Units

There are many different units used to measure radiation. However, the international units preferred are the International System (SI) units.

• The Gray (Gy) is used as a measurement of how much radiation is absorbed by a body.

  • 1 Gray = 1 Joule per kg of material

   

• The Sievert (Sv) is used as a measurement of not only the amount of radiation that is absorbed by a given body but it also takes into account quality (Q) of the radiation that is absorbed. For example, exposure to 1 Sievert of alpha radiation is more damaging than exposure to 1 Sievert of beta radiation in any given amount of time. Highly damaging radiation has a high value for Q.

  • 1 Sievert = 1 Gray * Q

   

• The Becquerel (Bq) is used to measure radioactivity or the decaying of radioactive material.

  • 1 Becquerel = 1 disintegration per second.

  A disintegration is the transformation an element undergoes. For example, Uranium-238 decays to Thorium-234 through alpha emission.

   

SI unit prefixes

Source: newnet.lanl.gov