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The focusing and coherence properties of the NanoMAX Kirkpatrick–Baez mirror system at the fourth‐generation MAX IV synchrotron in Lund have been characterized. The direct measurement of nano‐focused X‐ray beams is possible by scanning of an X‐ray waveguide, serving basically as an ultra‐thin slit. In quasi‐coherent operation, beam sizes of down to 56 nm (FWHM, horizontal direction) can be achieved. Comparing measured Airy‐like fringe patterns with simulations, the degree of coherence |μ| has been quantified as a function of the secondary source aperture (SSA); the coherence is larger than 50% for SSA sizes below 11 µm at hard X‐ray energies of 14 keV. For an SSA size of 5 µm, the degree of coherence has been determined to be 87%. [ABSTRACT FROM AUTHOR]

The spatial strain distribution in and around a single axial InAs1- xP x hetero-segment in an InAs nanowire was analyzed using nano-focused X-ray diffraction. In connection with finite-element-method simulations a detailed quantitative picture of the nanowire's inhomogeneous strain state was achieved. This allows for a detailed understanding of how the variation of the nanowire's and hetero-segment's dimensions affect the strain in its core region and in the region close to the nanowire's side facets. Moreover, ensemble-averaging high-resolution diffraction experiments were used to determine statistical information on the distribution of wurtzite and zinc-blende crystal polytypes in the nanowires. [ABSTRACT FROM AUTHOR]

The upgraded ID01 beamline now offers a coherent X-ray probe, 56 nm × 141 nm in size (full width half maximum), combined with access to large swathes of reciprocal space with an area detector and sufficient working distance to host various sample environments. Coherent diffraction imaging at Bragg reflections offers picometre sensitivity to lattice distortions in crystals and access to the full strain tensor, in the case where three or more non-coplanar reflections are measured. Defects may have a strong effect on the physical properties of materials. As the majority of defects produce lattice distortions, hence these can be imaged. Here we describe the instrumentation at ID01 required to produce such foci and the protocols employed to ensure reliable data acquisition. The wavefront of the incident beam must be coherent in order to observe interference. Thus the coherent probe is recovered online via ptychography on a reference structure at the beginning of every experiment, and can be executed at any time to confirm beam quality and maintain experimental consistency. Due to the small source size in the vertical direction a diffraction limited spot is achieved, whereas in the horizontal the beam size is defined by the image of the source. With the upgrade of the ESRF this asymmetry is supposed to decrease substantially, and will be accompanied by an increase in coherent flux density by a factor of 30–100. [ABSTRACT FROM AUTHOR]