Bridgman growth and scintillation properties of calcium tungstate single crystal

CaWO4 single crystal with large size was grown by Bridgman method. The results of transmission spectra show that the transmittance of CaWO4 crystal reaches 79-85% in 320-800 nm wavelength range. The refraction index is near 1.80 in visible and infrared region. CaWO4 crystal shows a broad emission band centered at 424 nm under X-ray excitation and centered at 416 nm under ultraviolet (λex = 280 nm) excitation. The decay kinetics of CaWO4 single crystal shows double-exponential decay with fast decay constant τ1 = 5.4 μs and slow decay constant τ2 = 177.1 μs. The energy resolution of CaWO4 crystal was found to be 31.6% in the net peak of 545.9 channel. Meanwhile, the absolute output is at the lever of 19,000 ± 1000 photons/MeV. The results indicate the scintillator of CaWO4 single crystal has great potential in the applications of high-energy physics and nuclear physics due to its high light output and great energy resolution.