Enhanced luminescence in Tb3+-doped germanate glass ceramic scintillators containing CaF2 nanocrystals

Tb³⁺-doped germanate glass ceramics containing CaF₂ nanocrystals were prepared by melt quenching method with subsequent heat treatment. Their microstructures were investigated by XRD and TEM techniques. Their optical properties were studied by the transmittance, the photoluminescence, and the X-ray excited luminescence (XEL). The luminescence intensity in the glass ceramics under 377 nm light and X-ray excitations is significantly enhanced. The maximum integrated XEL intensity of the glass ceramics is about 50% of that of the commercial Bi₄Ge₃O₁₂ (BGO) scintillating crystal. The results indicate that Tb³⁺-doped germanate glass ceramic could be a promising scintillating material used in X-ray detection for slow event.     

Scintillating properties of gallogermanate glass scintillators doped with Tb3+/Eu3+

Compared with single-crystal scintillator, the glass scintillators have the benefits of low cost, big size, straightforward manufacturing method, and adjustable component. In this work, a succession of diaphanous gallogermanate glass scintillators doped with Tb³⁺ or Eu³⁺ were manufactured using melt-quenching technique. The thermal, structural, photoluminescent, and scintillating properties were studied. For photoluminescent properties, 12 mol% Tb³⁺-doped glass sample has high internal quantum efficiency (87.8%) and no obvious concentration quenching phenomenon can be observed. For scintillating properties, the optimal doping concentration of Tb³⁺ and Eu³⁺ are 4 mol% and 8 mol%, respectively. The integral intensity of X-ray excited luminescence of Tb³⁺-doped sample is 73.1% of that of Bi₄Ge₃O₁₂ scintillator, while the ratio of Eu³⁺-doped sample is 26.5%. The radiation damage of 4 mol% Tb³⁺-doped sample resulted by high power X-ray could be repaired through heat-treatment, while 8 mol% Eu³⁺-doped sample exhibits fine stability that the transmittance keeps constant after exposed to high power X-ray. Our research indicates Tb³⁺ or Eu³⁺ doped gallogermanate glass might be candidate for X-ray detection of slow events.     

Superior scintillation property of Tb3+-doped sodium silicate glass

The ability of a scintillator to absorb and convert the high-energy X-ray photons to low-energy visible photons is crucial for the application of X-ray in medical tests, security checks and scientific research. However, traditional scintillation crystals are synthesized by complex preparation process with high cost, hindering the wide development in practical applications. Here, Tb³⁺ doped sodium silicate glass, which exhibits remarkable scintillation property and recoverability to X-ray irradiation, was successfully prepared by an exercisable melt-quenching method. The obtained scintillator shows intense radioluminescence, which is about 1.5 times higher than that of the reference of Bi₄Ge₃O₁₂. The damaged glass to X-ray irradiation can be returned to the original state after heat treatment again, indicating excellent recovery. Moreover, the scintillator displays wonderful thermal stability with the fluorescence intensity at 573 K still remaining 96% at room temperature. These results demonstrate that the obtained scintillating glass has potential application towards the real world.     

Photoluminescence and X-ray excited scintillating properties of Tb3+-doped borosilicate aluminate glass scintillators

lthough single crystal scintillators have excellent performance, they have some drawbacks such as high cost, complicated elaboration method and difficulty of growth on large-scale. Glass scintillators are widely investigated to replace single crystal scintillators because of their simple fabrication method and low cost. In this paper, a series of transparent borosilicate aluminate glass scintillators doped with Tb³⁺ were successfully prepared by traditional melt-quenching method. The structural, luminescent, and X-ray excited scintillating properties were investigated. These glass samples show high stability and high transparency, and present good luminescent and scintillating properties. Sample with Tb³⁺ doping concentration of 10% has the best scintillating performance. The integrated intensity of X-ray excited luminescence is 66.6% of that of commercial Bi₄Ge₃O₁₂ single crystal scintillator, and the quantum efficiency (under 378 nm excitation) is 70.3%. Our findings suggest that Tb³⁺-doped borosilicate aluminate glasses with high light yield might be used as potential scintillators.     

