X-ray induced fluorescence measurement of segregation in a DyI<sub>3</sub>–Hg metal-halide lamp
Nimalasuriya, T; Curry, J J; Sansonetti, C J; Ridderhof, E J; Shastri, S D; Flikweert, A J; Stoffels, W W; Haverlag, M; van der Mullen, J J A M; Nimalasuriya, T; Department of Applied Physics, Eindhoven University of Technology, PO Box 513, 5600 MB Eindhoven, The Netherlands; Curry, J J; National Institute of Standards and Technology, 100 Bureau Drive, Stop 8422, Gaithersburg, MD 20899-8422, USA; Sansonetti, C J; National Institute of Standards and Technology, 100 Bureau Drive, Stop 8422, Gaithersburg, MD 20899-8422, USA; Ridderhof, E J; Department of Applied Physics, Eindhoven University of Technology, PO Box 513, 5600 MB Eindhoven, The Netherlands; Shastri, S D; Advanced Photon Source, Argonne National Laboratory, Argonne, IL 60439, USA; Flikweert, A J; Department of Applied Physics, Eindhoven University of Technology, PO Box 513, 5600 MB Eindhoven, The Netherlands; Stoffels, W W; Department of Applied Physics, Eindhoven University of Technology, PO Box 513, 5600 MB Eindhoven, The Netherlands; Haverlag, M; Department of Applied Physics, Eindhoven University of Technology, PO Box 513, 5600 MB Eindhoven, The Netherlands; van der Mullen, J J A M; Department of Applied Physics, Eindhoven University of Technology, PO Box 513, 5600 MB Eindhoven, The Netherlands
Журнал:
Journal of Physics D: Applied Physics
Дата:
2007-05-07
Аннотация:
Segregation of elemental Dy in a DyI<sub>3</sub>–Hg metal-halide high-intensity discharge lamp has been observed with x-ray induced fluorescence. Significant radial and axial Dy segregation are seen, with the axial segregation characterized by a Fischer parameter value of λ = 0.215 ± 0.002 mm<sup>−1</sup>. This is within 7% of the value (λ = 0.20 ± 0.01 mm<sup>−1</sup>) obtained by Flikweert et al (2005 J. Appl. Phys. 98 073301) based on laser absorption by neutral Dy atoms. Elemental I is seen to exhibit considerably less axial and radial segregation. Some aspects of the observed radial segregation are compatible with a simplified fluid picture describing two main transition regions in the radial coordinate. The first transition occurs in the region where DyI<sub>3</sub> molecules are in equilibrium with neutral Dy atoms. The second transition occurs where neutral Dy atoms are in equilibrium with ionized Dy. These measurements are part of a larger study on segregation in metal-halide lamps under a variety of conditions.
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