Monte Carlo simulation of the radiolysis of the ceric sulfate dosimeter by low linear energy transfer radiation

The ceric sulfate dosimeter is based on the radio-induced reduction of Ce4+ in acidic medium. For low linear energy transfer (LET) radiation, the yield of Ce3+ is 2.4 molecules / 100 eV, regardless of the presence of oxygen. To investigate the reaction mechanisms of the ceric sulfate dosimeter, we simulated the chemical reaction kinetics curves and the evolution of G(Ce3+), G(O2), and G(H2) in the ceric sulfate solution with and without oxygen. Studies of G(Ce3+) as function of the initial concentration of Ce3+ and of the LET were also done. One important finding of this study is that •OH radicals are scavenged by the reaction •OH + HSO4– → SO4•– + H2O, rather than by the reaction •OH + Ce3+ → Ce4+ + OH–.