Observed light yield of scintillation pixels: Extending the two-ray model

•A model describing light output as a function of crystal size is proposed.•Absorption and reflection losses are considered.•The model predictions agree well with experimental data.

In this paper we propose an extended, two dimensional model describing the propagation of scintillation photons inside a cuboid crystal until they reach a PMT window. In the simplest approach the model considers two main reasons for light losses: standard absorption obeying the classical Lambert–Beer law and non-ideal reflectivity of the “mummy” covering formed by several layers of Teflon tape wrapping the sample. Results of the model calculations are juxtaposed with experimental data as well as with predictions of an earlier, one dimensional model.