Reduction of crystallization ability of sodium zinc phosphate glass under X-ray radiation

The effect of X-ray radiation on the crystallization ability of maximally homogenized sodium zinc phosphate glass with a minimal light scattering value of V _v = 4 × 10^?6 cm^?1 has been investigated. The crystallization kinetics of the sodium zinc phosphate glass of the 33.9P₂O₅ · 56.6ZnO · 9.5Na₂O (mol % from analysis) composition under the conditions of homogeneous nucleation and X-ray radiation have been studied. It has been demonstrated that the crystallization properties of phosphate glasses are more sensitive to the synthesis method than those of silicate glasses. It has been established that sodium zinc phosphate glass crystals represent the main crystalline phase precipitated in the glass of the above composition. The main parameters of nucleation have been determined in glass without preliminary radiation, including stationary nucleation rate I _st, nonstationary nucleation time ??, and nucleation activation energy E _??. It have been found that the effect of the CuK _?? X-ray radiation leads to the slowing down or even cessation of the nucleation of crystals in glass (the result depends on the change in the radiation intensity along the sample depth) in the case when radiation takes place immediately during the nucleation thermal treatment of the sample in a high-temperature chamber of the X-ray device. The kinetics of sodium zinc phosphate crystallization in the samples upon their pretreatment by CuK _?? X-ray irradiation has been investigated. It has been shown that the rate of crystal nucleation in glasses exposed to X-ray radiation is lower than that in glasses without preliminary irradiation.     

Reproducible X-ray excited luminescence performance with transparent Tb3+-doped NaGd2F7 scintillating glass ceramics

Oxyfluoride glass ceramics with low toxicity, high stability and strong X-ray excited luminescence intensity are introduced as scintillating material. Herein, a series of novel NaGd₂F₇:xTb³⁺ (x = 0, 0.1, 0.2, 0.3, 0.4) were synthesized through in situ growth self-crystallization. X-ray diffraction, fourier transform infrared spectrometer and transmission electron microscopy were measured to investigate the structure and morphology of NaGd₂F₇ glass ceramics. These investigations demonstrate that NaGd₂F₇ nanocrystals are uniformly distributed in glass matrix with 20–30 nm diameter. Photoluminescence and X-ray excitation spectra are greatly enhanced after further thermal treatment which verify better crystallization of NaGd₂F₇ glass ceramics. The X-ray excited luminescence of the GC2–640 sample can reach 143.8% of the commercial BGO. More importantly, the damaged material can be completely repaired by annealing at 350 °C for 30 min. Our investigation indicates that Tb-doped transparent NaGd₂F₇ glass ceramics are potential candidates of X-ray scintillating material.     

Glass-forming region and enhanced Bi NIR emission in sodium tantalum silicate laser glass

Bismuth (Bi)-doped glasses and fibers are of current interest as promising active media for new fiber lasers and amplifiers due to their 800-1700 nm near-infrared (NIR) emission. However, the optically active Bi centers in silica are easily volatilized during high-temperature fiber drawing, which results in low Bi doping concentration and low gain NIR luminescence. Here, we explored the glass-forming region in a model glass system of sodium tantalum silicate (Na₂O-Ta₂O₅-SiO₂) glass and attained suitable glass host for enhancing Bi NIR emission, right followed by detailed analysis on optical and structural characterization. Glass-forming region roughly lies in where Ta₂O₅ ≤ 30 mol%, SiO₂ ≥ 40 mol%, and Na₂O ≤ 40 mol%. Not only is glass-forming ability improved but also Bi NIR emission is enhanced (~60 times) by the introduction of Ta into glass network. Dissociated Na cations are restricted beside Ta, the high-field-strength element, so that the negative impacts of Na cations on glass formation and Bi NIR emission are weakened, which is responsible for the highly enhanced Bi NIR emission. This work helps us understand the glass-forming of tantalum silicate glass systems and luminescent behaviors of Bi. Hopefully, it could contribute to designing the Bi-doped laser glasses and high gain fibers with stable luminescent properties in future.     

Enhancement of emission intensity in Ce3+-activated aluminoborosilicate scintillating glass synthesized in air

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.     

Microstructure and Faraday effect of Tb2O3-Al2O3-SiO2-B2O3 glasses for fiber-based magneto-optical applications

For the fiber-based magneto-optical (MO) devices, like Faraday optical isolator, the target MO glasses are supposed to strike a balance among the following properties: high Verdet constant, chemical and physical stabilities, compatibility with the fiber drawing process, and the connectivity to the silica glass fiber networks. In this work, we report on the MO application of Tb₂O₃-Al₂O₃-SiO₂-B₂O₃ (TASB) glasses as a derivative of the yttrium aluminum silicate (YAS) glass fiber systems which have been intensively studied for their huge potential in the context of all-fiber lasers. We found that MO properties of the obtained TASB glasses vary systematically with the B₂O₃ contents. The effects of B₂O₃ on the local glass structures and the valence state of Tb ions were clarified via nuclear magnetic resonance, electron spin resonance, X-ray photoemission spectroscopy, and Raman spectroscopy. B₂O₃ content in TASB glasses leads to a certain degree of depolymerization in glass network and most of Tb⁴⁺ ions from the raw material of Tb₄O₇ are reduced to Tb³⁺ ions even in air, resulting in an improved MO properties. Due to the relatively high Verdet constant (∼70 rad/T/m) and suitable rheology of the glass melt speculated from the thermal analysis, TASB glass system in this work is adaptable to stable fiber-based Faraday effect devices.     

