A study of the radiolysis and luminescence behavior of Dioxane-Benzene mixtures

Abstract

G values for gas products in 7-irradiation of pure, liquid dioxane were constant over the dose range (0.46-4.6) X 1019 e.v. g.-1. These G values for a dose rate of 1.9 X 1018 e.v. g.-1 min.-1 are as follows: H2, 2.1; C2H4, 0.50; C2H6, 0.051; CO, 0.23; CH4, 0.035. Study of the polymer product indicated that dioxane dimers constitute the initial polymer product. (?(monomer dimer) ~ 3.9. Hydrogen, biphenyl, polymer, and relative luminescence G values (p-terphenyl as scintillator) were measured for benzene-dioxane mixtures. The parallel behavior of hydrogen and polymer G valué curves suggests that a common dioxane precursor of hydrogen and polymer is protected from reaction by some kind of interaction with benzene. Kinetic analysis of the (?(H2) results gives a = 0.21 M ~l as the ratio of speeific rate of excitation transfer to that of decay for the excited dioxane species that yields hydrogen. This analysis also indicates that thermal H atoms make a negligible contribution to the hydrogen yield from dioxane. A similar treatment of relative luminescence G values leads to an estimate of 65 Af-1 as the corresponding ratio for the excited dioxane species that gives rise to luminescence. It is concluded that the latter species makes a negligible contribution to the yield of decomposition products and that the excited species that yields decomposition products is of very short lifetime. For protection to compete with decomposition it may be necessary that a molecule of benzene be a nearest neighbor to the labile excited dioxane species at the time of its formation.