MONTE-CARLO SIMULATION OF COLLIMATED BEAM TRANSMISSION THROUGH TURBID MEDIA

An accurate Monte Carlo (MC) computer model is used to calculate the reflectances (R) and transmittances (T) of isotropic scattering media for the case of collimated beam illumination and for a wide range of absorption and scattering coefficients κ and δ per unit length. The MC results are presented by means of sets of curves with distance scaling in order to give an overall understanding of the subject. Numerical comparisons are made with analytical expressions obtained with a 3-flux model or derived from the equation of radiative transfer. These comparisons indicate the range of K and δ values where these expressions are applicable. A simple diagram is constructed with accurate MC results and can be used for direct graphical determination of K and δ from R and T measurements. The effects of reflections at the boundaries are described in the last section.