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Ce3+‐doped 20Gd2O3–20Al2O3–60SiO2 (GAS:xCe3+) glasses (x = 0.3, 0.7, 1.1, 1.5, 1.9 mol%) with Si3N4 as a reducing agent were prepared. The density of the glasses is around 4.2 g/cm3. With the increase in the Ce3+ concentration, both the photoluminescence (PL) and PL excitation peaks of GAS:xCe3+ glasses show a redshift because the 4f–5d energy levels of Ce3+ ions are narrowed. PL quantum yield and PL decay time of GAS:xCe3+ glasses are 28.32–50.59% and 43–64 ns, respectively. In addition, they both first increases and then decreases with the Ce3+ concentration increasing, reached the maximum when x = 1.1 mol%. The integrated X‐ray excited luminescence (XEL) intensity of the GAS:1.1Ce3+ glass is 23.86% of that of Bi4Ge3O12 (BGO) crystal, and the light yield reaches 1200 ph/MeV with an energy resolution of 22.98% at 662 keV when exposed to γ‐rays. The PL and XEL thermal activation energies of GAS:xCe3+ glasses are independent of Ce3+ ions concentration. Scintillating decay time of the glasses exhibits two components consisting of nanosecond and microsecond levels, and the scintillating decay time gradually decreases with the Ce3+ concentration increasing. The difference between PL and scintillating decay time is discussed regarding the different luminescent mechanisms. [ABSTRACT FROM AUTHOR]

Motivated by the detection of neutrons, europium‐doped Li2B4O7 glasses enriched with both lithium and boron elements with high cross‐section capture were developed. A highly effective method of realizing the self‐reduction of Eu3+ to Eu2+ ions in europium‐doped Li2B4O7 glasses prepared by high temperature melt‐quenching technology in air was revealed. The self‐reduction of Eu3+ to Eu2+ ions can be easily achieved by the partial replacement of B2O3 with BN within 2 mol% concentration. And the effect of partially replacing B2O3 with BN on the optical properties of europium‐doped Li2B4O7 glass are systematically studied by transmittance, photoluminescence, and radioluminescence spectra, together with the luminescence decay curves. [ABSTRACT FROM AUTHOR]

A highly effective method of synthesizing transparent and colorless Ce3+‐activated aluminoborosilicate glass in air by high temperature melt‐quenching is reported. This is achieved by partial substitution of AlN for Al2O3 without using any reduction in atmosphere. The optimized Ce3+‐activated aluminoborosilicate scintillating glass is featured with a density of ~4.5 g/cm3 and a lifetime of 41.74 ns. Compared to the glass synthesized without AlN substitution, both the photo and raidoluminescence intensity of the optimized Ce3+‐activated aluminoborosilicate scintillating glass are enhanced by a factor of 24.4 and 6.76, respectively. The corresponding integrated raidoluminescence intensity is about 17.6% of that of BGO crystal under X‐ray excitation at 30 kV and 3 mA, respectively. [ABSTRACT FROM AUTHOR]

Novel Tb3+‐activated borogermanate‐tellurite scintillating glasses with a maximum density of 7.15 g/cm3 aimed at detection of high‐energy rays were prepared by a melt‐quenching method for the first time. The concentration‐dependent optical properties including transmittance, photoluminescence, luminescence dynamic behaviors, and X‐ray excited luminescence in the as‐prepared Tb3+‐activated borogermanate‐tellurite glasses were studied. The optimal content of Tb2O3 in the superdense borogermanate‐tellurite glasses is revealed to be 7 mol% under both 275 nm ultraviolet light and X‐ray excitation. The integral scintillation efficiency of Tb3+‐activated borogermanate‐tellurite scintillating glass is about 33.71% of the standard Bi4Ge3O12 (BGO) scintillating crystal. [ABSTRACT FROM AUTHOR]

