• S. Sakanaka, M. Akemoto, T. Aoto, D.A. Arakawa, S. Asaoka, 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. Katagiri, H. Kawata, Y. Kobayashi, Y. Kojima, T. Matsumoto, H. Matsushita, S. Michizono, T.M. Mitsuhashi, T. Miura, T. Miyajima, H. Miyauchi, S. Nagahashi, H. Nakai, H. Nakajima, E. Nakamura, K. Nakanishi, K. Nakao, T. Nogami, S. Noguchi, S. Nozawa, T. Obina, S. Ohsawa, T. Ozaki, C.O. Pak, H. Sakai, H. Sasaki, Y. Sato, K. Satoh, M. Satoh, T. Shidara, M. Shimada, T. Shioya, T. Shishido, T. Suwada, M. Tadano, T. Takahashi, R. Takai, T. Takenaka, Y. Tanimoto, M. Tobiyama, K. Tsuchiya, T. Uchiyama, A. Ueda, K. Umemori, K. Watanabe, M. Yamamoto, S. Yamamoto, Y. Yamamoto, Y. Yano, M. Yoshida
  KEK, Ibaraki
• M. Adachi, M. Katoh, H. Zen
  UVSOR, Okazaki
• R. Hajima, R. Nagai, N. Nishimori, M. Sawamura
  JAEA/ERL, Ibaraki
• H. Hanaki
  JASRI/SPring-8, Hyogo-ken
• H. Iijima, M. Kuriki
  HU/AdSM, Higashi-Hiroshima
• I. Ito, H. Kudoh, N. Nakamura, S. Shibuya, K. Shinoe, H. Takaki
  ISSP/SRL, Chiba
• H. Kurisu
  Yamaguchi University, Ube-Shi
• M. Kuwahara, T. Nakanishi, S. Okumi
  Nagoya University, Nagoya
• S. Matsuba
  Hiroshima University, Graduate School of Science, Higashi-Hiroshima
• T. Muto
  Tohoku University, School of Scinece, Sendai
• K. Torizuka, D. Yoshitomi
  AIST, Tsukuba

Future synchrotron light source using a 5-GeV-class energy recovery linac (ERL) is under proposal by our Japanese collaboration team, and we are conducting active R&D efforts for that. We are developing super-brilliant DC photocathode guns, two types of cryomodules for both injector and main superconducting linacs, 1.3 GHz high CW-power rf sources, and other important components. We are also constructing a compact ERL for demonstrating the recirculation of low-emittance, high-current beams using those key components. We present our recent progress in this project.

• T. Sugimura, M. Akemoto, D.A. Arakawa, A. Enomoto, S. Fukuda, K. Furukawa, T. Higo, H. Honma, M. Ikeda, E. Kadokura, K. Kakihara, T. Kamitani, H. Katagiri, M. Kurashina, S. Matsumoto, T. Matsumoto, H. Matsushita, S. Michizono, K. Mikawa, T. Miura, H. Nakajima, K. Nakao, Y. Ogawa, S. Ohsawa, M. Satoh, T. Shidara, A. Shirakawa, T. Suwada, T. Takenaka, Y. Yano, K. Yokoyama, M. Yoshida
  KEK, Ibaraki

The next generation B-factory 'SuperKEKB' project whose target luminosity is 8 ×10³⁵ cm^-2s^-1 is under consideration. A 'nano-beam scheme' is introduced to the SuperKEKB. In the scheme, an electron beam (Energy = 7 GeV, Charge = 3-4 nC/bunch, Vertical emittance =2.8 x 10^-5 m) and a positron beam (Energy = 4 GeV, Charge = 4 nC/bunch, Vertical emittance = 1.6 x 10^-5 m), are required at the end of injector linac. They are quite challenging targets for the present linac. In order to meet the requirements, we will introduce some new components to the linac. They are a photo-cathode RF gun for an electron beam, a positron capture section using new L-band cavities, a newly designed positron-generation target system and a damping ring for a positron beam. This presentation shows a strategy of our injector upgrade.