Absorbed Dose
The fundamental dosimetric quantity D is defined as:
D = dE /dm
where, ‘dE’ is the mean energy imparted by ionising radiation to the matter in a volume element and ‘dm’ is the mass of matter in the volume element. The energy can be averaged over any defined volume, the average dose beingequaltothetotalenergyimpartedinthevolumedividedbythemassinthevolume.TheSIunitofabsorbed dose is joule/kg (J.kg-1), termed the gray(Gy).
Acceptable Limits
Limits acceptable to the regulatory body for radiation exposure under accident (or on potential exposure if they occur).
Accident
Any unintended event, including operating errors, equipment failures or other mishaps, the consequences or potential consequences of which are not negligible from the point of view of protection or safety
Source: www.aerb.gov.in