Analysis of the duoplasmatron-type discharge as a source of multiply charged heavy ions

Abstract

The yield of multiply charged ions from a steady-state Duoplasmatron ion source has been investigated. With some simplifying assumptions regarding the discharge plasma structure, one can calculate the density distribution of various charge states for a given feed material and main discharge parameters. The obtainable yields for highly charged ions can also be estimated. Such calculations have been made for the rare gases Ar, Kr and Xe, and these have been compared with experimental results. The comparisons show quite good agreement. It is shown that, besides technological limitations, the attainable yield for highly charged ions is limited by the typical structure of the discharge itself as well as by instabilities in the ion source plasma.