This week, we’ve looked at calculating radiation doses. The absorbed dose, measured in Grays, takes into account the mass of the absorbing tissue, while the equivalent dose (in Sieverts) gives an indication of the potential for biological harm.
Equivalent dose is calculated using a weighting factor. More damaging forms of radiation have a larger weighting factor.
Absorbed dose and equivalent dose are usually expressed in smaller units; uGy, mGy, uSv, mSv.
Here is a poster from the excellent xkcd site that explores examples of the different levels of equivalent dose.
Click on the picture for a larger version.
Notice that the scale changes as you move through the poster from blue to green to red.
The dosimetry topic is very short and comprehensively covered at BBC Bitesize.