Synthesis and spectroscopic investigations of uranyl ion doped SrBPO5

Uranyl compounds are known to exhibit distinctive spectral characteristics that have been attributed to effect of ligands. During the past few years, our group has carried out spectroscopic characterization on a number of uranium doped alkaline earth molybdates, sulphates and borate compounds using PL, TSL and EPR techniques. PL investigations of these compounds have helped in identification of UO22+/UO66-/UO42-species in these hosts. Stabilization of these species was governed by synthesis conditions and structure of the host. In the present work, uranyl ion was added to SrBPO5 host lattice as a luminescent activator at concentration level of 1 mol% and synthesized by solid state reaction method. The product was characterized by powder X-ray diffraction. The PL emission spectrum exhibited peaks at 502, 524, 547, 569 and 597 nm with ex=248 nm. In γ-irradiated uranium doped SrBPO5 samples at room temperature (dose=1 kGy), a single glow peak at 390 K was observed. Spectral studies of the peak were carried out using narrow band interference filters and transmittance filters. Emission groups around 510 and 540 nm characteristic of uranate ion (UO66-) were observed indicating its role as luminescent centre. The trap parameters viz. activation energy and frequency factor for the glow peak were determined using variable heating rates method. The dose dependence of the peak was studied in the 0.1-2 kGy range. (author)