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Ebihara, K.

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MOOCMH02 Overview of Short Pulse X-ray Generation using Crab Cavities at SPring-8 39
 
  • T. Fujita, H. Hanaki, T. Nakazato
    JASRI/SPring-8, Hyogo-ken
  • K. Akai, K. Ebihara, T. Furuya, K. Hara, T. Honma, K. Hosoyama, A. Kabe, Y. Kojima, S. Mitsunobu, Y. Morita, H. Nakai, K. Nakanishi, M. Ono, Y. Yamamoto
    KEK, Ibaraki
  • M. Matsuoka, K. Sennyu, T. Yanagisawa
    MHI, Tokyo
  • M. Monde
    Mitsubishi Heavy Industries Ltd. (MHI), Takasago
 
 

We have been developing a system to generate a short pulse X-ray using crab cavities at SPring-8 Storage Ring. The ring holds 30-m long straight sections and the vertical beam size at the center of the straight sections is 6.5 micrometers in standard deviation. If we install four superconducting crab cavities and a mini-pole undulator in one of the straight sections, we can convert the time distribution of the electron bunch into the spatial distribution. After slicing the emitted photons with vertical slits, we can obtain a sub-picosecond X-ray pulse. In this scheme, the maximum repetition rate of the short pulse X-ray is the same as the acceleration frequency of the ring (508MHz) and user experiments at other beam-lines are not disturbed by this short pulse generation. We are planning to install KEKB type crab cavities as vertical deflectors. Phase fluctuation among crab cavities must be reduced less than 14 mdeg in order to avoid residual deflection in the vertical direction. In this paper, we report an overview of the short pulse generation scheme and topics of hardware development for stabilization of the RF phase fluctuation.

 

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MOOCMH03 Beam Commissioning Status of Superconducting Crab Cavities in KEKB 42
 
  • Y. Yamamoto, K. Akai, K. Ebihara, T. Furuya, K. Hara, T. Honma, K. Hosoyama, A. Kabe, Y. Kojima, S. Mitsunobu, Y. Morita, H. Nakai, K. Nakanishi, M. Ono
    KEK, Ibaraki
  • T. Kanekiyo
    Hitachi Technologies and Services Co., Ltd., Kandatsu, Tsuchiura
 
 

Two superconducting crab cavities have been operated stably without any significant trouble for three years in KEKB since Feb/2007. At present (Dec/2009), maximum beam current with 'Crab ON' achieves 1200mA for HER (High Energy Ring, electron) and 1640mA for LER (Low Energy Ring, positron), respectively. RF trip rate per day due to crab cavity during 'physics run' was 2.8/day for HER and 0.4/day for LER at the beginning, and is 0.8/day for HER and 0.1/day for LER at present, respectively. Although Piezo actuator was frequently broken down at the beam abort with RF trip of the crab cavity, it was controlled stably by only LLRF (Low Level RF) feed-back system without Piezo actuator. Maximum HOM (Higher Order Mode) power, which is measured at HOM dampers made from ferrite, is 9.1kW for HER and 14.6kW for LER at the maximum beam current, respectively. LER crab voltage, which had suddenly dropped from 1.50MV to 1.10MV on March/2007, was gradually recovered from 1.14MV to 1.33MV in 2008.

 

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WEOAMH02 Recent Progress of KEKB 2372
 
  • Y. Funakoshi, T. Abe, K. Akai, Y. Cai, K. Ebihara, K. Egawa, A. Enomoto, J.W. Flanagan, H. Fukuma, K. Furukawa, T. Furuya, J. Haba, T. Ieiri, N. Iida, H. Ikeda, T. Ishibashi, M. Iwasaki, T. Kageyama, S. Kamada, T. Kamitani, S. Kato, M. Kikuchi, E. Kikutani, H. Koiso, M. Masuzawa, T. Mimashi, T. Miura, A. Morita, T.T. Nakamura, K. Nakanishi, M. Nishiwaki, Y. Ogawa, K. Ohmi, Y. Ohnishi, N. Ohuchi, K. Oide, T. Oki, M. Ono, M. Satoh, Y. Seimiya, K. Shibata, M. Suetake, Y. Suetsugu, T. Sugimura, Y. Susaki, T. Suwada, M. Tawada, M. Tejima, M. Tobiyama, N. Tokuda, S. Uehara, S. Uno, Y. Yamamoto, Y. Yano, K. Yokoyama, M. Yoshida, S.I. Yoshimoto, D.M. Zhou, Z.G. Zong
    KEK, Ibaraki
 
 

KEKB is an e-/e+ collider for the study of B physics and is also used for machine studies for future machines. The peak luminosity of KEKB, which is the world-highest value, has been still increasing. This report summarizes recent progress at KEKB.

 

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WEPEA034 Development and Operational Status of PF-Ring and PF-AR 2561
 
  • T. Honda, T. Aoto, S. Asaoka, K. Ebihara, K. Furukawa, K. Haga, K. Harada, Y. Honda, T. Ieiri, N. Iida, M. Izawa, T. Kageyama, M. Kikuchi, Y. Kobayashi, K. Marutsuka, A. Mishina, T. Miyajima, H. Miyauchi, S. Nagahashi, T.T. Nakamura, T. Nogami, T. Obina, K. Oide, M. Ono, T. Ozaki, C.O. Pak, H. Sakai, H. Sakai, Y. Sakamoto, S. Sakanaka, H. Sasaki, Y. Sato, K. Satoh, M. Shimada, T. Shioya, M. Tadano, T. Tahara, T. Takahashi, R. Takai, S. Takasaki, Y. Tanimoto, M. Tobiyama, K. Tsuchiya, T. Uchiyama, A. Ueda, K. Umemori, M. Yamamoto, Ma. Yoshida, S.I. Yoshimoto
    KEK, Ibaraki
 
 

KEK manages two synchrotron radiation sources, Photon Factory storage ring (PF-ring) of 2.5 GeV and Photon Factory advanced ring (PF-AR) of 6.5 GeV. These rings share an injector linac with the two main rings of KEK B-factory, 8-GeV HER and 3.5-GeV LER. Recently, the linac has succeeded in a pulse by pulse multi-energy acceleration. A top-up operation of PF-ring has been realized as the simultaneous continuous injection to the 3 rings, PF-ring, HER and LER. Development of new injection scheme using a pulsed sextupole magnet continues aiming at practical use in the top-up operation. A rapid-polarization-switching device consisting of tandem two APPLE-II type undulators has been developed at PF-ring. The first undulator was installed in 2008, and the second one will be installed in 2010 summer. PF-AR, operated in a single-bunch mode at all times, has been suffered from sudden lifetime drop phenomena attributed to dust trapping for many years. Using the movable electrodes installed for experiment, we confirmed that the discharge created by the electrode was followed by the dust trapping, and succeeded in a visual observation of luminous dust streaking in front of CCD cameras.