Room temperature luminescence properties of Pr3+ doped β-PbF2 powders

Low cost cubic lead fluoride (beta-PbF2) is an attractive light-emitting material for dual readout purpose in homogeneous hadronic calorimeter (HHCAL), and introducing available scintillation light in PbF2 is desperately needed. Among rare earth ions RE3+, Pr3+ ions usually show a unique fast and broad electric dipole allowed 5d-4f emission transition in luminescent inorganic materials. In this work, Pr3+ doped and Pr3+, Li+ co-doped beta-PbF2 powders of Pb1-xPrxF(2+) beta (x = 0.1%, 0.5%, 1%, 3%, 5%) and Pb0.995-yPr0.005LiyF2+ beta (y = 0.3%, 0.5%, 1%, 3%, 5%) were synthesized by solid state reaction in vacuum tube furnace to obtain a fast light. Typical 4f-4f emission transitions of Pr3+ ions were observed under 3H4-3P(2) excitation in Pb1-xPrxF2+ beta amples. Only 4f-4f emission transitions were observed under 4f-5d excitation because of the nonradiative relaxation of the 5d level into the lower 4f levels due to the low 4f-5d excitation transition energy (4.28 eV) of the Pr3+ ions in Pb1-xPrxF2+ beta samples. The co-doping of monovalent Li ions can increase the luminescent intensity of Pr3+ ions in PbF host owing to the charge compensation. The decay time monitoring the 481 nm (under 4f-5d excitation) and 483 nm (under 3H4-3P2 excitation) emission of Pr3+ ions in PbF2 host is 17.5 and 24.9 beta s, respectively.