Numerical simulation of secondary electron emission yield in the case of volume and surface trapping evolution

The aim of this work is to analyze by numerical simulation a one-dimensional unsteady mathematical modeling, describing spatial/temporal charge trapping in an insulator submitted to an electron beam irradiation. The main features of the modeling is its ability to compute the evolution of the secondary electron emission yield see(t) as a function of the global trapped charge per surface unit Qp(t). It assumes given, the current of incident primary electrons, the penetration depth of the primary electrons, the electron/hole creation source term and describes the nonlinear coupling between a) the electrons/holes current, splitted into forward/backward contributions thanks to a two-fluxes method, which takes into account the creation, trapping and diffusion of electron/holes charges, b) the electric field inside the sample induced by the charge density, c) the saturation effect of the surface trapping sites, d) the number of electrons/holes trapped in volume, e) the saturation effect of the volume trapping sites. Numerical simulations showing the evolution of see(t) and Qp(t) with respect to the value of the incident electron beam energy are presented and discussed.