Thermal-neutron scintillator: Ce3+ activated Rb2LiYBr6

Scintillation and luminescence characteristics of Rb2LiYBr6 doped with 0.1%, 0.5%, 1%, and 5% Ce3+ are presented. Under optical and x-ray excitation, Ce3+ doublet emission is observed at 385 and 420 nm. Rb2LiYBr6:0.5% Ce3+ shows very high thermal neutron scintillation light output of 83 000 photons/neutron. An excellent neutron peak resolution of 3.6% (full width at half maximum over peak position) is observed for the 4.8 MeV neutron-reaction products energy response in Rb2LiYBr6:0.1% Ce3+. This peak shows up at 3.6 MeV γ-equivalent energy and therefore it gives an α∕β ratio of 0.74. The combination of a large fraction of neutron absorption in natural L6i (62%), a sharp neutron response peak, high light yield, and large α∕β ratio makes Rb2LiYBr6:Ce3+ an efficient scintillator for thermal neutron detection.