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Shobuda, Y.

Paper Title Page
MOPEC068 High Intensity Beam Operations in the J-PARC 3-GeV RCS 624
 
  • H. Hotchi, H. Harada, P.K. Saha, Y. Shobuda, F. Tamura, K. Yamamoto, M. Yamamoto
    JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken
  • Y. Irie
    KEK, Ibaraki
  
 

We have recently demonstrated 300-kW output in the J-PARC 3-GeV RCS. In this paper we will discuss beam dynamics issues in such a high intensity beam operation together with the corresponding beam simulation results.

  
TUPD044 Horizontal Impedance of the Kicker Magnet of RCS at J-PARC 2024
 
  • Y. Shobuda, J. Kamiya, M. Watanabe
    JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken
  • T. Toyama
    J-PARC, KEK & JAEA, Ibaraki-ken
  
 

There is the famous formula of the horizontal impedance for the matched-traveling wave kicker. However, the real and the imaginary parts of the impedance do not satisfy the Hilbert transformations. On the other hand, the impedance measured by a loop method does not directly give the beam impedance. In this paper we theoretically derive the beam impedance and reproduce the impedance by using the estimated inductances of the kicker by the loop measurement.

  
WEPEB036 Bunch by Bunch Feedback Systems for J-PARC MR 2767
 
  • M. Tobiyama, Y.H. Chin, Y. Kurimoto, T. Obina, M. Tejima, T. Toyama
    KEK, Ibaraki
  • Y. Shobuda
    JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken
  
 

Transverse bunch by bunch feedback systems for J-PARC MR accelerator has been designed and tested. Bunch positions are detected by Log-ratio position detection systems with center frequency of 12 MHz. The digital filter which consists of two LLRF4 boards samples the position signal with 64 times of RF frequency. Up to four sets of 16 tap FIR filter with one-turn delay and digital shift gain can be used. Preliminary results of beam test of the system are also shown.

  
THPE069 Simulation of Space Charge Effects in JPARC 4677
 
  • K. Ohmi, K. Fan, S. Igarashi, Y. Sato
    KEK, Ibaraki
  • H. Hotchi, Y. Shobuda
    JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken
  
 

Nonlinear space charge interaction in high intensity proton rings causes beam loss, which limits the performance. Simulations based on particle in cell method has been performed for JPARC-Rapid Cycle Synchrotron and Main Ring. Beam loss estimation during acceleration and resonances analysis are discussed with various simulations using dynamic and frozen models.