Abstract
This new Boltzmann equation approach to secondary electron emission does away with most of the simplifying assumptions generally encountered until now in similar studies. The main processes governing the phenomenon, such as elastic and inelastic scattering, the effect of the primary beam diffusion in the excitation function and the fundamental characteristics such as variation of electron density with depth inside the sample and energy dependence of the mean free paths, are simultaneously taken into account. The validity of the present method has been tested by comparing the theoretical results for polycrystalline aluminium with those predicted by previous models and with experimental data. The results obtained satisfactorily describe the energy as well as the angular distribution and the secondary electron yield of emitted electrons.