Direct measurement of electron drift parameters in pixelated cadmium zinc telluride semiconductor detectors

Abstract

The single-polarity charge-sensing electrode is widely used in wide-bandgap room-temperature CdZnTe detectors; in such systems, the drift of electrons is the primary contribution to the induced signal at the anode. Thus, it is important to accurately evaluate the parameters that describe the electron transport properties because they affect the performance of detectors. This paper proposes a method to directly measure the electron mobility and their mean free drift time in a pixelated CdZnTe detector using a depth-sensitive technique. The presented method considers the effect of the nonideal weighting potential in an actual detector, which has not been accounted for in previously proposed methods. In addition, by fitting the cathode waveform to avoid the effect of the time–amplitude walk due to the trigger threshold, improved measurement accuracy of the electron drift parameters can be achieved.