Effect of Aspect Ratio on the Light Output of Scintillators

The influence of the geometry of the scintillators is presented in this paper. We focus on the effect of narrowing down the section of crystals that have a given length. The light output of a set of crystals with very similar scintillating properties but different geometries measured with several coupling/wrapping configurations is provided. We observe that crystals shaped in thin rods have a lower light output as compared to bulk or sliced crystals. The effect of unpolishing the crystal faces is also investigated, and it is shown that highest light outputs are not necessarily obtained with crystals having all faces polished. Simulation results based on a realistic model of the crystal that implements light scattering on the crystal edges are in agreement with the experimental data. Fine-tuning of this model would allow us to further explore the details of light propagation in scintillators and would be highly valuable to fast timing detection and highly granular detectors.