Photoluminescence and scintillation properties of Yb²⁺-doped SrCl₂ crystals

The photoluminescence and scintillation properties of undoped SrCl₂ and SrCl₂:Yb²⁺ (0.025, 0.25, 0.5, and 1 mol%) crystals have been investigated. These crystals were grown by the vertical Bridgman method. We observed two emission bands centered at 380 nm and 407 nm whose decay time constants are 500 ns and 550 μs, respectively, and are ascribed to spin-allowed (Yb^sa) and spin-forbidden (Yb^sf) Yb²⁺ 5d-4f transitions, respectively. 0.025%SrCl₂:Yb²⁺ showed the highest light yield of 55 000 photons/MeV for various concentrations of SrCl₂:Yb²⁺ and this value is comparable with 56 000 photons/MeV reported for 0.5%SrI₂:Yb²⁺.