Optimising tandem accelerator stripping efficiency by simulation of charge changing processes

Abstract

The knowledge of charge changing processes which affect the quality of an ion beam is of great importance for the design of a beam transport system of maximum transmission through the accelerator. The stripping yield depends on the cross sections of charge exchange processes, the ion velocity, the stripper medium and the stripper thickness. We have determined the cross sections for electron loss and capture processes for C and Be in the range from 1 to 6 MeV. A simulation procedure was developed for the charge distribution of an ion beam in order to optimise the stripping yield and to estimate mass fractionation effects in these processes. From curves fitted to the experimental data, the stripping yield and beam losses due to charge exchange processes can be calculated for various tandem accelerators and stripper configurations as a function of terminal voltage and stripper medium and density. The model was tested with our new stripper.