Sub-Microsecond X-Ray Imaging Using Hole-Collecting Schottky type CdTe with Charge-Integrating Pixel Array Detectors

摘要

CdTe is increasingly being used as the x-ray sensing material in imagingpixel array detectors for x-rays, generally above 20 keV, where silicon sensorsbecome unacceptably transparent. Unfortunately CdTe suffers from polarization,which can alter the response of the material over time and with accumulateddose. Most prior studies used long integration times or CdTe that was not ofthe hole-collecting Schottky type. We investigated the temporal response ofhole-collecting Schottky type CdTe sensors on timescales ranging from tens ofnanoseconds to several seconds. We found that the material shows signalpersistence on the timescale of hundreds of milliseconds attributed to thedetrapping of a shallow trap, and additional persistence on sub-microsecondtimescales after polarization. The results show that this type of CdTe can beused for time resolved studies down to approximately 100 ns. Howeverquantitative interpretation of the signal requires careful attention to biasvoltages, polarization and exposure history.