Modeling and Optimization of Scintillator Arrays for PET Detectors

A new Zemax model has been developed, which reliably predicts the light output of scintillator crystal pins for Positron Emission Tomography. Different configurations, including pin shape, surface finish and reflector types are investigated. The simulations use the actual measured wavelength-dependent parameters of the scintillator crystal, of the reflector and of the PMT's components. Good agreement is demonstrated between simulated and measured light output figures for 33 different pin configurations. The highest light output was found by both simulation and experiment for the pins with polished superficies (either polished or diffuse gamma-side) with a non-coupled high reflectivity specular reflector around the superficies and an optically coupled high reflectivity diffuse reflector on the gamma-side. We also present the measured light output homogeneity of a scintillator array fabricated according to one of the best pin configurations.