The cross-section per unit volume of a given material for a specified process. For
a pure
nuclide, it is the product of the
microscopic cross-section and the number of target nuclei per unit volume; for a mixture of nuclides, it is
the sum of such products.
Source:
PAC, 1994, 66, 2513
(Nomenclature for radioanalytical chemistry (IUPAC Recommendations 1994))
on page 2517