Properties of Y2O2S:Tb X-Ray Intensifying Screens

Experimental radiographic screens of Y2O2S:Tb, when using ordinary (blue-sensitive) medical x-ray film, are shown to have a speed three to four times that of commercial CaWO4, and about twice that of Gd2O2S:Tb in the medical x-ray energy range of 30 to 100 kVp. The resolutions in each case were comparable. Calculations of the relative speed of these screens are made from the x-ray attenuation coefficients, the cathodoluminescent efficiencies, and the spectral response of the film. These calculations agree quite well with the observed values. Resolution data are presented in terms of the square wave response function for experimental and commercial radiographic screens. Results of exposures made with an experimental x-ray film sensitized for the green spectral region with Y2O2S:Tb and Gd2O2S:Tb radiographic intensifying screens are presented.