Density dependence of the spur lifetime and the 'escape' hydrated electron yield in the low-LET radiolysis of supercritical water at 400 °C

Abstract

The "spur lifetime" (τ_s) in the low-LET radiolysis of supercritical water (SCW) at 400°C has been determined as a function of density by using a simple model of energy deposition initially in spurs, followed by the random diffusion of the species formed until spur expansion is complete. The values of τ_s are found to decrease from ~5.0 × 10^-6 to ~5.0 × 10^-8 s over the density range ~0.15 to 0.6 g/cm³. Using Monte-Carlo simulations, our calculated density dependence of the "escape" hydrated electron (e^-_aq) yield (i.e., at time τ_s) reproduces fairly well Bartels and co-workers' scavenged e^-_aq yield data, strongly suggesting that these data may have been measured at time close to τ_s.