• G. Isoyama, S. Kashiwagi, R. Kato
  ISIR, Osaka
• H. Hayano, T. Muto, J. Urakawa
  KEK, Ibaraki
• M. Kuriki
  HU/AdSM, Higashi-Hiroshima

Funding: This research is partly supported by the accelerator support program to universities conducted by the High Energy Accelerator Research Organization in Japan.
We have begun a three-year project to develop a photocathode rf electron gun for the 40 MeV L-band linac at ISIR, Osaka University in collaboration with KEK. The L-band linac with an rf frequency of 1.3 GHz is equipped with a thermionic electron gun and it can accelerate a high-intensity single-bunch electron beam with charge up to 91 nC/bunch. Because the large emittance of ~100 pi mm x mrad is a limiting factor in the experiments, it is required to develop a new electron gun capable of providing an electron beam with much lower emittance. Since a group at the Accelerator Laboratory of KEK is developing a photocathode rf electron gun in the L-band for the International Linear Collider Project, we have joined the group to learn how to develop such an rf gun and also to obtain support from KEK. In this first year, characteristics of the rf gun will be measured at KEK for ILC fabricated by FNAL. We plan to optimize the structure of the rf gun for ISIR with computer simulation. We will report the plan and progress to develop a photocathode rf gun for the L-band linac.

• Y. Kato, A. Fujita, Y. Hama, T. Hirose, C. Igarashi, A. Masuda, A. Murata, T. Nomoto, K. Sakaue, T. Suzuki, M. Washio
  RISE, Tokyo
• H. Hayano, T. Takatomi, N. Terunuma, J. Urakawa
  KEK, Ibaraki
• Y. Kamiya
  University of Tokyo, Tokyo
• S. Kashiwagi
  ISIR, Osaka
• M. Kuriki
  HU/AdSM, Higashi-Hiroshima
• R. Kuroda
  AIST, Tsukuba, Ibaraki

Funding: Work supported by MEXT High Tech Research Project HRC707, JSPS Grant-in-Aid for Scientific Research (B)(2) 16340079
At Waseda University, we have been developing a high quality electron source based on photo-cathode rf gun which has a Cs-Te cathode with high quantum efficiency. Until now, at the Waseda University we have succeeded the soft X-ray generation via inverse-Compton scattering and pulse radiolysis system for studying the early processes of radiation chemistry with electron beams generated by copper cathode rf gun. Cs-Te rf gun is expected to generate higher charge electron bunches with a low emittance than a copper cathode because of its high quantum efficiency and also the high-quality multi-bunch electron beams. That enables us to extend the range of electron beam parameters for our application experiments. However, a Cs-Te cathode has a short life compared with a copper, so it has to be exchanged occasionally, thus we have developed a new rf-gun cavity which can be attached the compact cathode load-lock system. Moreover, we improved the design of an existing rf-gun cavity for the reduction of the dark current and the higher electric field. In this conference, the performance of the improved cavity and the result of electron beam generation experiments will be reported.

• Y. Iwashita
  Kyoto ICR, Uji, Kyoto
• H. Hayano, K. Watanabe
  KEK, Ibaraki

Inspections of superconducting rf cavities seem essential in achieving high achieving gradient. The inspection of interior surface of a superconducting rf cavity with high enough resolution to find defects more than several tens microns is achieved by our high resolution camera system. This system revealed undiscovered defects at just inner sides of the locations predicted by passband-mode and thermometry measurements. This system will help to improve cavity fabrication processs and their yield. This system will be delivered world wide for that purpose. We are planning to widen our activity in this field: developments of new termometry system with easy installation and less cabling and high sensitivity Eddy Current Surface Inspection system for bare niobium sheets. The detailed systems and some preliminary data obtained from the systems will be presented.

• S. Fukuda, M. Akemoto, H. Hayano, H. Honma, H. Katagiri, S. Kazakov, S. Matsumoto, T. Matsumoto, S. Michizono, H. Nakajima, K. Nakao, T. Shidara, T. Takenaka, Y. Yano, M. Yoshida
  KEK, Ibaraki

Phase 0.5 and Phase 1.0 of the Superconducting RF Test Facility (STF) have been developed since 2005 in KEK. We have completed the two rf-sources and they have been used for the evaluation for the components of power distribution system (PDS) and couplers which were installed in the 5m-cryomodules. We have developed some rf components which is used in the power distribution system(PDS). Phase 1.0 have been conducted now and we attempt the R&D of PDS required in ILC project. This report describes the recent status of the rf source of STF in KEK including the modulator, PDS and LLRF.