The results of the experimental study at the KISI-Kurchatov synchrotron source of the new phase-contrast imaging scheme for micro-objects using a nanofocusing compound refractive lens are presented. Visualization with submicron spatial resolution of a Fresnel zone plate with the width of the outer zones less than 0.5 µm is demonstrated. It is found that in the performed experiments the main contribution to the instrumental function, which limits the spatial resolution, is due to the vibrations of the optical scheme elements. The possibility of using the proposed scheme for estimating the beam transverse size at the focus of the compound refractive lens, with allowance for the instrumental function, is demonstrated.

The investigation focuses on the development and research of plasma etching processes for the manufacturing of silicon refractive X-ray optical elements: planar compound lenses and also reflective devices - mirror interferometers. Although silicon is not the best material for refractive optics because its refractive and absorption characteristics are concede to materials made from lighter chemical elements, impressive advances in silicon technology in MEMS (micro-electromechanical systems) and nanoelectronics have made it possible to achieve record-breaking precision in the formation of structures, which concerns not only geometry but also minimal roughness. A 100-lens interferometer (with 29 lenses in each channel) was manufactured using the proposed technology. Its' focusing capabilities were investigated both numerically and experimentally, although the fringes with a width of 2.0μm turned out to be wider than the calculated ones $(0.5 \mu\mathrm{m})$; these effects should be attributed to the finite size of the radiation source. The peak-to-peak surface roughness of the lenses was measured to be approximately 20 nm, whereas RMS (root mean square) sidewall roughness measured by SEM, AFM and Optical Profiler does not exceed 2 nm/um. This level of roughness does not significantly affect the formation of interference patterns.

Analysis of Pb+Pb data for net-charge fluctuations at LHC energies using the HYDJET++ model is presented. The strongly intensive quantities D and Σ were used to remove the effects related to system volume fluctuations. We employed two versions of HYDJET++ for the analysis. The first one is the standard or default version,whereas the second one is a modification that takes into account explicit event-by-event conservation of the electric net-charge of produced particles. The inclusion of the canonical net-charge conservation in the model allows for better description of the experimental data obtained by the ALICE and CMS Collaborations. A comparison with calculations from other models is also presented.

The prospects for using high-resolution X-ray microlenses for coherent visualization tasks are discussed. Modern technologies and methods of microprocessing for the manufacture of 2D microlenses are considered using laser systems, ion-beam lithography, and additive technologies as an example. The efficiency of various materials for X-ray micro-optics applications is evaluated, and the time spent on manufacturing 100 nm resolution micro objectives using ion-beam lithography systems is optimized.

The data on charge balance function in Pb+Pb collisions at center-of-mass energy 2.76 TeV per nucleon pair are analyzed with the HYDJET++ model. For central collisions, the width of the charge balance function at low transverse momentum intervals is larger in the model than in data. An approach, which takes into account the event-by-event charge conservation, has been implemented into the thermal part of the model at the stage of hadron production. This approach implies two particle charge correlations with a certain length and allows to reproduce experimental widths.

The experimental study of optical properties of X-ray silicon planar compound refractive lenses at the synchrotron radiation source “KISI–Kurchatov” (Moscow, Russia) are presented. The capability to generate a submicron X-ray beam using refractive optics was demonstrated for the first time at this facility. The parameters of the focused beam were determined using the knife-edge technique. The measured minimum lateral focal spot size was 460 ± 70 nm. Additionally, the spatial structure of the beam in the focal spot area was examined. Theoretical estimates of the lenses optical properties and the corresponding computer simulation results are in agreement with the experimental data.

The important role of kinematic constraints for the origin of the alignment of hadron and photon families observed by the Pamir Collaboration in emulsion experiments with cosmic rays is discussed. Within the framework of the suggested approach, it is shown that the high degree of alignment of the interaction products of the target nuclei and cosmic rays can be a consequence of the selection procedure of the most energetic clusters of particles together with the law of conservation of transverse momentum. The results correctly describe the experimental data for three energetic centers and are also close enough to the measurements in the case of four and five clusters, which indicates encouraging prospects for the proposed method of explaining the alignment phenomenon.

Compound refractive lenses, crafted from single-crystal materials like diamond and silicon, are increasingly favored, particularly in cutting-edge facilities, such as free electron lasers and fourth-generation synchrotrons. These lenses are prized for their low parasitic scattering and resistance to significant radiation doses over extended periods. However, they do encounter a notable drawback known as the “glitch effect”, wherein undesired diffraction can occur across various X-ray energies. This phenomenon leads to a decrease in transmitted intensity, impacting experiments, particularly in spectroscopy. Typically, a series of lenses is employed to achieve optimal beam parameters, and each lens has its own spectrum of glitches. This paper presents experimentally measured glitches in stacks of 1, 4, 8, and 16 diamond compound refractive lenses, elucidating the theory behind glitch formation and offering strategies to predict and mitigate glitches in diverse focusing systems employing lenses made from single-crystal materials.

In this work, we present a new generation of ultra-compact and high-vacuum cooled transfocators based on refractive lenses for the collimation, transport, and focusing of hard X-ray radiation. A transfocator is an optical device capable of changing the position of the focus depending on the number of refractive X‑ray lenses that are exposed along the X-ray optical path. The design features of this device make it possible to control individual optical elements independently of each other, providing more flexible focal-length adjustment for a wide range of applications. The small overall dimensions and light weight of the devices make it possible to integrate them into any synchrotron-radiation station.

Single-crystal planar compound refractive lenses under diffraction losses (glitches) conditions, when a part of radiation incident on an optical element diffracts from some set of atomic planes, have been investigated. A detailed experimental study using synchrotron radiation of the influence of glitches on the focal spot formed by lenses has been performed. An analysis of the data obtained showed that diffraction losses arise on different parts of the parabolic lens profile due to the refraction effect at radiation energies differing by a few electronvolts. As a result, the shape of the focused beam changes with a change in energy near the energy of the glitch.

