Further polarization effect of CdZnTe detectors under high flux X-ray irradiation

It has been observed that pixellated CdZnTe detectors fabricated from crystals experience a further polarization effect. In this case, in some areas of the CdZnTe detector, polarization occurs without high incident flux. Results from these studies reveal that at very high photon flux rates, a space charge region with high density develops and extends, consistent with the accumulation of positive space charge due to the trapping of free-carrier holes created by the X-ray irradiation. The further polarization is caused by the extending of space charge region. The extending of space charge region observed without high X-ray has a direct influence on the irradiation hardness and charge collection efficiency of the devices.