Radiation Protection Glossary

A radiation protection glossary for Radiation Protection Supervisors (RPS), Radiation Protection Advisers (RPA) and anyone else interesting in radiation safety terms and definitions. The glossary is a mixture of health physics , phrases related to radiation protection legislation, transport, practical safety, technical terms and similar.

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For formal advice, see our Radiation Protection Adviser pages. 

Fluence Rate

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.

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