https://doi.org/10.1351/goldbook.09359
Total number of electrons emitted from a sample divided by the total number of electrons incident at a given energy and angle of incidence. \(\sigma = \delta + \eta\), where \(\delta\) is the secondary-electron yield and \(\eta\) is the backscattering coefficient.
Note: The total secondary-electron yield is often simply called the secondary-electron yield. This leads to confusion with the term of that name, which is restricted to secondary electrons with energies less than or equal to \(\pu{50 eV}\).