Towards design and optimization of scintillation-detector systems: A Monte-Carlo simulation framework

A complete simulation framework that combines Monte Carlo simulation with the digital-signal-processing algorithms developed in-house is presented for designing and optimizing scintillation detector systems. The framework covers basic components of a practical scintillation detector system and includes all relevant physical processes. With the complete simulation individual physical factors that can affect the performance of a detector system, such as detector geometry, surface finishing, decay time and scintillation yield of scintillator as well as responses of photodetector and front-end electronics, can be taken into account. As a demonstration of the simulation framework, the light collections of plastic (EJ200), NaI(Tl) and BGO scintillators with different surface types have been simulated as a function of the reflectivity of a diffuse reflector. Optical simulations were further performed to investigate the homogeneity of light transportation and detection in plastic scintillators with different surface finishing properties and coupled to one or two PMT(s). Finally, detector signals simulated for a NaI(Tl) detector have been compared with measured mean pulses. The simulated signal can be further digitized and used as input of digital signal processing.