Simulation research on time resolution based on Cherenkov radiation

摘要

Purpose A faster time performance can be achieved by focusing on prompt emitted photons, such as Cherenkov photons. In this study, the time fluctuations of Cherenkov photons transmission in the three Cherenkov radiators were first simulated, and we evaluated the detector performance and discussed ways to improve the coincidence time resolution (CTR) results for the detector with the three radiators. Finally, we compared detection efficiency of Cherenkov radiation in three radiators. Methods In this work, we recorded the step-by-step information of Cherenkov photons and the electrons that produced them in the radiator, information of photons on the photon outputting surface, and the step-by-step information tracing of the parent charged particles (electrons) to evaluate the factors influencing the performance time of the detector based on Geant4. Specially, we usually use a photon amplitude timing in the experimental implements, and the arrival time of an event is defined as the arrival time of the first photon of the event accordingly. Results The time fluctuations of Cherenkov photons transmission in the three Cherenkov radiators with a 5 mm length were simulated as 28.5 ps for PbF, 40.1 ps for PbWO4, and 24.7 ps for Al2O3. After considering other factors such as quantum efficiency (QE) of 30% and transit time spread (TTS) of 10 ps from the process of practical electronics, the CTR of a pair of single-pixel detectors were 56.6 ps for PbF2, 78.8 ps for PbWO4, and 46.3 ps for Al2O3 with a thickness of 5 mm. The detection efficiency of PbF2 is 32.25%, PbWO4 of 31.91% and Al2O3 of 8.14% in the case of 5 mm length. Conclusions The simulation results indicated that using the Cherenkov photons produced in PbF2, PbWO4, Al2O3 for detector timing can obtain good CTR results. In this study, it demonstrates that it is possible to achieve a pretty good CTR with an improved QE and a reduced TTS of the photodetector.