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

Johannes Kiefer (Corresponding Author), Bo Zhou, Zhongshan Li, Marcus Alden

Research output: Contribution to journalArticle

12 Citations (Scopus)


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
Original languageEnglish
Pages (from-to)4221-4226
Number of pages6
JournalApplied Optics
Issue number13
Publication statusPublished - 1 May 2015


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