On OH radicals in water under heavy ion irradiation

Taguchi, Mitsumasa; Kimura, Atsushi; Baldacchino, G.*; Katsumura, Yosuke*; Hirota, Koichi

Heavy ions give unique irradiation effects on target materials. Reactions in water under heavy ion irradiation are mainly induced by OH (hydroxyl) radicals. OH radicals yields have been investigated by the (1) product analysis and (2) pulse radiolysis methods. (1) Aqueous phenol solutions were irradiated with He, C and Ne ions. The yields of the OH radicals were estimated by analyzing the yields of the irradiation products of phenol. The yields of the OH radicals increased with the specific energy, but decreased with both the mass of each ion and elapsed time. (2) Transient absorption measurement system was developed for the direct observation of radical behaviors in water under heavy ion irradiation. A small absorbance change less than 10 was recorded. The transient absorbance of (SCN) formed by the reaction of OH radicals with SCN in aqueous KSCN solution was observed under pulsed C ion irradiation.