Structure and luminescence properties of a new heavy scintillator Zr:GdTaO4

Zr:GdTaO4 (Zr:GTO) polycrystalline powders with various Zr4+ doping concentrations were synthesized by solid-state reaction. The structure of Zr:GTO was investigated by X-ray diffraction and Raman spectrum, and the luminescence properties were studied by UV and X-ray excitation. The results show that the density of 0.3 ​at% Zr:GTO is 8.816 ​g/cm3, higher than famous heavy scintillator PbWO4 (8.3 ​g/cm3), and the maximum Zr4+ doping concentration should be lower than 5 ​at%. The Raman spectrum of the polycrystal is the sum of the Raman scatterings of little single crystals with different crystallographic planes. The photoluminescence intensity of 0.3 ​at% Zr:GTO is about three times higher than GTO and the radioluminescence intensity is probably twice higher. Its average decay time is 52.49 ns, close to Ce-doped fast scintillators such as Ce:Lu2SiO5. Zr4+ doping increases the concentration of self-trapped excitons Ta4+-O- and inhibits the process of recapturing migratory electrons and holes via deep traps.