Synthesis and functionality of the storage phosphor BaFBr:Eu2+

The present paper relates to a method for synthesizing the photostimulable storage phosphor BaFBr:Eu(2+) that features high stimulation characteristics for use in image plates. All previous synthesis routes consist of a multistep process whereas the presented route is a one-step synthesis. Starting compounds are BaCO(3), NH(4)F, and NH(4)Br, as well as EuF(3) where the ammonium compounds are highly volatile at temperatures below 300 degrees C. Their reaction products initiate the decomposition of BaCO(3) and form BaFBr. The incorporation of F-centers and europium ions occurs at temperature exceeding 550 degrees C. The individual reaction steps are monitored by simultaneous thermal analysis (thermogravimetry/differential thermal analysis) and the gaseous reaction products are detected by in situ mass spectroscopy. Intermediate and final products are characterized by x-ray diffraction techniques to determine the involved phases. Photoluminescence spectra reveal the typical emission peak of Eu(2+) accompanied by a redshifted emission band at 470 nm, which was assigned to oxygen incorporated into the BaFBr lattice. The synthesized powders exhibit small grain sizes well suited for the use in image plates.