Storage Ring Compton Gamma Sources

Transcription

1 Storage Ring Compton Gamma Sources DFELL, Triangle Universities Nuclear Laboratory Department of Physics, Duke University August 30, 2010 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 Work supported by U.S. Grant and Contract: DOE DE-FG02-01ER41175 and AFOSR MFELFA

2 A Compton Light Source is An Electron-Photon Collider 2

3 Outline Compton Gamma-ray Sources A brief historical overview Major storage ring Compton gamma-ray facilities and new projects High Intensity Gamma-ray Source (HIGS) Accelerator facility Operation modes Beam diagnostics Optical resonator issues Performance summary Research and Applications of Compton Gamma-ray Beams Critical Issues for Storage Ring Compton Gamma Sources Impacts on storage ring operation with a Compton gamma source Critical issues for developing ring based Compton gamma sources 3

4 History of Storage Ring Based Compton Gamma Facilities H.R. Weller et al. Progress in Particle and Nuclear Physics 62, p (2009). From LADON to HIGS ( , about 30 years) Total flux: gamma/sec; Flux increment: > 10 times/decade 4

5 New Ring Based Compton Source Projects New Compton Source Projects in Planning and Development Shanghai Laser Electron Gamma Source (SLEGS), SSRF 3.5 GeV electron beam New parameters Old parameters from 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). Compton Gamma Source Project at Canadian Light Source 2.9 GeV and circulating current of 500 ma A CO2 laser or solid state lasers of powers >100W Top up mode of operation of the storage ring Total photon flux: up to few 109 γ/s Gamma energies: up to 15 MeV Where necessary, tagging will be employed C. Rangacharyulu, University of Saskatchewan, Saskatoon, Saskatchewan, Canada, private communication (2010). 5

6 Major Storage Ring Based Compton Gamma Source Facilities Around the World Past, Present, and Future Past Facilities: LADON, LEGS, GRAAL; Operational Facilities: HIGS, LEPS Canadian LS MAX-Lab ROKK GRAAL LEGS HIGS LADON LEPS SLEGS 6

7 A Storage Ring Compton Gamma Source High Intensity Gamma-ray Source (HIGS) at Duke University 7

8 High Intensity Gamma-ray Source (HIGS) at Duke University - World's Most Powerful Compton Gamma-ray Source 9 International Collaborating Institutions 22 US Collaborating Institutions Industrial Partners 8

9 HIGS Accelerators High Intensity Gamma-ray Source (HIGS) Accelerators Recent Accelerator Upgrades New lattice for OK-5 FEL New HOM-damped RF cavity New OK-5 FEL with circular polarization A New Booster synchrotron for top-off injection Typical User Operation Modes FEL: single-bunch, up to 95 ma HIGS: two-bunch, ma 9

10 HIGS Accelerators Full Energy, Top-off Booster Injector ( GeV) 2009 Performance Injection: MeV Extraction: GeV Cycle time: sec (one to six bunches) Charge into storage ring: nc/sec Injection energy [GeV] Maximum energy [GeV] Circumference [m] RF frequency [MHz] Harmonic number Operation cycle [sec] Emittance ex, ey [nm.rad] Betatron tunes Qx/Qy Momentum compaction / /

11 HIGS Accelerators OK-5 and OK-4 FELs (Since Aug. 2005) OK-5 helical wiggler, OK-5A OK-4 Planar wigglers OK-5 helical wiggler, OK-5B m OK-5 wigglers OK-4 wigglers et al., High-Gain Lasing and Polarization Switch with a Distributed Optical-Klystron Free-Electron Laser, Phys. Rev. Lett. 96, (2006). 11

12 HIGS Research Operation Principle of HIGS 52.8 m 12

13 HIGS Research Operation Modes of HIGS Operation Modes of HIGS Qusi-CW operation vs Pulsed High-flux vs high energy resolution FWHM 13

14 HIGS Research High Energy-Resolution Operation Asymmetric Bunch Pattern: one large (lasing) and one small (non-lasing) Improving stability of gamma energy resolution and increase flux Develop a reliable way to measure bunch pattern, and An automatic injection scheme to maintain charge distribution 14

15 Beam Diagnostics/Feedback Aiming Stability of Gamma-ray Beam E-beam horizontal angle at Collision Point 15

16 Beam Diagnostics/Feedback Bunch Length and FEL Spectrum Monitors Beam Diagnostics Live Spectrum Monitor Live bunch length monitors 349 MeV, 27 ma 16

17 HIGS Research Stability of Gamma Operation in Electron-loss Mode Current Current Gamma flux Gamma flux with closed apertures 17

18 High-Finesse FEL Resonator High Reflectivity FEL Mirrors Mirror degradation Carbon deposition on the surface Vertical Horizontal 780 nm, CCV020, downstream cavity mirror, D=50 mm 18

