MeasurementExperimental Layout

12m

Collimated (d=3/4”), γ-beam image

Collimated flux: 3.68%

Ebeam: 514 MeV, about 88 mA in two equally populated bunches

FEL beam λ = 545 nm;

Gamma-beam collimator: d = 0.75”


Intracavity FEL Power MeasurementIntracavity FEL Power Measurements: γ-Spectrum

Ebeam: 514 MeV, about 88 mA in two equally populated bunches

FEL beam λ = 545 nm;

Gamma-beam collimator: d = 0.75”

True γ-spectrum

Avg Flux Density from 11B at 8.916 MeV

11B data: Pb = 800 (+/-100) W, PFEL = 1.6 kW (+/- 0.2 kW)

C. Sun et al. NIMA 605, p 312(2009)


Intracavity FEL Power MeasurementIntracavity FEL Power Measurements

Ebeam: 514 MeV; FEL beam λ = 545 nm; Collimator: d = 0.75”

HPGe data

Preliminary Results: HPGe data


Gamma Energy Tuning Range with OK-5 FEL (3.5 kA)


Highest Total Flux (2009): > 1010 γ/s @ 9 – 11 MeV

H. R. Weller et al., “Research Opportunities at the Upgraded HIγS Facility,” Prog. Part. Nucl. Phys. Vol 62, Issue 1, p. 257-303 (2009).


Nuclear Physics and AstrophysicsNuclear Physics and Astrophysics Research at HIGS

Nuclear StructureFew-Nucleon PhysicsAstro-physicsGerasimov-Drell-Hearn (GDH) Sum RuleCompton Scattering from NucleonsPhoton-Pion Physics

H. R. Weller et al., “Research Opportunities at the Upgraded HIγS Facility,” Prog. Part. Nucl. Phys. Vol 62, Issue 1, p. 257-303 (2009).

HIGS


Accelerators for Compton Light Sources

Advantages of storage rings– High repetition rate– Orbit stability and beam stability (at higher energies)– Adequate ebeam emittance and energy spread– Known technologies– Powering a high average flux Compton source

Other Accelerators– Warm temperature Linacs:

• Low rep-rate pulsed operation• Expensive laser• Less stable• Powering a high peak flux source

– Super-conducting linac (e.g. ERL)• High rep-rate• Costly• Less mature technology• A potential driver for very high average flux source


– Tuneable wavelength => a large Compton photon energy range– Self-synchronization and self alignment– Complex and Expensive– High intracavity power– Driver for a versatile, high-flux Compton source for a wide range of research

programsExternal Lasers

– Ti:sapphire m TW lasers, low reprate, time syn, low stability, costly– CW lasers–––

Laser Cavities– Used in LADON project (low finesse)– High finesse Fabry-Perot cavity

• DC laser with high finesse– JLAB, Compton polarimeter, 1064 nm, finesse 30,000, 1.6

kW• CW pulsed laser

– Laboratoire de l’Acce´le´rateur Line´aire, C.N.R.S./IN2P3, Orsay, France

– Ti:sapph, 76 MHz, 1 ps, finesse 30,000

V. Brisson, e t al. Nucl. Instrum. Meth. A 608(2009)S75–S77


– 0.1 eV photons, 10 – 100 keV x-rays, e-beam: 80 – 250 MeV;– 1eV photons, 10 – 100 keV x-rays, e-beam: 25 – 80 MeV;– E-beam, 2 GeV, 0.1 eV photons, γ-ray: 6 MeV– E-beam, 2 GeV, 1 eV photons, γ-ray: 60 MeV– E-beam, 3 GeV, 0.1 eV photons, γ-ray: 14 MeV– E-beam, 3 GeV, 1 eV photons, γ-ray: 140 MeV

Figure of Merits for Gamma-ray Beams:– Brightness is no longer a good figure of merit for gamma-ray beam– New merits: flux (γ/s), spectral flux (γ/s/eV, avg, peak), relative energy spread

(FWHM)Compton X-ray Source Driven by a Storage Ring

– Don Ruth, SLAC, www.lynceantech.com.– Next talk: “Experience with the Compact light source”


Critical Issues for Storage Ring Compton Gamma SourcesImpact On the Storage Ring Light Source when

Operating Compton Gamma Source as an Optical Insertion Device (OID)Effect of Electron LossWhen Compton scattered electron loses more energy than allowed by the energy aperture (smaller of energy

dynamic aperture and energy acceptance limited by RF/vacuum chambers).Two strategies:

– “Hide” loss among beam lifetime• Electron-loss mode operation (Energy loss > Aperture)• Good for higher energy gamma operation• Limited flux: 10^6 – few 10^7 γ/s• Gamma-ray energy determination: Tagging of electrons

– Prevent electron loss• No-loss mode (Energy loss < Aperture)• Good for lower energy gamma operation• High flux possible (greater than 10^9 γ/s)• Gamma-ray energy selection: Collimation of gamma-beam

