Growth of Large-Area Cd₀.₉Zn₀.₁Te Single Crystals and Fabrication of Pixelated Guard-Ring Detector for Room-Temperature γ-Ray Detection

摘要

Large-volume detector-grade Cd_0.9Zn_0.1Te (CZT) single crystals were grown using a vertical Bridgman technique. The bulk resistivity of the as-grown crystal was found to be $sim 5imes 10^{10},,Omega $ -cm from current–voltage measurements. A $19.0imes 19.0imes5.0$ mm^{3 block of the crystal was used to fabricate a detector with $10imes 10$ pixelated anode configuration integrated with interpixel guard rings. The detector was tested for its radiation detection properties using 662-keV gamma rays from a 137Cs source. The pixels exhibited well-resolved gamma pulse-height spectra (PHS) with percentage energy resolution ~1.6% at 662 keV. A few pixels exhibited tailing of the photopeak on the lower energy side indicating the presence of hole traps. Biparametric plots (BPs) were obtained from digitally recorded preamplifier pulses. The BPs showed anomalous behavior, which was correlated with the gamma interactions in the active region of the detector in virtual Frisch grid configuration. The BPs also enabled to extract PHS free from the extensive tailing of the photopeak.}