Recent developments in X-ray storage phosphor materials

The X-ray storage phosphor BaFBr doped with Eu2+ is widely used in digital radiography, although the mechanisms of energy storage and read-out processes are not fully understood. The present understanding of the point defect mechanisms behind storage and recombination is critically discussed. Shortcomings of BaFBr in spatial resolution can, in principle, be overcome by the use of optically isotropic systems, such as cubic crystals. RbBr and CsBr doped with Ga+ as well as doped with Eu2+ show excellent figures of merit as storage phosphor materials. The mechanisms in the Ga+-doped alkali halides are reviewed. They are fully understood. In contrast, Eu2+ has a propensity to aggregate rendering the systems unreliable. They are poorly understood. Some recent results using various spectroscopic methods are briefly summarised. A new class of storage phosphors are glass ceramics doped with rare earth ions. A short summary of recent results is presented