CdZnTe x-ray detector for 30- to 100-keV energy

High-pressure-Bridgman grown CdZnTe x-ray detectors 1.25 approximately 1.7 mm thick were tested using monochromatic x-rays of 30 to 100 keV generated by a high energy x-ray generator. The results were compared with a commercially available 5 cm thick Nal detector. A linear dependence of the counting rate versus the x-ray generator tube current was observed at 58.9 keV. The measured pulse height of the photopeaks shows a linear dependence on energy. Electron and hole mobility-lifetime products were deduced by fitting bias dependent photopeak channel numbers at 30 keV x-ray energy. Values of 2 X 10-3 cm2/V and 2 X 10-4 cm2/V were obtained for (mu) (tau) e and (mu) (tau) p, respectively. The detector efficiency of CdZnTe at a 100 V bias was as high as, or higher than 90 percent compared to a Nal detector. At x-ray energies higher than 70 keV, the detection efficiency becomes a dominant factor and decreases to 75 percent at 100 keV.