Radiolytic Oxidation of Ferrous Solutions with Standardized Internal Sources of Polonium-210

Abstract

THE G-value of the oxidation in the aerated ‘Fricke’ dosimeter solution for irradiation with the α-particles of polonium-210 does not appear to be established accurately. Values ranging from 6.3 to 5.1 have been published with a tendency towards the lower figures as time progressed. The latest values, 5.5 and 5.1, published simultaneously by Lefort and Tarrago¹ and Trumbore and Hart² respectively, do not agree. We have redetermined this value by radiolysis with polonium-210 dissolved in 0.8 N sulphuric acid containing ferrous ammonium sulphate and sodium chloride both at a concentration of 10⁻³ M. The energy dissipated by radioactive decay, and absorbed by the system, was determined from standardization of the specific activity by 4π-internal liquid scintillation counting and an acceptance of the value 5.305 MeV. (ref. 3) for the energy of the polonium-210 particle. No account was taken of possible effects caused by the recoiling lead-206 nucleus.