Beam intensity fluctuation characteristics of the metal vapor vacuum arc ion source

Abstract

High current beams of metal ions can be produced by the metal vapor vacuum arc (MEVVA) ion source, providing an important tool for injection into particle accelerators and for ion implantation. A characteristic of the beam that is critical in many applications is the beam current fluctuation level. In this paper we report on some experimental observations of the variation of the beam noise level with source operational parameters. We find that the fractional beam noise varies with the arc current, and that the noise is minimum at the perveance match condition. At this optimum operational point, the rms fractional noise level can be as low as 7% of the mean.