19 Intracavity FEL Power Measurement Experimental Layout Ebeam: 514 MeV, about 88 ma in two equally populated bunches FEL beam = 545 nm; Gamma-beam collimator: d = 0.75 Collimated (d=3/4 ), -beam image Collimated flux: 3.68% 12m 19

20 Intracavity FEL Power Measurement Intracavity FEL Power Measurements: -Spectrum Ebeam: 514 MeV, about 88 ma in two equally populated bunches FEL beam = 545 nm; Gamma-beam collimator: d = 0.75 C. Sun et al. NIMA 605, p 312(2009) Avg Flux Density from 11B at MeV True -spectrum 11B data: Pb = 800 (+/-100) W, PFEL = 1.6 kw (+/- 0.2 kw) 20

21 Intracavity FEL Power Measurement Intracavity FEL Power Measurements Ebeam: 514 MeV; FEL beam = 545 nm; Collimator: d = 0.75 HPGe data Preliminary Results: HPGe data with 9 Mev Gamma-ray beam Max total flux: 1.6 (+/-0.2) x1010 γ/s 21

22 Gamma Energy Tuning Range with OK-5 FEL (3.5 ka) HIGS Eγ: MeV Ebeam: GeV FEL: nm 22

23 HIGS Performance HIGS Capabilities for User Programs in 2010 Parameter E-beam Configuration E-beam current [ma] Gamma-ray Energy [MeV] Value Symmetric two-bunch beam (a) No-loss mode Total flux [γ /s] 1 3 MeV (a) 3 5 MeV 5 13 MeV MeV (b) Loss mode 1 x x x x x x x x 10 9 Total flux [γ /s] MeV MeV 10 8 (b) >2x 1 2 x 10 8 (b) (c) Collimated flux ( E/E ~ 5%) [γ /s] 6 x x x x x x x x 10 8 Collimated flux ( E/E ~ 5%) [γ /s] > 1 x x 10 7 Comments High flux configuration with mirrors 1064 to 190 nm Available with existing hardware Extending wiggler current to 3.5 ka Both Horizontal and Circular Polarizations To extend mirror lifetime, circular polarization is preferred 190 nm mirrors, Fall 2010 or 2011 With present configuration of OK 5 wigglers separated by 21 m, the circular polarization is about ½ the values here. The flux in loss mode is mainly limited by injection rate. (c) Thermal stability of FEL mirror may limit the maximum amount of current can be used in producing FEL lasing, thus flux. (a) (b) Highest Total Flux (2009): > 1010 γ 9 11 MeV Promised user parameters: 1/2 to 1/3 of the highest flux realized with new optics Workshop on H. R. Weller et al., Research Opportunities at the Upgraded HIγ S Facility, Prog. Part. Nucl. Phys. Vol 62, Issue 1, p (2009). Development and Application of SLEGS, Aug. 30,

24 Nuclear Physics and Astrophysics Scientific Research Programs at HIGS Physics Research Nuclear Structure Few-Nucleon Physics Astro-physics Gerasimov-Drell-Hearn (GDH) Sum Rule Compton Scattering from Nucleons HIGS Photon-Pion Physics Workshop on H. R. Weller et al., Research Opportunities at the Upgraded HIγ S Facility, Prog. Part. Nucl. Phys. Vol 62, Issue 1, p (2009). Development and Application of SLEGS, Aug. 30,

25 Applications Research Applications of High Intensity Compton Gamma Beams Some Areas of Applications of Compton Gamma-ray Beams National Security Special nuclear materials detection Energy Industry Nuclear waste management and treatment Medical Applications Isotope production Cancer diagnostics Industrial Applications Industrial product inspection Materials Research Novel scintillators and detectors Applications in fundamental research, space program, industry, and medicine 25

26 Applications Research Nuclear Resonance Fluorescence Technique 138 Ba(γ,γ ) Eγ = 5.40 ± 0.11 MeV 90 Zr(γ,γ ) Eγ = 8.10 ± 0.40 MeV High detection sensitivities: resonance states with Γtot 1meV Courtesy of Anton Tonchev, TUNL&Duke U. S. Hammond et al, TUNL&UNC-CH 26

27 Applications Applications of Nuclear Resonance Fluorescence (NRF) NRF Applications National Security Cargo inspection for special nuclear materials Nuclear Energy Nuclear waste management using active nondestructive assay (NDA) Medicine Cancer research and diagnostic R1: C. A. Hagmann et al. J. OF Appl. Phys. 106, (2009). R2: R. Walton and H. Menlove, Nondestructive Assay for Nuclear Safeguards, Los Alamos Science, p. 88, summer

28 Applications Applications of High Intensity Compton Gamma Beams 28 From a talk at CLS by H. Weller, TUNL/Duke

29 Applications Research Photofission Research Research at HIGS: A new method to Identify Special Nuclear Materials Using Polarized (g,n) Asymmetry H. R. Weller, M. Ahmed,, TUNL/Duke H. Weller et al, TUNL&Duke 29

