Determination of the IMFP from electron elastic backscattering probability

Abstract

Theoretical models for elastic electron backscattering from surfaces have gained much attention in the recent years. One of the stimulating factors is the need for a reliable theoretical relation between the elastic backscattering probability and the electron inelastic mean free path (IMFP) in the surface region. Such a relation would provide a convenient tool for determining the IMFP. At present, the Monte Carlo simulations are considered to be most reliable for a description of elastic electron backscattering. This approach, however, usually needs considerable computing time. The analytical theoretical models are derived after introducing additional simplifying assumptions that may lead to a certain systematic deviation with respect to the Monte Carlo simulations. In the present work, a modification of the theoretical model proposed by Oswald, Kasper and Gaukler (OKG) is compared with Monte Carlo simulations. Calculations were made for the most frequently used experimental geometry (cylindrical mirror analyses with normal incidence of the primary beam) and a wide range of energies and atomic numbers. It has been found that the elastic backscattering probabilities calculated from the OKG model and the Monte Carlo model compare very well if we assume realistic values of the IMFP. For this reason, the OKG model is recommended for calculations associated with determination of the IMFP when the experimental geometry similar to that of the CMA is used. Copyright © 2000 John Wiley & Sons, Ltd.