The grid efficiency or grid selectivity describes the efficiency in % of the primary beam transmission / % of transmitted scatter. The absorption of the primary beam is around 20 - 40%.

Compton scattering is the deflection of gamma- and x-ray photons by electrons.

See also Compton Continuum, Compton Effect, Air Kerma, Filter Grid, Focused Grid, Grid Efficiency, and Compton Arthur Holly.