Monte Carlo track chemistry simulations were used to investigate the effects of multiple ionization (MI) of water on the yields (<i>G</i>-values) of the ferrous sulfate (Fricke) dosimeter which was irradiated with low-energy α and lithium ion recoils from the <sup>10</sup>B(<i>n</i>,α)<sup>7</sup>Li nuclear reaction as a function of temperature from 25 to 350 °C. Calculations were performed individually for 1.47 MeV α-particles and 0.84 MeV lithium nuclei with dose-average linear energy transfer (LET) values of ~196 and 225 keV/μm at 25 °C, respectively. The total yields were obtained by summing the <i>G</i>-values for each recoil α and Li ion weighted with its fraction of the total energy absorbed. At room temperature, our <i>G</i>(Fe<sup>3+</sup>) values calculated under aerated and deaerated conditions only agreed well with the experimental results, provided the multiple ionization of water was incorporated in the simulations. This strongly supports the importance of the role of MI of water molecules in the high-LET radiolysis of water. We also simulated the effects of MI of water on <i>G</i>-values for the primary species of the radiolysis of deaerated 0.4 M H<sub>2</sub>SO<sub>4</sub> aqueous solutions by <sup>10</sup>B(<i>n</i>,α)<sup>7</sup>Li recoils. As with the Fricke dosimeter, the best agreement between experiment and simulation was found at 25 °C when the MI of water was included in the simulations. It was also shown that <i>G</i>(Fe<sup>3+</sup>) decreases slightly as a function of temperature over the range of 25–350 °C. However, at elevated temperatures, no experimental data were available with which to compare our results.
Understanding the Role of
α
Particles in Oblique Heliospheric Shock Oscillations