高剂量X射线辐照下碲锌镉探测器的深度极化效应  

Further polarization effect of CdZnTe detectors under high flux X-ray irradiation

作　　者：王玺[1] 肖沙里[1] 黎淼[1] 张流强[1] 曹玉琳[2] 陈宇晓[2] 

机构地区：[1]重庆大学光电技术及系统教育部重点实验室,重庆400030 [2]中国工程物理研究院电子工程研究所,四川绵阳621900

出　　处：《强激光与粒子束》2013年第3期773-777,共5页High Power Laser and Particle Beams

基　　金：国家自然科学基金项目(10876044);中央高校基本科研业务费专项资金项目(CDJXS11122219)

摘　　要：采用双向辐照的方法研究了碲锌镉晶体中的深度极化效应,实验结果表明,深度极化效应与直接辐照的X射线剂量无关。通过对晶体内电场分布的模拟,进一步分析了深度极化的形成机制,认为深度极化效应与极化效应一样,都是由于高浓度的堆积电荷使得晶体内电势畸变从而阳极不能收集信号,但它与通常极化效应有所不同,造成这种极化的高浓度空间电荷是从更高浓度的空间电荷区扩散而来的,发生深度极化的区域本身并没有受到X射线的强烈辐照。It has been observed that pixellated CdZnTe detectors fabricated from crystals experience a further polarization effect. In this case, in some areas of the CdZnTe detector, polarization occurs without high incident flux. Results from these studies reveal that at very high photon flux rates, a space charge region with high density develops and extends, consistent with the accumulation of positive space charge clue to the trapping of free-carrier holes created by the X ray irradiation. The further po- larization is caused by the extending of space charge region. The extending of space charge region observed without high Xray has a direct influence on the irradiation hardness and charge collection efficiency of the devices.

关 键 词：X射线探测器 CdZnTe探测器 高剂量X射线 极化效应 

分 类 号：TL834[核科学技术—核技术及应用]