30 Applications Applications of Photofission Photonfission Applications National Security Cargo inspection for special nuclear materials Nuclear Energy Nuclear waste management Nuclear waste treatment using transmutation Medicine Medical isotope production 30

31 Applications Applications of Gamma-beam Imaging Gamma-beam Imaging Applications Industrial Applications Nondestructive inspection of industrial products using transmission radiography and Computerized Tomography (CT) 31

32 Applications Research Compton Gamma-beam Radiograph 32 C. Sun and, TUNL&Duke U.

33 Applications Research Compton Gamma-beam Radiograph 33 C. Sun and, TUNL&Duke U.

34 Industrial Applications Compton Gamma-beam Imaging Using CT AIST, Tsukaba, Ibaraki, Japan Radiograph TH571A Tetrode tube Sample CT images using 10 MeV LCS photon beam 34 H. Toyokawa, NIM A545, p. 469 (2005)

35 Space Applications Gamma-ray Telescope Calibration MEGA Project (Max-Planck-Institut für extraterrestrische Physik) Medium Energy Gamma-Ray Astronomy Telescope: 400 kev and 50 MeV Essential component for next-generation astrophysics satellite observatories A tracker: silicon strip detectors + a calorimeter with segmented CsI(Tl) bars MEGA Prototype detector calibrated at HIGS ( ) Workshop on Development and R. Andritschke et al., NewAR 48 (2004) p Application of SLEGS, Aug. 30,

36 Design Considerations for Compton Light Sources Critical Issues Energy Range (x-ray, γ-ray) E 4 2 E ph E ph~1 4.7 ev, 0.1 ev CO2, ev photons, kev x-rays, e-beam: MeV; 1eV photons, kev x-rays, e-beam: 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 Important gamma-ray beam parameters: Energy Flux (γ/s, average, peak) Spectral flux (γ/s/ev, average, peak) Relative energy spread (FWHM) Repetition Rate (Hz) Polarization (degree of polarization, linear, circular, helicity switch) 36

37 Critical Issues for Storage Ring Compton Gamma Sources Impact On the Storage Ring Light Source when Operating Compton Gamma Source as an Optical Insertion Device (OID) Effect of Electron Loss When 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 > Energy Aperture) Good for higher energy gamma operation Limited flux: few 10^6 few 10^7 γ/s Gamma-ray energy determination: Tagging of electrons Prevent electron loss No-loss mode (Energy loss < energy Aperture) Good for lower energy gamma operation High flux possible (greater than 10^9 γ/s, total flux) Gamma-beam energy selection: Collimation of gamma-beam Impact on Operation and Electron Beam Parameters Beam loss and more frequent injections At extremely high flux, Compton gamma-ray source will impact both longitudinal and transverse distributions of the electron beam 37

38 Critical Issues for Storage Ring Compton Gamma Sources Gamma-beam Energy Spread Tagging High gamma beam energies <=> User research programs Additional flux limitation due to tagging rate, 10^5 10^6 e-/s per tagging channel High efficiency: tagging a large amount of Compton gamma-rays: 30% - 60% Energy resolution as limited by the absolute energy spread of the e-beam Reliability issue of tagging signal at high rates Collimation Low gamma beam energies <=> User research programs Fixed gamma energy: if wavelength of laser and the electron beam energy are both fixed; 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 gamma beamline Good e-beam aiming stability Example: 3.5 GeV e-beam, to achieve a γ-beam energy spread (FWHM) of 3%: Half opening angle: ~25 micro-radians If collimator aperture r = 2.5 mm, beamline length ~ 100 m; Stability of ebeam aiming; 2 3 micro-radians 38

39 Summary Summary: A brief historical overview of Compton sources and major storage ring Compton gamma-ray facilities and projects An overview of High Intensity Gamma-ray Source (HIGS) at Duke University A survey of applications of Compton gamma beams Critical issues for storage ring based gamma-ray sources HIGS Summary HIGS Capabilities (2010) Energy Tuning: MeV ( MeV expected in Fall, 2010) Maximum Total Flux: > 1010 γ /s around 9-11 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 and Long-term Development Higher Gamma-beam Energy: MeV for photon-pion physics research Higher-flux Operation: γ /s total, 2-20 MeV in the first stage 39

40 Energy Spread of γ -beam Energy Distribution of Compton Gamma-beam E-beam Energy Spread (Scaled) Collimator Effect (Scaled) Emittance Collimator Effect Effect (Scaled) Monochromatic electron and Effect photon beams New Merit: Degree of Collimation Part of Ph.D. thesis work of Changchun Sun Phys. Rev. ST Accel. Beams 12, (2009) 40

41 HIGS Operation Summary (Aug. 1, 2009 Jul. 31, 2010) 41

42 HIGS Operation Summary (Aug. 1, 2009 Jul. 31, 2010) HIGS beam-on-target: 1452 hr in 8.5 months 170 hr/month 2-shift, 5-day per week operation 42

43 The End 43