Author: Shirasawa, K.
Paper Title Page
MOPC018 Operation Status of C-band High Gradient Accelerator for XFEL/SPring-8 (SACLA) 104
 
  • T. Inagaki, C. Kondo, T. Ohshima, Y. Otake, T. Sakurai, K. Shirasawa
    RIKEN SPring-8 Center, Sayo-cho, Sayo-gun, Hyogo, Japan
  • T. Shintake
    RIKEN Spring-8 Harima, Hyogo, Japan
 
  XFEL project in SPring-8 have constructed a compact XFEL facility*. In order to shorten an accelerator length, a C-band (5712 MHz) accelerator was employed due to a higher accelerating gradient than that of an S-band accelerator. Since a C-band accelerating structure generates a gradient of higher than 35 MV/m, the total length of an 8 GeV accelerator fits within 400 m, including 64 C-band RF units, 4 S-band RF units, an injector and three bunch compressors. The accelerator components were carefully installed by September 2010. Then we have performed high power RF conditioning. After 500 hours of the conditioning, the accelerating gradient of each C-band structure was reached up to 35 MV/m without any particular problem. The RF breakdown rate is low enough for an accelerator operation. Since February 2011, we started the beam commissioning for XFEL. The C-band accelerator has accelerated the electron beam up to 8 GeV, with an accelerating gradient of 33-35 MV/m in average. The energy and the trajectory of the electron beam was stable, thanks to the stabilization of a klystron voltage of 350 kV within 0.01% by a high precision high voltage charger.
*The facility was recently named SACLA (SPring-8 Angstrom Compact free electron LAser).