PHOTOSTIMULABLE LUMINESCENCE - PHYSICS AND APPLICATIONS

Photostimulable phosphors are currently used in X-ray screens for digi tal medical imaging. Many inorganic phosphors which show photostimulat ed luminescence (PSL) have been discovered for this application and th e most widely used material is BaFX:Eu2+ with X chosen as Cl or Br and with a small addition of I. The other applications of the PSL imaging plate can be found in X-ray diffraction, X-ray topography and in beta and gamma autoradiography. The PSL based IP has become an integral pa rt of the X-ray instrumentation in all the synchrotron facilities. Its uses in industrial X-ray radiography as a replacement of the photogra phic plate and in neutron radiography [with (n-gamma) converters] are being actively explored. In this paper, the basic aspects involved in the functioning of the imaging plate (IF) are first described. Admitte dly, to claim that the IP will replace the photographic plate in radio logical applications will require convincing evidence with hard data,; Is the photographic plate has reached the status of gold standard. Whi le this aspect is not comprehensively discussed, the salient points ar e presented and relevant references mentioned. The physical mechanisms responsible for the ability of the Photostimulable luminescence (PSL) screen to write, read and erase images are next discussed in the ligh t of experimental results available on the phosphors. The paper closes with a short report on the design and development of an imaging plate reader system, recently set up at IGCAR, Kalpakkam.