Electron spin resonance (ESR) studies of CO2- radicals in irradiated A andB-type carbonate-containing apatites

ESR spectra of irradiated carbonate-containing hydroxyapatites are complex and strongly dependent on the method of preparation of these materials. Thi s paper describes results of our studies of the ESR spectra of irradiated A - and B-type carbonated hydroxyapatites. The most intense and stable lines in these spectra are attributed to CO2- radicals. The ESR spectrum of A-typ e carbonated apatite can be predominantly due to either axial or orthorhomb ic CO2- species, depending on whether the apatite was cooled in or without a CO2- flow. The B-type carbonated apatite has an ESR spectrum composed bas ically of signals from isotropic and orthorhombic CO2- species. These signa l are different in intensity, line width, and g-factor for samples heated f or 3 h at 200, 400 and 600 degrees C. The effect of the method of preparati on of the A- and B-type carbonated apatites on the ESR spectra and the appl ication of these materials to the ESR dating and dosimetry are discussed. ( C) 2000 Elsevier Science Ltd. All rights reserved.