Testing the Potential of Magnetic Resonance Dosimetry: The Case of Lithium Carbonate

Magnetic resonance techniques are powerful, nondestructive, non-invasive tools with broad applications in radiation dosimetry. Electron paramagnetic resonance (EPR) enables direct quantification of dose-dependent radiation-induced paramagnetic defects, while nuclear magnetic resonance (NMR) reflects the influence of such defects through changes in line width and nuclear spin relaxation. To date, these methods have typically been applied independently. Their combined use to probe radiation damage in the same material offers new opportunities for comprehensive characterization and preferred dosimetry techniques. In this work, we apply both EPR and NMR to investigate radiation damage in lithium carbonate (Li₂CO₃). A detailed EPR analysis of γ-irradiated samples shows that the concentration of paramagnetic defects increases with dose, following two distinct linear regimes: 10-100 Gy and 100-1000 Gy. A gradual decay of the EPR signal was observed over 40 days, even under cold storage. In contrast, ⁷Li NMR spectra and spin-lattice relaxation times in Li₂CO₃ exhibit negligible sensitivity to radiation doses up to 1000 Gy, while ¹H NMR results remain inconclusive. Possible mechanisms underlying these contrasting behaviors are discussed.