Approximations of coincidence time resolution models of scintillator detectors with leading edge discriminator

Abstract

Coincidence time resolution (CTR) of scintillator detectors is of high importance in high energy physics, medical imaging, and many other time-of-flight (TOF) application areas. Recent progress in developments of fast silicon photomultipliers (SiPM) and dedicated fast timing electronics resulted in significant improvements in CTR of SiPM-based scintillator detectors. CTR of 10 ps is considered as an ultimate goal of these improvements. Approaching to that goal, the most sophisticated devices (multichannel digital SiPM, 3D SiPM) and methods (TOF estimators based on multi-photon time-stamps, intense computational algorithms) are evaluated.Despite these cutting-edge approaches, conventional analog SiPMs and vacuum PMTs with a conventional leading-edge discriminator (LED) are expected to be relevant solutions in large-scale experiments and applications for a long time. However, CTR estimation even in these cases requires specific numerical or Monte Carlo simulations because to the best of the author’s knowledge, there are no widely recognized closed-form expressions of CTR.This study is an attempt to develop simple and reasonably realistic closed-form approximations of the CTR from a filtered marked point process model of the photomultiplier response, and clarify the CTR dependence on the main scintillator detection parameters.