A model of optical reflection on rough surface and its application to Monte Carlo simulation of light transport

Photon transport is important for designing an optical system of scintillation counters or Cherenkov counters. Monte Carlo simulations are useful in predicting the characteristics, since they are flexible and cost us less. Optical reflection is an important part of such simulation studies. Light reflection on a rough surface is usually treated by Lambert's law that holds for reflection on an isotropically diffusive surface, while mirror reflection is the other extreme case. P. Beckmann's theory (1967) of reflection on rough surfaces lies in-between. A Monte Carlo program was developed based on this model. The programs were tested on the calculations of light collection efficiency and photon transport problems. The results were compared with those with pure mirror reflectors and that with isotropically diffusive reflectors.