Berlin 2018 – scientific programme
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MM: Fachverband Metall- und Materialphysik
MM 20: Topical session (Symposium MM): Hydrogen in Materials
MM 20.6: Talk
Tuesday, March 13, 2018, 12:15–12:30, H 0107
Depth-resolved hydrogen content measurement using Laser-induced Ablation-Quadrupole Mass Spectrometry (LIA-QMS) — •Jannis Oelmann, Sebastijan Brezinsek, Cong Li, and Christian Linsmeier — Institut für Energie und Klimaforschung - Plasmaphysik, Forschungszentrum Jülich GmbH, 52425 Jülich, Deutschland
Monitoring the quantitative sample’s material composition is important for both- industrial process control as well as for post mortem analysis in research and industrial development. Still there is a lack of diagnostics, providing depth resolved information without using standard samples, although those cannot be used in several cases. We present a new method for measuring volatile sample species, using residual gas analysis with quadrupole mass spectrometry after picosecond laser-induced ablation.
A layer-wise sample analysis in the order of O(100 nm) is achieved by using the third harmonic (λ = 355 nm) of a Nd:YVO4 laser with a pulse duration of τ = 35 ps and pulse energies up to E = 50 mJ for material ablation. To show the capability of the method, results for well characterized multilayer thin film solar cells (µc-Si:H and a-Si:D on ZnO:Al) are shown and compared to standard techniques like Thermal Desorption Spectroscopy (TDS). Additionally, hydrogen content measurements of graphite samples from the fusion test reactor Wendelstein 7-X (W7-X) are shown to study the impact of heat flux on the graphite limiter tiles on hydrogen retention, which is essential for an in-depth understanding of the plasma wall interaction processes.