Author: Okada, M.
Paper Title Page
TUPWA009 Bunch by Bunch Intra-Bunch Feedback System for Curing Transverse Beam Instabilities at the J-PARC MR 1739
  • O. A. Konstantinova, Y.H. Chin, Y. Kurimoto, T. Obina, M. Okada, K. Takata, M. Tobiyama, T. Toyama
    KEK, Ibaraki, Japan
  • Y. Shobuda
    JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan
  At the J-PARC Main Ring (MR), transverse instabilities have been observed during the injection and at the onset of acceleration with large particle losses. The present bunch by bunch feedback system, operating in a narrowband mode, has been effectively suppressing these instabilities, allowing the beam power to reach 230kW with only 400W of particle losses. The observed beam signals show that bunches are still executing complicated intra-bunch oscillations even if the narrowband feedback system is on, though they are not imposing significant particle losses at present. The new and more advanced broadband feedback system has been developed for control of the intra-bunch oscillations and further reduction of particle losses. The elaborate analysis code has been also developed on the MATLAB platform to analyse effects of the broadband feedback system on intra-bunch oscillations. This paper describes the development of these advanced instruments and presents the analysis of the latest beam test results using the MATLAB code.