[en] Full text: X-rays are invaluable to obtain the three dimensional structure of materials in a non destructive manner. A virtually unlimited range of length scales can be covered as the X-ray energy can be increased to obtain sufficient transmission while enough contrast is preserved down to the nanoscale by exploiting phase sensitivity. Furthermore, the temporal resolution is constantly improved thanks to faster detector technology, exploration of the synchrotron time structure and new generation X-ray sources. Full field microscopy methods are of particular interest because of their speed, simplicity and stability. Complementary, scanning methods offer alternative contrast mechanisms such as X-ray fluorescence and diffraction. X-ray nano-tomography is a practical method to zoom non-destructively into the three-dimensional structure of matter and map the electron density with improved sensitivity, spatial and temporal [4] resolution. X-ray holography and near field ptychography exploit the divergent beam behind a (nanofocus) secondary source to record magnified in-line holograms and reach a spatial resolution of a few tens of nanometer. These methods are very complementary to X-ray fluorescence analysis acquired with the sample in the focus for label-free, highly efficient trace element quantification. This correlative nanoprobe approach is implemented on ESRF beamline ID16A. All measurements can be performed under cryogenic conditions to preserve biological samples close to their native hydrated state and reduce radiation damage. The cutting edge capabilities of the instrument enable unprecedented studies in metallo-biology, neuro sciences, bio-materials and energy related materials, thus opening new scientific frontiers. The new ESRF source provides a 30-fold increase in brilliance and coherent fraction of the X-ray beams. This ‘Extremely Brilliant Source’ is ideally suited for fast nanoprobe and coherent imaging applications. In this context, we will present the current achievements and challenges to fully exploit the new source. (author)

[en] The theoretical description and experimental implementation of a speckle-tracking-based instrument which permits the characterisation of X-ray pulse wavefronts. An instrument allowing the quantitative analysis of X-ray pulsed wavefronts is presented and its processing method explained. The system relies on the X-ray speckle tracking principle to accurately measure the phase gradient of the X-ray beam from which beam optical aberrations can be deduced. The key component of this instrument, a semi-transparent scintillator emitting visible light while transmitting X-rays, allows simultaneous recording of two speckle images at two different propagation distances from the X-ray source. The speckle tracking procedure for a reference-less metrology mode is described with a detailed account on the advanced processing schemes used. A method to characterize and compensate for the imaging detector distortion, whose principle is also based on speckle, is included. The presented instrument is expected to find interest at synchrotrons and at the new X-ray free-electron laser sources under development worldwide where successful exploitation of beams relies on the availability of an accurate wavefront metrology

[en] A KB focusing mirror width profile has been optimized to achieve nano-focusing for the nano-imaging end-station ID22NI at the ESRF. The complete mirror and flexure bender assembly has been modeled in 3D with finite element analysis using ANSYS. Bender stiffness, anticlastic effects and geometrical non-linear effects have been considered. Various points have been studied: anisotropy and crystal orientation, stress in the mirror and bender, actuator resolution and the mirror-bender adhesive bonding... Extremely high performance of the mirror is expected with residual slope error smaller than 0.6 μrad, peak-to-valley, compared to the bent slope of 3000 μrad.

[en] Hard X-ray fluorescence microscopy and magnified phase contrast imaging are combined to obtain quantitative maps of the projected zinc mass fraction in whole cell of PC12 cell lines. The experiments were performed on freeze dried cells at the nano-imaging station ID22NI of the European Synchrotron Radiation Facility (ESRF). X-ray fluorescence analysis gives the areal mass of most major, minor and trace elements while quantitative phase contrast imaging provides maps of the projected mass. The combined method was validated on calibration samples by comparison with other alternative techniques such as Atomic Force Microscopy (AFM) and Scanning Transmission Ion Microscopy (STIM). Up to now, absolute quantification at the sub-cellular level was impossible using X-ray fluorescence microscopy but can be reached for the first time with the use of the proposed approach

[en] Anisotropic elasticity of single-crystal silicon, applications to modelling of a bent X-ray mirror, and thermal deformation of a liquid-nitrogen-cooled monochromator crystal are presented. The crystal lattice of single-crystal silicon gives rise to anisotropic elasticity. The stiffness and compliance coefficient matrix depend on crystal orientation and, consequently, Young’s modulus, the shear modulus and Poisson’s ratio as well. Computer codes (in Matlab and Python) have been developed to calculate these anisotropic elasticity parameters for a silicon crystal in any orientation. These codes facilitate the evaluation of these anisotropy effects in silicon for applications such as microelectronics, microelectromechanical systems and X-ray optics. For mechanically bent X-ray optics, it is shown that the silicon crystal orientation is an important factor which may significantly influence the optics design and manufacturing phase. Choosing the appropriate crystal orientation can both lead to improved performance whilst lowering mechanical bending stresses. The thermal deformation of the crystal depends on Poisson’s ratio. For an isotropic constant Poisson’s ratio, ν, the thermal deformation (RMS slope) is proportional to (1 + ν). For a cubic anisotropic material, the thermal deformation of the X-ray optics can be approximately simulated by using the average of ν_1_2 and ν_1_3 as an effective isotropic Poisson’s ratio, where the direction 1 is normal to the optic surface, and the directions 2 and 3 are two normal orthogonal directions parallel to the optical surface. This average is independent of the direction in the optical surface (the crystal plane) for Si(100), Si(110) and Si(111). Using the effective isotropic Poisson’s ratio for these orientations leads to an error in thermal deformation smaller than 5.5%

