Influence of ionization density on radiolysis of cyclohexane-benzene mixtures

Abstract

Cyclohexane-benzene mixtures were irradiated by 210Po-α-radiation (LET = 200 eV/nm) with the effective energy of 3 MeV and the results were compared with those obtained by 1.25 MeV λ-irradiation of 60Co (LET = 0.2 eV/nm). While during λ-irradiation—similarly to the data known from the literature—the G(c-C 6H 10) and the G((c-C 6H 11) 2) values were decreased even by a small amount of benzene, the yields of both products obtained by α-irradiation were in the same range practically constant, and began to decrease only above the benzene concentration of 0.3 mol dm -3 (about 3 electron %). The “protection” in the case of λ-irradiation was interpreted by positive ion scavenging, S 1 excited cyclohexane molecule quenching and thermal H atoms scavenging. The low efficiency of all these three components of “protection” in α-radiolysis is attributed principally to the very high concentration of intermediates in the track/core compared to the relatively low concentration of benzene. The conclusions were also supported by comparison with the data obtained in cyclohexane-iodine systems.