Lithium-drift detectors based on the solid solutions Si1−x-Gex

Abstract

Results of experiments to determine the effect of germanium content in single crystals of silicon-germanium solid solutions on the electrophysical, radiometric, and spectrometric characteristics of lithium drift detectors are presented. Surface and volume uniformity of the experimental semiconductor crystals was determined by measuring current, capacitance, noise, and spectrometric and radiometric parameters. Energy resolution and counting rates for beta particles as a function of external bias voltage at 300 K. The contribution of the variable parameters of the semiconductor detectors to the radiometric characteristics of silicon-germanium detectors was determined by establishing a correlation between electric, spectrometric, and radiometric parameters. Counting rates increased as germanium content increased, and it was determined that semiconductor structures with 2-6% germanium had the maximum structural uniformity in the presence of large-scale traps. For this optimal germanium content in lithium drift detectors, detection efficiencies were determined to be from 2.5 to 3 times higher than for silicon-lithium semiconductor detectors. 11 refs., 3 figs.