On the Current Intensity Limit of a Vacuum-Arc Ion Source

The maximum ion current that can be extracted 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 metal-vapor vacuum-arc II (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 percent 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 found to be in the extractor design.