Characterization of LFS-3 scintillator in comparison with LSO

Performance of Lutetium Fine Silicate (LFS-3) scintillator in gamma-ray spectrometry has been investigated in comparison with the well known LSO crystal. The tests covered measurements of light output in terms of number of photoelectrons, energy resolution and non-proportionality. Time resolution was measured in coincidence experiments with 511 keV annihilation quanta from a 22Na gamma source. Decay time constants of the light pulse were calculated on the basis of timing spectra obtained using Thomas–Bollinger single photon method. Afterglow was measured about 30 ms after the crystal was irradiated by a strong 13.9 GBq 241Am source. Improvement in the energy resolution for 662 keV γ-rays from 137Cs, shorter decay time constants and better time resolution were observed in case of LFS-3, when compared with LSO. For LFS-3 energy resolution for 662 keV from 137Cs, decay time and time resolution were equal to about 7.66±0.23%, 40.5±1.2 ns and 161±5 ps, respectively, whereas for LSO the same parameters were equal to 8.13±0.23%, 43.9±1.3 ns and 173±5 ps, respectively. The study showed that LFS-3 crystal is an excellent substitute for LSO crystal.