Luminescent materials for X-ray intensifying screen

Self activated calcium tungstate (CaWO4:W), terbium activated yttrium oxysulfide (Y2O2S:Tb) and terbium activated gadolinium oxysulfide (Gd2O2S:Tb) are typical luminescent material (phosphors) used in the manufacture of X-ray intensifying screens. In order to improve the speed of the photographic system used in medical and industrial radiology, the intensifying screens (I.S.) have to fit the X-ray film sensitivity. The utilization of a certain phosphor for IS manufacture depends on particle size distribution and luminescent properties that are regulated during the synthesis stage. The paper presents some of our results referring to the synthesis of CaWO4:W, Y2O2S:Tb and Gd2O2S:Tb phosphors for the manufacture of intensifying screens. Morpho-structural and luminescent properties were evaluated by using optical microscopy, X-ray diffraction patterns and photoluminescence spectroscopy. Some attempts for the manufacture of tungstate-intensifying screens were also made. Screens with powder packing densities equal to 100, 300 and 500 g/m2, respectively, were prepared, on PET substrate. The X-ray intensification effect on the radiological film was determined in comparison with a standard (CAWO-product). (authors)