X-ray Excited Luminescence Intensity Research Articles

Enhanced scintillating performance in Tb3+ doped oxyfluoride glass for high-resolution X-ray imaging

Scintillators that exhibit excellent scintillation performance coupled with superior radiation resistance are anticipated to cater the growing demand of X-ray detection across various fields including medicine and scientific research. Oxyfluoride glasses, which combine the benefits of both fluorine and oxide glasses, show significant potential as scintillator candidates. Here, highly transparent Tb3+ doped oxyfluoride glasses with splendid radioluminescence were successfully synthesized by melt quenching method with the aid of a two-step component tuning strategy. The luminescence excited by X-ray and ultraviolet light are significantly enhanced by boosting the effective atomic number of glass components and optimizing the B2O3/Al2O3 ratio. The integrated X-ray excited luminescence intensity of representative specimen reaches 219% of that of BGO. Exceptional anti-irradiation recoverability and thermal stability of 93% @ 573 K are conferred in the resultant glass. Moreover, X-ray imaging with a spatial resolution of up to 20 lp mm−1 was triumphantly achieved. These properties testify that the prepared oxyfluoride glass owns an enormous application foreground in X-ray imaging.

Tb-doped borosilicate glass scintillators with high thermal stability for high-resolution X-ray imaging

Scintillators with high thermal stability and excellent spatial resolution are desirable for X-ray imaging applications in harsh environments. Here, Tb3+-doped borosilicate glass scintillators were prepared using conventional melt-quenching method. The optimized Tb3+-doped borosilicate glass (G-15Tb) scintillator exhibited a significantly higher X-ray excited luminescence intensity (147 % of Bi4Ge3O12). Furthermore, it possessed a remarkable imaging spatial resolution of 20 lp/mm, surpassing the standard requirement for X-ray imaging and medical computed tomography scans (2 lp/mm). Moreover, the X-ray excited luminescence intensity of G-15Tb glass sample remained unchanged even after being submerged in water for 30 days, indicating exceptional water resistance. Additionally, the integral intensity of photoluminescence at 573 K is 96.7 % of its initial value. Most importantly, the G-15Tb glass scintillator remains high-quality X-ray images even at elevated operating temperatures. Therefore, the Tb3+-doped borosilicate glass scintillator holds immense potential for high-resolution X-ray imaging in harsh environments.

Excellent irradiation stability of Ce3+-doped Na5Lu9-xGdxF32 glass-ceramics scintillator for X-ray imaging

Scintillators, owing to their exceptional ability to convert high-energy ionizing radiation into visible light, are the core component of X-ray radiography. However, conventional single-crystal scintillators are inadequate to satisfy the modern social and scientific demands. So, the development of novel scintillator materials is imminent. Herein, a series of Na5Lu9-xGdxF32:Ce3+ glass-ceramics (GCs) scintillators were elaborated by an exercisable and low-cost method. Benefiting from the proper introduction of Al powder and Gd3+, as well as the crystallization of Na5Lu9-xGdxF32 nanocrystal (NCs) after heat treatment, luminescence excited by ultraviolet and X-ray of the sample is enhanced significantly. The integrated X-ray excited luminescence intensity of the representative sample can reach up to 128% of that of Bi4Ge3O12. More importantly, the sample has excellent irradiation stability that is almost undamaged even exposed to high-energy X-ray radiation. Finally, satisfactory X-ray imaging based on the resultant sample was realized. The spatial resolution is as high as 14 lp mm−1, which exceeds that of many novel perovskite scintillators. Thus, this investigation promotes the development of low-cost, stable and high-performing Ce3+-activated GCs scintillators.

