闪烁晶体几何形状、表面处理和单双面读出对伽马射线探测器光收集的影响

Impact of Geometry,Surface Treatment and Single and Double-sided Readout on Light Collection of Scintillation Crystals for Gamma-ray Detectors

能量分辨率是闪烁体探测器的一个重要性能指标,特别是对于伽马能谱仪等伽马射线探测和识别领域。光收集是影响闪烁体探测器能量分辨率的一个重要因素,本工作利用Geant4工具包对闪烁体探测器中的光子传输进行了模拟,模拟了CsI(Na)晶体形状、表面处理和探测器的读出方式等对伽马射线探测器的光收集效率和光收集均匀性的影响。模拟结果表明,通过对圆柱、圆台、长方体和正方体等晶体形状的结果进行对比,圆台具有较高光收集效率和光收集均匀性;晶体表面研磨后具有更好的光收集特性;双面读出方式比单面读出方式的光收集性更高,能够提高10%~20%。为验证该模型的可靠性,搭建了实验平台进行实验验证工作,实验结果与蒙特卡罗模拟结果在2%范围内一致,该研究工作为优化伽马射线探测器以提高能量分辨率提供了关键设计依据。

The energy resolution is an important performance parameter of scintillation detectors,particularly in the field of gamma-ray detection and identification applications.Light collection is a crucial factor affecting the energy resolution of scintillation detectors.In this work,we utilized the Genat4 Monte Carlo toolkit to simulate the photon transport in scintillation detectors,investigating the effects of CsI(Na)crystal shape,surface treatment,and detector readout methods on the light collection efficiency and uniformity of light collection for gamma-ray detectors.The simulation results indicate that compared to cylindrical,rectangular,and square crystals,the conical crystal have higher light collection efficiency and uniformity.Additionally,scintillation crystal surfaces exhibited improved light collection efficiency after grinding.Furthermore,the detector using double-ended readout resulted in higher light collection efficiency,with an increase of 10%up to 20%compared to single-ended readout.Finally,the results of the simulations were confirmed by carrying out measurements of the light collection efficiencies of scintillation crystals.A comparison of simulated and measured values of light output shows a consistent agreement within a 2%range.This study provides essential design principles for optimizing gamma-ray detectors to improve energy resolution.