• K. Umemori, T. Furuya, H. Sakai, T. Takahashi
  KEK, Ibaraki
• M. Sawamura
  JAEA/ERL, Ibaraki
• K. Shinoe
  ISSP/SRL, Chiba

A construction of the Compact ERL is planned in KEK, Japan. A demonstration of the performance of the main linac super-conducting accelerating system is one motivation of the project. We have been designing a cryo-module, which works under CW operation, and contains two 9-cell cavities, with input couplers, frequency tuners and HOM dampers. Most of these components have been specially developed for ERL operation. Two proto-type of the 9-cell cavity were constructed. First one was vertically tested and suffered from field emissions. Second one is now waiting a measurement. High power component tests have been carried out for input coupler. At first, large temperature rise was observed at a ceramic window part due to unexpected dipole resonance. After that, new version of window was designed and successfully passed 20kW CW power with reflection. Proto-types of HOM damper were also constructed. Cooling tests have been performed for them to verify cooling ability against more than 100W heat load, under vacuum condition. A cryo-module will be completed in 2012, and cooling tests and beam tests will follow.

• Y. Yamamoto, H. Hayano, E. Kako, S. Noguchi, M. Satoh, T. Shishido, K. Umemori, K. Watanabe
  KEK, Ibaraki

MHI#10 and #11 cavities are measured in KEK-STF as the s0 plan for ILC. After these vertical tests, they will be sent to J-Lab and tested at least once there. Moreover, two new cavities without HOM coupler are fabricated and measured in STF, which are made by two new vendors (HITACHI and TOSHIBA). As the international collaboration, one cavity from IHEP in Beijing will be sent to KEK, optical inspected, high pressure rinsed and vertical tested. Although MHI#8 cavity for S1-Global reached 38MV/m, it could not achieve ILC specification (35MV/m, 0.8x10⁹) due to the heavy field emission. To overcome this problem, the various tests were done in the stage of the surface treatment. For example, the EP parameters and the rinsing procedure were changed. In this report, the recent results of the vertical tests including the surface treatment in KEK-STF will be presented in detail.