Performance improvement of large Sr2+ and Ba2+ co-doped LaBr3:Ce3+ scintillation crystals

The performance improvement of large size (φ = 60 mm, ℓ = 80 mm) Sr²⁺ and Br²⁺ co-doped LaBr₃:Ce³⁺ scintillation crystals is reported. The scintillation light output of both Sr²⁺ and Br²⁺ co-doped crystals are significantly improved. Compared to 70,000 ph/MeV (at 662 keV) for Ce³⁺ only LaBr₃, Sr²⁺ and Ba²⁺ co-doping increase the light output by ~25% to 88,000 ph/MeV and 89,000 ph/MeV, respectively. The energy resolutions of both Sr²⁺ and Ba²⁺ co-doped crystals are improved over a wide energy range as well. The scintillation decay time is slightly lengthened with co-doping. No secondary slow component is observed. Co-doped crystals exhibit very similar emission and excitation characteristics to the Ce³⁺ only crystal. Both Sr²⁺ and Ba²⁺ show improved light output proportionality in the low energy range.