Author: Hatakeyama, S.
Paper Title Page
MOPPD074 Localization of Large Angle Foil Scattering Beam Loss Caused by Multi-Turn Charge-Exchange Injection 535
  • S. Kato
    Tohoku University, Graduate School of Science, Sendai, Japan
  • H. Harada, S. Hatakeyama, J. Kamiya, M. Kinsho, K. Yamamoto, Y. Yamazaki, M. Yoshimoto
    JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan
  In the J-PARC RCS, the significant losses were observed at the branch of H0 dump line and the Beam Position Monitor which was put at the downstream of the H0 dump branch duct. These losses were caused by the large angle scattering of the injection and circulating beam at the charge exchange foil. To realize high power operation, we have to mitigate these losses. So, we started to develop a new collimation system in the H0 branch duct and installed in October 2011. In order to optimize this system efficiently, we primarily focused on the relative angle of collimator block from scattering particles. We simulated behavior of particles scattered by foil and produced by collimator block and researched most optimized position and angle of the collimator block. In this process, we devised the method of angular regulation of collimator block. We present the method of angular regulation and performance of this new collimation system.  
MOPPR030 Various Methods to Measure the Betatron Tune of the Synchrotoron 843
  • S. Hatakeyama
    JAEA/J-PARC, Tokai-mura, Japan
  Generally in the synchrotron, the frequency of transverse oscillation of the bunched beam for each single turn (usually called betatron tune or just "tune") is one of fundamental controllable knobs to avoid the instability of the accelerator. In this report, it is not mentioned about the effect to the beam instability but it is focused to various methods to measure the betatron tune by using bunch-by-bunch transverse beam position. The following items will be presented, (1) least square fitting to the time-domain beam position at specific location. (2) peak finding of the frequency-domain beam position at specific location. (3) phase space analysis of the beam position at specific location.(4) frequency-domain analysis of the beam position in the normalized coordinate at many locations in the ring orbit. For the application to the real accelerator, data of the J-PARC (Japan Proton Accelerator Research Complex) will be shown.  
THPPP005 Space Charge Effect in the Presence of x-y Coupling in J-PARC MR 3731
  • K. Ohmi
    KEK, Ibaraki, Japan
  • S. Hatakeyama
    JAEA/J-PARC, Tokai-mura, Japan
  It is crucial issue to suppress beam loss due to space charge force in J-PARC MR. We focus x-y coupling as a source of the beam loss. x-y coupling is measured by turn-by-turn beam position monitors in J-PARC MR. A space charge simulation under the measured x-y coupling evaluates the beam loss. Tolerance of x-y coupling and how to improve the beam loss are discussed.  
THPPP070 Comparison of the Residual Doses Before and After Resumption of User Operation in J-PARC RCS 3901
  • K. Yamamoto, H. Harada, S. Hatakeyama, N. Hayashi, H. Hotchi, M. Kinsho, R. Saeki, P.K. Saha, M. Yoshimoto
    JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan
  J-PARC Facilities were damaged by East Japan Earthquake in March 2011, but All Facirities resumed a beam operation from December 2012. In this paper, we report and compare the beam loss distribution and the residual doses before and after resumption of user operation in J-PARC RCS.