Simple Theory Concerning the Reflection of Electrons from Solids

Abstract

A simple theory concerning the reflection of electrons from solid targets is derived, based on the following assumptions: (1) the primary cause of electron reflection from a solid material is Rutherford scattering through angles greater than 90°; (2) the energy loss of electrons penetrating a solid target is given by the Thomson‐Whiddington law, or a modified version of it; (3) no multiple scattering is allowed. An expression for the reflection coefficient r is derived that agrees surprisingly well with experimental data, in view of the above simplifying assumptions. In particular, the correct variation of r with atomic number Z is obtained, and the observed value of the fractional escape energy is calculated in the limit as Z → 0, where the theory is most accurate. A critical discussion of the simplifying assumptions is given, and the range of validity of the theory is estimated. This theory leads to a better understanding of the related phenomena of secondary emission at primary electron energies between 2 and 50 kev.