a Programa de Engenharia Nuclear-PEN/COPPE/Universidade Federal do Rio de Janeiro, CP 68509, CEP 21945-970 Rio de Janeiro, Brazil
b Centro Brasileiro de Pesquisas Físicas, Rua Dr. Xavier Sigaud 150, CEP 22290-180 Rio de Janeiro, Brazil
Abstract:
Irradiated A-type carbonated apatites with carbonate content ranging from 1.45% to 4.84% are studied by using electron paramagnetic resonance (EPR). The EPR spectra are mainly constituted of lines associated to axial CO2− species (g=2.0028 and g=1.9973) and orthorhombic CO3− species (g1=2.0170, g2=2.0090 and g3=2.0041). The production of CO2− species on gamma irradiation depends on the carbonate concentration and the hydroxyapatite stoichiometry. The lowest dose detection limit was achieved with stoichiometric samples and carbonate concentration of 3.7%.