Kinetics of the radiation-induced radical species in gamma irradiated solid sodium ascorbate

Abstract

In the present work, radicals induced in γ-irradiated solid sodium ascorbate (SA) were studied by electron spin resonance (ESR) spectroscopy. While unirradiated samples presented no ESR signal, irradiated samples were found to present a spectrum of an unresolved doublet with a shoulder at the low-magnetic field side. Structural and kinetic features of the radical species responsible for the experimental ESR spectrum were explored through the variations of the signal intensities associated with spectrum maxima and minima with applied microwave power, sample temperature, and room temperature storage time. Activation energies of the involved species were also determined using the data derived from annealing studies performed at high temperatures. Produced radical species were observed to be relatively stable at room temperature. This gave the opportunity to distinguish irradiated SA or SA containing irradiation products from unirradiated ones even long after irradiation. SA presented also the features of a dosimetric material, which could be used in the estimation of dose range in accidental dosimetry.