LYSO-SiPM 闪烁脉冲动力学的统一分析框架
A Unified Analytical Framework for LYSO-SiPM Scintillation Pulse Dynamics
AI总结：
该研究提出 LYSO-SiPM 闪烁探测器的统一分析框架，关联各过程并经实验验证，能预测波形与计时极限，加深对探测器响应的物理理解。
AI中文摘要：
现有闪烁探测器模型通常将闪烁动力学、光传输、硅光电倍增管（SiPM）响应和计时统计分开处理，限制了对波形形成和探测器性能的端到端预测。我们提出了一种用于镥钇正硅酸盐（LYSO）-SiPM 闪烁探测器的统一分析框架，在单个正向模型中关联这些过程。该框架纳入了有限热化、深度相关的光传输时间展宽以及微单元占据动力学，以提供基于物理的宏观脉冲形成描述。它在线性区域产生闭合形式的指数修正高斯脉冲，在饱和区域产生状态相关的积分解，并恢复了传统双指数脉冲模型——该模型在闪烁脉冲拟合和稀疏采样重建中被广泛使用但此前仅得到经验性证明——作为完整光电级联的受控简化。对 10000 个直接数字化的 Na-22 脉冲的实验验证表明，动态饱和模型能够捕捉与幅度相关的波形失真，且在 100 个高幅度脉冲中的 100 个、100 个中等幅度脉冲中的 98 个上，经赤池信息准则（AIC）判定，该模型优于匹配的双指数基线模型。通过将动态触发率与复合泊松统计耦合，该框架还能预测电流方差包络和基于费希尔信息的计时极限，包括参考 511-keV LYSO-SiPM 配置下约 100 ps 半高全宽（FWHM）的固有符合计时分辨率下限。这些结果通过阐明闪烁动力学、光传输和 SiPM 微单元动力学如何共同塑造观测响应，加深了对闪烁探测器波形形成和计时极限的物理理解。
英文摘要：
Existing scintillation-detector models typically treat scintillation kinetics, optical transport, silicon photomultiplier (SiPM) response, and timing statistics separately, limiting end-to-end prediction of waveform formation and detector performance. We present a unified analytical framework for lutetium-yttrium oxyorthosilicate (LYSO)-SiPM scintillation detectors that links these processes within a single forward model. The framework incorporates finite thermalization, depth-dependent optical transit-time spread, and microcell occupancy dynamics to provide a physics-based description of macroscopic pulse formation. It yields closed-form exponentially modified Gaussian pulses in the linear regime, state-dependent integral solutions in saturation, and recovers the conventional bi-exponential pulse model---ubiquitously used yet hitherto only empirically justified in scintillation pulse fitting and sparse-sampling reconstruction---as a controlled reduction of the full optoelectronic cascade. Experimental validation on 10,000 directly digitized Na-22 pulses shows that the dynamic saturation model captures amplitude-dependent waveform distortion and is favored by the Akaike information criterion (AIC) over a matched bi-exponential baseline in 100/100 high-amplitude pulses and 98/100 medium-amplitude pulses. By coupling the dynamic triggering rate to compound Poisson statistics, the framework also predicts current-variance envelopes and Fisher-information-based timing limits, including an intrinsic coincidence timing resolution lower bound of about 100 ps full width at half maximum (FWHM) for a reference 511-keV LYSO-SiPM configuration. These results deepen the physical understanding of scintillation-detector waveform formation and timing limits by clarifying how scintillation kinetics, optical transport, and SiPM microcell dynamics jointly shape the observed response.
