Luminescence efficiency of (Lu,Gd)2SiO5:Ce (LGSO:Ce) crystals under X-ray radiation

• Six (Lu,Gd)2SiO5:Ce single crystals were examined under radiographic X-ray energies.
• LE was found maximum at 130 kVp for the 3 × 3 × 15 mm3 crystal (25.40 E.U).
• The 10 × 10 × 10 mm3 LGSO:Ce was found with higher LE than both GSO:Ce and LSO:Ce.
• The emission spectrum is excellent matched with the sensitivities of PMTs and SiPMs.

The aim of the present study was to investigate the absolute luminescence efficiency (AE) of mixed oxyorthosilicate (Lu,Gd)2SiO5:Ce (LGSO:Ce) single crystals, under X-ray irradiation. Six (Lu,Gd)2SiO5:Ce crystal samples, with dimensions of 3 × 3 × 5, 3 × 3 × 6, 3 × 3 × 10, 3 × 3 × 15, 10 × 10 × 10 and 10 × 10 × 20 mm3 were examined. The light emitted by the crystals, was evaluated by performing measurements of the AE under X-ray exposure conditions, with tube voltages ranging from 50 to 130 kV. Results were compared with previously published data for GSO:Ce and LSO:Ce crystals. The spectral compatibility of the (Lu,Gd)2SiO5:Ce crystal, with various existing optical detectors, was investigated after emission spectra measurements. Absolute efficiency was found maximum at 130 kVp for the 3 × 3 × 15 mm3 (Lu,Gd)2SiO5:Ce crystal (25.40 E.U). AE of the 10 × 10 × 10 mm3 (Lu,Gd)2SiO5:Ce crystal was found higher than both GSO:Ce and LSO:Ce crystals, in the whole X-ray tube range. The emission spectrum of (Lu,Gd)2SiO5:Ce is excellent matched with the spectral sensitivities of photocathodes and silicon photomultipliers often employed in radiation detectors. Considering the high luminescence efficiency values and the spectral compatibility with the various photodetectors, (Lu,Gd)2SiO5:Ce crystal could be considered for use in combined medical imaging detectors i.e. integrated PET/CT detectors.