Intense radioluminescence from transparent CsGd2F7: Ce3+ nano-glass scintillator

Nano-glasses are next-generation scintillators combining favorably the merits of both scintillator crystals and glasses. Here, a new nano-glass scintillator is prepared embedding CsGd2F7:Ce3+ nanocrystals (NCs). The microscopic morphology, particle size, and distribution of the NCs are studied by high resolution transmission electron microscopy. Significantly enhanced radioluminescence efficiency is obtained in the nano-glasses. The largest integrable intensity of X-ray excited luminescence is 316% of the standard Bi4Ge3O12 (BGO) crystal. A well-resolved full-energy peak with an energy resolution of 17.4% is registered for the 662 keV gamma rays, and the light yield is determined to be 827 ± 8 ph/MeV. The nano-glass scintillators exhibit good radiation hardness and thermal stability. As a proof of concept, an X-ray imaging system of a good resolution is built on the nano-glass scintillators.

Design and elaboration of highly resolved and efficient Cu+-doped oxyfluoride glass scintillators for X-ray image based on response surface methodology

Bulk glass scintillators, which process the advantages of low cost, cheap elaboration, excellent transparency and high uniformly, have garnered great attention for X-ray imaging application. Cu+-doped oxyfluoride glass scintillators were designed and elaborated by using Al powder as reducing agent. The relationship of X-ray excited luminescence (XEL) of Cu+-doped glasses with doping concentration of Cu+ and the addition of Al content were investigated by the response surface methodology to get the optimal glass. The optimal glass scintillator shows high transmittance (90.0% at visible region), short lifetime (42.9 μs), high absorption efficiency (93.0% at 290 nm) and good internal quantum yield (75.2%). Excitedly, the integrated XEL intensity of optimal sample is 141% of that of Bi4Ge3O12 crystal. And its spatial resolution reaches 20 lp/mm for X-ray imaging. Above results illustrate the potential application of Cu+-doped oxyfluoride glass scintillators in X-ray imaging filed.

Luminescence properties of CsPbBr3 single crystals and CsPbBr3 crystalline phases dispersed in a KBr matrix

Spectra of steady-state X-ray excited luminescence (XEL) and thermally stimulated luminescence (TSL) of CsPbBr3 single crystals in the temperature range of 80–294 K were studied. Each of the measured XEL spectra of CsPbBr3 single crystal contain only one elementary band peaking at 535 nm, which can be attributed to the radiative decay of the matrix exciton. The activation energy of exponential luminescence thermal quenching in this range, as determined by Mott's formula, is equal to 75 meV, close to the hole trap depth of 110 meV obtained for the main TSL peak of this crystal at 125 K. This value of the XEL quenching activation energy is associated with the thermal deactivation of the exciton hole component in the CsPbBr3 matrix.Doping of KBr crystals with CsPbBr3 perovskite impurities (0.05–1 mol. %) leads to the formation of CsPbBr3 micro- and nanocrystals in a KBr matrix with characteristic spectra of exciton photo- and XEL luminescence. A five-fold increase in the intensity of XEL was registered in KBr: CsPbBr3 (0.05 mol. %) samples at 294 K compared to that of CsPbBr3 single crystal.The temperature dependence of the XEL intensity of KBr: CsPbBr3 crystals and the analysis of their TSL integral curves allow us to make a conclusion about the hole mechanism of high-energy excitation energy transfer from the matrix to the activator resulting in the appearance of typical exciton luminescence in CsPbBr3 nanoparticles.

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.

Study on the luminescent properties of Eu3+-doped TeO2-GeO2-BaO scintillation glasses

Scintillation glasses for hadron calorimeter need high density and excellent luminescent properties. Eu3+-doped TeO2-GeO2-BaO scintillation glasses with the nominal composition of xTeO2-(60-x)GeO2-39BaO-1Eu2O3 (x = 20, 25, 30, 35, 40, 45, and 50) were prepared by melt-quenching method. The structural information induced by various TeO2/GeO2 ratios were discussed by means of density, FTIR spectra and transmittance spectra, together with the asymmetric ratios of Eu3+ ions and Judd-Ofelt analysis. The luminescent properties of Eu3+-doped TeO2-GeO2-BaO scintillation glasses are described byphotoluminescence (PL) and X-ray excited luminescence (XEL) spectra. The results suggest that both PL and XEL intensity of Eu3+-doped TeO2-GeO2-BaO scintillation glasses are observed to drops clearly with an increase in x values, whereas the glass density shows a slight increase. Therefore, a balance should be search for the possible scintillation application between the luminescent efficiency and the strict density requirement.

