Neutron and β/γ Radiolysis of Water up to Supercritical Conditions. 1. β/γ Yields for H₂, H· Atom, and Hydrated Electron

Abstract

Cross-check ExperimentsThe HD yield at room temperature (Table 1) is very low compared to earlier measurements of H • atom yield, and we were not certain that a 0.02 m concentration of ethanol-d6 gives enough scavenging power (5.4×10 4 s -1 at room temperature) to compete efficiently for H • atoms with other second order reactions or impurities. As a test we performed a series of experiments with 0.01 m (normal) ethanol aqueous solutions with 2.5×10 -3 m N 2 O. Figure S1 shows the radiation yields of H 2 in 0.01 m ethanol compared to the HD+H 2 yield in 0.02 m ethanol-d6. Both yields compare well from 100 o C up to 300 o C, justifying the small concentration of ethanol-d6 used for the H • atom yield determination.

Neutron and β/γ Radiolysis of Water up to Supercritical Conditions. 2. SF6 as a Scavenger for Hydrated Electron

“…Survey of fluoride production for several KOH and phenol concentrations (2.5 × 10 -4 m SF 6 ) as a function of density at 380 °C.The G value indicated is fluoride yield divided by 6, to give the (e -) aq yield. Neutral solutions of 0.01 m phenol agree reasonably well with work conducted by Janik et al6,7…”

“…(The original report was corrected for a small pressure measurement error in a recent erratum. 7 ) These measurements are complementary to similar measurements made in a flow loop 8 at the University of Wisconsin reactor facility, which will be described in part 3 of this series. The complementary measurements allow separation of radiolysis effects due to β/γ radiation from those due to neutron radiation.…”

“…Radiation yields of the solvated electron, (e − ) aq , during radiolysis of 0.01 m phenol/2.5 × 10 −4 m SF 6 neutral solution compared to work by Janik et al , (0.01 m phenol/2.5 × 10 −3 m N 2 O solution) as a function of density at 380 and 400 °C.…”

“…An extensive series of measurements were made vs temperature up to 400 °C on a 250 bar isobar, and two series were measured vs density (pressure) for constant temperatures of 380 and 400 °C. (The original report was corrected for a small pressure measurement error in a recent erratum at the University of Wisconsin reactor facility, which will be described in part 3 of this series.…”

First observation of HO˙ reactivity in water under high energy ions at elevated temperature

“…[28][29][30][31][32] We conclude that temperature effects were investigated mainly with low LET radiations and pulse radiolysis since the 1980s 33 and that only recent experiments in reactors start to bring new approaches under combined radiations. 34,35 However temperature and LET have inversed effects on the radiolytic yields of HO . It is therefore expected a competition when LET and T increases, between the acceleration of recombinations in the track and the escape of species with the increase of diffusion.…”