# Publication Citation: X-Ray Induced Fluorescence Measurement of Segregation in a DyI3 Metal-Halide Lamp

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Author(s): T Nimalisuriya; John J. Curry; Craig J. Sansonetti; E J. Ridderhof; S Shastri; A J. Flikweert; W W. Stoffels; M Haverlag; J J. van der Mullen; X-Ray Induced Fluorescence Measurement of Segregation in a DyI3 Metal-Halide Lamp April 19, 2007 X-ray induced fluorescence measurements, using high energy synchrotron radiation generated on the Sector 1 Insertion Device beamline at the Advanced Photon Source, were performed on a metal-halide lamp containing Hg and DyI$_{3}$. Density distributions of Dy show significant axial and radial segregation. Density distributions of I show little axial and radial segregation, a surplus of I is formed in the discharge as Dy forms Dy silicates at the wall of the lamp burner. Axial segregation is quantified using the Fischer axial segregation parameter $\lambda$. For Dy $\lambda = 0.215 \pm 0.002$ mm$^{-1}$, this is in agreement with $\lambda$ found with a laser absorptionmethod \cite{Flikweert05}. The $\lambda$ value for Iodine was found to be four times smaller. From the Hg density distribution a temperature profile was constructed, using a wall temperature measurement for calibration. Journal of Physics D-Applied Physics 40 pp. 2831 - 2838 dysprosium,lighting,plasma,spectroscopy,x-ray Click here to retrieve PDF version of paper (338KB)