Skip to main content
U.S. flag

An official website of the United States government

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Secure .gov websites use HTTPS
A lock ( ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.

Direct Observation of De-Mixing in a Ceramic Metal-Halide Arc Lamp



John J. Curry, H G. Adler, S Shastri, W -. Lee


De-mixing of additives in a vertically-operated DyI3-CsI-Hg ceramic metal halide arc lamp has been observed by examining the ratios of absolute elemental densities as a function of position. As the elemental densities have been obtained directly by x-ray induced fluorescence(Curry, Adler, Shastri, and Lee, to be published in J. Appl. Phys.), this approach reveals the extent of mixing (or de-mixing) with no intervening assumptions about equilibrium, the local temperature, or the accuracy of partition functions. The metal additives show complex de-mixing. Depletion of Dy and Cs from the core is attributed to ambipolar cataphoresis. These same additives also exhibit a relative enhancement in a layer just outside the core before decreasing again toward the wall. Thermochemical data are used to derive radial distributions of molecular species given the experimentally obtained elemental densities and the gas temperature assuming a lamp operating pressure of ten atmospheres.
Journal of Physics D-Applied Physics


arc, lighting, plasma, plasma chemistry, plasma diagnostic, x-ray fluorescence spectroscopy


Curry, J. , Adler, H. , Shastri, S. and Lee, W. (2003), Direct Observation of De-Mixing in a Ceramic Metal-Halide Arc Lamp, Journal of Physics D-Applied Physics (Accessed June 18, 2024)


If you have any questions about this publication or are having problems accessing it, please contact

Created June 18, 2003, Updated February 17, 2017