Probing Defects in a Small Pixellated CdTe Sensor Using an Inclined Mono Energetic X-Ray Micro Beam
Probing Defects in a Small Pixellated CdTe Sensor Using an Inclined Mono Energetic X-Ray Micro Beam
复制标题
DOI：
10.1109/tns.2013.2257851
复制
发表时间：
2012-10
影响因子：
1.8
通讯作者：
E. Frojdh;C. Frojdh;E. Gimenez;D. Krapohl;D. Maneuski;B. Norlin;V. O’Shea;H. Wilhelm;N. Tartoni;G. Thungstrom;R. M. Zain
中科院分区：
文献类型：
--
作者：
E. Frojdh;C. Frojdh;E. Gimenez;D. Krapohl;D. Maneuski;B. Norlin;V. O’Shea;H. Wilhelm;N. Tartoni;G. Thungstrom;R. M. Zain
高量子效率在X射线成像应用中是重要的。这意味着使用高Z传感器材料。不幸的是，这些材料中的许多都存在导致非理想电荷传输的缺陷。为了增加对这些缺陷的理解，我们使用79 keV的单能微束，绘制了两个1 mm厚、像素尺寸不同（55 μm和110 μm）的CdTe传感器中一些缺陷的三维响应。传感器被凸块键合到Timepix读出芯片。以光子计数以及时间超过阈值模式收集数据。时间超过阈值模式是一个非常强大的工具，研究电荷传输特性和荧光像素化探测器，因为每个光子存款在每个像素的电荷的信号可以进行分析。结果表明，扭曲的电场周围的缺陷，过量的漏电流和电子收集和空穴收集模式之间的行为有很大的差异的迹象。实验是在金刚石光源的极端条件光束线I15上进行的。
High quantum efficiency is important in X-ray imaging applications. This means using high-Z sensor materials. Unfortunately many of these materials suffer from defects that cause non-ideal charge transport. In order to increase the understanding of these defects, we have mapped the 3D response of a number of defects in two 1 mm thick CdTe sensors with different pixel sizes (55 μm and 110 μm) using a monoenergetic microbeam at 79 keV. The sensors were bump bonded to Timepix read out chips. Data was collected in photon counting as well as time-over-threshold mode. The time-over-threshold mode is a very powerful tool to investigate charge transport properties and fluorescence in pixellated detectors since the signal from the charge that each photon deposits in each pixel can be analyzed. Results show distorted electrical field around the defects, indications of excess leakage current and large differences in behavior between electron collection and hole collection mode. The experiments were carried out on the Extreme Conditions Beamline I15 at Diamond Light Source.