CdZnTe探测器的辐照损伤研究

Cadmium Zinc Telluride (CdZnTe, CZT) is regarded as the most promising compound semiconductor materials for room-temperature nuclear radiation detectors, which have a wide range of applications in the various domains of human society, including border security, medical imaging, industrial inspection, environmental monitoring, astrophysics and so on. However, these applications require CZT detectors to be operative in a hostile environment, for example, being exposed to high-energy and high-dose radiation for a long time, which can markedly alter the detector performances, and cause the so-called radiation damage. This program is dedicated to the research of the radiation effects in CdZnTe:In detectors. A series of energy exchange and transfer processes during irradiation were systematically analyzed, in order to build a theoretical model and to reveal the microscopic mechanism of radiation damage, thus obtaining a deep understanding of the nature of the radiation effects. Experimentally, radiation induced defective states were studied by applying the thermally stimulated current technology, and then, we are able to investigate the effects of radiation damage on the electrical, optical properties and detector performances. Furthermore, a through discussion of the radiation hardness properties and the recovery of the radiation effects were realized, thus providing theoretical guidance for the optimization of the detector performances and the improvement of the utilization efficiency in the practical application environment.

碲锌镉（CdZnTe，CZT）室温核辐射探测器在边防安检、医疗成像、工业检测、环境监测、天体物理等人类社会的各个重要领域具有广泛的应用前景。然而，这些应用使得探测器长时间工作于高能高剂量的辐照环境下，不可避免地对器件性能产生恶劣的影响。本项目主要研究CdZnTe:In探测器的辐照效应。系统分析辐照过程涉及的一系列能量交换与传递过程，构建理论模型，揭示辐照损伤的微观机制，有利于实现对辐照效应的本质的深入理解。采用热激电流谱技术，研究辐照诱导产生的缺陷状态，在此基础上，揭示辐照损伤对材料特性和器件性能的影响规律。深入探讨探测器的抗辐照特性以及辐照效应的恢复过程，对于实际应用中探测器性能的优化和有效利用率的提高具有重要的指导意义。

高阻碲锌镉（CdZnTe，CZT）晶体制备的核辐射探测器，由于其在室温下优良的光电性能，在10 keV~1 MeV的硬X射线及γ射线探测领域，如核医学成像、场站安检等，具有广阔的应用前景。然而，CZT探测器应用于宇宙射线和加速器粒子等的探测过程中，常常需要长时间工作于高能高剂量的辐照环境下，不可避免地在晶体材料内部产生辐照缺陷，从而对材料本身特性和探测器性能产生影响。因此，CZT材料和CZT探测器的辐照效应越来越多地受到人们的关注。本项目主要研究CZT探测器的辐照损伤机制，将理论模型与实测结果进行对比分析，更深入的探索辐照诱导产生的缺陷及其对材料特性、器件性能的影响。主要研究成果包括：（1）获得了质子辐照损伤对CZT探测器能谱特性及电荷收集均匀性的影响规律，确定了辐照损伤引入的缺陷类型及其分布；（2）研究了高能重离子辐照损伤对CZT探测器能谱特性的影响，提出了减小辐照损伤对探测器能谱特性影响的方法。通过研究CZT探测器的抗辐照特性，对于器件的实际应用条件和工作环境的界定具有重要的指导意义。