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

Abstract

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.

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

“…It can also be assumed that the slight increase in amplitude and increase in transit time are associated with a suboptimal illumination level for that particular region. As was shown in [ 37 ], an excessive level of IR illumination leads to a deterioration in the spectrometric properties of hemispherical detectors. Excessive IR illumination not only causes an increase in current noise but also significantly increases the transit time.…”

“…Turning to IR illumination with a wavelength of 1050 nm changed radically the waveforms of the output pulses and improved the amplitude spectra and transit time distributions. The wavelength of 1050 nm was selected because it made it possible to significantly improve the stability of the quasi-hemispherical detectors at low temperatures, as shown in [37]. The duration of the rising edge of the pulses increased significantly over time.…”

“…Improvements in the spectrometric characteristics of quasi-hemispherical detectors were reported in [ 25 , 29 , 36 , 37 ].…”

“…In [ 37 ], the possibility of significant improvement and stabilization of the spectrometric characteristics of quasi-hemispherical detectors operating under various conditions with IR stimulation was shown. Thus, when a detector of 4000 mm 3 volume was exposed to IR illumination with a wavelength of 940 nm, the energy resolutions of 2.5% and 1.3% at 662 keV line were obtained at room temperature and +5 °C, respectively.…”