110 mA operation of J-PARC cesiated RF-driven H ion source

Ueno, Akira  ; Okoshi, Kiyonori ; Ikegami, Kiyoshi*; Takagi, Akira*; Shinto, Katsuhiro   ; Oguri, Hidetomo  

On 2018, the stable operation of the J-PARC cesiated RF-driven H ion source (IS) with a 62 keV 100 mA beam, whose emittances were suitable for the radio-frequency quadrupole LINAC (RFQ), was reported. In the J-PARC IS operation, the stable plasma production with a 50 kW 2 MHz RF power for more than 3 months, an RF power efficiency higher than 2.4 mA/kW and the possibility of the space charge limited beam intensity pulling up by increasing the extraction and acceleration voltages were proven. On the other hand, the withstand voltage for the stable operation with an RF plasma production of the present 2 MHz matching circuit and the high voltage power supply was measured as about 66 kV. In the operation with the presently highest beam energy of 65 keV, a 110 mA beam with emittances suitable for the RFQ was stably produced. Since 102.5 mA of the beam was measured inside the emittances used for the RFQ design, the next generation 100 mA LINAC will be possible with the IS.