Skip to ContentSkip to Navigation
Education Programmes Other study opportunities Groningen Academy for Radiation Protection

Directional dose equivalent


The operational quantity directional dose equivalent (H'(d,Ω)) is defined as the equivalent dose at point P at a depth of d mm in the ICRU-sphere. The corresponding unit is sievert (Sv).

The radiation field in point P of the ICRU-sphere is extended, but - contrary to H*(d) - not aligned. The equivalent dose will, therefore, depend on the direction from which the radiation comes. From the definitions, it follows that H*(d) = H'(d,0°).

One distinguishes H'(10,Ω) for penetrating radiation, H'(3,Ω) for the lens of the eye, and H'(0.07,Ω) for the skin.

Related dose quantities:

Last modified:16 January 2021 09.31 a.m.
View this page in: Nederlands