Bunch by Bunch Feedback Systems for J-PARC MR

Transverse bunch-by-bunch feedback systems for JPARC MR accelerator has been designed and tested. Bunch positions are detected by Log-ratio position detection systems with center frequency of 12 MHz. The digital filter, which consists of two LLRF4 boards, samples the position signal at the 64th harmonics of the RF frequency. Up to four sets of 16 tap FIR filter with one-turn delay and digital shift gain can be used. Preliminary results of beam test of the system are also shown.