Advantages and limitations of n-type low-resistivity cadmium telluride nuclear radiation detectors

Cadmium telluride detectors were fabricated from low resistivity (50-500 Ω.cm) n-type crystals grown by the sealed-ingot-zone refining method. Physical parameters of this kind of detector were discussed and the factors influencing them were analysed. The main advantage of n-type low resistivity CdTe detectors is high energy resolution for low energy X- and γ-rays at room temperature; the best value for the 5.9 keV line from a 55Fe source was 1.1 keV fwhm. The main limitation is small active volume (diameter of active surface 1-2 mm. thickness of active region below 100 μm), which is relevant to the counting efficiency and the range of registered γ-energies. As a result of the performed analysis a miniature room temperature probe with high energy and spatial resolutions was designed. (Auth.)