High Power Laser and Particle Beams, Volume. 34, Issue 10, 104010(2022)
A very compact inverse Compton scattering gamma-ray source
Figures & Tables(21)
Fig. 1. Schematic diagram of the very compact inverse Compton scattering gamma-ray source (VIGAS)
Fig. 3. Relation between bunch length and emittance plus energy spread after optimization
Fig. 4. Pareto front of emittance and bunch length with 200 pC bunch charge and 500 pC bunch charge
Fig. 5. Beam dynamics simulation results in the case of 200 pC bunch charge
Fig. 6. Bunch energy and emittance versus the ratio of acceleration gradient
Fig. 11. Photon bandwidth and the proportion within the collection angle versus the collection angle
Fig. 12. Photon spectroscopy within different collection angles using 800 nm scattering laser
Fig. 13. Photon spectroscopy within different collection angles using 400 nm scattering laser
Fig. 14. Photon spectroscopy in simulation taking jitter into consideration
Table 1. Performance parameters of VIGAS
View tableView in ArticleTable 1. Performance parameters of VIGAS
parameter value γ ray photon energy continuously adjustable between 0.2～4.8 MeV relative bandwidth (RMS)/% ＜1.5 (after collimation) photon yield/(photons·s−1) ＞4.0×108@0.2～2.4 MeV；＞1.0×108@2.4～4.8 MeV photon yield within 1.5% bandwidth ＞4.0×106@0.2～2.4 MeV; ＞1.0×106@2.4～4.8 MeV degree of polarization adjustable from linear to circular polarization
Table 2. Parameters of electron beam in VIGAS
View tableView in ArticleTable 2. Parameters of electron beam in VIGAS
parameter value bunch energy/MeV 50～350 bunch charge/pC ＞200 normalized emittance/(mm·mrad) ＜0.6 bunch length/ps ＜2 energy spread/% ＜0.3 focused spot size/µm ＜20 repetition rate/Hz 10
Table 3. Parameters of scattering laser in VIGAS
View tableView in ArticleTable 3. Parameters of scattering laser in VIGAS
parameter value 800 nm 400 nm bandwidth/nm ＜15 ＜8 pulse energy/J ＞1.5 ＞0.8 pulse length (FWHM)/ps ＜10 focused spot size (RMS)/μm ＜10
Table 4. Variable parameters in the optimization
View tableView in ArticleTable 4. Variable parameters in the optimization
parameters range optimization result 200 pC 500 pC laser duration/ps [4, 20] 7.27 7.09 laser beam size (RMS)/mm [0.2, 2] 0.2 0.33 launch phase/(°) [−20, 20] 5.4 3.0 gun solenoid strength/T [0.15, 0.35] 0.2024 0.2018 gun solenoid center/m [0.213 7, 0.213 7] 0.2137 0.2137 buncher field strength/(MV·m−1) [20, 50] 36.1 43.4 buncher center/m [0.73, 0.9] 0.9665 0.9665 buncher phase/(°) [−110, −80] −100 −98.5 linac center/m [1.5, 2] 2.402 2.402 linac solenoid center/m [1.5, 2] 1.6 1.6 linac solenoid strength/T [0, 0.2] 0.0804 0.109
Table 5. Optimized beam parameters with 200 pC bunch charge and 500 pC bunch charge
View tableView in ArticleTable 5. Optimized beam parameters with 200 pC bunch charge and 500 pC bunch charge
normalized emittance/(μm·rad) bunch length (RMS)/mm bunch energy/MeV energy spread (RMS)/MeV bunch charge/pC 0.294 0.208 361.3 0.45 200 0.623 0.202 361.5 0.40 500
Table 6. Parameters of the driving laser system
View tableView in ArticleTable 6. Parameters of the driving laser system
parameters value central wavelength/nm 267 repetition rate/Hz 10 pulse energy/μJ 2～500 pulse width (FWHM)/ps 5-10 rising and falling edge (10%～90%)/ps 1.0 beam size (RMS)/mm 0.2～2 energy jitter (RMS)/% ＜2.0 time jitter between RF and laser (RMS)/ps ＜0.1
Table 7. Parameter jitter range in the joint parameter sweep
View tableView in ArticleTable 7. Parameter jitter range in the joint parameter sweep
parameters jitter range bunch charge/% $ \pm 2 $ laser duration/% $ \pm 2 $ laser beam size/% $ \pm 2 $ gun field strength/% $ \pm 0.1 $ gun phase $ \pm 0.5 $ buncher field strength/% $ \pm 0.1 $ buncher phase $ \pm 0.5 $ S band linac field strength/% $ \pm 0.1$ S band linac phase $ \pm 0.5 $ X band linac field strength/% $ \pm 0.1 $ X band linac phase $ \pm 1 $ scattering laser pulse energy/% $ \pm 2$ relative position between electron and laser beam/μm $ \pm 3 $ arrival time/ps $ \pm 0.25 $
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Yingchao Du, Han Chen, Hongze Zhang, Qiang Gao, Qili Tian, Zhijun Chi, Zhi Zhang, Hao Zha, Jiaru Shi, Lixin Yan, Rui Qiu, Cheng Cheng, Taibin Du, Renkai Li, Huaibi Chen, Wenhui Huang, Chuanxiang Tang. A very compact inverse Compton scattering gamma-ray source[J]. High Power Laser and Particle Beams, 2022, 34(10): 104010
Paper Information
Category: Free Electron Laser and New Light Source
Received: Apr. 29, 2022
Accepted: --
Published Online: Sep. 9, 2022
The Author Email: Tang Chuanxiang (tang.xuh@mail.tsinghua.edu.cn)
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