Composition of Noble Gas Ion Beams Produced with a Duoplasmatron

Abstract

Beams of noble gas ions produced with a duoplasmatron ion source were magnetically analyzed while the gas pressure in the source was varied. At high pressure the beam consisted primarily of singly charged ions. With decreasing pressure the yield of multiply ionized ions increased and was finally limited by the rising arc voltage which caused overheating of the anode. No measurable amount of He²⁺ or Ne²⁺ was detected. In the other gases the following maximum yields were measured for the more highly ionized species: 63% A²⁺, 54% Kr²⁺, 16% Kr³⁺, 24% Xe²⁺, and 1.2% Xe³⁺. Traces of molecular ions were detected in all the noble gases studied.