Mainz 2022 – scientific programme
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P: Fachverband Plasmaphysik
P 12: Magnetic Confinement / Plasma Wall Interaction I
P 12.4: Talk
Wednesday, March 30, 2022, 14:45–15:00, P-H12
Double-pulse laser ablation molecular isotopic spectroscopy with picosecond laser pulses: Swan band analyses for 13C-12C distinction in graphite — •Erik Wüst, Jannis Oelmann, and Sebastijan Brezinsek — Forschungszentrum Jülich GmbH, Institut für Energie- und Klimaforschung - Plasmaphysik, 52425 Jülich, Germany
Laser-based methods for spatially and depth resolved measurements of material composition are well-established. Laser ablation molecular isotopic spectroscopy or spectrometry (LAMIS) is a technique for the determination of isotope concentrations in material mixtures. A laser-induced plasma on the material’s surface is used to derive the material isotope composition by optical emission spectroscopy (OES). In double-pulse LAMIS (DP-LAMIS) a second laser pulse is focussed into the laser-induced plasma to enhance the plasma’s emission and thus improve the limit of detection for isotopes with smaller concentrations. Laser pulses from a Nd:YAG-laser with 35 ps pulse duration were used to induce the plasma and a second laser pulse from the same laser was used to enhance the plasma’s emission. Both laser pulses arrive at the sample with a relative delay of 50 ns. A Littrow spectrometer (focal length: f=750 mm, spectral resolution at 473 nm: A=6000, étendue: E=62 µ m2/sr) was used to analyse the band structure. The analysed materials were graphite either with only natural amounts of 13C or coated with a 13C rich layer. The isotopic composition was determined with the aid of the C2 molecule’s Swan band with Δv=1 at 473.7 nm.