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A long x-ray pathway based on an x-ray back-diffraction cavity for coherent x-ray beam experiments is presented. In the present work, such a setup was tested and used for propagation-based x-ray phase contrast imaging (PBI). This setup showed to be useful for PBI purposes, with the advantage of being compact (3 m long) when compared with long x-ray synchrotron beamlines with dimensions from tens to hundreds of meters.

Diffraction-enhanced images have been obtained using two silicon crystals in a non-dispersive set-up at the XRD2 beamline at the Brazilian Synchrotron Light Laboratory (LNLS). A first asymmetrically cut silicon crystal using the (333) reflection vertically expanded the monochromated beam from 1 mm to 20 mm allowing the imaging of the whole sample without movements. A symmetrically cut Si(333) second crystal was used as a Bragg analyzer. Images of biological samples including human tissue were recorded using a direct-conversion CCD detector resulting in enhancement of the contrast compared with absorption-contrast images.

The mechanical properties of InSe and GaSe single crystals have been studied by means of nanoindentation tests. Both bulk crystals are well ordered and present a predominant γ-type interlayer stacking sequence as determined by x-ray diffraction and transmission electron microscopy measurements. The course of plastic deformation induced in the crystals by application of a definite shear stress through the penetration of a Berkovich tip indicates that the deformation occurs predominantly by pop-in events along easy slip directions having a fairly elastic character between displacements. Hardness anisotropy along crystal axes is clearly seen and the measured elastic modulus presents a discrepancy smaller than 5% in comparison with theoretical calculations performed using previous experimental values of the elastic constants. © 2002 American Institute of Physics. [ABSTRACT FROM AUTHOR]

Magnetic and structural properties of Heusler PdMnSn with x = 0.05, 0.10, 0.17, 0.20 and 0.25, have been studied by magnetisation and X-ray diffraction measurements at room and low temperatures. The crystal structure at room temperature is L2 cubic phase for x = 0.17, 0.20, 0.25 and B2 cubic phase for x = 0.10. Martensite structure 10M, was observed at room temperature for x = 0.05. X-ray measurements at low temperatures revealed a structural transformation from B2 to 14 M for the x = 0.10 case. The lattice parameter of the L2 phase decreases linearly with the concentration, x. A ferromagnetic behaviour has been detected for L2 compounds, but the ferromagnetic exchange characteristic of each composition is of different strength. This gives rise to different Curie temperatures. [ABSTRACT FROM AUTHOR]

We characterized GaSb single crystals containing different dopants (Al, Cd, and Te), grown by the Czochralski method, using x-ray topography and high-angular-resolution x-ray diffraction. Lang topography revealed dislocations parallel and perpendicular to the crystal surface. Double-crystal GaSb 333 x-ray topography showed dislocations and vertical stripes that could be associated with circular growth bands. We compared our high-angular- resolution x-ray diffraction measurements (rocking curves) with findings predicted by the dynamical theory of x-ray diffraction. These measurements show that our GaSb single crystals have a relative variation in the lattice parameter (Δ d/ d) on the order of 10−5. This means that they can be used as electronic devices (e.g., detectors) and as x-ray monochromators. [ABSTRACT FROM AUTHOR]

Several recent papers have shown the implementation of analyzer based X-ray phase contrast imaging (ABI) with conventional X-ray sources. The high flux is always a requirement to make the technique useful for bio-medical applications. Here, we present and discuss three important parameters, which need to be taken into account, when searching for the high flux ABI: anisotropic magnification, double image, and source size spread due to intrinsic dispersive diffraction by asymmetrically cut crystals. These parameters, if not well optimized, may cause important features in the acquired images which can mislead the interpretation. A few ways to minimize these effects are implemented and discussed, including some experimental results. [ABSTRACT FROM AUTHOR]

Abstract The life expectance in canines is increasing due to the improvement in health care. However, some age diseases as mammary cancer are arising and represent about 50% of the cancers diagnosed in females. Nowadays, researches are focusing efforts to identify structural changes into canine mammary tissues due to cancer progression. In this sense, X-ray diffraction is a powerful tool for this purpose. Therefore, this study aims to characterize structurally the normal and cancerous canine mammary tissue by X-ray diffraction. A total of 83 canine mammary samples histopathologically classified as normal, benign and malignant, were used in this study. Using a commercial powder diffractometer, the scattering profiles of each sample were determined. From these scattering profiles, two broad peaks were identified at q = 13.9 nm−1 and q = 19.8 nm−1. The values of intensity of both peaks and the ratio of these intensities were obtained. Significant difference between all pairs of group of investigated tissues was observed. Finally, the strong similarity between normal and pathological human and canine tissue found in this study corroborates to comparative oncology between humans and canines. Highlights • X-ray diffraction is used to check the structural rearrangement in canine mammary tumor. • The scattering profiles distinguish between health and tumoral canine mammary tissue. • A strong similarity between human and canine mammary tissue was found. [ABSTRACT FROM AUTHOR]

Abstract: Incommensurate spin-density wave (SDW) in chromium presents Q-domain configurations that can be studied through X-ray diffraction (XRD) due to charge-density wave satellites at (001) and (111) crystal faces. In the present work, we investigated superficial domains reorientation in the bulk multi-Q state, after the crystal had been maintained in the bulk single-Q state artificially prepared by field cooling under 90kOe applied in (010)direction. Reciprocal lattice scans were performed along the three directions H, K and L to ensure proper CDW satellite measurements. Our results are in agreement with previous experiments where observed that the preferential orientation of CDW occurs naturally with Q perpendicular to the surface, parallel to (100). [Copyright &y& Elsevier]