Reaction-diffusion and two-fluxes method computation of secondary electron emission yield

The aim of this work is the analysis by numerical simulation of charge trapping in an insulator submitted to an electron beam irradiation. The purpose of this paper is two-fold. First of all we present a two-fluxes method which splits the electron/hole currents into forward and backward currents to compute the initial secondary electron emission yield. We will establish that a reformulation of the modeling into a reaction-diffusion equation is possible. In the second part of the paper, we present some results of a new mathematical model recently developed, describing the spatial and temporal charge trapping, which computes the temporal evolution of the secondary electron emission, see(t), as a function of global trapped charge, Q_p, for various values of the kinetic energy of the primary electrons. A Comparison with some experimental data is done.