PNNL

Abstract

This paper reports the first success of fabricating dense and optical transparent cadmium tungstate (CWO) films by sol-gel processing and the study on their optical and X-ray scintillation properties. A new sol-gel processing was developed using tungstic acid and cadmium nitrate as precursors, hydrogen peroxide as solvent; homogeneous and stable CWO sol was synthesized and ready for fabricating CWO films. A rapid sintering process was investigated and found necessary in order to make dense and optically transparent nanocrystalline CWO films. CWO films were uniform, fully dense, and crack-free, with CWO as the only detectable crystalline phase as determined by XRD. The thickness, density, grain size and crystallinity of CWO films are all found to be strongly dependent on the sintering conditions and in turn impact on optical and X-ray scintillation properties. Sol-gel derived dense CWO films demonstrated high photoluminescence (PL) and X-ray excitation optical luminescence (XEOL) intensity. The relationships between sol-gel processing, nanostructures, and optical and X-ray scintillation properties were discussed in detail.