Impact of plasma dynamics on equivalence ratio measurements by laser-induced breakdown spectroscopy

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Abstract

The systematic errors introduced by triggering a USB spectrometer for laser-induced breakdown spectroscopy equivalence ratio measurements are studied. We analyze the temporal behavior of laser-induced plasma in a nonreacting methane/air mixture and investigate the influence of the dynamics on equivalence ratio measurements with gated and ungated detection. For use of gated detectors, optimal delay times were found to be between 500 and 2000 ns to allow effective suppression of interferences while maintaining sufficient signal-to-noise levels. Good precision was found for short and long exposure time intervals when an intensified CCD camera was employed. On the other hand, the jitter of an externally triggered ungated spectrometer leads to high uncertainties. Running the ungated spectrometer freely, the single-shot uncertainty can be reduced by more than 1 order of magnitude. (C) 2015 Optical Society of America

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  • Atom and Molecular Physics and Optics
Original languageEnglish
Pages (from-to)4221-4226
JournalApplied Optics
Volume54
Issue number13
Publication statusPublished - 2015
Publication categoryResearch
Peer-reviewedYes