Effects of spatially correlated generation of macroradicals in the radiolysis of polymers

The radiation-chemical yield of macroradicals was found to be many times higher under exposure of polymers (polystyrene, poly(methyl methacrylate), and polycarbonate) to ionizing radiation at extremely low dose rates (0.1-1 mGy/s) in a vacuum at room temperature. A model of the radiolysis was suggested, which is based on the mechanism of preferable generation and stabilization of macroradicals in the neighborhood of already existing macroradicals in the course of polymer irradiation. This mechanism results in the formation of free-radical clusters (swarms). The efficiency of spatially correlated generation of macroradicals, the degree of swarming, and the multiplicity of swarming in a number of polymers and polymer-based scintillators were found in luminescence quenching experiments.