scatteringkoefficienten

Scatteringkoefficienten is a term used in physics to describe the rate at which incident radiation or particles are scattered as they travel through a medium. In practice, the main quantity is the scattering coefficient μs, typically expressed in inverse meters. The plural form is used when comparing different media, wavelengths, or conditions.

A homogeneous medium containing scatterers with number density n and scattering cross section σs yields μs = n σs. The total attenuation coefficient μt is the sum of absorption and scattering, μt = μa + μs, where μa is the absorption coefficient. The mean free path for scattering is ℓs = 1/μs. The scattering cross section σs is related to the differential cross section via σs = ∫ (dσs/dΩ) dΩ over all solid angles. The angular distribution of scattered light is described by a phase function, and radiative transfer equations use μs to describe scattering into and out of a direction.

Applications and variants occur across optics, atmospheric science, biomedical optics, and acoustics. In tissue optics, a reduced scattering coefficient μs' = μs (1 − g) is often used, where g is the asymmetry parameter ⟨cos θ⟩ of the phase function. In acoustics, the scattering coefficient plays a similar role for sound, quantifying how much energy is redirected per unit length.

Measurement and use involve inferring μs from transmission, reflection, or backscattered measurements and modeling with radiative transfer, Monte Carlo simulations, or diffusion approximations. Scatteringkoefficienten thus enable characterization of media such as fog, clouds, skin, or medical phantoms.