DIRECT MONTE-CARLO SIMULATION OF INCIDENT-ANGLE DEPENDENCE OF SECONDARY-ELECTRON EMISSION FROM ALUMINUM

A direct Monte Carlo simulation of secondary electron emission from Al is carried out in order to describe its dependence on the incident angle. The results show that the dependence of the electron yield at low energy is under the inverse cosine of the angle measured from the surface normal. At high energy, however, it is slightly over the inverse cosine at least for angles of less than 60-degrees. These are mainly caused by small penetration and large backscattering of primary electrons for high incident angles. The calculation describes the experiment better than the conventional simulation based on continuous slowing-down approximation. Furthermore, the energy and angular distributions of emitted secondary electrons are insensitive to the incident angle. In electron emission statistics at higher energies than an energy where the secondary electron yield is maximum. the probabilities for no emission and high n electron emission (n > 2) are larger than the Poisson distribution, being enhanced for high incident angle due to the backscattering.