Status of the J-PARC RF-driven H ion source

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

A cesiated RF-driven negative hydrogen ion source was initiated to operate in September, 2014 in response to the need for upgrading J-PARC's linac beam current. The ion source mainly comprises a stainless-steel plasma chamber, a beam extractor and a large vacuum chamber equipped with two turbo molecular pumps, each having the pumping speed of 1500 L/s, for differential pumping. The user operation was started with the beam current of 33 mA from the ion source. We gradually increased both beam current and continuous operation time of the ion source. In July, 2018 (Run#79), approximately 2,200 hours operation was achieved with the typical beam current, pulse length and repetition rate of 47 mA, 300 s and 25 Hz, respectively. Since October, 2018 (Run#80), the ion source has been delivering a nominal beam current of approximately 60 mA.