Recent operation status of Japan Proton Accelerator Research Complex H ion source

Oguri, Hidetomo  ; Ueno, Akira  ; Ikegami, Kiyoshi*; Namekawa, Yuya; Okoshi, Kiyonori 

A cesium-free H ion source driven with a LaB filament is being operated for J-PARC. The beam commissioning of J-PARC accelerators started in November 2006. As of May 2009, the ion source has been successfully operated in two different modes such as a low current mode of 5 mA and a high current mode of 30 mA. According to the task of the run, one of the two modes was selected. However, it has been restricted to only the low beam current mode for the stable operation of the RFQ linac which has serious discharge problem from September 2008. The total interruption time during the runs due to the ion source failure is about 50 h as of May 2009. The availability of the ion source is calculated to be 99%. The interruptions were mainly (about 90%) caused by the insufficient lifetime of the filament. By a few modifications on the filament shape administered, we succeeded in achieving the lifetime of 2,030 h, which included 1,250 h in the low beam current mode and 780 h in the high mode. The interruption due to the filament failure does not occur in the last one year. Another cause of the interruption is a discharge at the ceramics insulator. Recently, the discharge occurs once a few weeks. Although the interruption time due to the discharge is much shorter than the filament failure, we are now studying how to stop the discharge for more stable operation.