Production mechanism in an ECR-type multiply-charged ion source

A calculation model is proposed for the production of multiply-charged ions in an ECR plasma. Numerical calculations have been carried out using this model to estimate the charge state distribution of multiply-charged ions. It was expected that the K-shell ionization process or the charge exchange process would considerably affect the charge state distribution in the ECR plasma. Thus the charge state distributions of ions produced in the ECR plasma were measured as functions of gas pressure and input microwave power, and on comparing the measured and calculated distributions, it was recognized that K-shell ionization and charge exchange can not be neglected for a high input-power of about 1000 W and a high gas-pressure of 2.4 x 10-4 Torr. (author)