Radiation Protection Glossary

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

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Specific Activity

Specific activity is taken to be the Activity (Bq) per unit mass (grams),normally expressed as Bq/g. Specific activity is related to Half-Life such that the shorter the half life the higher the specific activity. For example, the specific activity of natural Uranium is 25.4 kBq/g and has a half life of 4.51 E9 years (4510 million years). Compare this to Polonium - 210 which has a specific activity of 166500 GBq/g and a half life of 138 days.

Nothing in life is to be feared, it is only to be understood. Now is the time to understand more, so that we may fear less

– Marie Curie -