Study of surface roughness of CsI:Tl crystals treated by various abrasives

The study of the surface roughness of CsI:Tl scintillators processed by abrasives with different grain size was performed to obtain the optical characteristics that are important for simulation of light collection processes in scintillators. The degree of roughness of the surface was studied qualitatively by optical microscopy and quantitatively by measuring light scattering indicatrices at different angles of incident light on the samples. Micrographs of the sample surfaces, obtained by means of optical microscopy, allowed the estimation of the typical roughness for each abrasive. The micro-facet slope distribution functions were extracted from the measured light scattering indicatrices. It was found that these functions depend only on the grain size of abrasive. For the same abrasive, the micro-facet slope distribution functions do not depend on the incident light angle which is a good demonstration of the reliability of the results. Micro-facet slope distributions obtained for CsI:Tl can be used for the simulation of light collection processes in different scintillators with similar hardness and elastic properties.