Abstract
Barium sulphate (BaSO
4) 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 5
G linewidth. The response to γ-ray dose ranging from 5 to 10
3 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.