Berlin 2018 – scientific programme

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MM: Fachverband Metall- und Materialphysik

MM 20: Topical session (Symposium MM): Hydrogen in Materials

MM 20.7: Talk

Tuesday, March 13, 2018, 12:30–12:45, H 0107

Sensitive 3D Microscopy of H and D in Metals using MeV Protons. — •Patrick Reichart and Günther Dollinger — LRT2, Universität der Bundeswehr München, Neubiberg, Germany

At the Munich microprobe SNAKE (Superconduction Nanoscope für Applied nuclear (Kern–) physics Experiments) a coincidence detection system has been installed to analyze proton-proton scattering events with up to 25 MeV incident protons. This allows to quantitatively analyze atomic H distributions in three dimensions with micrometer resolution. Due to transmission geometry the sample or foil thickness is limited to maximum 50 µ m e.g. for W or 150 µ m for Si.

The technique is the only nuclear microscopy method with low enough irradiation damage, i.e. not altering the H distribution before sufficient signal is detected. Sub-ppm sensitivity has been achieved for light materials like diamond, worse sensitivity of few ppm is demonstrated in heavy metals like Fe or W. We present a selection of previous studies of H in materials e.g. H in nominally anhydrous minerals of the earth mantle, H adsorption in thin metal films, H retention in irradiated tungsten that is of large interest for potential diverter material in future fusion reactors.

We also demonstrate that sensitive D detection is possible by using a deuteron beam and detect deuteron-deuteron coincidences. This gives the possibility to study adsorption, retention as well as diffusion processes of H in materials by isotope marking.