The self-absorption effect on the X-ray excited luminescence and cathodoluminescence spectra of YAG: Yb crystals

Y3Al5O12:Yb (YAG:Yb) crystal has been applied as not only the laser crystal with infrared (IR) luminescence but also the fast scintillation crystal with the fast ultraviolet (UV) scintillation light. In the investigation, both the X-ray excited luminescence (XEL) and cathodoluminescence (CL) spectra of YAG:Yb crystals with various Yb concentrations were measured and compared. Generally, the CL spectrum is considered to be equivalent to the XEL spectrum in characterizing the luminescence of scintillation crystals. However, the inconsistent correlations between Yb concentrations and the spectrally integrated XEL, CL intensities were observed for the UV luminescence. Meanwhile the consistent correlations between Yb concentrations and the spectrally integrated XEL, CL intensities were observed for the IR luminescence. The phenomenon was attributed to the stronger self-absorption effect in the XEL spectra measurements, compared to the CL spectra measurement. It indicates the correction on the luminescence intensity is needed in comparing the integrated XEL intensity of scintillation crystal with self-absorption effect.

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.

Effect of Al powder on Tb3+-doped borogermanate glass for X-ray detection

Here, we successfully prepared Tb3+-activated borogermanate glass by the traditional melt-quenching method. The optical and scintillating properties were investigated by using photoluminescence, transmission spectra, luminescence decay curves and X-ray excited luminescence. High content of Gd2O3 was added into borogermanate glass to improve the density of glass (about 5.52 g/cm3), and thus to enhance the radiation stopping power. Al powder was introduced into the composition as reducing agent. Due to incorporation of Al powder, the internal quantum efficiency of glass increases from 18.8% to 56.3%. Meanwhile, the integrated intensity of X-ray excited luminescence of glass promotes from 29.8% to 46.6% compared to Bi4Ge3O12 scintillating crystal. All above results declare that Al powder as reducing agent can strengthen the optical and scintillating properties of Tb3+-activated borogermanate glass.

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.

Scintillation properties of Ce3+/Tb3+ co-doped oxyfluoride aluminosilicate glass for exploration of X-ray imaging

Ce3+ or Tb3+ single-doped and Ce3+/Tb3+ co-doped oxyfluoride scintillation glass samples were prepared by high temperature melting method. The structures were analyzed by X-ray diffraction (XRD), the optical and luminescent properties were studied by transmittance, photoluminescence excitation, photoluminescence, X-ray excited luminescence (XEL) and fluorescence decay. The luminescence intensity in the Ce3+/5 mol% Tb3+ co-doped (CT5) glass sample under 304 nm light and X‐ray excitation is significantly enhanced compared to 5 mol% Tb3+ single-doped (T5) glass sample. The maximum integrated XEL intensity of CT5 glass sample is about 67% of the standard Bi4Ge3O12 (BGO) crystal. Through the study of energy transfer mechanism, the results indicate that there is an energy transfer from Gd3+ ions or Ce3+ ions to Tb3+ ions. The lifetime of CT5 glass sample is 2.13 ms. The obtained results confirm that CT5 glass sample could be a promising scintillating material used in X-ray imaging. So we have demonstrated X-ray imaging using Ce3+/1–15 mol% Tb3+ co-doped (CT1-15) glass samples and confirmed they can reach a spatial resolution of 10.0 lp/mm. Further, the X-ray imaging effect of CT5 glass sample is the best, and the capability of CT5 glass sample for X-ray imaging application is confirmed.

