Conceptual Design For A Beamline For A Hard x-ray Nanoprobe with 30 nm Spatial Resolution

Coherent Bragg nanodiffraction at the hard X-ray Nanoprobe beamline

Bragg coherent diffraction with nanofocused hard X-ray beams provides unique opportunities for quantitative in situ studies of crystalline structure in nanoscale regions of complex materials and devices by a variety of diffraction-based techniques. In the case of coherent diffraction imaging, a major experimental challenge in using nanoscale coherent beams is maintaining a constant scattering volume such that coherent fringe visibility is maximized and maintained over the course of an exposure lasting several seconds. Here, we present coherent Bragg diffraction patterns measured from different nanostructured thin films at the Sector 26 Nanoprobe beamline at the Advanced Photon Source and demonstrate that with nanoscale positional control, coherent diffraction patterns can be measured with source-limited fringe visibilities more than 50% suitable for imaging by coherent Bragg ptychography techniques.

Oxidation of PtNi nanoparticles studied by a scanning X-ray fluorescence microscope with multi-layer Laue lenses

We report a study of the oxidation process of individual PtNi nanoparticles (NPs) conducted with a novel scanning multi-layer Laue lens X-ray microscope. The elemental maps reveal that alloyed PtNi NPs were transformed into Pt/NiO core-shell NPs by thermal oxidation. The observations furthermore indicate that a coalescence of Pt/NiO core-shell NPs occurred during oxidation.

Modeling of kinematic diffraction from a thin silicon film illuminated by a coherent, focused X-ray nanobeam

A rigorous model of a diffraction experiment utilizing a coherent, monochromatic, X-ray beam, focused by a Fresnel zone plate onto a thin, perfect, single-crystal layer is presented. In this model, first the coherent wave emanating from an ideal zone plate equipped with a direct-beam stop and order-sorting aperture is computed. Then, diffraction of the focused wavefront by a thin silicon film positioned at the primary focal spot is calculated. This diffracted wavefront is propagated to the detector position, and the intensity distribution at the detector plane is extracted. The predictions of this model agree quite well with experimental data measured at the Center for Nanoscale Materials nanoprobe instrument at Sector 26 of the Advanced Photon Source.