A Study on the Simulated Spectra Responses of a Scintillation Detector by Tracking Secondary Particle Generated from the Gamma-Ray Interaction

Background:In the simulation of gamma-ray spectral response from a scintillation detector, the energy deposited in the detector is often calculated from the energy lost by each incident gamma ray due to the interaction, no matter where it may happen.In reality, the light collection efficiency of the scintillator will not be uniform over the entire scintillator, which affects the spectral response that can actually be obtained by the scintillator.The energy resolution and peak efficiency, as well as overall shape of the gamma-ray spectrum can deviate from reality. Materials and Methods:We simulated the gamma-ray response of a 5.08 cm5.08 cm (22) Cs2LiYCl6:Ce (CLYC) scintillation detector considering the transport of associated information carriers: gamma rays only, gamma rays and electrons, and scintillation photons additionally, using Monte Carlo N-Particle version 6.1 (MCNP6.1)and GEometry ANd Tracking version 4 (GEANT4) code.The effect of the secondary particle transport was analyzed by comparing the simulation and measurement results. Results and Discussion:The absolute peak efficiency calculated from the simulation that includes electron transport is closer to the measurement result than that from the simulation considering only gamma-ray transport.The discrepancy decreased from 24.6% (gamma only) to 21.2% (including electron transport) by MCNP6.1 calculation, and from 13.6% (gamma only) to 7.9% (including electron transport) by GEANT4 calculation.Through simulation considering the transport of scintillation photons, the phenomenon of peak broadening on the energy spectrum became observable. Conclusion:In the gamma-ray response simulation of scintillation detectors, we confirmed that the deviation from the measurement results was reduced by including secondary particle transfers into consideration.