Definitions for **"Absorption Coefficient, Linear"**

The fractional decrease in the intensity of a beam of gamma or X-radiation as it passes through an absorbing medium. It is expressed per unit thickness of medium (usually cm). The specific value of the linear absorption coefficient depends on the type of absorbing material, energy of the gamma or X-ray, and the density of the absorbing medium. The value of m is used in the equation I = I Ae- mx; where I is the intensity and x is the thickness of the absorber in the same base units as m.

The fractional decrease in transmitted intensity per unit of absorber thickness. It is usually designated by the symbol ยต and expressed in units of (cm-1.2).