RF design of C-band photocathode electron gun for Southern Advanced Photon Source

Liu Shengjin; Jiang Shimin; Liu Xingguang; Xiao Yongchuan; Cao Xiuxia; Lü Yongjia; Li Xiao

doi:10.11884/HPLPB202537.240195

Volume 37 Issue 1

Dec. 2025

Turn off MathJax

Article Contents

Article Navigation > High Power Laser and Particle Beams > 2025 > 37(1): 014005

Liu Shengjin, Jiang Shimin, Liu Xingguang, et al. RF design of C-band photocathode electron gun for Southern Advanced Photon Source[J]. High Power Laser and Particle Beams, 2025, 37: 014005. doi: 10.11884/HPLPB202537.240195

Citation:

Liu Shengjin, Jiang Shimin, Liu Xingguang, et al. RF design of C-band photocathode electron gun for Southern Advanced Photon Source[J]. High Power Laser and Particle Beams, 2025, 37: 014005. doi: 10.11884/HPLPB202537.240195

Citation:

PDF( 2622 KB)

RF design of C-band photocathode electron gun for Southern Advanced Photon Source

doi: 10.11884/HPLPB202537.240195

Liu Shengjin^{1, 2
,},
Jiang Shimin^{1, 2},
Liu Xingguang^{1, 2
,
,},
Xiao Yongchuan^{1, 2},
Cao Xiuxia^{1, 2},
Lü Yongjia^{1, 2},
Li Xiao^{1, 2}

1.
Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049, China
2.
Spallation Neutron Source Science Center, Dongguan 523803, China

Received Date: 2024-06-11
Accepted Date: 2024-11-29
Rev Recd Date: 2024-11-29

Available Online: 2024-12-14

Publish Date: 2025-12-13

Abstract

Abstract

The C-band photocathode electron gun is designed. As one of important equipments for the linear injector of the Southern Advanced Photon Source. This paper discusses its RF and coupler design. The C-band electron gun has a working frequency of 5.712 GHz, a 3.6-cell structure, a π-mode acceleration mode, and it adopts a coaxial coupling method. The CST and Superfish codes are used to optimize the cavity microwave structure, reducing the surface electric field of the cavity to enhance the accelerating field strength and suppressing the multimode transmission. Furthermore, COMSOL Multiphysics is applied to analyze the cavity cooling system, reducing frequency drift caused by the cavity heating. Additionally, a water cooling design for the cavity ensures that the maximum temperature rise of the cavity is less than 20 ℃. Under an input power of 18.15 MW, the acceleration gradient of 180 MV/m on the cathode surface is achieved, the ratio of the acceleration gradient to the cathode surface electric field is approximately 0.93, and the cavity quality factor is greater than 10000. The design of the coupler suppresses the transmission of dipole and quadrupole modes, with the S₁₁ parameter being less than −40 dB.
- Southern Advanced Photon Source,
- photocathode electron gun,
- RF structure,
- coupler,
- C-band

FullText(HTML)

References(24)

