Charge Changing Collision Cross-Section of Atomic Ions

Abstract

A device has been built to measure charge changing cross-sections of atomic ions. It consists of an ECR ion source (Micromafios) that delivers oxygen ions up to charge + 8, argon ions up to charge + 13. The ion source potential may be varied from 1 up to 10 kV. A first magnet is used to charge analyze the extracted beam. For a given charge state, the ion beam is passed in a collision cell whose pressure may be varied. The ions undergoing collisions on the target are analyzed by a second magnet and collected.The single collision condition is checked. Different collisions are considered:(1) Charge exchange collisions of argon ions with charge 2 ⩽ Z ⩽ 12 on argon. Cross-sections for capture of 1, 2 and 3 electrons are given.(2) Stripping of argon ions (1 ⩽ Z ⩽ 4) on argon atoms.(3) Charge exchange of oxygen ions (2 ⩽ Z ⩽ 8) colliding on deuterium. One and two electron capture cross-sections are presented.