Performance of a Medipix3RX Spectroscopic Pixel Detector With a High Resistivity Gallium Arsenide Sensor
Performance of a Medipix3RX Spectroscopic Pixel Detector With a High Resistivity Gallium Arsenide Sensor
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DOI：
10.1109/tmi.2014.2317314
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发表时间：
2015-03-01
影响因子：
10.6
通讯作者：
Fiederle, Michael
中科院分区：
文献类型：
--
作者：
Hamann, Elias;Koenig, Thomas;Fiederle, Michael
高电阻率砷化镓被认为是用于光谱X射线成像探测器的合适的传感器材料。这些传感器通常具有几百μ m和1mm之间的厚度，以确保高的光子检测效率。然而，对于小到几十μ m的像素尺寸，称为电荷共享的效应降低了检测器的光谱性能。最近开发的Medipix3RX读出芯片通过实现电荷求和电路克服了这一限制，该电路允许在单个像素中重建光子相互作用的全部能量信息。在这项工作中，我们提出了一个500 μ m厚的高电阻率，铬补偿砷化镓传感器的第一Medipix3RX检测器组件的特性。我们分析了它的属性，并证明了功能的电荷求和模式的能量响应函数记录在同步加速器。此外，成像性能的检测器，在其调制传递函数和信噪比方面，进行了研究。经过十多年的尝试，将砷化镓作为光子计数探测器的传感器材料，我们的结果代表了获得探测器级材料的突破。因此，我们介绍的传感器适用于高分辨率X射线成像应用。
High resistivity gallium arsenide is considered a suitable sensor material for spectroscopic X-ray imaging detectors. These sensors typically have thicknesses between a few hundred mu m and 1 mm to ensure a high photon detection efficiency. However, for small pixel sizes down to several tens of mu m, an effect called charge sharing reduces a detector's spectroscopic performance. The recently developed Medipix3RX readout chip overcomes this limitation by implementing a charge summing circuit, which allows the reconstruction of the full energy information of a photon interaction in a single pixel. In this work, we present the characterization of the first Medipix3RX detector assembly with a 500 mu m thick high resistivity, chromium compensated gallium arsenide sensor. We analyze its properties and demonstrate the functionality of the charge summing mode by means of energy response functions recorded at a synchrotron. Furthermore, the imaging properties of the detector, in terms of its modulation transfer functions and signal-to-noise ratios, are investigated. After more than one decade of attempts to establish gallium arsenide as a sensor material for photon counting detectors, our results represent a breakthrough in obtaining detector-grade material. The sensor we introduce is therefore suitable for high resolution X-ray imaging applications.