Study on a cold-cathode H^- PIG-type ion source

A cold-cathode Penning Ion Gauge (PIG) type ion source as the internal ion source of an 11 MeV cyclotron is designed and tested at Institute of Fluid Physics. The design considerations and some testings are presented. Experimental results of Balmel-line-Emission show that the discharge characteristic, which is mainly determined by gas-flow rate, is not very sensitive to arc current and magnetic field in the operation ranges of the cyclotron. The arc power decreases and ascends while the gas-flow rate goes up from 0.5 SCCM to 20 SCCM. By improving the sealing design and reducing the machine tolerance of the source, the minimum power consumption reduces from 9 SCCM to 4 SCCM, thus having better energy efficiency and benefiting for the pumping system. Preliminary DC extractions show that H^- microampere current ranges from several tens to hundreds under different operation conditions. Some problems during the experiments and future plan are discussed in the end. (authors)