The Ways of Performance Imrovement of Radiation-Type Germanium Detectors

The results on the resolution of radiation detectors are analyzed. It is pointed out that resolution is limited by the ho le trapping on deep centers, that compensate initial conductivity. This trapping can be lowered by the elect ric fields exceeding the values 1.2 - 1.4 kV/cm, though the decrease of the background of impurities, that are present in Ge equally to chemical donors, is more radical way. By this method one can get the detectors with resolution better than 0.2% for E¿ = 662 keV ¿-rays at the donor concentration 1012 cm-3 The resolution can be improved by the reduction of the inhomogeneous properties of monocrystals, that leads now to the hole life-time relief in detectors up to 100%. The possibility of obtaining stable at room temperature germanium detectors attracted the investigators for a long time. For this purpose in works the usage of method of doping n-type germanium by gamma-ray irradiation acceptor damages. Detectors, obtained by this technique (so-called radiation-type detectors) can spectrometrize gamma-ray mean energy with a resolution better than 1% at the depleted depth 5-8 mm and also are precise spectrometers short ran ge radiations: ¿, ß-particles, X-rays Recently as a result of works of Hall et al. the germanium with the presence of extraordinary low impurity concentration (~1010 cm-3) was obtained. This allows to develop the depleted depth (actually to 10 mm), without additional compensation10-12 As a result of high perfection of germanium these detectors have extremely high energy resolution.