Impact of anti-charge sharing on the zero-frequency detective quantum efficiency of CdTe-based photon counting detector system: cascaded systems analysis and experimental validation.
Impact of anti-charge sharing on the zero-frequency detective quantum efficiency of CdTe-based photon counting detector system: cascaded systems analysis and experimental validation.
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DOI：
10.1088/1361-6560/aab9c9
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发表时间：
2018-05-01
影响因子：
3.5
通讯作者：
Li K
中科院分区：
文献类型：
--
作者：
Ji X;Zhang R;Chen GH;Li K
为了解决光子计数探测器（PCD）系统中的电荷共享问题，将像素间通信和反电荷共享技术引入到光子计数探测器（PCD）系统中。除了提高PCD的能量分辨率外，ACS还可能影响PCD性能的其他方面，如探测器多重性（即每个相互作用光子触发的像素数）和探测量子效率（DQE）。在这项工作中，开发了一个理论模型来解决ACS如何影响PCD系统的多重性和零频率DQE [DQE(0)]。这项工作的重点是基于碲化镉（CdTe）的PCD，它通常涉及k荧光光子的产生和传输。在平行级联系统分析框架下，该理论既考虑了光电效应，又考虑了散射效应，同时考虑了光子的重吸收和逸出。在ACS的一种新的理论处理中，它被认为是传统的单像素（即非ACS）模式的改进版本，但减少了电荷扩散距离和k荧光传播距离。提出的理论模型不需要事先了解每个特定PCD的详细ACS实现方法，并且可以使用放射性同位素实验确定其参数，而无需调用任何蒙特卡罗模拟。在确定模型参数后，使用诊断x射线管和四种不同的多色光束（从50到120 kVp）进行独立验证实验。理论和实验结果都表明，除了阈值水平远低于x射线能量水平的情况外，ACS增加了大多数x射线能量和阈值水平的第一和第二多重矩。然而，在所有测试的能量和阈值水平上，ACS总是提高DQE(0)。
Inter-pixel communication and anti-charge sharing (ACS) technologies have been introduced to photon counting detector (PCD) systems to address the undesirable charge sharing problem. In addition to improving the energy resolution of PCD, ACS may also influence other aspects of PCD performance such as detector multiplicity (i.e., the number of pixels triggered by each interacted photon) and detective quantum efficiency (DQE). In this work, a theoretical model was developed to address how ACS impacts the multiplicity and zero-frequency DQE [DQE(0)] of PCD systems. The work focused on cadmium telluride (CdTe)-based PCD that often involves the generation and transport of K-fluorescence photons. Under the parallel cascaded systems analysis framework, the theory takes both photoelectric and scattering effects into account, and it also considers both the reabsorption and escape of photons. In a new theoretical treatment of ACS, it was considered as a modified version of the conventional single pixel (i.e., non-ACS) mode, but with reduced charge spreading distance and K-fluorescence travel distance. The proposed theoretical model does not require prior knowledge of the detailed ACS implementation method for each specific PCD, and its parameters can be experimentally determined using a radioisotope without invoking any Monte-Carlo simulation. After determining the model parameters, independent validation experiments were performed using a diagnostic x-ray tube and four different polychromatic beams (from 50 to 120 kVp). Both the theoretical and experimental results demonstrate that ACS increased the first and second moments of multiplicity for a majority of the x-ray energy and threshold levels tested, except when the threshold level was much lower than the x-ray energy level. However, ACS always improved DQE(0) at all energy and threshold levels tested.
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影响因子：
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