Design, fabrication, and testing of low-group-velocity S-band traveling-wave accelerating structure  

作　　者：Xian-Cai Lin Hao Zha Jia-Ru Shi Liu-Yuan Zhou Yi-Fan Liang Jian Gao Qiang Gao Huai-Bi Chen Chuan-Xiang Tang 

机构地区：[1]Department of Engineering Physics,Tsinghua University,Beijing 100084,China [2]Key Laboratory of Particle and Radiation Imaging(Tsinghua University),Ministry of Education,Beijing 100084,China

出　　处：《Nuclear Science and Techniques》2022年第11期133-143,共11页核技术（英文）

基　　金：supported by the National Natural Science Foundation of China(NSFC)(Nos.11922504 and 12027902).

摘　　要：To implement the Tsinghua Thomson Scattering X-ray Source upgrade plan and the Very Compact Inverse Compton Scattering Gamma-ray Source (VIGAS) program, a new 1.5-m traveling-wave accelerating structure was designed to replace the old 3-m SLAC-type structure with the aim of increasing the accelerating gradient from15 to 30 MV/m. The new type of structure works in the 3π/4 mode with a comparatively low group velocity varying from 0.007c to 0.003c to increase the accelerating gradient at a given power. An elliptical iris was employed to reduce the surface field enhancement. The filling process of the low-group-velocity structure was analyzed using a circuit model. After fabrication, the structure was precisely tuned using the non-contact tuning method, followed by detailed low-power radiofrequency measurements. The structure was first installed and utilized at a beamline for the terahertz experiment at Tsinghua University. After 120 h of conditioning, it is now operating at a gradient of 24.2 MV/m and a 20.7-MW input power, with the klystron operating at its full power. It is expected to generate an accelerating gradient of 30 MV/m when the klystron power is upgraded to 30 MW in the near future.

关 键 词：Traveling-wave accelerating structure Cavity optimization Tuning method High-power test 

分 类 号：O434.1[机械工程—光学工程]