When a beam of electrons strikes a target or specimen there are three ways in which the electrons may lose energy (low energy collisions, X-ray production, and formation of a spectral continuum). The average energy loss per unit distance travelled along the electron path is called electron
stopping power,
.
Source:
PAC, 1980, 52, 2541
(Nomenclature, symbols, units and their usage in spectrochemical analysis - IV X-ray emission spectroscopy)
on page 2545