Аннотация:Qualitative and quantitative analysis of accumulation of paramagnetic species upon low-temperature radiolysis of polystyrene at total doses up to 130 kGy was carried out by means of ESR spectroscopy and computer simulation. It was concluded that at small doses trapped electrons and benzyl substituted radicals resulted from the reactions of primary radical cations of polystyrene were the principal paramagnetic species. With increasing the absorbed dose the built-up of cyclohexadienyl type radicals due to secondary ionic reactions is observed. The mechanism of polystyrene radiolysis is proposed which is consistent with the requirements of balance of active species.