用于医学成像的碲锌镉单极型探测器的研究进展

Progress in the development of CdZnTe unipolar sensing detector for medical imaging

摘要:

碲锌镉半导体材料具有探测效率高、能量分辨率高和体积小重量轻的特点,是目前公认的最有希望成为下一代的伽马射线探测装置的材料。然而,空穴俘获导致的电荷收集不完全限制了碲锌镉半导体探测器的性能。解决空穴俘获最有效的方法是单极型探测器技术。本文首先简要介绍半导体探测器中电荷收集的相关理论,然后重点阐述单极型探测器技术的实现方法,包括各种电极的结构设计原理、典型的探测器原型机介绍、性能特点以及其结构设计的优缺点。最后简要展望了碲锌镉半导体探测器未来的发展方向。

Abstract:

The CdZnTe semiconductor is now regarded as the most promising candidate for the next generation of gamma ray detectors, providing good stopping power for gamma rays, lightweight camera heads and improved energy resolution. However, the performance of CdZnTe detector is limited mainly by incomplete charge collection problems resulting from charge carriers trapping. Single charge sensing techniques are the most effective ways to solve that trapping problem with some electronic correction methods. This paper reviews the methods and techniques to improve performance of CdZnTe detectors. We will first briefly introduce the relevant theories. Thereafter, the single charge sensing techniques are summarized in detail. CdZnTe detectors of different geometries are discussed particularly, covering the principal of the electrode geometry design, some detector prototypes development and special correction techniques to improve the energy resolution. Finally, future development of CdZnTe detector is also discussed. Spectroscopic performance of CdZnTe semiconductor detector will be greatly improved even to approach the statistical limit on energy resolution with the combination of some of these techniques.