We synthesized the 0.1, 0.5, 1.0, and 1.5% Ce-doped mullite single crystals by the floating zone method and evaluated their photoluminescence (PL) and thermally stimulated luminescence (TSL) ...properties. The single-phase orthorhombic structure was confirmed in all the samples from powder X-ray diffraction patterns. The transmittance spectra of all the samples showed the absorption related to the 4f-5d transitions of Ce3+ ions and optical band gap of mullite. The Ce-doped mullite single crystals had the PL attributed to the 5d-4f transitions of Ce3+ ions. In TSL properties, TSL glow curves had the glow peaks at 250 and 370 °C, and TSL spectra heated at 250 and 370 °C had the peak at around 390 nm owing to the Ce3+ ions. TSL dose response functions showed linear response from 0.01 mGy to 10 Gy for the 1.0% Ce-doped mullite single crystal and from 0.1 mGy to 10 Gy for the 0.1, 0.5, and 1.5% Ce-doped ones. The 1.0% Ce-doped mullite single crystal could be used multiple times for dosimetry. In addition, the TSL intensity of the 1.0% Ce-doped mullite single crystal after 7 days from X-ray irradiation was about 82.4% from immediately one after X-ray irradiation.
•We have synthesized Ce-doped Al4SiO8 single crystals by floating zone method.•We have characterized the photoluminescence, and thermally stimulated luminescence.•All the samples showed luminescence properties due to the 5d-4f transitions of Ce3+.•The lower detection limit of the 1.0% Ce-doped Al4SiO8 single crystals was better than those of a part of commercial dosimeters.
This paper presents the results of photoluminescence and X-ray induced scintillation properties of xCe:33.3BaO-66.6SiO2 (x = 0, 0.05, 0.1, 0.5, 1.0, 2.0) glasses produced by the Floating Zone (FZ) ...method. We observed intense emission from 5d–4f transition of Ce3+ and the concentration quenching with the increase of Ce concentration in photoluminescence (PL) and scintillation properties. The lowest Ce-doped sample indicated the highest scintillation intensity in the X-ray induced scintillation measurement. The non-doped sample had the highest afterglow level, and the afterglow levels decreased with Ce addition amount. From these results, it was found to be in a trade-off relationship between the scintillation intensity the and afterglow characteristics in present samples.
•Succeeded in making Ce-doped BaO–SiO2 glass using Floating Zone furnace.•The lowest Ce-doped glass shown the highest scintillation intensity among our samples.•We found that it is effective to introduce more Ce to reduce afterglow levels in this glass compositions.
Ce-doped CaHfO
3
crystals were synthesized by the floating zone method, and the photoluminescence and scintillation properties were evaluated. The crystals exhibit photoluminescence peaking at ...440 nm, and the decay time constants are typical value due to the 5d–4f transition of Ce
3+
. The X-ray-induced scintillation decay time curves indicate short decay time constant around 15–35 ns. From the pulse height spectra under
57
Co (122 keV) gamma-ray irradiation, the scintillation light yields are estimated; and, the 0.3% Ce-doped sample shows the highest light yield of approximately 8100 ph/MeV among the samples. The light yield is comparable with that of Bi
4
Ge
3
O
12
and
M
HfO
3
(
M
= Ba, Sr or Ca) which is a scintillator with high density.
