e-Περιοδικό Επιστήμης & Τεχνολογίας

e-Journal of Science & Technology, (e-JST)

Luminescence Efficiency of Europium activated Gd₂O₂S Powder Phosphors
for Medical Imaging applications

Christos M. Michail¹, Adrianos Toutountzis², Ioannis G. Valais², Ioannis Seferis², Michalis Georgousis²,
George Fountos², Ioannis S. Kandarakis^2* and George S. Panayiotakis¹
 

¹ Department of Medical Physics, Medical School University of Patras 265 00 Patras, Greece

² Department of Medical Instruments Technology  Technological Educational Institution of Athens Ag. Spyridonos, Aigaleo, 122 10 Athens, Greece

 Corresponding author:  kandarakis@teiath.gr

 Abstract. The aim of the present study was to examine the performance of the Gd₂O₂S:Eu powder scintillator for use in medical imaging applications. For this purpose various scintillator screens with coating thicknesses 33.1, 46.4, 63.1, 78.3 and 139.8 mg/cm² were prepared in our laboratory by sedimentation of Gd₂O₂S:Eu powder on silica substrates. Quantum Detection Efficiency (QDE) and Energy Absorption Efficiency (EAE) were evaluated. Light emission efficiency and optical emission spectra of the screens were measured under X-ray excitation using X-ray tube voltages (50–140 kVp) employed in X-ray radiography. Spectral compatibility with various optical photon detectors (photodiodes, photocathodes, charge coupled devices, films) were determined using emission spectrum data. Gd₂O₂S:Eu showed peak emission in the wavelength range 620–630 nm. The 139.8 mg/cm² phosphor screen appeared with the maximum light emission efficiency. Due to its reddish emission spectrum, Gd₂O₂S:Eu showed excellent compatibility with the sensitivity of many currently used photodetectors and could be considered for application in X-ray imaging especially in various digital detectors.

Keywords: Luminescence Efficiency, Matching Factor, Powder Phosphors, Gd₂O₂S:Eu.
 

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