Valence distribution of radiophosphorus in potassium chloride single crystals. Part 3.—Effect of ionizing radiation

Abstract

The effect of gamma radiation on the valence distribution of radio-phosphorus in KCl single crystals has been studied. The radio-phosphorus was produced by the nuclear reaction ³⁵Cl(n,α)³²P, using either reactor spectrum neutrons or 14 M eV neutrons from a D-T source. Post-gamma irradiation at 77 K produced no change in the amount of phosphate [P(V)], but at 298 K small doses (about 0.1 Mr) caused rapid oxidation. These results have been interpreted in terms of reactions between ³²P and transient hole species (radiolysis products). The ³²P valence distribution is less sensitive to pre-gamma irradiation of the crystals. At 77 K the P(V) fraction only increased by a small amount, whereas at 298 K, the marked decrease in P(V) required relatively large doses(about 60 Mr). This decrease has been ascribed to pre-gamma irradiation inhibiting an efficient in-pile oxidation reaction. In addition, results of experiments in which the length of the reactor irradiation was varied have been interpreted in terms of reactions of energetic ³²P recoil species.