Kohei Mizoi, Yutaka Fujimoto, Daisuke Nakauchi, Masanori Koshimizu, Takayuki Yanagida, Keisuke Asai
Abstract
Photoluminescence (PL) and scintillation properties are reported for SrBrI:Yb2+ and BaBrI:Yb2+ crystals grown by a self-seeding solidification method. In both samples, the Yb2 spin-allowed and spin-forbidden 4f135d1 → 4f14 transitions were observed for both PL and scintillation. For scintillation, a single emission band at approximately 460 nm was observed for both samples, which was attributed to the spin-allowed Yb2+ 5d–4f transition. The scintillation decay time constants of SrBrI:Yb2+ and BaBrI:Yb2+ were estimated to be 1.6 and 1.4 μs, respectively. The light yields of SrBrI:Yb2+ and BaBrI:Yb2+ were 20,000 and 28,000–44,000 photons/MeV, respectively. The light yield of 1 mol% Yb2+-doped BaBrI (44,000 photons/MeV) was higher than that of NaI:Tl (40,000 photons/MeV), and the energy resolution of 0.5 mol% Yb2+-doped BaBrI (7.7%) was comparable to that of NaI:Tl (7.5%). BaBrI:Yb2+ has potential for application in pulse-counting mode detectors owing to its high light yields, high energy resolution, moderate scintillation decay time constants with ~1 μs, and low deliquescence.
