Assessment of the X-ray Luminescence Efficiency of Cerium-doped Lutetium-Yttrium Oxyorthosilicate (LYSO:Ce) Single Crystal upon Temperature

The light output (luminescence efficiency-LE) of three Cerium-doped single crystal scintillators under X-ray excitation was evaluated in the influence of external heating. The examined samples were the Lutetium Oxyorthosilicate (Lu 2 SiO 5 :Ce-LSO:Ce), the Lutetium-Yttrium Oxyorthosilicate ((Lu,Y) 2 SiO 5 :Ce or LYSO:Ce) and the Gadolinium Orthosilicate (Gd₂SiO₅:Ce or GSO:Ce). The crystals were irradiated, with an X-ray medical source (CPI/CMP/200/DR), using a 90 kVp X-ray spectrum. The temperature in each crystal surface was elevated from ambient (i.e. 18-25 o C) to a maximum of 171 o C. The luminescence efficiency of all Oxyorthosilicates was found to decrease constantly with increasing temperature. The luminescence efficiencies of LYSO:Ce and LSO:Ce crystals decreased by 51.76% and 67.98%, respectively with increasing temperature, in the examined range. The LE of GSO:Ce crystal decreased by 25.33% exhibiting greater thermal stability in terms of its luminescence performance for applications requiring stable performance in warmer environmental temperature conditions.