The Time-of-Flight Ebis with Unusual Cathode Operation

The principle of an electron beam ion source in time-of-flight mode was verified in an experimental arrangement with low electron currents but high current densities due to an unusual cathode process. By varying only the applied axial electric field, maxima in the relative abundance of the charge state distributions up to 4+ for Ar and 5+ for Xe could be obtained. Relative abundances as well as absolute ion yields and their dependence on the different parameters can be explained by a theoretical model using a Monte Carlo program. Based on these investigations an extrapolation has been made for ion yields which may be obtained in a TOFEBIS with high electron current and current densities.