Study of detection efficiency of Cd1-xZnxTe detectors for digital radiography

In this paper, the signal-to-noise ratio (S/N) of resistive Cd/sub 1-x/Zn/sub x/Te semiconductor detectors, at different directions of irradiation, within the X-ray diagnostic energy range, has been experimentally studied. In addition, the dependence of the spatial resolution of a planar Cd/sub 1-x/Zn/sub x/Te substrate both on the applied bias voltage and thickness has been experimentally determined. The detection efficiency of semiconductor detectors depend upon the energy absorption efficiency as well as the collection efficiency. This study suggests that high signal-to-noise ratios can be obtained by optimally choosing which polarizing electrode is directly exposed to the incident X-ray beam, as well as on both the detector thickness and applied bias voltage. In addition, the experimental results on the temporal system MTF indicate a spatial resolution of >6 cy/mm. Besides the intrinsic charge transport characteristics of the semiconductor sample, by decreasing the collector size and optimizing the X-ray digital system geometry and temporal response, the temporal system MTF can be improved significantly. The research imaging detector system allows one to investigate methods to improve the detection and imaging performance parameters as part of the development of a digital radiographic system.

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