Author: Kinsho, M.
Paper Title Page
TUPVA090 Performance and Status of the J-PARC Accelerators 2290
 
  • K. Hasegawa, N. Hayashi, M. Kinsho, H. Oguri, K. Yamamoto, Y. Yamazaki
    JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan
  • Y. Hori, N. Yamamoto
    J-PARC, KEK & JAEA, Ibaraki-ken, Japan
  • T. Koseki, F. Naito
    KEK, Tokai, Ibaraki, Japan
 
  The J-PARC is a high intensity proton facility and the accelerator consists of a 400 MeV linac, a 3 GeV Rapid Cycling Synchrotron (RCS) and a Main Ring Synchrotron (MR). We have taken many hardware upgrades. The beam powers for the neutrino experiment and hadron experiment from the MR have been steadily increased by tuning and reducing beam losses. The designed 1 MW equivalent beam was demonstrated and user program was performed at 500 kW from the RCS to the neutron and muon experiments. We have experienced many failures and troubles, however, to impede full potential and high availability. In this report, operational performance and status of the J-PARC accelerators are presented.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-TUPVA090  
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TUPVA093 Radio-Activation Caused by Secondary Particles Due to Nuclear Reactions at the Stripper Foil in the J-PARC RCS 2300
 
  • M. Yoshimoto, H. Hotchi, S. Kato, M. Kinsho, K. Okabe, K. Yamamoto
    JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan
 
  The most important issue in realizing such a MW-class high-power routine beam operation is to keep machine activations within a permissible level, that is, to preserve a better hands-on-maintenance environment. Thus, a large fraction of our effort has been concentrated on reducing and managing beam losses. However the high residual activation is appeared around the stripper foils. It is caused by not primary particles due to the beam losses but secondary particles due to nuclear reaction at the foil. This radio-activation is an intrinsically serious problem for the RCS which adopts the charge exchange multi-turn beam injection scheme with the stripper foil. In this presentation, we report a detail measurement of the residual dose around the stripper foil together with the cause estimated based on simulation studies.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-TUPVA093  
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WEPVA062 Improvements of Vacuum System in J-PARC 3 GeV Synchrotron 3408
 
  • J. Kamiya, Y. Hikichi, M. Kinsho, Y. Namekawa, K. Takeishi, T. Yanagibashi
    JAEA/J-PARC, Tokai-mura, Japan
  • A. Sato
    Nippon Advanced Technology Co., Ltd., Tokai, Japan
 
  The RCS vacuum system has been upgraded since the completion of its construction towards the objectives of both better vacuum quality and higher reliability of the components. For the better vacuum quality, (1) pressure of the injection beam line was improved to prevent the H beam from converting to H0; (2) leakage in the beam injection area due to the thermal expansion was eliminated by applying the adequate torque amount for the clamps; (3) new in-situ degassing method of the kicker magnet was developed. For the reliability increase of the components, (1) A considerable number of fluoroelastmer seal was exchanged to metal seal with the low spring constant bellows and the light clamps; (2) TMP controller for the long cable was developed to prevent the controller failure by the severe electrical noise; (3) A number of TMP were installed instead of ion pumps in the RF cavity section as an insurance for the case of pump trouble.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-WEPVA062  
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WEPVA063 Development of a New Pulsed Power Supply with the SiC-MOSFET 3412
 
  • T. Takayanagi, K. Horino, J. Kamiya, M. Kinsho, T. Ueno, K. Yamamoto
    JAEA/J-PARC, Tokai-mura, Japan
  • Y. Mushibe, A. Tokuchi
    Pulsed Power Japan Laboratory Ltd., Kusatsu-shi Shiga, Japan
 
  A new power supply has been developed using linear transformer driver (LTD) technology that adopts SiC-MOSFETs and capacitors without a thyratron switch or a pulse forming network (PFN) device. A new power supply was also designed by connecting the SiC-MOSFETs and the LTD modules in parallel-series. The output voltage and current were 40 kV and 4 kA, respectively with a pulse width of 1500 nsec at a repetition rate of 25 Hz. Furthermore, by adjusting the correction module, to an output voltage per stage of 1/1000, a resolution of the voltage correction of ±0.1 % could be achieved. It was possible to output the current with arbitrary timing by using a trigger input for each LTD module. As a result, fine adjustment of the output voltage waveform was possible within the order of nanoseconds. This new power supply with high voltage output, cur-rent output, and very fast pulse operation is one of the most important key technologies for a kicker system using SiC-MOSFETs. The design and preliminary test results of this prototype power supply are presented here.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-WEPVA063  
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