Measurement of the luminescence properties of Gd2O2S:Pr,Ce,F powder scintillators under X-ray radiation

• Two Gd2O2S:Pr,Ce,F screens (35.7 & 71.2 mg/cm2) were prepared by sedimentation.
• Peak absolute efficiency was obtained for the 71.2 mg/cm2 screen at 60 kVp.
• Gd2O2S:Pr,Ce,F showed very good spectral compatibility with CMOS and CCD sensors.

The aim of the present study was to investigate the absolute luminescence efficiency of gadolinium oxysulfide powder scintillators, doped with praseodymium, cerium and fluorine (Gd2O2S:Pr,Ce,F). Gd2O2S:Pr,Ce,F is a non-hygroscopic material, emitting green light with short decay time. For the purposes of this study, two scintillating screens with coating thicknesses 35.7 and 71.2 mg/cm2, were prepared in our laboratory from Gd2O2S:Pr,Ce,F powder (Phosphor Technology, Ltd) by sedimentation on silica substrates. The light emitted by the phosphors under investigation was evaluated by performing measurements of the absolute efficiency under X-ray exposure conditions with tube voltages ranging from 50 to 130 kV. Results were compared with previously published data for Gd2O2S:Eu screens. The spectral compatibility of Gd2O2S:Pr,Ce,F with various existing optical detectors, was investigated after emission spectra measurements. Particle size and morphology parameters of the Gd2O2S:Pr,Ce,F powder phosphor were verified via scanning electron microscope (SEM) micrographs. Absolute efficiency was found to maximize at 60 kVp for the 71.2 mg/cm2 and at 90 kVp for the 35.7 mg/cm2 Gd2O2S:Pr,Ce,F screens. Absolute efficiency of the 71.2 mg/cm2 Gd2O2S:Pr,Ce,F screen was higher in the whole X-ray tube voltage range showing potential interest for non-CT medical imaging (i.e. dental radiology) or industrial digital radiography.