Measuring Radiation

Simplest measure of radioactivity - Becquerel(Bq). Measures activity of nucleus. Activity - no. of decays per second from an unstable nucleus. However this particle could be alpha/beta ∴ have a different effect on the body: - Beta particle has lot of energy but may not cause lots of damage due to its low ionisation power - Alpha has less energy but cause more damage in a shorter distance as its bigger Sievert (Sv) is the unit to measure radiation dose and is the amount of damage that would be caused by the absorption of 1 joule of energy per kilogram of body mass. Usually absorption is less than 1 Sv, so milliSieverts (mSv) are often used instead. 1,000 mSv = 1 Sv.