Author: Oishi, M.
Paper Title Page
TUPC18 Development of a Highly Efficient Energy Kicker for Longitudinal Bunch-by-Bunch Feedback 407
 
  • M. Masaki, T. Fujita, K. Kobayashi, T. Nakamura, H. Ohkuma, M. Oishi, S. Sasaki, M. Shoji
    JASRI/SPring-8, Hyogo-ken, Japan
  
  A highly ef­fi­cient en­ergy kicker has been de­vel­oped for lon­gi­tu­di­nal bunch-by-bunch feed­back to sup­press syn­chro­tron os­cil­la­tion of a high-cur­rent sin­gle elec­tron bunch, and to cure pos­si­ble lon­gi­tu­di­nal multi-bunch in­sta­bil­ity if lower beam en­ergy is to be adopted for emit­tance re­duc­tion and elec­tric power sav­ing in a fu­ture up­grade plan of SPring-8. Through the per­for­mance test using a pro­to­type kicker, a new wa­ter-cooled cop­per kicker was de­signed and fab­ri­cated, and it has been in­stalled in the stor­age ring. The new kicker con­sists of three cells with each cav­ity length of 96 mm, its res­o­nant fre­quency of 1.65 GHz, which is 3.25 times of RF fre­quency of the stor­age ring, and low Q-fac­tor of 4.2. In beam kick test, the syn­chro­tron os­cil­la­tion am­pli­tude of 0.64 ps was ex­cited by kick volt­age with con­tin­u­ous am­pli­tude mod­u­la­tion at syn­chro­tron fre­quency when the RF input power was 132 W/3cells. The kick volt­age eval­u­ated from the ex­per­i­men­tal re­sult is 920 V/3cells. Shunt im­ped­ance of each kicker cell is es­ti­mated as 1.1 kΩ. As we in­tended, the shunt im­ped­ance per length is about three times higher than those of widely used wave­guide over­loaded cav­ity type kick­ers.  
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