Impact on Electron Beam Parameters– An issue with extremely high flux operation– Impact on e-beam energy and longitudinal distributions– (estimates using damping wiggler model; need real simulation)– Impact on transverse beam distribution (emittance)


– High gamma beam energies <=> User research programs– Additional flux limitation due to tagging rate, 10^5 – 10^6 e-/s per tagging channel– High efficincy: tagging a large amount of Compton gamma-rays: 30% - 60%– Energy resolution as limited by the absolute energy spread of the e-beam

• Example: 3 GeV e-beam, 0.1% (sigmaE), 150 MeV gamma-ray • dE (FWHM) = 7.1 MeV; dE/E (γ,FWHM) = 5%;

– Reliability of tagging signal at high ratesCollimation

– Low gamma beam energies <=> User research programs– If OID, fixed gamma energy with a fixed e-beam energy; how to vary gamma energy?– Potentially very high flux– Low efficiency: collimation selects only a few percent Compton gamma-rays– Challenge in high precision flux measurement (pileups, scattering, secondary particles, etc)– Energy spread issues: collimation effect, e-beam energy spread, emittance effect

• Long beamline• Good e-beam aiming stability• Example: 3 GeV e-beam, ~5% γ-beam energy spread (FWHM)

– Half opening angle: 30 micro-radians– If collimator aperture r = 3 mm, beamline length ~ 100 m;– Stability of ebeam aiming; a few micro-radians


Part of Ph.D. thesis work of Changchun SunPhys. Rev. ST Accel. Beams 12, 062801 (2009)

Energy Spread of γ-beamEnergy Distribution of Compton Gamma-beam

Monochromatic electron and photon beamsEmittance Effect (Scaled)E-beam Energy Spread Effect (Scaled)Collimator EffectCollimator Effect (Scaled)

New Merit:Degree of Collimation


Industrial and Medical ApplicationsCompton Gamma-beam Imaging at HIGS

Polarization Effect: Linear vs Circular22.5 MeV Gamma-beam

680 MeV-ebeam, 378 nm FEL, 27 m from collision


Industrial and Medical ApplicationsCompton Gamma-beam Imaging at HIGS

Imager Resolution Test with a bar phantom test and 2.75 MeV gamma-beam


Industrial and Medical ApplicationsCompton Gamma-beam Radiograph


The End


1 MeV Gamma-beamHigh Resolution Mode:


Switch-yard for OK-4 and OK-5 Wigglers

Photon-pion physics150 – 160 MeV operation with the OK-5 FEL lasing around 150 nm


Summary

High Intensity Gamma-ray Source Development and User ResearchAn Overview of HIGS Accelerator Facility and Development Program: Accelerator Physics and FEL ResearchAn Overview of HIGS User Research Program: Nuclear Physics Program

HIGS Capabilities (2009) Energy Tuning: 1 - 100 MeV Maximum Total Flux: > 1010 γ/s around 9 - 10 MeV

Maximum Spectrum Flux: : ~ 103 γ/s/eV around 5 - 10 MeV

High Energy Resolution: 0.8% (< = 5 MeV) Polarization: linear, and switchable left- and right-circular

HIGS Near-Term Development Higher Gamma-beam Energy: 100 - 160 MeV for photon-pion physics research Higher Flux Operation: 1011 γ/s total below 20 MeV


HIGS beam-on-target: 1584 hr

HIGS Operation Summary (Aug. 1, 2008 – Jul . 31, 2009)


Industrial and Medical ApplicationsCompton Gamma-beam Imaging

RadiographTH571A Tetrode tube

H. Toyokawa, NIM A545, p. 469 (2005) Sample CT images using 10 MeV LCS photon beam

AIST, Tsukaba, Ibaraki, Japan



General Optics, GSI (2008)

Tmin ~ 0.0015%

High Reflectivity Mirrors (1060 – 520 nm)Spec: R > 99.95%Example: transmission 15 ppm @ 780 nm (Vendor measurement)


Intracavity FEL Power MeasurementIntracavity FEL Power MeasurementsEbeam: 514 MeV; FEL beam λ = 545 nm; Collimator: d = 0.75”

HPGe data

Preliminary Results: HPGe data


Industrial and Medical ApplicationsRadiation Therapy and Diagnostics

K. J. Weeks., NIM A393 (1997) p. 544-547.

15 MeV Compton g-beam

g-beam from 15 MeV Linac

Radioisotopes

Cancer treatment: 1012 – 1014 g/s

Diagnostic: 1012 g/s


Industrial and Medical ApplicationsRadiation Therapy and Diagnostics

B Girolami et al. Phys. Med. Biol._v41, p1581(1996).

Radiation Dose for Cancer Treatment

A solid epithelial tumor ranges: 60 - 80 Gy

Lymphoma tumor: 20 – 40 Gy

storage ring compton light sources · 2010-09-09 · dfell, duke university 48th icfa future light...

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