Investigation of the Influence of Infrared Illumination on the Pulse Shapes of Output Signals of CdZnTe Detectors.

The spectrometric characteristics of CdZnTe detectors are largely determined by the nonuniformity of the material and the influence of the negative polarization effects associated with the formation of space charges in the sensitive volume of the detector. They change the electric field distribution in the detector and affect the efficiency of the charge carrier collection. An analysis of the waveforms of the output pulses was used to investigate the uniformity of the charge collection and electric field distribution in the detectors when irradiated by the alpha particles. The influence of infrared (IR) illumination on these parameters was evaluated. IR illumination had no positive effect on the planar detector but greatly improved the charge collection in quasi-hemispherical detectors in the peripheral (corner) regions. The output pulse amplitude increased, and the rise time notably decreased. Polarization that occurred predominantly in the corner regions at low temperatures (from -30 °C to -20 °C) was eliminated using IR illumination.

Use of CdZnTe Quasi-Hemispherical Detectors under the Impact of Low Temperatures and High-Gamma Radiation Fluxes.

This article discusses the possibilities and limitations of CdZnTe (CZT) quasi-hemispherical detectors operating over a wide temperature range and at high-gamma radiation fluxes. The results of the negative influence of low- and high-operating temperatures, as well as high-radiation fluxes on spectrometric characteristics of CZT detectors and possible ways to eliminate performance deterioration, are presented. The impact of infrared (IR) illumination parameters, such as wavelength and irradiation intensity on the spectroscopy performance of detectors, was investigated. A correctly chosen IR illumination wavelength and intensity were shown to significantly improve the energy resolution of CZT quasi-hemispherical detectors, allowing their stable operation in high-gamma radiation fluxes and extend the operating temperature range toward low temperatures. The influences of bias voltage values and temperatures on the quasi-hemispherical CZT detectors' operating ability at high-gamma radiation fluxes were studied.