Author: Konstantinova, O. A.
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.