A new method is proposed for determining experimentally the size of a synchrotron radiation beam in the focus of planar compound refractive lenses. The method consists in measuring the angular divergence of radiation after the focus using Bragg diffraction in a perfect crystal during its rotation. This method determines the beam size, which depends only on the focusing properties of the lenses in use, in contrast to other currently applied methods. The efficiency of the proposed approach has been experimentally demonstrated using nanofocusing planar silicon lenses as an example.

The HYDJET++event generator is a phenomenological model of heavy-ion collisions that treats the collision process as a combination of a soft hydro-type state and a hard state resulting from hard parton scattering. On the one hand, it allows one to quickly simulate relativistic heavy-ion collisions, and on the other hand, it reproduces and describes a number of experimental phenomena in the soft and hard sector. It also allows you to study many features of the interaction as interplay of soft and hard processes. Here we present some selected results of recent studies. Basically, new results on the correlation of elliptical flows at small and large transverse momenta at LHC energies are described. Current studies of the charge balance function at LHC energies and the A-dependence of the flow in heavy-ion collisions are also discussed.

The intensity loss of a transmitted beam due to parasitic diffraction (glitches) is an inherent property of single-crystal X-ray optics. This effect can lead to a weakening of the radiation, up to its complete disappearance. Therefore, understanding the effect of diffraction loss is essential for any experiments that use single-crystal optics. We present the theory of glitch formation and demonstrate its application to experimental data to determine the orientation and cell parameters of optical elements made of single-crystal diamond. A systematic error is found in determining the absolute energy of X-ray radiation, which occurs due to the inexact tuning of a monochromator (error in determining the absolute 2θ angle). The described error very often occurs during the experiment due to the fact that determining the absolute 2θ angle of a monochromator crystal is a technically difficult task. Simultaneous determination of the orientation and lattice parameters of the studied sample, together with compensation of the systematic error in the monochromator tuning, made it possible to significantly improve the accuracy of processing the obtained data.

We propose a method for determining the collimation ratio of a coherent X-ray beam using a planar multilens interferometer. The method is based on the analysis of Talbot images, which are periodic patterns of interference fringes formed by the interferometer at corresponding distances. The high sensitivity of the position and period of the interference fringes to the shape of the X-ray beam wavefront enables determination of its collimation degree and evaluation of the coherence properties of the radiation. The effectiveness of the proposed approach is experimentally demonstrated at the ID15B beamline of the European Synchrotron Radiation Facility (ESRF) synchrotron radiation source. A theoretical study is carried out, and the corresponding results of computer simulation are presented. The experimental data obtained correspond fully to the theoretical estimates.

Data from the Large Hadron Collider on the charge balance function in Pb+Pb collisions at center-of-mass energy 2.76 TeV per nucleon pair are analyzed and interpreted within the framework of the HYDJET++ model. This model allows us to qualitatively reproduce the experimentally observed centrality dependence of the balance function widths at relatively low transverse momentum intervals due to the different charge creation mechanisms in soft and hard processes. However, a fully adequate description of the balance function in these intervals implies an essential modification of the model by including exact charge conservation via the canonical rather than the grand canonical ensemble. A procedure is proposed for introducing charge correlations into the thermal model without changing other model parameters. With increasing transverse momenta, the default model results describe the experimental data much better because the contribution of the soft component of the model is significantly reduced in these transverse momentum intervals. In practical terms, there is a transition to a single source of charge correlations, namely, charge correlations in jets in which exact charge conservation holds at each stage.

The observed alignment of spots in the X-ray films in cosmic ray emulsion experiments is analyzed and interpreted in the framework of geometrical approach. It is shown that the high degree of alignment can appear partly due to the selection procedure of most energetic particles itself and the threshold on the energy deposition together with the transverse momentum conservation.

Directed formation of the structure of the culture of living cells is the most important task of tissue engineering. New materials for 3D scaffolds of living tissue are critical for the mass adoption of regenerative medicine protocols. In this manuscript, we demonstrate the results of the molecular structure study of collagen from Dosidicus gigas and reveal the possibility of obtaining a thin membrane material. The collagen membrane is characterized by high flexibility and plasticity as well as mechanical strength. The technology of obtaining collagen scaffolds, as well as the results of studies of its mechanical properties, surface morphology, protein composition, and the process of cell proliferation on its surface, are shown in the given manuscript. The investigation of living tissue culture grown on the surface of a collagen scaffold by X-ray tomography on a synchrotron source made it possible to remodel the structure of the extracellular matrix. It was found that the scaffolds obtained from squid collagen are characterized by a high degree of fibril ordering and high surface roughness and provide efficient directed growth of the cell culture. The resulting material provides the formation of the extracellular matrix and is characterized by a short time to living tissue sorption.

The intensity loss of transmitted beam due to parasitic diffraction (glitches) is an inherent property of single-crystal X-ray optics. This effect can lead to a weakening of the radiation, up to its complete disappearance. Therefore, understanding the effect of diffraction loss is essential for any experiments that use single-crystal optics. We present theory of glitch formation and demonstrate its application to experimental data to determine the orientation and cell parameters of optical elements made of the single-crystal diamond. A systematic error was found in determining the absolute energy of X-ray, which occurs due to the wrong monochromator tuning (an error in determining the absolute 2θ angle). The described error very often occurs during the experiment as a result of the fact that determining the absolute 2θ angle of the monochromator crystal is a technically difficult task. Simultaneous determination of the orientation and lattice parameters of the studied sample, together with the compensation of the systematic error in the monochromator tuning, made it possible to significantly improve the accuracy of processing the obtained data.