Monte Carlo Simulation-Based Maximum-Likelihood Position Estimate for Monolithic Scintillation Detectors

In this paper, we propose a Monte Carlo simulation-based maximum-likelihood position estimate (MLPE) for the localization of photons in monolithic scintillator detectors. The difference between the new method and the existing MLPEs is that the new method does not require repeated experiments to generate the look-up table (LUT), which contains the detector response for two-dimensional space; instead, a single Monte Carlo simulation generates the LUT. The LUT generated from the simulation was then directly applied to experimental measurements with a Gaussian noise model-based MLPE algorithm. Using the new method, monolithic scintillator detector, which was assembled from monolithic NaI(Tl) and digital SiPM, a differential linearity 0.1 mm and a spatial resolution of 2.0 mm full width at half maximum (FWHM) offering 64.1% and 60.9% improvements, respectively compared to the results obtained over the center-of-gravity method.