A new analytical approach for the transport and the emission yield of secondary electrons from insulators

Simple analytical expressions for the transport of low energy electrons in insulating specimens are derived by assuming isotropic random walk. The proposed approach explains why the measured fraction of the emitted secondary electrons (with respect to the generated ones) is often found to be larger than 50% for materials having a negative affinity, such as cesiated diamond surfaces or rare gas solids. The correspondence between parameters involved in the present approach and those used in an exponential attenuation function of the form B exp(-z/<s>) are given. One direct consequence is the possibility to extract from the experimental secondary yield curves, physical information on the dynamics of low energy electrons (range and transport mean free path) in insulators. (C) 2002 Elsevier Science B.V. All rights reserved.