back scatter coefficient

in in situ microanalysis
https://doi.org/10.1351/goldbook.B00582
Number of
back scattered electrons (BSEs)
generated per
primary electron
for a given specimen and experimental condition. It depends on (mean)
atomic number
of the excited area of the sample,
angle
between electron beam and sample surface, primary electron energy and thickness of the sample.
Source:
PAC, 1983, 55, 2023. (Nomenclature, symbols and units recommended for in situ microanalysis (Provisional)) on page 2026 [Terms] [Paper]