CSNS High Current H^- Ion Source and Its Improvement

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.