3-D position sensitive CdZnTe gamma-ray spectrometers

Two 3-D position-sensitive room temperature semiconductor gamma-ray spectrometers have been built using 1 cm(3) cubic CdZnTe crystals. The lateral coordinates of gamma-ray interaction are obtained from the location of the 11(x) x 11(y) pixellated anodes and the depth (z) is obtained from the ratio of the signals coming from the cathode and the anode. Energy spectra from 662 keV incident gamma-rays have been collected from each of the 11(x) x 11(y) x 20(z) voxels in both of the CdZnTe devices. After corrections for electron trapping, the difference of weighting potentials in 3-D, and for the gain variation of the readout circuitry, energy resolutions of 1.70% (11.3 keV) FWHM and 1.84% (12.2 keV) FWHM were obtained at 662 keV gamma-ray energy on the first and second detectors, respectively, from the whole bulk for single-pixel events. Possible improvements in the detector performance are discussed. (C) 1999 Elsevier Science B.V. All rights reserved.