[en] Samples of binary Al-Cu alloys quenched from the mushy state during permeability measurements [O. Nielsen, L. Arnberg, A. Mo, H. Thevik, Metall. Mater. Trans. A 30A (1999) 2455-2462] were mapped in 3D using microtomography at the European Synchrotron Radiation Facility. Using 3D image analysis, the tomograms were binarised in order to separate the Al dendrite skeleton from the quenched Al-Al₂Cu eutectic, i.e., the interdendritic liquid during the permeability measurement. Subsequently, the complete permeability tensor was calculated for each sample by solving Stokes equations in the 3D tomogram domain constituted by the interdendritic liquid. In general, there is a reasonable agreement between the trace of the calculated permeability tensors and the experimental reference data. Some deviations have been attributed to a tendency for preferential flow channels in one of the samples and to a too small calculation volume compared with the characteristic lengths of the microstructure in one of the samples

[en] It is demonstrated that scanning X-ray diffraction tomography of heterogeneous and polycrystalline samples can provide real-space semi-quantitative threedimensional structural information at a submicrometre spatial resolution. The capabilities of this technique are illustrated by the study of a slice of a spherical particle consisting of a UMo core (about 37 μm in diameter) surrounded by a UMoAl shell (5 μm thick). The technique allows precise characterization of the embedded UMo/UMoAl interface where the phases α-U (in the core), UAl₂ and U₆Mo₄Al₄₃ (in the shell) are found. Moreover, an unexpected phase (UC) is detected at a trace level. It is shown that the thickness of the UMoAl shell is locally anticorrelated with the amount of UC, suggesting that this phase plays a protective role in inhibiting thermally activated Al diffusion in UMo. (orig.)

[en] To fabricate and qualify nanodevices, characterization tools must be developed to provide a large panel of information over spatial scales spanning from the millimeter down to the nanometer. Synchrotron x-ray-based tomography techniques are getting increasing interest since they can provide fully three-dimensional (3D) images of morphology, elemental distribution, and crystallinity of a sample. Here we show that by combining suitable scanning schemes together with high brilliance x-ray nanobeams, such multispectral 3D volumes can be obtained during a single analysis in a very efficient and nondestructive way. We also show that, unlike other techniques, hard x-ray nanotomography allows reconstructing the elemental distribution over a wide range of atomic number and offers truly depth resolution capabilities. The sensitivity, 3D resolution, and complementarity of our approach make hard x-ray nanotomography an essential characterization tool for a large panel of scientific domains.

[en] Synchrotron-radiation computed laminography (SRCL) was developed as a nondestructive three-dimensional (3D) imaging technique for flat and laterally extended objects. Complementing the established method of computed tomography, SRCL is based on the inclination of the tomographic axis with respect to the incident x-ray beam by a defined angle. Its ability for 3D imaging of regions of interest in flat specimens was demonstrated in various fields of investigation, e.g. in nondestructive testing, material science and life sciences. We introduce the principles of the method and report on the latest developments of SRCL. The experimental set-ups at the ESRF beamlines ID19 and ID22NI are dedicated to 3D micro- and nano-scale imaging, respectively, utilising different contrast modes including absorption, phase contrast and fluorescence. Selected examples from materials science outline the potential of the method for an unparalleled nondestructive 3D characterisation of flat specimens.

[en] The availability of three-dimensional measuring techniques coupled to specific image processing methods opens new opportunities for the analysis of bone structure. In particular, synchrotron radiation microtomography may provide three-dimensional images with spatial resolution as high as one micrometer. Moreover, the use of a monoenergetic synchrotron beam, which avoids beam-hardening effects, allows quantitative measurements of the degree of mineralization in bone samples. Indeed, the reconstructed gray levels of tomographic images correspond directly to a map of the linear attenuation coefficient within the sample. Since the absorption depends on the amount of mineral content, we proposed a calibration method to evaluate the three-dimensional distribution of the degree of mineralization within the sample. First a theoretical linear relationship modeling the linear attenuation coefficient as a function of the hydroxyapatite concentrations was derived. Then, an experimental validation on phantoms confirmed both the accuracy of the image processing tools and the experimental setup used. Finally, the analysis of the degree of mineralization in four iliac crest bone biopsy samples was reported. Our method was compared to the reference microradiography technique, currently used for this quantification in two dimensions. The concentration values of the degree of mineralization were found with both techniques in the range 0.5-1.6 g of mineral per cubic centimeter of bone, both in cortical and in trabecular region. The mean difference between the two techniques was around 4.7%, and was slightly higher in trabecular region than in cortical bone