exposure
in nuclear chemistry
For X- or gamma-radiation in air: the sum of the electrical charges of all the ions of one sign produced when all electrons liberated by photons in a suitably small element of volume of air completely stopped, divided by the mass of the air in the volume element.
Source:
PAC, 1982, 54, 1533 (Glossary of terms used in nuclear analytical chemistry (Provisional)) on page 1541
This definition replaces an earlier definition of exposure.