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Morishita, T.

Paper Title Page
MOP078 Transverse Beam Matching and Orbit Corrections at J-PARC LINAC 260
 
  • H. Sako, Y. Kondo, T. Morishita
    JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken
  • H. Akikawa, M. Ikegami
    KEK, Ibaraki
  • T. Ohkawa
    JAEA, Ibaraki-ken
  • A. Ueno
    KEK/JAEA, Ibaraki-Ken
 
 

In the design of the very high intensity proton beam of the J-PARC LINAC, precise control of transverse beam dynamics is extremely important for suppression of beam loss. We present results of transverse beam matching and orbit corrections. The linac has 7 matching sections, each of which consists of 4 quadrupole magnets and 4 wire scanners. At 5 matching sections, beam widths at wire scanners are designed to agree with each other. This condition is used in the newly developed algorithm of quadrupole field correction based on a transport model, XAL. Excellent matching performance has been achieved with mismatch factor less than 5% at beam current of 5 to 30 mA. Control of beam parameters from linac into RCS is important for RCS paint injection. Beam studies and comparison to a model have been performed with linac wire scanners combined with multi-wire proportional monitors in the injection line. Orbit corrections with dipole steering magnets based on XAL model have been performed. Orbit deviations were suppressed within 1 mm in horizontal and vertical directions in the whole linac. For these measurements, detailed comparisons to a multi-particle simulation will be shown.

 

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Slides

 
THP056 Improvement in the ACS Cavity Design for the J-PARC Linac Energy Upgrade 915
 
  • H. Ao, K. Hasegawa, K. Hirano, T. Morishita, A. Ueno
    JAEA/LINAC, Ibaraki-ken
  • H. Asano
    JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken
  • M. Ikegami, F. Naito
    KEK, Ibaraki
  • V.V. Paramonov
    RAS/INR, Moscow
  • Y. Yamazaki
    J-PARC, KEK & JAEA, Ibaraki-ken
 
 

The ACS (Annular-ring Coupled Structure) cavities were under development for the J-PARC Linac from 190 MeV to 400 MeV. We have fixed the cavity specification, taking into account the results of the high-power conditioning and the fabrication experience. The mass production of the ACS with a tight time schedule is now an issue, since the user community strongly requests the beam power upgrade as early as possible. Therefore, the design and the fabrication process of the ACS cavity have been reexamined on the basis of the experience, stored during the course of the fabrication and the tuning of the prototype ACS tanks. Here, we also discussed about the key issues on the mass production with a manufacturer. The cavity shape, that required complicated machining, was simplified to some extent, while the frequency tuning strategy was reconsidered to reduce the production period. The paper describes these recent activities on the ACS development.