Radiolysis of Hydrogen Sulfide at Very High Dose Rates. The Effect of SF61

Abstract

Gaseous H2S has been irradiated with electron pulses from a Febetron 705 at a dose rate of ~2 × 1027 eV g−1 s−1. For single pulse experiments, the yield of hydrogen is G(H2) = 12.0 ± 0.5, independent of pressure from at least 350 to 1600 Torr. Addition of SF6 reduces the yield to G(H2) = 7.9 ± 0.3 which is fairly close to that observed for pure H2S at low dose rates. The reduction, ΔG(H2) = 4.1 ± 0.3, agrees very well with the ion pair yield based on a W value of 25.3 eV.In multi-pulse irradiations, for pure H2S, the yield falls off with dose giving a limiting yield close to G(H2) = 8.0. No similar fall-off is observed for H2S–SF6 mixtures. It is proposed that at high absorbed doses and at low dose rates, there is no contribution to the hydrogen yield from neutralization processes; and that this is due to neutralization of H3S+ by an ion of the type Sn− rather than a free electron.