Browsing by Author "Townsend P."

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    Luminescence of levitated Zr-Ba-La-Al-Na fluoride glass
    (1997) Yang B.; Townsend P.; Can N.
    Radioluminescence, cathodoluminescence, and thermoluminescence of Zr-Ba-La-Al-Na (ZBLAN) fluoride glass reveal different aspects of the intrinsic imperfections and impurities which control the emission. Except for weak low-temperature thermoluminescence signals which could be attributed to rare-earth impurities, the majority of the emission bands were common to all samples. These are considered to arise from intrinsic electron-hole recombination processes, either during relaxed exciton emission or at intrinsic defect sites in the glass network. Deconvolution of the spectra indicates that six emission bands occur in all the samples. Production of crystallite inclusions or intrinsic defects enhance the signal intensities. The luminescence is shown to be a useful probe of the quality of the ZBLAN glass, both in the preform stage, and after fiber drawing, even when working with the very high grade material produced by gas film levitation growth. © 1997 The American Physical Society.
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    Orientation dependence of the ion beam and cathodoluminescence of albite
    (2007) Garcia-Guinea J.; Finch A.; Can N.; Hole D.; Townsend P.
    Ion beam induced luminescence and cathodoluminescence of albite produce unexpected differences between (010) and (001) aligned samples. The emission spectra are modified by temperature and different components change in their relative intensity as a result of excitation by different ion beams of H +, H2 + and He+. A consideration of processes which can induce the orientation dependence and the role of excitation density that influences the component features are both discussed. © 2007 WILEY-VCH Verlag GmbH & Co. KGaA.