Photostimulable X-ray storage phosphors: a review of present understanding

Photostimulable re-ray storage phosphors in form of image prates are a prom ising alternative to conventional two-dimensional x-ray detectors. By absor ption of ionizing radiation, electrons and holes are generated and captured locally to form a dose proportional latent image. The stored information i s read out by scanning with a focussed HeNe laser. This leads to a local ex citation of the trapped electrons which subsequently recombine with the tra pped holes causing the emission of light. The information is then recorded by means of a photomultiplier, digitized by an A/D converter and displayed with the aid of a computer. The present state of the field of storage phosp hors is reviewed in the following areas: the image principle, today's under standing of the nature of the storage centers, their physical generation, a nd the optically stimulated charge transfer paths. In addition, improvement s and applications of these phosphors will be discussed for existing and fu ture commercial devices.