A novel way to production yttrium glass microspheres for medical applications

In this paper a novel method of producing yttrium aluminum silicate microspheres is reported. Yttrium aluminum silicate microspheres around 20–50 μm in size were obtained when an aqueous solution of Y(NO₃)₃ and Al(NO₃)₃ was added to tetraethyl orthosilicate (TEOS) and pumped into stirred silicone oil. The particles produced by this method are regularly shaped and very close to spherical. The amorphous structure, Y-O-Si bonds, spherical shapes, composition, and element distribution were investigated by X-ray diffraction (XRD), fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), X-ray fluorescence spectroscopy (XRF), carbon/sulfur analysis, and SEM/EDS mapping analysis. The results obtained demonstrate that the silicone oil spheroidization method is suitable for the production of yttrium aluminum silicate microspheres. This study also reveals that a high temperature is not required for the production of yttrium aluminum silicate microspheres.     

Superdense Tb3+-activated borogermanate-tellurite scintillating glasses

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.     

Formation of modified areas of porous glass saturated with glycerin under the action of laser radiation

The formation of modified areas with changed optical properties in the volume of thin plates of porous glass (composition of 94.73SiO₂ · 4.97B₂O₃ · 0.30Na₂O), saturated with glycerin—a substance with a high polarization capacity, under the action of laser radiation was investigated. A continuous wave ytterbium fiber laser with radiation wavelength λ = 1.07 μm weakly absorbed by porous glass was used as the radiation source. When the radiation power was within the range of 9.6–16.5 W and the irradiation time was 270–300 s, optical-grade modified areas were obtained. During the experiment, the dependences of temperature in the spots of the impact and of the power of the radiation transmitted through a thin plate of porous glass, on irradiation time were registered.     

Coordination state of aluminum and boron in barium aluminoborate glass

This paper considers the coordination state of boron and aluminum ions in barium aluminoborate glass with a constant ratio of BaO: B₂O₃ = 0.5 and a variable ratio of Al₂O₃: BaO = 0–3. The dependence of the concentrations of boron and aluminum atoms with a variable coordination number on the Al₂O₃ content was estimated by IR, ¹¹B and ²⁷Al NMR spectroscopy. The nonlinear nature of the obtained dependences was attributed to variations in the aluminum oxide properties. At a content of less than 30 mol % Al₂O₃ serves primarily as a network former, while an increase in the Al₂O₃ concentration results in its higher modifying role in the studied glass.     

Preparation and characterization of some multicomponent silicate glasses and their glass–ceramics derivatives for dental applications

The chemical corrosion and UV–vis absorption and infrared absorption spectra of binary and multicomponent lithium silicate glasses and corresponding glass–ceramics were investigated. The chemical durability of the glasses and derived glass–ceramics was found to be excellent to all leaching media. The IR absorption spectra of the glass and glass–ceramic samples reveal absorption bands of characteristic groups mainly due to major silicate network besides the possible sharing of network units due to some involving oxide constituents. X-ray analysis of glass–ceramics indicates the separation of lithium disilicate phase as the main constituent beside other phases according to the specimen chemical constituents. The obvious promising investigated chemical and physical properties are correlated with the presence of multioxides such as Al₂O₃, TiO₂, MgO and ZrO₂. Transmission and reflectivity properties reveal acceptable data. The prepared glass–ceramics are recommended for dental applications.     

Role of Al3+ on tuning optical properties of Ce3+‐activated borosilicate scintillating glasses prepared in air

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.     

WS2/bioactive glass composites: Fabrication,structural, mechanical and radiation attenuation properties

Ionizing radiation interaction might occur during diagnostic imaging and radiotherapy procedures. It has been reported that gamma-ray radiation can damage the living cells through the energy transfer. Therefore, investigation the ionization radiation attenuation properties of biomaterials have a crucial importance. In the current study, tungsten disulphide (WS₂) nanopowder-containing borate-based bioactive glass composites were prepared. Their physical, structural, mechanical and ionization radiation attenuation properties were investigated in detail. Monte Carlo simulations and radiation attenuation properties were studied through MCNPX and Phy-X/PSD. Results showed that sintering performed at 575 °C for 1 h in air atmosphere caused formation of some tungsten trioxide in the structure. Addition of WS₂ nanopowders increased the bulk density and improved the mechanical properties of the prepared bioactive glass composites. Simulation studies revealed the influence of WS₂ content on reduction the build-up factors and enhancement of the photon attenuation ability for all the considered photon energies.     

