Analysis of the Ion Spot Phenomenon on Beam-Charged Dielectrics

Computer simulation of particle trajectories in two dimensions using a simple static accumulated charge model reveals the mechanism for the focussing of ions into a central, sharply defined "spot", duplicating the luminescent spot which did not arc-discharge observed during laboratory exposure of polymer film to monoenergetic electrons and low energy ions. A model which follows the time evolution of such charging situations is developed and initial results are presented.