A new fast dense scintillator of Zr:GdTaO4 single crystal

A good quality Zr:GdTaO4 single crystal with an 8.84 g/cm3 density, higher than the well-known dense scin-tillator PbWO4, was successfully synthesized by the Czochalski method for the first time. The effective segre-gation coefficient of Zr in Zr:GdTaO4 is 0.288. The light yield and the energy resolution of Zr:GdTaO4 are approximately the same as GdTaO4. The scintillation decay time of Zr:GdTaO4 contains a fast decay of 9.51 ns, close to the fast scintillator PbWO4, and a slow decay of 755.61 ns, which is much faster than that of GdTaO4 whose fast decay time is 101.82 ns and slow decay time is 3290.52 ns. With Zr4+ doping, the photoluminescence band of GdTaO4 is blueshifted and the traps are shallowed, which may help accelerate the scintillation decay. As far as we know, the Zr:GdTaO4 single crystal is the densest scintillator with a less than 10 ns scintillation decay time, which can be used in electromagnetic calorimeters.