Hydrated electron yields in the proton radiolysis of water

The yields of hydrated electrons have been measured in the radiolysis of water with protons of 2 to 15 MeV using scavenging techniques. Glycylglycine was used as the scavenger and the results at low concentrations are compared with data from other ions to elucidate the overall effect of track structure on hydrated electron yields. Variation of the glycylglycine concentration gives an effective probe of the hydrated electron yield at various times in the relaxation of the proton track. Comparison of the results with those found in gamma radiolysis shows considerable intratrack reactions on the nanosecond to microsecond time scale in proton radiolysis. Good agreement between the experimental results and Monte Carlo track calculations allow one to accurately describe the physical structure of the proton track and its chemical consequences. (author)