An Etymological Dictionary of Astronomy and Astrophysics

The fraction of a beam of → X-rays or → gamma rays that is absorbed or scattered per unit thickness of the → absorber.

The linear attenuation coefficient, denoted by the symbol μ, appears in the equation I(x) = I₀e^-μx, where I(x) is the intensity at depth of x cm and I₀ is the original intensity.

See also: → attenuation; → coefficient.