EPR AND ENDOR INVESTIGATIONS ON THE X-RAY STORAGE PHOSPHORS BASO4 ANDSRSO4

X-ray storage phosphors are applied in many areas including medical di agnostics, crystallography or material inspection. The main advantage of this method compared to conventional X-ray films is the linearity o f dose response over more than six orders of magnitude. The readout pr ocedure by scanning with a laser, however, implies severe restrictions with respect to the decay time of the photostimulated luminescence. T herefore a need for fast phosphors exists. We found that BaSO4 and SrS O4 decay in the 10 ns range and therefore are very promising materials . Investigation of the thermally stimulated luminescence of these comp ounds after X-irradiation at room temperature and parallel of the phot ostimulability showed that a lot of X-ray energy is stored in centers not effective for the latter process. We therefore thoroughly investig ated by EPR and ENDOR the radiation effects in the two sulfates and th eir thermal stability. Phosphate and F+-centers turned out to play an important role for this application. Since their decay contributes to a TL glow peak above 350 degrees C, this system is also interesting wi th respect to dosimetric applications. Copyright (C) 1996 Elsevier Sci ence Ltd