Radiation Protection Glossary
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Fluence can be defined as the total number of particles (typically
Gamma Ray
Photons
) crossing over a sphere of unit cross section which surrounds a
Point Source
of
Ionising Radiation
. The Fluence rate is the number of particles crossing per unit time (which is numerically equal to the product of number of particles and their average speed). This is a useful quantity in
Radiation Protection
when calculating
Dose Rates
from point sources or other geometries (e.g. Line Sources, plane source or Volume Sources). The dose delivered by a fluence at a point in space will be related to the energy of the photons.