Over 60mA RF-driven H ion source for the J-PARC

Ueno, Akira  ; Namekawa, Yuya*; Yamazaki, Saishun; Okoshi, Kiyonori ; Koizumi, Isao; Ikegami, Kiyoshi*; Takagi, Akira*; Oguri, Hidetomo  

In order to satisfy the J-PARC second stage requirements of an H ion beam current of 60 mA within normalized emittances of 1.5 -mm-mrad both horizontally and vertically, a flat top beam duty factor of 1.25% (500 micros 25 Hz) and a life-time of more than 50 days, a cesiated RF-driven H ion source using a internal-antenna developed at the Spallation Neutron Source (SNS) was developed. The J-PARC RF-driven source was manufactured by modifying the J-PARC cesiated H ion source driven with two tungsten (W) filaments, which successfully produced a 76.2 mA H ion beam current but had an insufficient life time of about 500 hours. It successfully produced a 77.5 mA H ion beam with a flat top duty factor of 2% (800 micros 25 Hz) whose 87.7% (68 mA) and 89.1% (69 mA) are within horizontal and vertical 1.5 -mm-mrad emittances, respectively. It also had successfully produced more than 60 mA within 1.5 -mm-mrad emittances H ion beam continuously over 100 hours.