Eu-concentration dependence of optical and scintillation properties for Eu-doped SrF₂ single crystals

Some Eu-doped scintillators, such as Eu:SrI₂, emit around 400-nm wavelength that originates from 5d-4f transition of Eu²⁺, while some Eu-doped crystals have emissions from Eu³⁺ (f-f emission). In this report, effect of Eu-doping on optical and scintillation properties of SrF₂ crystals with Core-valence luminescence is discussed. The samples had 0.1, 0.2, 0.5, 1.0, and 2.0 mol% of Eu and were grown by an annealing method. As a result, ⁵D₀-⁷F_i (i =1, 2) transition (Eu³⁺) was detected in the SrF₂, containing over 0.5 mol% of Eu, while emission from 0.1 and 0.2-mol% Eu:SrF₂ originated from 5d-4f transition of Eu²⁺ and Core-valence luminescence. The light output of SrF₂ doped with 0.1, 0.2, 0.5, 1.0 and 2.0 mol% Eu was estimated to be 13,000 ± 1,000, 12,000 ± 1,000, 13,000 ± 2,000, 8,000 ± 1,000 and 7,000 ± 1,000 photons/MeV, respectively.