Design, fabrication and tests of a C-band spherical pulse compressor

Compared to traditional SLAC energy doublers (SLEDs), spherical pulse compressors are more compact while maintaining a high energy gain. This paper presents the design, fabrication and tests of a compact C-band pulse compressor for the linear injector of the proposed Jinhua Light Source (JHLS) project and high-power measurements on a 1-meter C-band accelerating structure. It consists of a dual-mode polarized coupler for producing two orthogonal TE11 modes simultaneously, and a spherical resonant cavity working at TE114 modes for storing the energy. Through optimizations, an equivalent power amplification factor of 4.49 can be expected for an input pulse width of 2.5 μs and a compression ratio of 8.33. Based on simulation studies, a prototype of this C-band spherical pulse compressor was then fabricated. Results from low-power radio-frequency (RF) measurements and preliminary high-power tests are in good agreement with simulated values.