Yamazaki S, Ikegami K, Ohkoshi K, Ueno A, Koizumi I, Takagi A, Oguri H
J-PARC Center, Tokai-mura, Naka-gun, Ibaraki-ken 319-1195, Japan.
Rev Sci Instrum. 2014 Feb;85(2):02B136. doi: 10.1063/1.4858155.
A cesium-free H(-) ion source driven with a LaB6 filament is being operated at the Japan Proton Accelerator Research Complex (J-PARC) without any serious trouble since the restoration from the March 2011 earthquake. The H(-) ion current from the ion source is routinely restricted approximately 19 mA for the lifetime of the filament. In order to increase the beam power at the linac beam operation (January to February 2013), the beam current from the ion source was increased to 22 mA. At this operation, the lifetime of the filament was estimated by the reduction in the filament current. According to the steep reduction in the filament current, the break of the filament was predicted. Although the filament has broken after approximately 10 h from the steep current reduction, the beam operation was restarted approximately 8 h later by the preparation for the exchange of new filament. At the study time for the 3 GeV rapid cycling synchrotron (April 2013), the ion source was operated at approximately 30 mA for 8 days. As a part of the beam current upgrade plan for the J-PARC, the front end test stand consisting of the ion source and the radio frequency quadrupole is under preparation. The RF-driven H(-) ion source developed for the J-PARC 2nd stage requirements will be tested at this test stand.
自2011年3月地震修复后，由LaB6灯丝驱动的无铯H(-)离子源在日本质子加速器研究中心（J-PARC）运行，未出现任何严重问题。为了延长灯丝寿命，离子源产生的H(-)离子流通常限制在约19 mA。为了在直线加速器束流运行期间（2013年1月至2月）提高束流功率，离子源的束流电流增加到了22 mA。在此运行过程中，通过灯丝电流的降低来估算灯丝的寿命。根据灯丝电流的急剧下降，预测灯丝会断裂。尽管在电流急剧下降约10小时后灯丝断裂，但通过准备更换新灯丝，约8小时后束流运行重新启动。在3 GeV快速循环同步加速器的研究期间（2013年4月），离子源以约30 mA的电流运行了8天。作为J-PARC束流电流升级计划的一部分，由离子源和射频四极杆组成的前端试验台正在筹备中。为满足J-PARC第二阶段要求而开发的射频驱动H(-)离子源将在该试验台上进行测试。
