back scattered electrons (BSEs)

in in situ microanalysis
https://doi.org/10.1351/goldbook.B00583
All
primary electrons
which are scattered out of the original direction and retransmitted through the surface of the solid. In practice, electrons emitted from the surface of a solid under electron bombardment which have a
kinetic energy
in the range between 50 eV and
excitation energy
(E0).
Source:
PAC, 1983, 55, 2023. (Nomenclature, symbols and units recommended for in situ microanalysis (Provisional)) on page 2026 [Terms] [Paper]