DISTRIBUTION OF THE NUMBER OF EMITTED ELECTRONS FOR MEV H+-ION AND HE2+-ION IMPACT ON METALS

The statistical distribution of the number of emitted electrons induced by MeV H+ and He2+ impact on aluminum, copper, and gold targets was measured. The obtained results are very well represented by a Pólya distribution. Based on a simplified theoretical picture the appearance of a Pólya distribution in this context can be explained by cascade processes, which permits a quantitative estimation of the distributions in good agreement with the experiments for all investigated projectile-target combinations. The deviation from a Poisson distribution is given by the relative importance of cascade processes compared to projectile-induced processes. © 1995 The American Physical Society.