Growth of Cdznte Crystal Under High Magnetic Field and its Photon-Counting Detector Performance

Abstract

In this paper, CdZnTe (CZT) crystal was grown by the Traveling Heater Method (THM) under 5T axial static magnetic field, which improved the quality of CZT crystal and the performance of photon-counting detector. The effect of high magnetic field on the quality of CZT crystal and the mechanism of internal defects were experimentally studied. The concentration of Te inclusions in CZT crystals grown by THM under high magnetic field is about 5×103 /cm3 with the size less than 5μm observed by infrared microscope, which are two orders of magnitude lower than those grown without magnetic field. Then the planar CZT detector was fabricated to study the photoelectric properties of CZT crystals grown by THM. The resistivity of CZT under high magnetic field is 2.83×1010Ω·cm, and its energy resolution to 241Am (59.5keV) is 5.9%. In the photocurrent response test, it maintains a good linearity under the tube current of 0.1mA-0.6mA. The results indicate that the detector prepared by CZT crystal grown under high magnetic field is better than that grown without magnetic field. Finally, the CZT wafers were made into 1×16 linear-array pixel detectors with a pixel size of 0.9×1.8 mm2. The photon-counting rate and imaging quality of the CZT linear array detector under X-ray irradiation were studied. The average saturated photon-counting rate reached 2.0×106 CPS/Channel (Counts Per Second/Channel).

Keywords: High Static Magnetic Field (SMF), Traveling Heater Method (THM), CdZnTe, Te Solvent, Photon-counting detector