Lifetime of the Highly Efficient H- Ion Sources

Factors limiting the operating lifetime of Compact Surface Plasma Sources (CSPS) are analyzed and possible treatments for lifetime enhancement are considered. Noiseless discharges with lower gas and cesium densities are produced in experiments with modified discharge cells. With these discharge cells it is possible to increase the emission aperture and extract the same beam with a lower discharge current and with correspondingly increased source lifetime. A design of an advanced CSPS is presented. Optimization of the discharge cells in a Penning H- ion source is a viable method for increasing the phase space of the stable region for noiseless discharge production. With this method, cesium usage would be decreased, potentially resulting in longer source lifetimes.