Growth of LiF/LiBaF eutectic scintillator crystals and their optical properties.

Li-containing materials can be applied as neutron scintillators, and LiBaF can discriminate neutron and gamma rays. Moreover, LIF/LiBaF can have higher cross section of thermal-neutron capture compared with LiBaF. In this study, LiF (82.5 mol%) and (Ba RE)F (17.5 mol%, RE = Ce and Eu, x = 0.002) eutectic crystals, LiF/RE:LiBaF, were grown by the micropulling down method with different pulling rates (growth rate) in order to observe the eutectic structure. Lamellar microstructure was formed for each pulling rate. LiF/Ce:LiBaF excited by 5.5-MeV alpha rays had a broad peak at ~350 nm corresponding to 5 d-4 f transition of Ce. On the other hand, LiF/Eu:LiBaF had two scintillation processes; a sharp emission was originated from P → S transitions in the 4 f electronic configuration of Eu at 360 nm, and a broad one was attributed to Eu trapped exciton recombination at 400-450 nm. Since scintillation light was observed for these materials, these scintillators are sensitive to neutrons. [ABSTRACT FROM AUTHOR]