公共格栅像素CdZnTe探测器的能谱特性  

Spectroscopic characteristics of common-grid pixelated CdZnTe detectors

作　　者：杨国强[1] 肖沙里[1] 马跃东[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400044 [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》2015年第7期267-271,共5页High Power Laser and Particle Beams

基　　金：国家自然科学基金项目(61274048);国家自然科学基金委员会-中国工程物理研究院联合基金项目(10876044)

摘　　要：使用同一块CdZnTe晶体设计制作了像素大小不等的4×4公共格栅像素CdZnTe探测器。通过能谱测定实验及权重势和电场仿真,研究了公共格栅像素CdZnTe探测器中的小像素效应和引导效应。结果表明:由于小像素效应较弱,较大的像素不能有效消除"空穴拖尾",能谱特性较差;由于晶体内部以及像素和公共格栅间隙表层的电荷损失,较小的像素能谱特性也较差。在像素宽度为0.8 mm时,得到了对662keV的137Cs放射源的最佳能量分辨率3.80%和峰谷比5.65。适当增大公共格栅偏压可以引导电子向阳极像素运动,促进电荷的完全收集,改善探测器的能谱特性。过大的偏压则会造成像素和公共格栅间表面漏电流的增加,探测器的能谱特性也会恶化。在像素宽度为0.8mm时最佳偏压为-60V。A 4 × 4 common grid pixelated CdZnTe detector with different pixel sizes is designed and fabricated using the CdZnTe crystal. By the spectra measurement combined with weighting potential and electric field simulation, the small pixel effect and guide effect in common grid pixelated CdZnTe detector are investigated. Results show that the spectroscopic character istics of lager pixels are degraded since the small pixel effect is not strong enough to remove the hole trailing. While the spectro scopic characteristics of smaller pixels are also degraded since the serious charge loss in volume and surface layer between pixels mm wide pix degrades gr el. id. An optimal energy resolution of 3.80% FWHM at 662 keV（137 Cs radiation source） is obtained Excessive high bias voltage increases the surface leakage current between pixels spectroscopic characteristics. The optimal bias voltage is --60 V for 0.8 mm wide pixel. from the 0.8 which in turn

关 键 词：CDZNTE 半导体探测器 公共格栅像素结构 小像素效应 能量分辨率 

分 类 号：TL816[核科学技术—核技术及应用]