• S. Sakanaka, M. Akemoto, T. Aoto, D.A. Arakawa, A. Enomoto, S. Fukuda, K. Furukawa, T. Furuya, K. Haga, K. Hara, K. Harada, T. Honda, Y. Honda, H. Honma, T. Honma, K. Hosoyama, M. Isawa, E. Kako, T. Kasuga, H. Kawata, M. Kikuchi, Y. Kobayashi, Y. Kojima, T. Matsumoto, H. Matsushita, S. Michizono, T.M. Mitsuhashi, T. Miura, T. Miyajima, T. Muto, S. Nagahashi, T. Naito, H. Nakai, H. Nakajima, E. Nakamura, K. Nakanishi, T. Nogami, S. Noguchi, T. Obina, S. Ohsawa, T. Ozaki, S. Sasaki, K. Satoh, M. Satoh, T. Shidara, M. Shimada, T. Shioya, T. Shishido, T. Suwada, T. Takahashi, R. Takai, Y. Tanimoto, M. Tawada, M. Tobiyama, K. Tsuchiya, T. Uchiyama, K. Umemori, K. Watanabe, M. Yamamoto, S. Yamamoto, Y. Yamamoto
  KEK, Ibaraki
• R. Hajima, H. Iijima, N. Kikuzawa, E.J. Minehara, R. Nagai, N. Nishimori, M. Sawamura
  JAEA/ERL, Ibaraki
• H. Hanaki
  JASRI/SPring-8, Hyogo-ken
• A. Ishii, I. Ito, T. Kawasaki, H. Kudo, N. Nakamura, H. Sakai, S. Shibuya, K. Shinoe, T. Shiraga, H. Takaki
  ISSP/SRL, Chiba
• M. Katoh
  UVSOR, Okazaki
• M. Kuriki
  HU/AdSM, Higashi-Hiroshima
• S. Matsuba
  Hiroshima University, Graduate School of Science, Higashi-Hiroshima
• K. Torizuka, D. Yoshitomi
  AIST, Tsukuba

Future synchrotron light source project using an energy recovery linac (ERL) is under proposal at the High Energy Accelerator Research Organization (KEK) in collaboration with several Japanese institutes such as the JAEA and the ISSP. We are on the way to develop such key technologies as the super-brilliant DC photo-injector and superconducting cavities that are suitable for both CW and high-current operations. We are also promoting the construction of the Compact ERL for demonstrating such key technologies. We report the latest status of our project, including update results from our photo-injector and from both superconducting cavities for the injector and the main linac, as well as the progress in the design and preparations for constructing the Compact ERL.

• N. Iida, K. Furukawa, M. Ikeda, T. Kamitani, M. Kikuchi, E. Kikutani, Y. Kobayashi, T. Mimashi, T.M. Mitsuhashi, T. Miura, Y. Ogawa, Y. Ohnishi, S. Ohsawa, M. Satoh, M. Suetake, T. Suwada, M. Tawada, A. Ueda, Y. Yano, K. Yokoyama, M. Yoshida
  KEK, Ibaraki

The e+/e^- injector LINAC in KEK usually successively injects into four rings, which are Low Energy Ring (LER) of KEKB (3.5GeV/e+), High Energy Ring (HER) of KEKB (8.0GeV/e-), Photon Factory (PF) (2.5GeV/e-) and Advanced Ring for pulse X-rays (PF-AR) (3.0GeV/e-). While LINAC continuously injects into LER and HER alternatively every about five minutes, keeping both of KEKB rings almost their full operating currents. It takes about one minute to switch beam mode of LINAC. PF and PF-AR are injected a few times in a day. Time for PF or PF-AR including mode-switch had taken about 20 minutes for each other. For PF injection, the switching time was shortened in 2005 and the occupancy time is about 5 minutes. In 2008, we succeeded to make the switching time shorter, 2 seconds for HER/LER, and Pulse-to-pulse alternatively injection for PF/HER using an event system. Especially for KEKB, the short switching time is contributed to provide high currents and to improve luminosity at which beam lives are too short to keep the high currents. In 2009, we have a plan to inject also for LER/HER pulse-to-pulse alternatively.