16:00 〜 18:00
▲ [17p-PA09-44] Optical and Scintillation Properties of Tb-doped La2Si2O7 Crystal
キーワード：scintillator, Tb3+, single crystal
The scintillator is one of the phosphor materials that can convert the high-energy ionizing radiations such as photons (X- or γ-ray), neutron, or charged particles into lower-energy photons such as ultraviolet (UV), visible, and near-infrared light. In the past, it was difficult to investigate the scintillation properties of Tb-doped scintillators due to limitations imposed by the pulse height setup, which resulted in an underestimation of the scintillation light yield of scintillators with a decay time in the ms range. A special pulse area setup has recently been developed for scintillators with ms decay time, using which a light yield for Tb-doped Sr2Gd8(SiO4)6O2 of 23,000 ph/MeV was reported. This study is the combination of the newly discovered pyrosilicate, the Lanthanum pyrosilicate La2Si2O7 (LaPS) single crystals. LaPS single crystals were successfully fabricated by the floating zone (FZ) method with 0.1, 0.5, 1.0, and 2.0% Tb-doping concentrations for scintillation and photoluminescence (PL) study. X-ray diffraction patterns of the samples indicate a single phase of LaPS from their consistency with the reference pattern. Tb-doped LaPS has multiple emissions from Tb3+ 4f-4f transitions including those at 380, 420, 440, 480, 540, 590, and 620 nm, as observed in both PL and X-ray-induced scintillation spectra with a PL quantum yield of up to 50.1%. The PL and scintillation decay time constants obtained were 2.64–3.26 and 1.54–2.00 ms, respectively. In the 137Cs (662 keV) γ-ray pulse area spectra, the 1.0% Tb-doped LaPS had the highest scintillation light yield of 47,700 ph/MeV. From all the results in this study, the optimum Tb-doping concentration in LaPS single crystal is considered to be at 1.0% for scintillator application