Gamma Ray Spectroscopy with THM CdZnTe Detectors

Good uniformity in electron transport has been observed on Cd
_0.9
Zn
_0.1
Te crystals grown by the Traveling Heater Method (THM) using alpha-particle measurements. Excellent electron mobility-lifetime products have been measured consistently on the order of 1times 10
^-2
cm
²
/V. A coplanar-grid detector of size 10times10times5 mm
³
has been fabricated from this material, and it shows an energy resolution of 2.1% FWHM at room temperature for 662 keV gamma rays. Pseudo Frisch-Grid 3times3times5 mm
³
detectors fabricated from THM Cd
_0.9
Zn
_0.1
Te materials routinely exhibit near 1% FWHM @ 662 keV and < 3% FWHM @ 122 keV at room temperature while 4% FWHM at 122 kev has also been measured on 20times20times5 mm
³
monolithic pixellated devices. Other material properties have been characterized using near-IR transmission microscopy, I-V, and Hall measurements. The material shows great potential toward producing large-volume detectors with excellent spectral performance for high-resolution gamma-ray spectroscopy, with uses in homeland security, nuclear nonproliferation, scientific research, and medical imaging applications.