ENERGY-TRANSFER AND DYNAMIC LUMINESCENCE OF MATERIAL CONTAINING RARE-EARTH IONS USED IN X-RAY MEDICAL IMAGING

LaOBr:Tb, Bi and BaFCl:Eu are two luminescence materials which show in teresting optical properties like energy transfer and photostimulated luminescence. They are also well known materials for the intensifying screens used in X-ray medical imaging. Four polycrystalline LaOBr:Tb, Bi with different concentration of Bi and Tb as well as ten samples of BaFCl:Eu with different Eu concentration have been synthesized. Energ y transfer between Bi and Tb will be investigated in detail for LaOBr: Tb, Bi. Nonexponential decays were observed. The time resolved lumines cence spectra and decay time of BaFCl:Eu will be presented. The intens ifying screens of BaFCl:Eu with different sizes were prepared. They we re used in some hospitals of Viet Nam with short time X-ray exposure, low afterglow and are suitable in the tropical conditions.