electron stopping power

in X-ray emission spectroscopy
https://doi.org/10.1351/goldbook.E02010
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, dE/dx.
Source:
PAC, 1980, 52, 2541. 'Nomenclature, Symbols, Units and their Usage in Spectrochemical Analysis—IV X-Ray Emission Spectroscopy' on page 2545 (https://doi.org/10.1351/pac198052112541)