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Microwave assisted laser-induced breakdown spectroscopy at ambient conditions

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Details

Original languageEnglish
Pages (from-to)29-36
Number of pages8
JournalSpectrochimica Acta Part B: Atomic Spectroscopy
Volume118
DOIs
Publication statusPublished - 1 Apr 2016
Publication typeA1 Journal article-refereed

Abstract

Signal enhancements in laser-induced breakdown spectroscopy (LIBS) using external microwave power are demonstrated in ambient air. Pulsed microwave at 2.45 GHz and of 1 millisecond duration was delivered via a simple near field applicator (NFA), with which an external electric field is generated and coupled into laser induced plasma. The external microwave power can significantly increase the signal lifetime from a few microseconds to hundreds of microseconds, resulting in a great enhancement on LIBS signals with the use of a long integration time. The dependence of signal enhancement on laser energy and microwave power is experimentally assessed. With the assistance of microwave source, a significant enhancement of ∼ 100 was achieved at relatively low laser energy that is only slightly above the ablation threshold. A limit of detection (LOD) of 8.1 ppm was estimated for copper detection in Cu/Al2O3 solid samples. This LOD corresponds to a 93-fold improvement compared with conventional single-pulse LIBS. Additionally, in the microwave assisted LIBS, the self-reversal effect was greatly reduced, which is beneficial in measuring elements of high concentration. Temporal measurements have been performed and the results revealed the evolution of the emission process in microwave-enhanced LIBS. The optimal position of the NFA related to the ablation point has also been investigated.

Keywords

  • Copper Detection, Laser-induced breakdown spectroscopy, Microwave signal enhancement

Publication forum classification

Field of science, Statistics Finland