CSNS强流负氢离子源及其改进

CSNS High Current H^-Ion Source and Its Improvement

摘要: 中国散裂中子源（CSNS）的离子源是1台强流负氢离子源，该离子源负氢束流的能量为50 keV，负氢流强可达40 mA，束流占空比最高为1.25%（重复频率为25 Hz，脉宽为500 μs）。目前该负氢离子源已投入到CSNS中使用。由于等离子体放电电极受带电粒子溅射的缘故，在1.5%（25 Hz，600 μs）的占空比、负氢流强30 mA运行下，离子源的寿命约为30 d。为提高离子源使用的稳定性，对离子源进行改进优化，提高了离子源的运行效率和稳定性。

Abstract: Chinese Spallation Neutron Source (CSNS) ion source is a type of high current H^- ion source. The H^- beam energy of this ion source is 50 keV, the H^-current intensity can reach 40 mA and the beam duty factor is up to 1.25% (the repetition frequency is 25 Hz, and the pulse width is 500 μs). At present, this ion source is running at CSNS. During ion source operation, the surfaces of discharge electrodes are subjected to erosion due to particles bombarding. Therefore, the life time of this ion source is around 30 d at the 30 mA H^- current under the duty factor of 1.5% (25 Hz and 600 μs). Some modifications were made. With these modifications, the operation efficiency and stability of ion source are enhanced.