Search for radiation-resistant compositions of plastic scintillation detectors

The performed investigations were aimed at the modification of polystyrene matrix and the search for radiation-resistant luminescent additions (LA) with optimal optical characteristics. The relative changes of scintillation efficiency (N/N₀) and the transparency to the scintillator´s own radiation light (T/T₀) were taken as the criterion for the radiation-resistance of the detectors. Polystyrene matrix was modified by the following ways: a) the copolymerization of styrene with bifunctional monomers and vinylated LA; b) the introduction of secondary solvent or the increase of the concentration of primary LA; c) the introduction of high-reactivity compounds promoting the destruction of stable macroradicals formed in the detectors in the process of γ-irradiation. Proposed was a special method for the purification of LA. The optimal composition of the plastic scintillator detectors was characterized by the following values: N/N₀=0.75; T/T₀=0.86