ELECTROSTATIC REFLEX PLASMA SOURCE AS A PLASMA BRIDGE NEUTRALIZER

A new type of plasma source is described, to be used as a plasma bridge neutralizer (PBN) for space and current compensation of low energy ion beams. In contrast to existing hollow cathode PBN, the present design has a discharge which operates down to a low neutral pressure (1-5 multiplied by 10** minus **3 torr), so that the plasma jet now effuses through an aperture which may be quite large (5-12 mm), according to the beam current to be compensated. Two anodes are provided: one is located within the source chamber whereas the second is outside, near the plasma emission aperture. Thus two different coupling modes of the PBN are possible. Typical performance and lifetime are reported for the neutralization of reactive beams (O//2 or CF//4).