Abstract
Electron paramagnetic resonance (EPR) evidence is presented for the radiation stabilization of pentavalent uranium in CaO matrix. From the theoretical predictions ofg value for U5+ in axial symmetries, it was concluded that U5+ at Ca2+ site is associated with a second neighbour charge compensating Ca2+ vacancy. EPR measurements also revealed the presence of Mn2+, Mn4+ and Cu2+ impurities in the samples. The thermal stability of U5+ was investigated using EPR and thermally stimulated luminescence (TSL) techniques. The TSL and EPR studies on gamma irradiated uranium doped calcium oxide samples had shown that the intense glow peak at 540 K is associated with the reduction in the intensity of EPR signal of U5+ ion around this temperature. This peak is associated with the process U5++hole→U6+*→U6++hv. The activation energy for this process was determined to be 1.4eV.
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Natarajan, V., Seshagiri, T.K. & Sastry, M.D. Radiation stabilization of U5+ in CaO matrix and its thermal stability: Electron paramagnetic resonance and thermally stimulated luminescence studies. Pramana - J Phys 47, 325–330 (1996). https://doi.org/10.1007/BF02848532
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DOI: https://doi.org/10.1007/BF02848532