References

[1]	Arthur J, Anfinrud P, Audebert P, et al. LCLS-conceptual design report for the LCLS project[EB/OL]. 2002(2002-04-08). http://www-ssrl.slac.stanford.edu/lcls/cdr/.
[2]	Materlik G, Tschentscher T. TESLA technical design report Part 5: the X-ray free electron laser[EB/OL]. 2001. http://tesla.desy.de/newpages/TDRD/PartV/xfel.html.
[3]	Poole M W, Bennett S L, Bowler M A, et al. 4GLS: a new type of fourth generation light source facility[C]//Proceedings of 2003 Particle Accelerator Conference. 2003: 189-191.
[4]	Corlett J N, Barletta W A, DeSantis S, et al. A recirculating linac-based facility for ultrafast X-ray science[C]//Proceedings of 2003 Particle Accelerator Conference. 2003: 186-188.
[5]	Park S J, Park J H, Parc Y W, et al. Status of PPI (Pohang Photo-Injector) for PAL XFEL[C]//Proceedings of 2005 Particle Accelerator Conference. 2005: 1733-1735.
[6]	Kramer D. Closing in on the design of the BESSY-FEL[C]//Proceedings of 2003 Particle Accelerator Conference. 2003: 1083-1085.
[7]	周奎, 李鹏, 周征, 等. 中物院太赫兹自由电子激光装置现状及升级计划[J]. 强激光与粒子束, 2022, 34:104013 doi: 10.11884/HPLPB202234.220091 Zhou Kui, Li Peng, Zhou Zheng, et al. Status and upgrade plan of CAEP THz-FEL facility[J]. High Power Laser and Particle Beams, 2022, 34: 104013 doi: 10.11884/HPLPB202234.220091
[8]	贾豪彦, 黄森林, 焦毅, 等. 超快X射线自由电子激光研究进展[J]. 强激光与粒子束, 2022, 34:054001 doi: 10.11884/HPLPB202234.220056 Jia Haoyan, Huang Senlin, Jiao Yi, et al. Research advances in ultrafast X-ray free-electron lasers[J]. High Power Laser and Particle Beams, 2022, 34: 054001 doi: 10.11884/HPLPB202234.220056
[9]	Vogt M, Faatz B, Feldhaus J, et al. The free-electron laser FLASH at DESY[C]//Proceedings of IPAC2013. 2013: 1167-1169.
[10]	Altarelli M. The European X-ray free-electron laser: toward an ultra-bright, high repetition-rate X-ray source[J]. High Power Laser Science and Engineering, 2015, 3: e18. doi: 10.1017/hpl.2015.17
[11]	Emma P, Akre R, Arthur J, et al. First lasing and operation of an ångstrom-wavelength free-electron laser[J]. Nature Photonics, 2010, 4(9): 641-647. doi: 10.1038/nphoton.2010.176
[12]	Prat E, Abela R, Aiba M, et al. A compact and cost-effective hard X-ray free-electron laser driven by a high-brightness and low-energy electron beam[J]. Nature Photonics, 2020, 14(12): 748-754. doi: 10.1038/s41566-020-00712-8
[13]	Alesini D, Cardelli F, Castorina G, et al. Design of a full C-band injector for ultra-high brightness electron beam[C]//Proceedings of the 10th International Particle Accelerator Conference. 2019: 1979-1982.
[14]	Liu Xiaohan, Tang Chuanxiang, Qian Houjun, et al. Design of a compact C-band high brightness photoinjector for an ultra-fast electron diffraction[J]. Chinese Science Bulletin, 2013, 58(36): 4577-4581. doi: 10.1007/s11434-013-6079-5
[15]	Schaer M, Bettoni S, Citterio A, et al. Study of a C-band standing-wave gun for the SwissFEL injector[C]//Proceedings of the 5th International Particle Accelerator Conference. 2014: 698-700.
[16]	Chen Tingjue, Pei Yuanji, Song Yifan. Design and simulation of a C-band photocathode RF gun with a coaxial coupler for UEM[C]//Proceedings of the 8th International Particle Accelerator Conference. 2017: 525-527.
[17]	Wang Lin, Fang Wencheng, Tan Jianhao, et al. Design, fabrication and cold-test results of a 3.6 cell C-band photocathode RF gun for SXFEL[J]. Nuclear Instruments and Methods in Physics Research Section A, 2021, 1003: 165320. doi: 10.1016/j.nima.2021.165320
[18]	Liu Xingguang, Li Xiao, Jiang Shiming, et al. A C-band test platform for the development of RF photo cathode and high gradient accelerating structures[C]//Proceedings of the 14th International Particle Accelerator Conference. 2023: 1995-1998.
[19]	姜世民, 陆志军, 刘星光, 等. C波段光阴极电子枪驱动激光整形研究[J]. 强激光与粒子束, 2024, 36:104003 doi: 10.11884/HPLPB202436.240162 Jiang Shimin, Lu Zhijun, Liu Xingguang, et al. Study of drive laser shaping system for C-band photocathode RF gun[J]. High Power Laser and Particle Beams, 2024, 36: 104003 doi: 10.11884/HPLPB202436.240162
[20]	Poisson Superfish[EB/OL]. https://laacg.lanl.gov/laacg/services/.
[21]	CST Studio Suite. Computer Simulation Technology (CST)[EB/OL]. https://3ds.com.
[22]	COMSOL Multiphysics software[EB/OL]. https://Comsol.com.
[23]	程诚, 程道喜, 郑曙昕, 等. 新型热阴极电子枪加热结构热分析[J]. 强激光与粒子束, 2010, 22(7):1607-1609 doi: 10.3788/HPLPB20102207.1607 Cheng Cheng, Cheng Daoxi, Zheng Shuxin, et al. Thermal analysis of heating structure for thermionic cathode electron gun[J]. High Power Laser and Particle Beams, 2010, 22(7): 1607-1609 doi: 10.3788/HPLPB20102207.1607
[24]	Rao T, Dowell D H. An engineering guide to photoinjectors[EB/OL]. 2014(2014-03-28). https://doi.org/10.48550/arXiv.1403.7539.