Optical properties of Dy2O3, Tb4O7 singly doped, Dy2O3/Tb4O7 codoped borogermanate-tellurite glasses for radiation application

In this paper, Dy2O3, Tb4O7 singly doped and Dy2O3/Tb4O7-codoped borogermanate-tellurite glasses for radiation application were synthesized by a melt-quenching method. The density of developed glasses exceeds 5.0 g/cm3, which is the fundamental requirement of dense scintillators in the application fields of medical imaging and high-energy physics engineering. The optical properties of these glass scintillators were systematically studied by transmittance, photoluminescence (PL) and X-ray excited luminescence (XEL) spectra, together with the corresponding photoluminescence dynamic process. The transmittance results reveal that the transmittance rate of all glasses can reach at the vicinity of 80%. The optimal content of Dy2O3 and Tb4O7 for both PL and XEL intensity were determined under ultraviolet light and X-ray excitation, respectively. The energy transfer occurred from Dy3+ to Tb3+ ions were demonstrated, and the energy transfer efficiency from Dy3+ to Tb3+ ions is observed to increase with higherTb4O7content. The scintillation efficiency of Dy3+, Tb3+doped, and Dy3+/Tb3+ co-doped borogermanate-tellurite scintillating glasses is about 10.45%, 41.38%, and 38.73% of the standard Bi4Ge3O12 (BGO) crystal, respectively.

Enhanced luminescence of CsPbBr3 nanocrystals-glass composite scintillators based on Ce3+-doped borosilicate glass

CsPbBr3 nanocrystals-glass composite scintillators based on Ce3+-doped borosilicate glass were prepared by melt-quenching method with further heat-treatment. Incorporating Ce3+ into borosilicate glasses matrix, highly enhanced green emission was observed under 365 nm ultraviolet and X-ray excitation. The transmittance of the prepared CsPbBr3 nanocrystals-glass is as high as 80% at 527 nm, fluorescence lifetime is 21.6 ns, and the luminescent quantum efficiency reaches up to 28% after thermal treatment (550 °C, 12 h). Compared with undoped CsPbBr3 nanocrystals-glass, the X-ray excited luminescence intensity of Ce3+ doped CsPbBr3 nanocrystals-glass is around 190%, which indicates that the issue of absorbing ray energy in glass matrix can be effectively solved by incorporation of Ce3+ ions.

Design, simulation, elaboration and luminescence of Tb3+-doped Ba0.84Gd0.16F2.16 fluoroaluminosilicate scintillating glass ceramics

Extensive researches on scintillators have been executed to satisfy the excellent radiation detection materials in broad applications. However, practical application of conventional scintillators is limited due to the limitations of high cost, time-consuming fabrication process and insufficient radioluminescence. Herein, high density precursor glass doped with Tb3+ was designed to absorb X-ray efficiently and produce green emission. Molecular dynamics simulation was used to simulate the phase separation process in melting process. Then, Tb3+-doped Ba0.84Gd0.16F2.16 glass ceramics (GCs) with excellent structural and optical properties were elaborated by melt quenching technic and further heat treating. Their structural properties, photoluminescence (PL) and X-ray excited luminescence (XEL) were explored detailedly. The internal quantum efficiency of PL is 64 % in GCs. The XEL intensity is 192 % of that of Bi4Ge3O12 (BGO) commercial scintillator. Our results suggest that Ba0.84Gd0.16F2.16:Tb3+ GCs might have potential application in X-ray detection.

Comparison of Photoluminescence and Scintillation Properties Between Lu₂O₃:Eu Single Crystal and Transparent Ceramic

Lu <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> O <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> :Eu single crystals (SCs) and transparent ceramics (TCs) were prepared by the optical floating zone (OFZ) method and hot isostatic pressing (HIP) sintering method, respectively. Their photoluminescence (PL) and scintillation properties, including photoluminescence excitation (PLE) and PL, PL decay, X-ray excited luminescence (XEL) and afterglow level curves, were measured and compared. Their transmission spectra were also recorded. The differences of the PL and scintillation performance between the Lu <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> O <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> :Eu SC and TC have been studied. It is shown that the transmittance of the SC is higher than that of the TC, reaching as high as 80%. The Eu( S <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">6</sub> )→ Eu(C <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> ) energy transfer states in the SC and TC are comparable through investigating the PL and PL decay curves. The main difference between the SC and TC in this work comes from the scintillation luminescence efficiency and afterglow level. The XEL intensity of the SC is 2.4 times that of the TC. The afterglow level of the TC is significantly higher than that of the SC, which probably results from the carrier traps formed in the forbidden gap related to the grain interface in ceramics sample.

