# Formula Equivalent Dose Radiation weighting factor    Absorbed dose

## Equivalent dose

Unit
The equivalent dose $$D$$ [Sv = J/kg] (Sievert) is the energy absorbed by the irradiated substance per biological mass.

Since the type of radiation (alpha, beta, gamma) differs in its biological effect, the absorbed dose $$D$$ is multiplied by the radiation weighting factor to obtain the equivalent dose. The radiation weighting factor is equal to 1 for gamma and beta radiation and 20 for alpha radiation.
The absorbed dose $$D$$ [Gy = J/kg] (Gray) is the energy absorbed by the irradiated substance per mass. The absorbed dose thus tells how well the irradiated substance can absorb the energy.