Sievert
The SI unit of equivalent dose, weighting absorbed dose by the biological damage the radiation type causes.
Formula / equation
H = D × w_R
Unit
Sv
In depth
The radiation weighting factor is one for beta and gamma but twenty for alpha particles, which deposit their energy over a very short track. The sievert is a large unit, so practical doses are quoted in millisieverts or microsieverts.
Examples in the real world
An intercontinental flight delivering about 0.08 mSv; occupational limits set at 20 mSv per year.