High-energy gamma-ray imaging is an important technique with applications in homeland security and medical imaging. Recent advancements in the cadmium zinc telluride (CdZnTe) OrionUM detector systems have enabled measurement of gamma-ray sources with energies up to 9 MeV. However, Compton imaging of photons above 3 MeV faces several challenges that degrade both spectroscopic and imaging performances in pixelated CdZnTe systems. These factors include the increase in pair-production events, incorrect event sequencing, and charge sharing from large electron clouds. They all result in shift-variant image artifacts that degrade the signal-to-noise ratio as well as create artifacts that might be mistaken for a hot spot. The degradation from artifacts is analyzed and discussed, and possible mitigation techniques are presented to allow for recovery of the Compton image signal. Simulation is compared with experimental measurements of 4.4-MeV gamma rays from a 238PuBe source to investigate the artifacts.

中文翻译：

---

使用 3D 位置敏感 CdZnTe 进行高能康普顿成像的伪影

高能伽马射线成像是在国土安全和医学成像中应用的重要技术。碲化镉锌 (CdZnTe) OrionUM 探测器系统的最新进展已经能够测量能量高达 9 MeV 的伽马射线源。然而，3 MeV 以上光子的康普顿成像面临一些挑战，这些挑战会降低像素化 CdZnTe 系统的光谱和成像性能。这些因素包括成对产生事件的增加、不正确的事件排序以及来自大型电子云的电荷共享。它们都会导致偏移变化的图像伪影，从而降低信噪比，并产生可能被误认为热点的伪影。分析和讨论了人工制品的退化，并提出了可能的缓解技术，以允许康普顿图像信号的恢复。将模拟与来自 238PuBe 源的 4.4-MeV 伽马射线的实验测量值进行比较，以研究伪影。