Scintillation γ spectrometers for use at nuclear power plants (review)

Abstract

In this review, it is shown that out of the 300 scintillators synthesized to date only LaBr₃:Ce, CeBr₃, YAlO₃: Ce, and CsI:Tl crystals with the corresponding silicon photosensors (SiPSs) can be used as detectors in industrial γ-ray spectrometers intended for nuclear power plants. They are superior in their energy resolution and their resistance to mechanical and electromagnetic effects to spectrometers used today with a NaI:Tl crystal and a photomultiplier tube (PMT). A p–i–n photodiode (PD), an avalanche photodiode (APD), and a silicon photomultiplier (SiPM) are promising SiPSs. The properties of various assemblies of listed scintillators and photosensors are analyzed. A PD matches well with any scintillator. A spectrometer does not require LED stabilization of the scale, but its noise level must be reduced by selective PD cooling and the use of a light guide for coupling a massive scintillator and a SiPS with a small area of its sensitive surface. A spectrometer with an APD does not require photosensor cooling; however, LED stabilization of its energy scale is necessary. Application of an SiPM can rule out the use of a light concentrator (which is important for large CsI:Tl scintillators) and selective cooling, but this introduces nonlinearity at a short decay time and a high light yield in the scintillator (LaBr₃:Ce and CeBr₃) and also calls for an LED stabilization system for the spectrometer. The prospects for the development and application of new scintillation γ-ray spectrometers are discussed in this review.