Forskning ved Københavns Universitet - Københavns Universitet


Roughness effects on the hydrogen signal in laser-induced breakdown spectroscopy

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W. Rapin, B. Bousquet, J. Lasue, P. Y. Meslin, J. L. Lacour, C. Fabre, R. C. Wiens, Jens Frydenvang, E. Dehouck, S. Maurice, O. Gasnault, O. Forni, A. Cousin

On Mars, Laser-Induced Breakdown Spectroscopy (LIBS) as performed by the ChemCam instrument can be used to measure the hydrogen content of targets in situ, under a low pressure CO2 atmosphere. However, unexpected variations observed in the Martian dataset suggest an effect related to target roughness. Here, we present a series of laboratory experiments that reproduce the effect observed on Mars and explore possible causes. We show that the hydrogen peak intensity increases significantly with increasing exposure of the target surface to the LIBS plasma, and that these variations are specific to hydrogen, as other emission lines in the spectra are not affected. The increase of the signal could be related to an addition of hydrogen to the plasma due to interaction with the surrounding target surface, yet the exact physical process to explain such effect remains to be identified. More generally, this effect should be taken into account for the quantification of hydrogen in any LIBS applications where the roughness of the target is significant.

TidsskriftSpectrochimica Acta Part B: Atomic Spectroscopy
Sider (fra-til)13-22
Antal sider10
StatusUdgivet - 1 nov. 2017

ID: 184072980