Attenuation coefficient

The quantity attenuation coefficient (commonly denoted by the Greek letter μ) describes how easily electromagnetic radiation penetrates into matter. Instead of the linear attenuation coefficient µ (in m^-1), often the mass attenuation coefficient μ/ρ (in m²·kg^-1) is given. Here, ρ is the density (in kg·m^-3) of the material.

The quantity half-value thickness (d_½) is the amount of material that reduces the intensity to half the original value. The relation between half-value thickness and attenuation coefficient is:

d_½ = ln(2) / μ

Related quantities

• buildup factor
• dose conversion coefficient
• half-value thickness
• inverse-square law
• kerma-rate constant
• radiotoxicity equivalent
• transmission