Numerical study on the gas mixing effect in ECR ion sources

Abstract The gas mixing effect in electron cyclotron resonance (ECR) ion sources provides a substantial increase of the current of high charge state ions. In order to understand the mechanism of the gas mixing effect, the effects of the support gas (O 2 ) on the ion (Ar) charge state distribution, the plasma potential, the potential dip, the average charge state, the electron scattering rate and the thermal electron density are studied numerically on the basis of a simple balance model. The dependence of the ion charge state distribution on the ion temperature is also calculated. Finally, we point out that it might be the combination of several factors that results in the gas mixing effect.