Anode Sputtering Characteristics of the Berkeley 2.5 MV Source

This paper reports an investigation of a number of parameters affecting the performance of the SuperHILAC 2.5 MV Adam injector source. The description will emphasize anode sputtered materials, and will discuss in some detail calcium and gold ion production. Parameters varied include electrode geometry, support gas type and electrode bias, to optimize beam intensity and electrode consumption. A factor of three improvement with high n+ gold ions appears evident with a new displaced electrode geometry. The source is operated in cold mode, is pulsed and operates usually at less than 0.6 amperes average current. Under these conditions source life has been measured to be sixteen hours at 25% duty factor, when generating calcium ions, with neon support gas.