Theoretical Calculation of Single and Multiple Impact Charge Distribution for Heavy Ion Sources

The optimal design of sources for multiply-charged heavy ions depends upon a better understanding of the physical processes involved. In this paper the equations for ionization are developed and discussed. Charge state distributions are calculated for the single impact model (the simultaneous removal of several electrons from an atom) and for the multiple impact (the removal of one electron at a time) model. The calculated ion charge distributions are then compared with experimental data from Penning sources, for which the multiple impact process appears to predominate.