Berlin 2018 – scientific programme

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MM: Fachverband Metall- und Materialphysik

MM 29: Nanomaterials

MM 29.2: Talk

Wednesday, March 14, 2018, 10:30–10:45, H 0106

3D X-ray Diffraction Microscopy (3DXRD) using high resolution X-ray nanodiffraction — •Hergen Stieglitz, Christina Krywka, and Martin Müller — Helmholtz-Zentrum Geesthacht, 21502 Geesthacht, Germany

The existing technology called 3DXRD, is a well-established technique to map the grain structure of polycrystalline systems (e.g. metals). This technology is based on reconstruction algorithms which trace the positions of multiple Bragg-Peaks as a function of the rotation angle during the rotation of the sample. Due to a given beamsize and the software-based limit only a few grains can be tracked, resulting in a minimum mappable grainsize.

The planned experiment shall utilize a nano-focused synchrotron beam (e.g. Nanofocus Endstation of P03, PETRA III) to examine very fine-grained systems. The small beamsize allows detecting grains below the size limit of standard 3DXRD. With respect to the small beamsize of about 100 nm cross section, the precise positioning of the sample becomes more important to secure a constant scanned volume (the so called gauge volume). Otherwise some grains may be outside the gauge volume in some scans therefore they cannot be traced and produce mistakes while reconstructing.

To meet this challenge a stable and wobble-free rotary stage is planned to ensure a constant gauge volume. We are planning to use an interferomenter-based feedback loop to compensate the runout of the sample with a XY-stage. A further step is the adjustment of the existing software for the needs of a nano-focused beam.