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A: Atomphysik
A 6: Spectroscopy
A 6.7: Talk
Tuesday, April 3, 2001, 17:15–17:30, H1028
Laser-Induced Plasma Spectroscopy for the Quantitative Characterisation of Carbon in Steel — •Mohamed Khater, Eugene Kennedy, John Costello, John-Paul Mosnier, and Paul van Kampen — School of Physical Sciences and National Centre for Plasma Science and Technology (NCPST),Dublin City University,Dublin 9,Ireland
We have recently shown [1] that spatially resolved spectroscopy, in the deep VUV region (40-160 nm), of laser induced plasmas provides a useful technique for quantifying the carbon content in steel target materials. The characterisation of low atomic number elements provides a particular challenge as many of the strong emission lines originate from ions and are at short wavelengths. We investigated three ionization stages of carbon, using a series of solid steel samples with carbon concentrations in the 0.001-1.32 % range. Calibration curves for six carbon ionic lines provided linear fits with coefficients of deviation (R2) better than 0.994. The best detection limit of 87 ppm was obtained with the 97.70 nm C2+ line.
Most recently we replaced the original MCP/PDA detector by a CCD array, and optimised parameters such as the focusing lens type, laser power density, background atmospheres and pressure, in order to decrease the limit of detection. This study concentrated on the 97.70 nm C2+ line. Our latest results provide a significant reduction in the detection limit to 2 ppm of carbon.
[1] M A Khater et al J. Phys. D: Appl. Phys. 33, 2252-2262 (2000)