ABSTRACT
Vacuum arc ion sources can deliver small emittance beams of metal ions for particle accelerators or large-area beams for ion implantation. The first reliable metal vapor vacuum arc (MEVVA) ion source was developed at Berkeley by Brown in the early 1980s, Humphries, Jr., and Picraux. A dc operated MEVVA was constructed by Brown in 1991. The metal-vapor vacuum arc occurs between hot cathode spots and a cold anode in vacuum. Vacuum arc ion sources produce a large amount of ions with charges higher than 1 because they originate from the dense near-cathode spot plasma. An axial magnetic field changes little with the discharge behavior of a vacuum arc ion source, but influences the plasma density in the extraction area by compression of the expanding plasma plum. In this way the current density of the extracted ion beam can be intensified by increasing the magnetic field until the plasma is compressed to the size of the extraction area.
