Compensation of random resonance for further beam loss mitigation and beam power ramp-up in J-PARC RCS

Kojima, Kunihiro ; Harada, Hiroyuki  ; Saha, P. K.   

We have studied the compensation of random resonance for further beam power ramp-up and beam loss mitigation in the 3 GeV rapid cycling synchrotron (RCS). The particle loss will produce high levels of radioactivity in high-intensity synchrotrons such as the RCS and can limit the available beam power. While the current beam loss has been successfully mitigated to 0.1 % at the designed beam power of 1 MW, further beam loss mitigation and expansion of the stability region are required to realize the beam power of 1.5 MW. For this purpose, we have conducted a tune survey with a low current beam to identify the beam loss source. We reveal the enhancement of the 2nd-order random resonance () and demonstrate the compensation of the resonance by using the trim quadrupole magnets (QDT). In addition, the resonance compensation using the QDT is confirmed to be effective in reducing beam loss for the high current beam provided to the material and life science facility. In this meeting, the results of the study of random resonance compensation will be presented.