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.

Search the Glossary by either clicking on a letter or typing a keyword into the search box. This glossary is relational so when looking at one term you can click through to other related terms as required.

For formal advice, see our Radiation Protection Adviser pages. 


Bremsstrahlung, also known as Braking Radiation occurs when ever a charged particle undergoes a change of velocity as it interacts with an absorber. Electromagnetic Radiation (X-Rays) are the result. For Radiation Protection purposes, Bremsstrahlung radiation resulting from the interaction of fast moving Electrons (Beta Particles) with shielding materials, are of particular concern. Here, the degree of conversion to Bremsstrahlung radiation and the magnitude of its energy is proportional to the incident electron energy and the atomic number of the absorber. Hence shielding for high energy Beta emitters like P-32, needs low atomic number material such as Perspex.

Be less curious about people and more curious about ideas

– Marie Curie -