Status of J-PARC accelerators

Hasegawa, Kazuo; Kinsho, Michikazu  ; Oguri, Hidetomo  ; Yamamoto, Kazami   ; Naito, Fujio*

After the summer maintenance in 2015, user operation for the hadron experimental facility (HD) and the life science experimental facility (MLF) was resumed in the middle of October after the tuning of accelerator at J-PARC. In December, we reduced the repetition cycle from 6.0 seconds to the 5.52 seconds at the main ring (MR) and therefore, we have improved beam power to 42 kW, while it was 24 kW in April. The peak beam current at the linac by December 2015 was 30 mA, but we have increased to 40 mA in January, and the tuning was followed by the 3 GeV synchrotron (RCS) and the MR for user operation condition. As a result we improved a beam power to the neutrino experimental facility (NU) to 390 kW by the tuning while it was ranged 300 to 330 kW at 30 mA. User program was performed at 500 kW at the MLF, but it was suspended by a defect of a target in November. It was replaced for a spare one and resumed at 200 kW in February. We have several faults to stop beam operations: ventilation system at the linac by a short circuit, a vacuum leak at the RCS collimator, a breakdown of bending magnet of the MR, etc.