A reminder of electron-matter interactions
Scanning electron microscopy - Principles and equipment

When an electron beam of $E_0$ penetrates a solid sample, it undergoes a number of interactions, both elastic and inelastic:

• inelastic interactions cause a progressive loss of its energy :

  • in part, by transferring electrons from atomic orbitals,

  • to a lesser extent, by radiative loss;

• elastic interactions, mainly with the nucleus, induce more or less abrupt variations in the direction of incident electrons. The result of these interactions is an "electron trajectory"...