Author: Hotchi, H.
Paper Title Page
MOPPD054 Effect of the 2011 Great East Japan Earthquake in the Injection and Extraction of the J-PARC 3-GeV RCS 490
  • P.K. Saha, H. Harada, H. Hotchi, S.I. Meigo, N. Tani, M. Yoshimoto
    JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan
  In the 3-GeV rapid cycling synchrotron (RCS) of the Japan Proton Accelerator Research Complex (J-PARC), the injection and extraction systems play important roles for the beam injection and extraction, respectively. Unfortunately, the 2011 great east Japan earthquake had a serious impact on the ongoing schedule due to the big damage of the whole accelerator facility and the infrastructure as well. The injection and extraction including the beam transport lines magnets suffered a noticeable displacement resulting with alignment errors. As realignment of the RCS magnets can not be done in this year, then based on the post earthquake measured alignment data, we have estimated the effect as well as possible solutions on the injected and extracted beam for as usual operation. Fortunately, the simulation results shows that there would not be any serious impact on both injected as well as extracted beam with present alignment errors and thus user operation can be resume as expected. The simulation result together with some experimental results will be presented.  
TUPPC019 Beam Dynamics Simulations of J-PARC Main Ring for Damage Recovery from the Tohoku Earthquake in Japan and Upgrade Plan of Fast Extraction Operation 1200
  • Y. Sato, K. Hara, S. Igarashi, T. Koseki, K. Ohmi, C. Ohmori
    KEK, Ibaraki, Japan
  • H. Hotchi
    JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan
  Magnets of Japan Proton Accelerator Research Complex (J-PARC) were shaken by the Tohoku Earthquake in Japan on March 11th, 2011. The alignment of J-PARC Main Ring (MR) received 20 mm displacement horizontally and 6 mm vertically. Beam dynamics simulations were performed to estimate the effect of the displacement on closed orbit distortions and beam loss in fast extraction (FX) operation of J-PARC MR. Based on the simulation results, we concluded that re-alignment of J-PARC MR was needed to achieve high-power beam. The re-alignment of MR was finished on October 28th, 2011. We also considered the effects of the earthquake on the upstream of MR to establish our upgrade plan, which was based on beam dynamics simulations optimizing collimator balance of injection beam transport (3-50BT) and MR, and RF patterns. J-PARC MR FX operation was resumed from December 2011.  
WEOAA03 Development of the Beam Halo Monitor in the J-PARC 3-GeV RCS 2122
  • M. Yoshimoto, N. Hayashi, H. Hotchi, M. Kinsho, S.I. Meigo, K. Okabe, P.K. Saha, K. Yamamoto
    JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan
  Transverse beam halo is one of the most important beam parameters due to limit the performance of the high intensity beam accelerator. Therefore the transverse beam halo measurement is required to increase the beam power of the J-PARC 3-GeV RCS. Transverse halo monitors, which are horizontal and vertical scanning aluminum plates type, has been installed in the extraction beam line. But the residual secondary electrons hindered the beam halo diagnostic. Thus we develop the new beam halo monitor with vibrating wire monitor.  
slides icon Slides WEOAA03 [6.701 MB]  
WEPPP085 Study on the Realignment Plan for J-PARC 3 GeV RCS after the Tohoku Earthquake in Japan 2909
  • N. Tani, H. Hotchi
    JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan
  J-PARC 3GeV RCS suffered the big damage to its building and cooling and electric facilities by the Tohoku Region Pacific Coast Earthquake on March 11, 2011. After the earthquake, RCS magnets were measured to confirm the state of accelerator beam line. As a result, it was found out that there was an alignment error of several millimeters in both horizontal and vertical directions that caused a deformation in the J-PARC 3GeV RCS tunnel. In this paper, we report the survey result in the accelerator tunnel after the earthquake and the realignment plan for J-PARC 3GeV RCS.  
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.  
THPPP080 Beam Halo Reduction in the J-PARC 3-GeV RCS 3918
  • H. Hotchi, H. Harada, P.K. Saha, Y. Shobuda, F. Tamura, K. Yamamoto, M. Yamamoto, M. Yoshimoto
    JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan
  • Y. Irie, T. Koseki, Y. Sato, M.J. Shirakata
    KEK, Ibaraki, Japan
  • K. Satou
    J-PARC, KEK & JAEA, Ibaraki-ken, Japan
  The J-PARC RCS (3-GeV rapid cycling synchrotron) has two functions as a proton driver to the MLF (Materials and life science facility) and an injector to the MR (50-GeV main ring synchrotron). One of important issues in the current RCS bam tuning is to suppress the beam halo formation, which is essential especially to reduce the beam loss at the MR. In this paper, we present beam study results on the formation mechanism and reduction of the beam halo in the RCS.  
THPPP081 Status of Injection Energy Upgrade for J-PARC RCS 3921
  • N. Hayashi, H. Harada, H. Hotchi, J. Kamiya, P.K. Saha, Y. Shobuda, T. Takayanagi, N. Tani, M. Watanabe, Y. Watanabe, K. Yamamoto, M. Yamamoto, Y. Yamazaki, M. Yoshimoto
    JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan
  • T. Toyama
    J-PARC, KEK & JAEA, Ibaraki-ken, Japan
  The injection energy upgrade for J-PARC RCS is planed in 2013. This includes the power supplies upgrade of injection pulsed magnet system, suppression for leakage field, quadrupole correction magnets, reduction of kicker impedance effect and improvements of beam diagnostic instrumentation. The paper reports the present status.