Resting bradycardia is an important symptom for early diagnosis of anorexia nervosa (AN) during weight loss, and it improves with body-weight recovery. However, chronotropic incompetence (CI) in ...exercise is observed in some patients with AN despite amelioration of resting bradycardia in the recovery phase. We examined the relationship between CI in exercise and other parameters in patients with AN during the recovery phase. Ninety-two girls with AN (aged 13–20 years, median 15 years) performed cardiopulmonary exercise tolerance tests with a bicycle ergometer in the post-treatment recovery phase. Subjects with a peak-heart rate (HR) of < 160 beats/min (bpm) on subjective maximum loading were assigned to the CI+ group (
n
= 7), and those with a peak-HR of ≥ 160 bpm were assigned to the CI− group (
n
= 85). The peak-oxygen uptake (
V
O
2
) of both groups was below the normal range. Although there was no difference in peak-
V
O
2
between these groups, both the resting-HR and ΔHR (peak-HR − resting-HR) were significantly lower in the CI+ group than in the CI− group (82 ± 8 vs. 93 ± 16 bpm, respectively; 72 ± 14 vs. 89 ± 13 bpm, respectively), suggesting lower exercise tolerance in patients with CI during the recovery phase of AN. Interestingly, the Δ
V
O
2
/ΔHR value was higher in the CI+ group than in the CI− group (0.31 ± 0.13 vs. 0.26 ± 0.06, respectively), suggesting excessive stroke volume for maintaining the cardiac output in patients with CI during their recovery phase. These data suggest that CI could be an index of insufficient recovery of AN and utilized for ideal exercise treatments of patients with AN during the recovery phase.
Optical and thermally-stimulated luminescence (TSL) properties of Ce-doped Al2O3 transparent ceramics were investigated. The transparent ceramics were synthesized by the spark plasma sintering ...method. The Ce-doped Al2O3 transparent ceramics showed photoluminescence (PL), radioluminescence, and TSL peaking at around 400 nm, caused by 5d-4 f transitions of Ce3+. The PL decay curve consisted of two components with decay time constants of 21 and 43 ns. The TSL glow curves had glow peaks at 71, 130, 184, 251, 284, and 362 °C. The 0.1% Ce-doped Al2O3 transparent ceramic exhibited the maximum TSL intensity among the present samples. The minimum detectable dose was turned out to be 0.03 mGy.
Eu:BaFBr is typically used in a ceramic form for imaging plate, and it has not been commonly studied in a single crystal form and for scintillator applications. In this study, we prepared Eu:BaFBr ...single crystal by the Bridgeman method and then evaluated the scintillation properties. The crystal showed an intense scintillation emission spectrum under X-ray excitation with a peak appeared at 395 nm due to the 5d-4f transitions of divalent Eu ion, and the scintillation decay time under X-ray irradiation was 1.4 μs. When we irradiated with γ-rays by 137Cs, a clear photoabsorption peak was observed in the pulse height spectrum, and the scintillation light yield was estimated to be 27000 ph/MeV. By using various radio isotopes, we investigated the relation between peak channels of photoabsorption peak and γ-ray energy, and we confirmed a linear relationship from 60 keV to 1.27 MeV. To the best of our knowledge, this is the first report of Eu:BaFBr crystal demonstrating as a scintillator for γ-ray detections.
•Scintillation properties of Eu-doped BaFBr crystal is investigated.•Emission due to Eu2+ 5d-4f transition is confirmed.•Gamma-ray responses of Eu-doped BaFBr is examined.•Eu-doped BaFBr shows a high scintillation light yield of 27000 ph/MeV.
Undoped and Ce-doped SrLu2O4 single crystals were synthesized by the floating zone method equipped with four Xe lamps, and the photoluminescence (PL) and scintillation properties were investigated. A ...broad emission band appeared at around 470 nm in PL and scintillation spectra due to the 5d–4f transition of Ce3+. In addition, the PL and scintillation decay time constants were close to typical values of the 5d–4f transition of Ce3+. The pulse height spectra of 137Cs gamma-ray demonstrated that the light yield of undoped and 0.3% Ce-doped SrLu2O4 were 1490 and 570 photons/MeV, respectively. In addition, relationship between gamma-ray energy and photoabsorption peak channel was evaluated.
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•Undoped and Ce-doped SrLu2O4 single crystals were synthesized by the floating zone method equipped with four Xe lamps.•Photoluminescence and scintillation properties of undoped and Ce-doped SrLu2O4 single crystals were investigated.•A broad emission band appeared at around 470 nm in PL and scintillation spectra due to the 5 d–4f transition of Ce3+.•Undoped SrLu2O4 single crystals demonstrated the highest scintillation light yield among the synthesized samples.
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