Berlin 2015 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 70: Structural Dynamics in Nanoscale Materials Probed by Ultrashort Electron Pulses
O 70.14: Poster
Mittwoch, 18. März 2015, 18:15–21:00, Poster A
Observation of heat transport by time-resolved x-ray diffraction using a conventional microfocus x-rax tube — •Mathias Sander1, Peter Gaal2, and Matias Bargheer1 — 1Institut für Physik und Astronomie, Universität Potsdam, Karl-Liebknecht-Str. 24-25,14476 Potsdam,Germany — 2Institut für Nanostrukturen und Festkörperphysik, Universität Hamburg, Jungiusstr. 11 20355 Hamburg, Germany
We demonstrate a table top setup for real-time observation of heat transport in crystalline layered structures via time-resolved x-ray diffraction on timescales from nanoseconds to milliseconds. The sample is excited either by an electronically heated microchip or by short laser pulses depending on the relevant timescale. The x-rays are generated by a conventional microfocus x-ray tube, focused by a polycapillary x-ray optic and monochromatized by a single reflection, e.g. from a Si or HAPG crystal. X-rays diffracted by the sample are detected in a fast x-ray phosphor and a photomultiplier and fed into a time-correlated single-photon counting module, which records histograms of events along the entire pump-probe delay. The resulting data shows time-dependent angular shifts of Bragg reflections which are interpreted as thermal diffusion dynamics on nano- and micrometer length scales.