Progress and status of the J-PARC 3 GeV RCS

Kinsho, Michikazu  

Big issue for the J-PARC rapid cycling synchrotron (RCS) was displacement of main magnets caused by last big earthquake because this made beam loss more than 400 kW beam power. Since realignment of main magnets and other components was essential to realize higher beam power and stable operation, this work has been done during maintenance period in 2013. To achieve the nominal performance 1MW beam power at the RCS and 0.75 MW at the MR, beam energy of linac was increased from 181 MeV to 400 MeV with a new accelerating structure ACS (Annular-ring Coupled Structure) linac from this January. It was successful 400 MeV beam injection and 3 GeV beam extraction at the RCS, and user operation has been performed with beam power of 300 kW. An equivalent beam power of 560 kW with a beam loss of only 0.3% could be achieved during short time for high intensity beam study.