Status of the J-PARC RF ion source

Okoshi, Kiyonori ; Ikegami, Kiyoshi*; Takagi, Akira*; Asano, Hiroyuki; Ueno, Akira  ; Shibata, Takanori*; Nammo, Kesao*; Shinto, Katsuhiro   ; Oguri, Hidetomo  

In 2014 October, operation of cesium-seeded Radio Frequency (RF)-driven negative hydrogen ion (H) source was started in J-PARC LINAC. Due to the skillful RF antenna screening and the proper pre-conditioning process, long term unscheduled beam stop due to the antenna failure did not occur for more than 1 year. The continuous operation of 1,350 hours with a peak beam current of 45 mA was achieved in the recent beam run. Moreover, the fluctuation of beam current in a low energy beam transport (LEBT) is kept within 2% of target value by application of three feedback systems. An ion source test-stand was assembled to investigate the ion source beam characteristic, for example, the emittance at the position of the RFQ entrance. In the presentation, we will report the recent status of the ion source operation and some experimental results obtained at the ion source test-stand.