Temperature Dependence of the Luminescence output of CdWO4 Crystal. Comparison with CaF2:Eu

Scintillators are radiation converters applied in medical imaging detectors, in applications at harsh environments, including in geophysical detectors for deep geology boreholes, non-destructive testing (NDT) in gas and oil facilities, space, marine exploration, etc. In this study the luminescence efficiency dependence of single-crystal scintillators was examined with increasing temperature. Cadmium tungstate (CdWO4) was examined against calcium fluoride doped with europium (CaF2:Eu). The dimensions of the single crystals' samples were 10x10x10 mm(3) and were irradiated using X-ray radiographic exposures (90 kVp, 63mAs) to measure the light output with temperature (22 to 128 degrees C). The luminescence efficiency was found in both cases maximum at the lowest examined temperature (23.06 efficiency units-E.0 for CdWO4 and 22.01 E.U. for CaF2:Eu, at 22 degrees C-environmental). With increasing temperature, the luminescence efficiency constantly decreased for both crystals due to thermal quenching (5.32 efficiency units for CdWO4 and 4.43 for CaF2:Eu, at 128 degrees C). In the mid-range (50-80 degrees C) CdWO4 shows increased differences compared to CaF2:Eu. CdWO4 has a higher density (7.9 g/cm(3)) and luminescence signal than CaF2:Eu (3.18 g/cm(3)), thus it is suitable, besides medical imaging, also for operation in harsh environments. (C) 2020 The Authors. Published by Elsevier B.V.