Thermal quenching of luminescence in (Lu,Gd,Y)3(Ga, Al)5O12:Ce complex garnet ceramics at high and low temperatures

Cerium-doped complex garnets with the general formula (Lu,Y,Gd)3,(Ga,Al)5O12:Ce are promising materials to be used in PET and CT scanners. By modifying garnet composition (bandgap engineering), one can adjust its scintillation properties to fit a specific set of requirements. In certain compositions, Ce3+ luminescence intensity can decrease upon cooling (negative thermal quenching). The reason for that is still a matter of active debate. This article is focused on negative thermal quenching in Ce-doped (Lu,Gd)3(Ga,Al)5O12 garnet ceramics. We have measured thermally stimulated luminescence, temperature dependence of the X-ray excited luminescence intensity, and other scintillation properties of samples which have different Lu and Ga content and were annealed in different conditions. We discuss that negative thermal quenching in our samples can be attributed to the process of charge carrier localization on traps at lower temperatures.

Improved Phase Stability and Enhanced Luminescence of Calcite Phase LuBO3:Ce3+ through Ga3+ Incorporation.

The application of LuBO3:Ce3+ (LBO:Ce) crystal as an excellent scintillation material has been limited due to its poor phase stability at high temperature or high pressure, so improving the phase stability is essential for promoting its development. Ga stabilized LuBO3:Ce3+ (LGBO:Ce) is synthesized by solid-state reaction at 1200 °C. Powder X-ray diffraction patterns and Raman spectra at ambient pressure show that all the samples are pure calcite phase. In situ high-pressure synchrotron radiation XRD patterns illustrate that calcite phase LGBO:Ce exhibits more excellent phase stability than that of LBO:Ce under high pressure due to the superior compressibility of the [GaO6] octahedral unit. The optical band gap of LGBO decreases from 5.58 to 4.64 eV after introducing 10% Ga, which leads to the decreased nonradiative transition and about double luminescence intensity as expected. More interestingly, the charge transition from O2- to Ce4+ is observed at about 290 nm in the absorption spectra. The X-ray photoelectron spectroscopy spectra indicate the ratio of Ce4+/Ce3+ increases with increasing concentration of Ga3+, which can be attributed to the variation of energy separation between the 4f ground state of Ce3+ and the Fermi energy level position. In contrast to the enhancement of PL intensity, the integrated X-ray excited luminescence intensity decreases after Ga3+ incorporation attributing to the result of both decreased effective atomic number and ionization energy between 5d1 level and conduction band. The thermal luminescence spectra show that after the incorporation of Ga3+ the oxygen vacancy and intrinsic defects in LBO remain unchanged but that the concentration of oxygen vacancy significantly reduces. The mechanism of Ga3+ incorporation on phase stability and luminescence properties of LBO:Ce has been proposed and discussed systematically.

Highly efficient luminescence in bulk transparent Sr2GdF7:Tb3+ glass ceramic for potential X-ray detection

The urgent demand for radiation detection in diverse applications boosts extensive investigations on scintillators. However, the current scintillating materials are mostly limited to mono-crystals with high cost, restricted volume and time-consuming fabrication techniques. Here, we report an efficient and transparent Tb3+-doped Sr2GdF7 glass ceramic (GC) prepared via simple melt-quenching method, and its optical response to X-ray. By incorporating Tb3+ into crystallized Sr2GdF7 inside a typical aluminosilicate glasses, highly enhanced green emission was observed under UV and X-ray excitation. After thermal treatment, the internal and external photo-luminescence quantum yields can be as high as 59.1 and 26.4%, respectively, with the high transparency (65%@550 nm) preserved. More interestingly, this composite material, combining the advantages of oxide glasses and fluoride crystals, presents strong X-ray excited luminescence (XEL). Its XEL intensity is 194% of that of commercial BGO scintillator. Evidenced by detailed optical and structural properties, it can be concluded that rare earth ions activated bulk oxyfluoride glass ceramics with unique merits, such as low-cost, high efficiency and intense radio-luminescence, could be alternative scintillating materials for high energy ray detection.