Abstract: A colorless Ce3+‐activated borosilicate scintillating glass enriched with Gd2O3 is successfully synthesized in air atmosphere for the first time. The full replacement of 10 mol% BaO by Al2O3, and the partial substitution of 3 mol% SiO2 by Si3N4 in the designed glass composition are crucial for this success. The role of Al3+ on tuning the optical properties of Ce3+‐activated borosilicate scintillating glass synthesized in air are analyzed by optical transmittance, X‐ray absorption near edge spectroscopy (XANES) spectra, photoluminescence (PL) and radioluminescence (RL) spectra. The results suggest that the stable Ce4+ ions can be effectively reduced to stable Ce3+ ions by the full replacement of BaO by Al2O3, and both the PL andRL intensity of the designed borosilicate scintillating glass are enhanced by a factor of 6.7 and 5.2, respectively. The integral RL intensity of the synthesized Ce3+‐activated borosilicate scintillating glass is ~17.2%BGO, with a light output of about 1180 ph/MeV. The strategy of substituting BaO by Al2O3 will trigger more scientific and technological considerations in designing novel fast scintillating glasses. [ABSTRACT FROM AUTHOR]

Transparent and colorless CeO2‐activated borogermanate glasses, with the nominal molar composition of 25B2O3–40GeO2–14Gd2O3–1CeO2–(20−x) BaO–xBaF2 (x = 0, 2.5, 5, 10, 15 and 20), were synthesized by a melt‐quenching method in air. Their optical investigation on the transmittance, photoluminescence (excitation and emission spectra), the luminescence decay curves, as well as the temperature‐dependent Ce3+ emission are studied systematically with the gradual substitution of BaF2 for BaO. The room‐temperature photoluminescence results reveal that the emission intensity can be improved by about 2.5 times with the full substitution of BaF2 for BaO. The blue shift of the cut‐off edge, excitation and emission spectra of Ce3+‐activated borogermanate glass, and the emission intensity of Ce3+ ions as a function of temperature range in 80–500 K are also discussed. [ABSTRACT FROM AUTHOR]

Tb3+-, Eu3+-activated, and Eu3+/Tb3+-coactivated oxyfluoride borogermanate scintillating glasses with the density of about 6.50 g/cm³ were successfully synthesized by a melt-quenching method. The structure and optical properties including transmittance, photoluminescence (excitation and emission spectra), photoluminescence decay, and X-ray excited luminescence behaviors were studied in detail. Our results reveal that the energy-transfer efficiency from Tb3+ to Eu3+ ions increases with an increase in Eu3+ concentration. The energy-transfer mechanism is also discussed by Dexter's and Reisfeld's semiexperimental methods. [ABSTRACT FROM AUTHOR]

Fast Ce3+-activated borogermanate scintillating glasses with the density of 5.58-5.67 g/cm3 were synthesized by melt quenching method in air atmosphere for the first time. The optical transmittance and X-ray absorption near edge spectroscopy results confirm that Ce4+ ions can be effectively reduced to Ce3+ ions by adding 0.31 mol% Si3 N4 as a strong reducing agent during glass synthesis. The luminescence behavior under both ultraviolet and X-ray excitations indicate that the proposed Ce3+-activated borogermanate scintillating glasses have a broad emission band centered at 430 nm and a decay time of less than 25 ns. This will be of great interest in high-energy physics and nuclear physics engineering. [ABSTRACT FROM AUTHOR]

Eu3+-activated borogermanate scintillating glasses with compositions of 25 B2 O3-40 GeO2-25 Gd2 O3-(10− x) La2 O3- x Eu2 O3 were prepared by melt-quenching method. Their optical properties were studied by transmittance, photoluminescence, Fourier transform infrared ( FTIR), Raman and X-ray excited luminescence ( XEL) spectra in detail. The results suggest that the role of Gd2 O3 is of significance for designing dense glass. Furthermore, energy-transfer efficiency from Gd3+ to Eu3+ ions can be near 100% when the content of Eu2 O3 exceeds x = 4, the corresponding critical distance for Gd3+- Eu3+ ion pairs is estimated to be 4.57 Å. The strongest emission intensities of Eu3+ ions under both 276 and 394 nm excitation are simultaneously at the content of 8 mol% Eu2 O3. The degree of Eu- O covalency and the local environment of Eu3+ ions are evaluated by the value of Ω t parameters from Judd-Ofelt analysis. The calculated results imply that the covalency of Eu- O bond increases with the increasing concentration of Eu3+ ions in the investigated borogermanate glass. As a potential scintillating application, the strongest XEL intensity under X-ray excitation is found to be in the case of 6 mol% Eu2 O3, which is slightly different from the photoluminescence results. The possible reason may be attributed to the discrepancy of the excitation mechanism between the ultraviolet and X-ray energy. [ABSTRACT FROM AUTHOR]