Author: Ando, A.
Paper Title Page
WEPPR052 Octupole Magnets for the Instability Damping at the J-PARC Main Ring 3045
  • S. Igarashi, T. Koseki, K. Ohmi, M.J. Shirakata, H. Someya, T. Toyama
    KEK, Ibaraki, Japan
  • A. Ando
    J-PARC, KEK & JAEA, Ibaraki-ken, Japan
  Octupole magnets have been installed for the instability damping at the J-PARC main ring. The transverse instability was observed during the injection and acceleration periods and caused the beam losses. The chromaticity tuning and bunch-by-bunch feedback system have been applied to suppress the instability. Octupole magnets were considered to create a larger amplitude dependent betatron tune shift and to supply additional option for the instability damping. The side effects of the dynamic aperture reduction and the resonances have been studied.