| Paper | Title | Page |
|---|---|---|
| MOPC018 | Operation Status of C-band High Gradient Accelerator for XFEL/SPring-8 (SACLA) | 104 |
|
||
|
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). |
||
| TUPS085 | Mass Production Report of C-band Choke Mode Accelerating Structure and RF Pulse Compressor | 1737 |
|
||
| RIKEN and JASRI already completed the construction of XFEL/SPring8. Recently the facility was named “SACLA” (SPring-8 Angstrom Compact Free Electron LAser). The commissioning team succeeded in acceleration of 8 GeV electron beam and observation of the undulator light of 0.8 angstrom wavelength in March 2011. Now the accelerator is stably operated for the XFEL commissioning. In this project, a C-band (5712 MHz) choke mode accelerating structures and C-band RF pulse compressors are employed to obtain a high acceleration gradient of more than 35 MeV/m. We completed the fabrication of 128 accelerating structures, 64 RF pulse compressors, and 64 units of waveguide components and conducted RF measurements on them until May 2010. We report the result of the mass-production of these 64 C-Band units. | ||
| THPC088 | Performance of RF System for XFEL/SPring-8 Injector | 3101 |
|
||
| In the XFEL/SPring-8 accelerator, the RF processing of an injector for the 8-GeV accelerator were carried out during two months after the installation of all the main components of the accelerator was completed in January 2011. To realize stable bunch compression process without the emittance growth, the injector adopts the combination of an extremely low emittance thermionic gun and multi-stage RF cavities for velocity bunching. In addition, in order to reduce the emittance growth occurring at the transition from the velocity bunching to acceleration, the newly developed L-band APS type accelerating structures and a waveguide system were introduced in the injector. Since an intensity of beam current is affected by the slight variations of RF power and phase of these RF equipment, we have carried out thorough countermeasures to complete highly-stabilized RF systems. Consequently, the stability of RF power and phase in rated operating condition of each RF cavity achieved 20 ppm (std.) and 0.06˚ (std.), respectively. In this paper, we describe the stability performances and RF processing of these RF systems in the injector. | ||