Optical,Spectral, and Radiation-Shielding Properties of High-Lead Phosphate Glasses

The spectral, optical, physicochemical, radiative, and radiation-shielding properties of glasses in the PbO-P₂O₅-R _m O _n system (where R _m O _n stands for Group I–V element oxides) are investigated as a function of their composition. The composition of a colorless radiation-resistant high-lead glass suitable for production on a semicommercial scale is determined. The properties and optical quality parameters of the glass are studied. The new phosphate glass is a lead metaphosphate containing aluminum, alkali, and alkaline-earth oxides. This glass is resistant to radiation at doses up to 10⁷ R and has an optical transmission edge at 360 nm. The coefficient of absorption of gamma radiation for the new glass is larger than those of dense silicate flints. According to the optical parameters, the new glass lies between dense flints and dense barium flints in the Abbe diagram and compensates for the absence of the latter flints in catalogues of radiation-resistant glasses.     

Thermal,mechanical, and dielectric properties of aluminum silicate fiber reinforced aluminum phosphate–poly(ether sulfone) layered composites

In this study, a novel aluminum phosphate (AlPO₄) heat‐resistant layer reinforced with aluminum silicate fiber (ASF) was successfully compounded on a poly(ether sulfone) (PES) matrix via the preparation process of high‐temperature heat treatment and vacuum hot‐pressing sintering technique. The influence of the ASF content on the morphology, thermal, mechanical, and dielectric properties of the as‐fabricated aluminum silicate fiber reinforced aluminum phosphate–poly(ether sulfone) (ASF/AlPO₄–PES) layered composite was investigated. The results reveal that the incorporation of aluminum silicate fiber/aluminum phosphate (ASF/AlPO₄) heat‐resistant layer can significantly improve the thermal stability and mechanical performances of the PES matrix composites. Compared with the pristine PES, the ASF/AlPO₄–PES layered composite containing 8.0 wt % ASF exhibited better high‐temperature resistance properties (300 °C) and a lower thermal conductivity (0.16 W m^?1 K^?1). Furthermore, the dielectric constant and dielectric loss tangent of this PES matrix composite decreased to 2.16 and 0.007, respectively. Meanwhile, the frequency stability of the dielectric properties for the ASF/AlPO₄–PES layered composites was remarkably enhanced with increasing ASF addition at frequencies ranging from 10² Hz to 5 MHz. This was attributed to the existence of microscopic pores within the ASF/AlPO₄ layer and the strong interfacial bonding between the ASF/AlPO₄ layer and the PES matrix. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134 , 45542.     

The effect of alkali metal oxide on the properties of borosilicate fireproof glass: Structure,thermal properties,viscosity, chemical stability

The purpose of the current work was to research the effect of alkali metal oxide on the structure, thermal properties, viscosity and chemical stability in the glass system (R₂O–CaO–B₂O₃–SiO₂) systematically. Because the glass would emulsify when Li₂O was added to the glass batch, this article did not discuss Li₂O. The results showed that when the amount of Na₂O was less than 4 mol.%, there was a higher interconnectivity of borate and silicate sub-networks in glass, as more mixed Si–O–B bonds were present in glass. The glass samples exhibited excellent thermal properties and chemical stabilities. As the amount of Na₂O exceeded 4 mol.%, the interconnectivity of borate and silicate sub-networks was weakened. The thermal properties and chemical stabilities of the glass samples were reduced. The connectivity of the silicate sub-network was weakened slightly as the Na/K ratio varied, and the coefficient of thermal expansion (CTE) of the glass samples gradually increased, and the resistance to thermal shock (RTS) value gradually decreased. Moreover, the viscosity of the glass samples decreased with the ratio of Na/Si and Na/K increased.     

Synthesis and properties of ferrimagnetic glass-ceramics and glass fibers derived from pyrite slag

Ferrimagnetic nano-crystal glass-ceramics and glass fibers were prepared based on the ferrosilicate glass system of SiO₂–Fe₂O₃–B₂O₃–Al₂O₃ using large amount of pyrite slag (PS) and small quantities of pure chemicals. Two different fabrication methods were employed, eg, annealing and fiber-drawing method, without performing any nucleation and crystallization heat treatments. The influence of PS content on the magnetite spontaneous crystallization is investigated by the X-ray diffraction, FTIR, SEM, and TEM. The X-ray diffraction patterns show the presence of nanometric magnetite crystals in glass matrix. The ferrimagnetic glass fibers with a diameter of about 20 μm were one-step drawn. The magnetic hysteresis loops of the glass-ceramic and glass fiber samples were analyzed using a vibrating sample magnetometer (VSM). Electromagnetic parameters of samples were also examined.