Furuya, T.

Paper	Title	Page
MOOPMA04	Crab Cavity Development	36
	Y. Morita, K. Akai, K. Ebihara, T. Furuya, K. Hara, T. Honma, K. Hosoyama, A. Kabe, Y. Kojima, S. Mitsunobu, H. Nakai, K. Nakanishi, M. Ono, Y. Yamamoto KEK, Ibaraki T. Kanekiyo Hitachi Ltd., Hitachi Research Laboratory, Ibaraki-ken K. Okubo, K. Sennyu MHI, Kobe M. M. Rahman University of Chittagong, Chittagong
	Tow superconducting crab cavities, witch will be installed in the KEKB accelerator, is being assembled. The KEKB (KEK B-factory) is a double-ring, asymmetric-energy, high luminosity electron-positron colliding accelerator with a finite angle beam crossing. A purpose of the crab cavities is to deflect the beam-bunch with time-varying RF fields, and to provide the head-on collision at the interaction point (crab crossing scheme). The head-on collision will drastically increase luminosity. The crab cavity is required to have high RF fields (kick voltage) to provide beam-bunch deflection. This mode (crab mode, 509 MHz) is not the lowest order mode (LOM) of the cavity. In order to damp the LOM as well as the HOMs, a coaxial coupler is attached along the beam pipe. Two crab cavities have been fabricated and tested in a vertical cryostat. These cavities have already achieved the required kick voltage. One cavity was recently tested with high RF power in a cryomodule. After some conditioning, this cavity has achieved the required kick voltage. The test revealed some modifications were needed. After improvements, the cavity will be ready for installation.
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TUPMA046	Future Light Source based on Energy Recovery Linac in Japan	172
	T. Kasuga, T. Furuya, H. Kawata, Y. Kobayashi, S. Sakanaka, K. Satoh KEK, Ibaraki R. Hajima JAEA/FEL, Ibaraki-ken N. Nakamura ISSP/SRL, Chiba
	After extensive discussions on the future light source of the Photon Factory at High Energy Accelerator Research Organization (KEK), it has been concluded that a 5 GeV energy recovery linac (ERL) should be the most suitable candidate to foster cutting edge experiments and support a large variety of user needs from VUV to X-rays. On the other hand, Japan Atomic Energy Agency (JAEA), which has already built a low energy (17 MeV) ERL, also proposed its own 5-6 GeV ERL as a light source. These two institutes with a participation of the members of the Institute for Solid State Physics (ISSP) of the University of Tokyo agreed to promote an ERL-based next-generation synchrotron light source in Japan. In order to realize a 5 GeV ERL, it is necessary to construct a prototype ERL with an energy of ~200 MeV and develop several critical components such as electron guns and superconducting accelerating structures. We are planning to construct together the prototype ERL at the KEK site. An R&D team for the prototype ERL is going to be organized in collaboration with accelerator scientists from the other facilities, UVSOR and SPring-8.
WEXMA01	Status of KEKB and Upgrade Plan to SuperKEKB	280
	M. Yoshida, T. A. Agoh, K. Akai, M. Akemoto, A. Akiyama, A. Arinaga, K. Ebihara, K. Egawa, A. Enomoto, J. W. Flanagan, S. Fukuda, H. Fukuma, Y. Funakoshi, K. Furukawa, T. Furuya, J. Haba, K. Hara, T. Higo, S. Hiramatsu, H. Hisamatsu, H. Honma, T. Honma, T. Ieiri, N. Iida, H. Ikeda, M. Ikeda, S. Inagaki, S. Isagawa, H. Ishii, A. Kabe, E. Kadokura, T. Kageyama, K. Kakihara, E. Kako, S. Kamada, T. Kamitani, K.-I. Kanazawa, H. Katagiri, S. Kato, T. Kawamoto, S. Kazakov, M. Kikuchi, E. Kikutani, H. Koiso, Y. Kojima, I. Komada, T. Kubo, K. Kudo, N. K. Kudo, K. Marutsuka, M. Masuzawa, S. Matsumoto, T. Matsumoto, S. Michizono, K. Mikawa, T. Mimashi, S. Mitsunobu, K. Mori, A. Morita, Y. Morita, H. Nakai, H. Nakajima, T. T. Nakamura, H. Nakanishi, K. Nakanishi, K. Nakao, H. Nakayama, S. Ninomiya, Y. Ogawa, K. Ohmi, Y. Ohnishi, S. Ohsawa, Y. Ohsawa, N. Ohuchi, K. Oide, M. Ono, T. Ozaki, K. Saito, H. Sakai, Y. Sakamoto, M. Sato, M. Satoh, K. Shibata, T. Shidara, M. Shirai, A. Shirakawa, T. Sueno, M. Suetake, Y. Suetsugu, R. Sugahara, T. Sugimura, T. Suwada, S. Takano, S. Takasaki, T. Takenaka, Y. Takeuchi, M. Tawada, M. Tejima, M. Tobiyama, N. Tokuda, S. Uehara, S. Uno, N. Yamamoto, Y. Yamamoto, Y. Yano, K. Yokoyama, Ma. Yoshida, S. I. Yoshimoto, K. Yoshino KEK, Ibaraki
	The KEKB is an electron-positron two-ring collider for the leading B meson factory. It consists of an 8 GeV electron ring (HER) and a 3.5 GeV positron ring (LER) and their injector linac. It has been operated since December 1998, and has recently marked the peak luminosity of 16.52 /nb/s. This peak luminosity is obtained under the crab-ready beam optics having the robust operating condition by some efforts to solve the optics problems. The integrated luminosity has also recently exceeded 1.2 /fb /day under the continuous injection mode. We are aiming more luminosity improvement after the crab cavity installation. Further the major upgrade plan for SuperKEKB is expected to achieve 400 /nb/s keeping the baseline of the original proposal and another upgrade plans are also considered towards over 1000 /nb/s based on the recent beam-beam simulation. This paper describes the recent status of KEKB and upgrade plans for SuperKEKB.
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THC2MA03	Design of L-band Superconducting Cavity for the Energy Recovery Linacs	570
	K. Umemori, T. Furuya, S. Sakanaka, T. Suwada, T. Takahashi KEK, Ibaraki H. Sakai, K. Shinoe ISSP/SRL, Chiba M. Sawamura JAEA/ERL, Ibaraki
	The ERL project in Japan has been started with the cooperation of?KEK, JAEA, ISSP and other SR institutes. For the ERL, superconducting cavities are key components to achieve high energy, high current and low-emittance electron beams. One challenging task, required for the cavity, is a strong damping of the higher-order-modes (HOMs), since they could cause the beam-breakup instabilities and the significant heat load on the cryomodule. We are proceeding with the cavity design, which is optimized for ERLs, with concentrating our attention on HOM damping. A large diameter beam-pipe with microwave absorber is adopted as HOM damping scheme. It can extract the HOM power effectively. We have also investigated optimization of the cavity shape for further suppression of the HOMs. In this report, our cavity design and its HOM characteristics are presented.
	Slides