Search results for "cerium"
showing 10 items of 140 documents
Time-Resolved Luminescence Characteristics of Cerium Doped YAG Nanocrystals
2007
Time-resolved luminescence characteristics have been studied for cerium doped YAG nanopowders (NP) and nanostructured ceramics (NC). The results obtained have been compared to the luminescence characteristics for the well studied YAG:Ce3+ single crystal (SC). It was detected that the luminescence decay kinetics of Ce3+ related emission in nanocrystals can be closely approximated by two exponents, whereas a single exponential decay was observed in the single crystal. It was also found that the luminescence decay time and light yield of Ce3+ emission are strongly dependent on the cerium concentration and an unusual concentration quenching of Ce3+ emission was observed in YAG nanocrystals. The…
Local environment of Barium, Cerium and Yttrium in BaCe1−xYxO3−δ ceramic protonic conductors
2007
Abstract Y-doped barium cerate protonic conductors with composition BaCe 1 − x Y x O 3 − δ ( x = 0.02, 0.1, 0.2, 0.3) have been synthesized by sol–gel route, giving by X-ray diffraction tests a homogeneous crystalline phase. A commercial sample BaCe 0.8 Y 0.2 O 3 − δ produced by combustion spray pyrolysis was also provided for comparison aim. The local structure around the cations was studied by X-ray absorption spectroscopy at the K-edges of Ba, Ce and Y. It is demonstrated that the insertion of yttrium in the site of cerium produces a remarkable local distortion of the dopant first-shell octahedral environment that affects also the next coordination shells by a static disorder increas…
Luminescence and vacuum ultraviolet excitation spectroscopy of cerium doped Gd3Ga3Al2O12 single crystalline scintillators under synchrotron radiation…
2020
Authors gratefully acknowledge the financial support from the Latvian Science Council grant LZP-2018/2-0358 . The research leading to this result has been supported by the project CALIPSO plus under the Grant Agreement 730872 from the EU Framework Programme for Research and Innovation HORIZON2020 . The work of A.P.K. was supported by the Ministry of Science and Higher Education of the Russian Federation , state contracts No. 11.6181.2017/ITR .
Influence of boron on the essential properties for new generation scintillators
2021
Abstract Cerium doped yttrium aluminum (YAG:Ce) and lutetium aluminum garnets (LuAG:Ce) are some of the most popular materials used as scintillators. While the scintillators themselves are materials that absorb and convert high-energy radiation into light. The decay time in YAG:Ce and LuAG:Ce is about 60 ns, therefore the essential task for their improvement would be to shorten it as much as possible. For this reason, in this work, the aforementioned garnets were doped with different amounts of boron. B3+ ion has a suitable neutron capture cross section and can therefore absorb gamma radiation. Because of the extremely strong absorption of thermal neutrons and the weak interaction with MeV …
Cerium-Doped Copper(II) Oxide Hollow Nanostructures as Efficient and Tunable Sensors for Volatile Organic Compounds
2018
Tuning sensing capabilities of simple to complex oxides for achieving enhanced sensitivity and selectivity toward the detection of toxic volatile organic compounds (VOCs) is extremely important and remains a challenge. In the present work, we report the synthesis of pristine and Ce-doped CuO hollow nanostructures, which have much higher VOC sensing and response characteristics than their solid analogues. Undoped CuO hollow nanostructures exhibit high response for sensing of acetone as compared to commercial CuO nanoparticles. As a result of doping with cerium, the material starts showing selectivity. CuO hollow structures doped with 5 at. % of Ce return highest response toward methanol sens…
Induced attenuation in Ce3+ and Nd3+ doped fibers irradiated with electron beams under low dose regime
2005
Abstract In this paper, we study the feasibility of rare earth doped optical fibers as dosimeters based on the attenuation induced by electron beams under standard conditions in radiotherapy. Neodymium and cerium doped fibers have been irradiated with 10 MeV electrons, the radiation-induced loss and the dynamic response have been measured in the wavelength range 1200–1600 nm. The sensitivity of the fibers is of the order of 0.1 (dB/m)/Gy and has a linear dependence on the dose.
Time-resolved cathodoluminescence spectroscopy of YAG and YAG:Ce3+ phosphors
2019
Abstract The phosphor powders, both undoped and Ce3+ doped with different concentration Y3Al5O12 (YAG), were synthesized by the solid-state reaction method with addition of BaF2 flux. SEM and XRD characterization of the samples were performed. The spectral and luminescence decay kinetic characteristics under the electron beam irradiation with nano- and picoseconds pulse duration and the electron energies of 250 keV and 55 keV were studied, respectively. Two bands in the cathodoluminescence spectrum of YAG:Ce3+ phosphors were observed with maxima at 2.19 ± 0.05 and 2.4 eV. The intensity ratio of these two bands depends on the electron energy and the duration of the excitation pulse. Instead,…
Studies of radiation defects in cerium, europium and terbium activated oxyfluoride glasses and glass ceramics
2015
Abstract Terbium, cerium and europium activated oxyfluoride glasses and glass ceramics have been studied by thermally stimulated luminescence (TSL) and optical absorption techniques after the X-ray irradiation. A creation of colour centres in oxyfluoride glass matrix and TSL peaks depending on the activator type were observed. LaF 3 and rare earth activators were analysed by SEM–EDS.
Effect of Ce3+ concentration on persistent luminescence of YAGG:Ce3+,Cr3+,Nd3+ nanophosphors obtained by the co-precipitation method
2020
Abstract Synthesis of Y3Al2Ga3O12 garnet (YAGG) nanophosphors co-doped with Ce3+, Cr3+, and Nd3+ ions by co-precipitation is reported. The effect of Ce3+ concentration on the structure of garnet and on optical properties including persistent luminescence was investigated. The X-ray diffraction measurements showed that single garnet phase was obtained. The contraction of the crystallites size was observed with increasing the cerium concentration. The combined emission of three used co-dopants together allows to extend persistent luminescence spectral range. The photoluminescence, excitation and persistent luminescence spectra were collected and the optimal Ce3+ concentration for the highest …
Thermomechanical properties and thermal degradation kinetics of poly(methyl methacrylate) (PMMA) and polycarbonate (PC) filled with cerium-doped yttr…
2016
This paper reports on the thermomechanical properties and thermal degradation kinetics of poly(methyl methacrylate) (PMMA) and polycarbonate (PC) composites filled with cerium-doped yttrium aluminium garnet (Ce:YAG) at different contents ranging between 0.1 and 5 wt%, and prepared by melt compounding. The interaction between PMMA and the filler was much stronger than that between PC and the filler, and this resulted in a significant improvement in the dynamic mechanical properties of the PMMA composites. The presence of filler did not significantly increase the thermal stability of the PC, while an observable increase in the thermal stability was only observed at higher filler loadings for …