Radiolysis of aqueous solutions with pulsed helium ion beams—2. Yield of SO4− formed by scavenging hydrated electron as a function of S2O2−8 concentration

Abstract

Yields of SO4− in the radiolysis of aqueous (NH4)2S2O8 solutions with pulsed 24 MeV 4He2+ ion beams were measured in the concentration range from 1×10−4 to 1 mol dm−3. The yield increased with increasing the concentration, and it was smaller than that in electron beam pulse radiolysis in the concentration range measured. The results were compared with the reported Ge−aq derived from various scavengers. Though the yields agree well for low LET radiations, the result of the present research for 4He ion beams is smaller than the yield determined by a product analysis method. This suggests that once formed SO4− disappears by the intra-track reactions and that this effect is more important in ion beam radiolysis because of more dense production of the initial species. Simulation by the deterministic diffusion kinetic model supports it qualitatively.