Statistical aspects of particle-induced electron emission

The emission statistics of electrons from a W target induced by neutral HeO and ArO projectiles have been studied. A probabilistic model is considered for the 'electron emission events' that take place when a projectile bombards the target. The usual two-step model involving initial liberation of electrons from the target atoms in a sequence of collisions and transport of these electrons away from the target surface forms the basis for discussion of the electron emission statistics. Poisson and negative binomial distributions are considered because these fit our measured data well, and their probabilistic postulates are not inconsistent with the known experimental data. It is shown that back-scattered electrons from the detector surface play no significant role in the statistical analysis of the measured data. The quantum efficiency of detection of low-energy particle detectors can differ by about 10% between calculations using Poisson and negative bionomial distributions. (Author)