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Ce3+-doped lithium alumino-silicate (Li-Al-Si) scintillating glass was prepared using a melting method and crystallized via heat treatment. X-ray diffraction and transmission electron microscopy confirmed the presence of nanocrystals in the materials. Radioluminescence spectra, obtained by X-ray excitation, and luminescence spectra, obtained by 338 nm excitation, showed that the luminescence intensity increased after crystallization. The glass was combined with pure silica as the inner cladding to fabricate a hybrid fiber core using a melt-in-tube technique. The composition of the fiber core was examined using an electron probe microanalyzer. The glass fiber produced strong blue luminescence under UV excitation. After a micro-crystallizing heat treatment of the hybrid fiber at 850 °C in a reducing atmosphere, a Ce3+-doped lithium alumino-silicate glass–ceramic scintillating hybrid fiber was obtained. The nanocrystal structure of the fiber core was examined using micro-Raman spectroscopy. Excitation and luminescence spectra of the hybrid fiber before and after micro-crystallization were measured using microspectrofluorimetry. The results demonstrated that the fiber remained luminous after micro-crystallization. Hence, this work provides a new way to prepare scintillating glass–ceramic hybrid fibers for neutron detection. [ABSTRACT FROM AUTHOR]

Trace/minor element variation in pyrite is a feature that has proved invaluable for reconstructing a wide range of geological processes. Routine reflectance observations commonly fail to constrain this variation due to the typically subtle and barely perceptible change in reflectance brought about by deviation from ideal stoichiometry. Such differences may be difficult or impossible to observe in conventional polished sections using standard optical microscopes, at least without oil immersion. Chemical etching and staining, although widely used, are destructive, hazardous, or both, and the etching process is not completely reproducible. Here we use the γ correction method to enhance optical digital signal differences obtained in reflected light to constrain compositional heterogeneity in pyrite from a representative hydrothermal ore deposit in eastern China. The γ-enhanced images show significant reflectance variation caused by compositional heterogeneity, confirmed by quantitative electron microprobe analysis and qualitative imaging. Higher reflectance domains in γ-enhanced images correspond to increases in the effective number of free electrons, whereas darker domains are attributed to the decrease of these free electrons by trace/minor element substitution in pyrite (e.g., As). Gamma correction provides a rapid, effective, non-destructive method to constrain compositional heterogeneity of pyrite through enhancement of reflectance variation. Used alone, this method is unable to determine the chemical composition due to simultaneous substitutions, causing a disparate increase or decrease of reflectance, in most ore minerals. Nevertheless, γ correction may be sufficient to predict the substitution of trace/minor elements under the optical microscope prior to scanning electron microscope imaging and quantitative investigation of mineral composition and may help constrain links between textures and compositions of pyrite in evolving ore systems, which could also be applied to other ore minerals with negligible bireflectance. [ABSTRACT FROM AUTHOR]

2-inch size Ce:GAGG single crystals with various ratio of Ga to Al (Ga/Al) were grown by the Cz method and the concentration of the grown crystals was measured by using EPMA. Scintillation properties such as light output, decay time and time resolution were evaluated and the dependence on the Ga/Al was characterized. As a result, the light output was reduced by increasing of the Ga/Al. On the other hand, the timing properties became worse by decreasing of the Ga/Al. [ABSTRACT FROM AUTHOR]

The Ce-doped (LuyGd1–x)3(Gay,Al1–y)5O12single crystals were grown by the micropulling down method. Their structure and chemical composition were checked by X-ray diffraction (XRD) and electron probe microanalysis (EPMA) techniques. Optical, luminescent, and scintillation characteristics were measured by the methods of time-resolved luminescence spectroscopy, including the light yield and scintillation decay. Balanced Gd and Ga admixture into the Lu3Al5O12structure provided an excellent scintillator where the effect of shallow traps was suppressed, the spectrally corrected light yield value exceeded 40 000 photons/MeV, and scintillation decay was dominated by a 53 ns decay time value which is close to that of Ce3ꘚⶢ宦詷걱 decay. This study provides an excellent example of a combinatorial approach where targeted single-crystal compositions are obtained by a flexible, time saving, and cost-effective crystal growth technique. [ABSTRACT FROM AUTHOR]

The paper is devoted to the study of the excitation capture efficiency of rare-earth ions emission levels upon electron-beam irradiation in well-known scintillation materials. The method is based on cathodoluminescent rise rate dependence on the electron beam current. Electron probe microanalysis was used to determine the composition of the samples. The technique allowed us to quantify the excitation capture efficiency for three emitting levels of rare-earth ions in Y 2 SiO 5 :Ce3+,Tb3+, to determine the energy transfer between high energy levels in Tm3+ and Cr3+ ions in Y 3 Al 5 O 12 matrix, and to study the effect of crystalline matrix perfection on the excitation capture efficiency of Eu3+ energy levels in Y 3 Al 5 O 12 :Eu3+. It was shown that the excitation capture efficiency coefficient may differ in orders of magnitude for various energy levels of one ion. • Method for estimation of emitting levels excitation capture efficiency is described. • Method is based on cathodoluminescent rise rate dependence on electron beam current. • Excitation capture efficiency was estimated for well-known scintillators. • Method may be applied for development of novel scintillating materials. [ABSTRACT FROM AUTHOR]