Compound refractive lenses printed in Al and Be are becoming the key X-ray focusing and imaging components of beamline optical layouts at the 3^rd generation synchrotron radiation sources. Recently proposed planar optical elements based on Si, diamond etc. may substantially broaden the spectrum of the refractive optics applicability. Planar optics has focal distances ranging from millimeters to tens of meters offering nano- and micro-focusing lenses, as well as beam condensers and collimators. Here we promote deep X-ray lithography and LIGA-type techniques to create high aspect-ratio lens structures for different optical geometries. Planar X-ray refractive lenses were manufactured in 1 mm thick SU-8 negative resist layer by means of deep synchrotron radiation lithography. The focusing properties of lenses were studied at ID18F and BM5 beamlines at the ESRF using monochromatic radiation in the energy range of 10 - 25 keV. By optimizing lens layout, mask making and resist processing, lenses of good quality were fabricated. The resolution of about 270 nm (FWHM) with gain in the order of 300 was measured at 14 keV. In-line holography of B-fiber was realized in imaging and projection mode with a magnification of 3 and 20, respectively. Submicron features of the fiber were clearly resolved. A radiation stability test proved that the fabricated lenses don't change focusing characteristics after dose of absorbed X-ray radiation of about 2 MJ/cm³. The unique radiation stability along with the high effficiency of SU8 lenses opens wide range of their synchrotron radiation applications such as microfocusing elements, condensers and collimators.

An algorithm for post-processing of the grayscale 3D computed tomography (CT) images of porous structures with the automatic selection of filtering parameters is proposed. The determination of parameters is carried out on a representative part of the image under analysis. A criterion for the search for optimal filtering parameters based on the count of "levitating stone" voxels is described. The stages of CT image filtering and its binarization are performed sequentially. Bilateral and anisotropic diffuse filtering is implemented; the Otsu method for unbalanced classes is chosen for binarization. Verification of the proposed algorithm was carried out on model data. To create model porous structures, we used our image generator, which implements the function of anisotropic porous structures generation. Results of the post-processing of real CT images containing noise and reconstruction artifacts by the proposed method are discussed.

In this paper, a new method for the mathematical tomographic reconstruction of time-varying objects (4D tomography) is presented. The method is applicable under the conditions that the amount of substance at each spatial point does not decrease, and only one projection image is available per time point during the process of the object changing. The temporal resolution of the proposed method is obtained by using an iterative approach to reconstruction. Prior knowledge about object morphology is exploited to improve the convergence of the algorithm by reducing the number of processed spatial points. Verification of the algorithm operation was carried out using model examples. The presented method was experimentally tested on the tomographic reconstruction of the dynamics of the capillary rise of a liquid. Our experiments demonstrated that monitoring fast processes, when the speed of the process does not allow to measure more than one tomographic projection, is potentially possible.

To solve the problems of spectral tomography, an X-ray optical scheme was proposed, using a crystal analyzer in Laue geometry between the sample and the detector, which allowed for the selection of predetermined pairs of wavelengths from the incident polychromatic radiation to obtain projection images. On a laboratory X-ray microtomography setup, an experiment was carried out for the first time where a mixture of micro-granules of sodium chloride NaCl, silver behenate AgC₂₂H₄₃O₂, and lithium niobate LiNbO₃ was used as a test sample to identify their spatial arrangement. The elements were chosen based on the presence of absorption edges in two of the elements in the energy range of the polychromatic spectrum of the probing radiation. The method of projection distortion correction was used to preprocess the obtained projections. To interpret the obtained reconstruction results, the segmentation method based on the analysis of joint histograms was used. This allowed us to identify each of the three substances. To compare the results obtained, additional “reference” tomographic measurements were performed: one in polychromatic and two in monochromatic (MoK_α-, MoK_β-lines) modes. It took three times less time for the tomographic experiment with the crystal analyzer, while the reconstruction accuracy was comparable to that of the “reference” tomography.