Department of Biomedical Engineering, University of California Davis, Davis, CA, United States of America.
Department of Radiology, University of California Davis, Davis, CA, United States of America.
Phys Med Biol. 2021 Oct 22;66(21). doi: 10.1088/1361-6560/ac2e18.
Cerenkov photons have distinctive features from scintillation photons. Among them is their polarization: their electric field is always perpendicular to the direction of propagation of light and parallel to the plane of incidence. Scintillation photons are instead considered unpolarized.
This study aims at understanding and optimizing the reflectance of polarized Cerenkov photons for optical Monte Carlo simulation of scintillation detectors with Geant4/GATE. First, the Cerenkov emission spectrum and polarization were implemented in the previously developed look-up-table Davis model of crystal reflectance. Next, we modified Geant4/GATE source code to account for scintillation and Cerenkov photons LUTs simultaneously. Then, we performed optical Monte Carlo simulations in BGO using GATE to show the effect of Cerenkov features on the photons' momentum at the photodetector face, using two surface finishes, with and without reflector.
In this work, we describe the new features added to the algorithm and GATE. We showed that Cerenkov characteristics affect their probability to be reflected/refracted and thus their travel path within a material.
We showed the importance of accounting for accurate Cerenkov photons reflectance while performing advanced optical Monte Carlo simulations.
切伦科夫光子具有与闪烁光子不同的特征。其中之一是它们的偏振：它们的电场总是垂直于光的传播方向，并且平行于入射平面。相比之下，闪烁光子被认为是无偏振的。
本研究旨在理解和优化偏振切伦科夫光子的反射率，以便使用 Geant4/GATE 对闪烁探测器进行光学蒙特卡罗模拟。首先，在之前开发的晶体反射率查找表 Davis 模型中实现了切伦科夫发射光谱和偏振。接下来，我们修改了 Geant4/GATE 源代码，以同时考虑闪烁和切伦科夫光子的查找表。然后，我们使用 GATE 在 BGO 中进行了光学蒙特卡罗模拟，以展示切伦科夫特征对光电探测器表面处光子动量的影响，使用了两种表面处理，有和没有反射器。
在这项工作中，我们描述了算法和 GATE 中添加的新功能。我们表明，切伦科夫特性会影响它们被反射/折射的概率，从而影响它们在材料中的传播路径。
我们表明，在进行高级光学蒙特卡罗模拟时，准确考虑切伦科夫光子的反射率非常重要。
