Simulation Study on Time Resolution of γ-Ray Measurement Using Scintillator

γ-Ray measurement techniques are used in positron emission tomography and positron annihilation lifetime measurement, and require a high time resolution. In this study, we investigated the design conditions for scintillation detectors to improve the time resolution of time-of-flight measurement using a Monte Carlo simulation. The time resolution is strongly affected by the scintillator shape and reflector properties. The result shows that, for thin scintillators, specular reflectors are effective for obtaining a good time resolution, while for thick scintillators, diffuse reflectors are effective. It also shows that, for thin scintillators, the time resolution can be improved by combining specular and diffuse reflectors on the side and bottom surfaces, respectively.