Archive | 2019
Crystal growth, characterization, and fabrication of large-area Cd0.9Zn0.1Te pixelated detectors for high-energy gamma-ray detectors
Abstract
Cd0.9Zn 0.1Te (CZT) based pixelated radiation detectors have been fabricated and characterized for high-energy gamma ray detection. Large-volume ingots with large single crystalline grains have been grown and several 10 × 10 pixilated detectors have been fabricated from the grown crystals for imaging studies. Guard ring grids have been designed and fabricated to reduce cross-talk and inter-pixel/inter-electrode leakage. The grown crystals were initially characterized in planar configurations through electrical and optical methods prior to the fabrication of pixilated structure. Current-voltage (I-V) measurements revealed very low leakage current in the range of nA at an operating bias voltage of 1000 V and a resistivity of ~ 6×1010 Ω-cm was obtained. Infrared transmission imaging revealed average tellurium inclusion size of <8 micron. Measurements through Pockels’ effect has revealed a near-uniform depth-wise distribution of the internal electric field. Gamma-ray spectroscopy using 137Cs (662 keV) radiation source on the monolithic pixelated structure showed excellent detection performance for all the 100 pixels, with a resolution ~1.5 % FWHM.