ESCIES: ESCC Radiation: Definitions

Unit of Activity

becquerel (Bq) where 1Bq = 1 disintegration / second
{ 1Ci = 1 Curie = 3.7 X 10e10 Bq }

Unit of Exposure

the quantity of X or gamma radiation at a point in space integrated over time, in terms of charge of either sign produced by showering electrons in a small volume of air about the point.
= 1 coulomb / Kg of air {roentgen = 1R = 2.58 x 10e-4 coul/Kg }
= 1 esu /cm³ = 87.8 erg released energy per gram of air.

Unit of Absorbed Dose

gray = 1Gy = 1 joule / Kg {= 10e4erg/g = 10e2rads}
= 6.24 X 10¹²MeV / Kg deposited energy.

Unit of Dose Equivalent

(for biological damage) = sievert =Sv { = 10e2rem }
Dose equivalent in Sv =grays X Q (where Q = quality factor).
Q = 1 for gamma rays.