in nuclear chemistry
For @X06703@ or @R02568@ in air: the sum of the electrical charges of all the @I03158@ of one sign produced when all @E01975@s liberated by @P04627@s in a suitably small element of volume of air completely stopped, divided by the mass of the air in the volume element.
PAC, 1982, 54, 1533. (Glossary of terms used in nuclear analytical chemistry (Provisional)) on page 1541 [Terms] [Paper]
This definition replaces an earlier definition of exposure.