Ambient dose equivalent

ICRU sphere

The operational dose quantity ambient dose equivalent (H*(d)) is defined as the equivalent dose at point P at a depth of d mm in the ICRU phere (see Figure). The corresponding unit is sievert (Sv).

It is assumed that the radiation field anywhere within the sphere is equal to that at point P (extended field) and that all radiation comes from the direction parallel to the shortest connection between the spherical surface and point P (aligned field).

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

Ambient dose equivalent

Related quantities