On the current intensity limit of a vacuum arc ion source

The maximum ion current that can be produced as a high energy beam from a metal vapor vacuum arc ion source is considered. Results are presented of measurements of the plasma ion current in the MEVVA II ion source. It is shown that this source is an efficient generator of metal ions, an intense flux of which is efficiently transported to the beam extractor. The maximum metal ion current that is available for extraction at the extractor location is 5% of the arc current. The limitation to the intensity of the metal ion beam that can be produced by this kind of ion source is in the extractor design. 27 refs., 6 figs.