Radiation induced radical in barium sulphate for ESR dosimetry: A preliminary study

Abstract

Barium sulphate (BaSO4) was irradiated by γ-rays and analyzed with electron spin resonance (ESR) to study radiation induced radicals for materials as radiation dosimeter. The ESR spectrum for the radical species is characterized by a hole-type center with g factor of 2.019, 2.0127 and 2.0103 and electron-type center with g factor of 2.0039, 2.0025 and 2.0001. The dosimetric signal with splitting factors of g=2.0039 is ascribed to SO 3- radicals and 5G linewidth. The response to γ-ray dose ranging from 5 to 103 Gy, energy dependence calculation and the thermal stability have been studied. The number of free radicals per 100 eV (G-value) was obtained to be 0.25±0.06 and 0.9±0.18 for BaSO 4 and alanine, respectively. The lifetime of radicals and the activation energy were estimated from Arrhenius plots to be approximately 325±60 days, and 0.50±0.09 eV respectively. © 2004 Elsevier B.V. All rights reserved.