Status of J-PARC 3 GeV rapid cycling synchrotron under the high power operation

Yamamoto, Kazami   ; Kinsho, Michikazu  

The J-PARC 3-GeV Rapid Cycling Synchrotron (RCS) aims to deliver 1 MW proton beam to the materials and life science experimental facility (MLF) and the main ring synchrotron. While the energy and the peak current of J-PARC linac had been increased in 2013 and 2014, preparations of RCS for 1 MW operation were also arranged. As a result of the injection energy upgrade in 2013, we confirmed that the space charge effect during acceleration process was well eased and the beam loss was drastically reduced. After increment of the peak current from the linac, we tried 1 MW-equivalent operation. This first trial revealed that the power supply of the RF cavity was insufficient to accelerate 1 MW-equivalent beam. The RF system was improved at the end of 2014, and 1 MW-equivalent beam operation was achieved in January, 2015. The beam power for MLF users was also increased to 500 kW in April. In this paper, we report the improvement and status of RCS for high power operation.