Monte Carlo simulation of the secondary electron yield of an insulating target bombarded by a defocused primary electron beam

We study the charge of an insulating target irradiated by a broad electron beam of a few keV with our Monte Carlo simulation model. We are particularly interested in the dynamics which leads the system towards a stationary state. We examine successively the role of parameters such as the density of current in the primary beam, the density of traps, their activation energy. According to the situation considered, one observes that the regulation of the system can sometimes be stopped, either because the traps become saturated, or, in the case of thin targets, by the appearance of a leakage current towards the ground, due to carriers released from the traps.