RIKEN/SPring-8, Hyogo
JASRI/SPring-8, Hyogo-ken
An 8-GeV C-band (5712 MHz) accelerator is employed as a main accelerator for XFEL/SPring-8. Since a C-band accelerating structure generates a high accelerating gradient of higher than 35 MV/m, the total length of the accelerator fits within 400 m, including the injector and three bunch compressors. We use 64 C-band rf units, which consist of 128 accelerating structures, 64 rf pulse compressors and waveguide components, 64 klystrons and modulators, etc. Mass-production of the C-band rf components has been done by several Japanese manufacturers. The components reliability has been improved during the production, and all the components finally have excellent quality. The production quality was also confirmed by a high power rf test. We achieved the accelerating gradient of 40 MV/m without any problem. Since XFEL realizes high bunch compression with precise control of the energy chirp, the rf should be quite stable. We developed a high precision high voltage charger combined with a low-noise klystron modulator. The pulse-to-pulse stability of the PFN voltage was less than 0.01%. Installation of the components started in August 2009 and was now almost completed on schedule.
