This work studies hafnium hydride as an absorber for fast neutron reactors. A high value of the neutron absorption cross section was noted which remains the same for all hafnium isotopes formed during neutron irradiation in the reactor. However, there is a risk of hafnium hydride decomposition in the range of 600–700°C which corresponds to the operating temperature of absorbers in fast neutron reactors. An approach has been proposed to reduce the release of hydrogen from hafnium hydride which consists of applying a protective coating of hafnium oxide to it. Hafnium hydride samples were annealed to temperatures of 1200°C in a simultaneous thermal analysis unit in helium. The beginning of hydrogen desorption corresponds to a temperature of 640°C. Complete release of hydrogen was shown at a temperature of 1200°C. Significant reduction in hydrogen desorption at low temperatures was shown when annealing samples with coatings,. A special installation has been developed that allows thermal testing of hydride materials in a liquid sodium environment. Hafnium hydride was annealed in liquid sodium at 700°C. Synchronous thermal analysis of samples after exposure to sodium showed a decrease in gas desorption which is associated with an increase in the thickness of the oxide layer on the surface of the samples.

The Monte-Carlo method for a vortex system is used to calculate the response of a layered high-temperature superconductor containing irradiation pinning centers to a current pulse of microsecond duration. Two different pulse shapes are analyzed: a rectangular and a triangular pulse. It is shown that the shape of the response approximately coincides with the shape of the initial pulse. The “echo” effect observed in an external magnetic field after switching off the external current is investigated. It is shown that the effect is observed for both rectangular and triangular pulses, the severity of the effect decreases with increasing efficiency of pinning centers in the sample.

Accelerator complexes with chain of accelerators have been created in recent years for solving relevant problems of particle physics and application research. These chains consist of accelerators for intermediate energies, the main accelerator for project beam parameters, experimental stations, and beam transfer channels. Operation with a synchrotron accelerator requires the correction of a closed beam orbit. Automatic software is developed for this purpose. The main features of software development for beam orbit correction in ring accelerators and colliders are described for the NICA complex booster synchrotron as an example. Multipurpose methods have been used for general application in beam orbit correction systems.

The DECOR coordinate-track detector is designed for registration of charged cosmic ray particles at large zenith angles. At the moment, analyses of the installation measurements are performed manually, which affects the performance. Application of deep machine learning methods allows to automate the processing process and increase the sample of processed data. The artificial neural network (ANN) architectures described in the paper have shown high accuracy in counting the multiplicity of muons in the data of the DECOR facility. Estimates of ANN performance on events with different muon multiplicity are given: for the number of particles 5–6 the accuracy was 1 track, and for more than 100 particles – 7 tracks.

Prototype amplifier with operating frequency of f = 2.8 GHz for pulsed RF power supply of high-power amplifying klystrons has been developed. The amplifier block diagram has been developed. The board topologies for each amplifier module have been proposed. The amplifier module models have been assembled and adjusted. The amplifier model has been assembled and tested.

A method for calibration of the URAN array, which consists of thin scintillation detectors, is discussed. It is based on comparing of detected extensive air shower events with events in the NEVOD-EAS array. The results of reconstruction of the air-shower parameters according to the URAN array data, obtained taking into account the calibration coefficients, are presented.

Modern crystal focusing devices are suitable for applications at TeV-class accelerators because theyhave small transverse dimensions. To increase the acceptance of the device, a device consisting of several  crystals assembled into an array is proposed. The paper presents the results of testing a new device on the U-70 beam.

The main features of the frozen and quasi-frozen spin lattice were calculated in the spinor formalism, such as a spin-tune and a direction of the invariant spin axis. As the radial field perturbations play a crucial role in the Electric Dipole Moment (EDM) measurement procedure, the difference of frozen and quasi-frozen spin lattices was investigated in this regard. The possibility of subtraction of a nonlinear term in the spin-precession frequency with the change of the injection direction in the quasi-frozen case was investigated. Furthermore, the frequency summation law was derived for the structure of a general form with perturbations in the radial, vertical and longitudinal directions.

The paper considers the use of the transition energy jump to ensure the stability of the beam in the NICA collider. The features of barrier and harmonic accelerating RF stations and their influence on the dynamics of the particles longitudinal motion are described. The study of these features is intended to expand the understanding of the transition energy crossing process.

The cyclotron complex DC-140, which is under development at the Laboratory of Nuclear Reactions, is designed to solve a wide range of applied research with the use of heavy ions accelerated beams. The research works on radiation physics, radiation resistance of materials and the production of track membranes are planned. Following the requirements of experiments DC-140 should accelerate the heavy ions up to fixed energies 2.1 and 4.8 MeV per unit mass in a wide mass range from Ne to Bi with the intensity up to 10¹² particles per second (for Xe ions). In accordance with the working diagram of DC-140 cyclotron the ion source should provide the ion beams with mass-to-charge ratio A/Z of the range from 5 to 8 (from Ne⁴⁺ to Bi³⁸⁺).

In 1967 article, Academician of the USSR Academy of Sciences A.D. Sakharov formulated three necessary conditions that the process of baryogenesis had to satisfy in order for matter and antimatter in the primordial Universe to be produced at different rates. The impetus for the formulation was the discovery of cosmic background radiation and CP parity violation in the system of neutral K mesons. Sakharov’s three necessary conditions are: nonconservation of the baryon number; violation of charge symmetry of C- and CP-symmetry; interaction outside thermal equilibrium. If they exist the electric dipole moment (EDM) of particle violate P- and T-symmetries, which means, according to the CPT theorem, their existence can be associated with the violation of CP symmetry. The Standard Model (SM) of elementary particles allows us to take into account CP violation through the Cabibbo–Kabayashi–Masakawa matrix, however, EDM predicted by it for, for example, a neutron lie in the range from 10^–33 to 10^–30 e cm. In the same time, the SUSY (super symmetry) theory predicts the presence of an EDM of a much larger magnitude (at the level of 10^–29–10^–24 e cm). Thus, the EDM of elementary particles is a sensitive indicator of physics beyond the SM. Currently, purely electrostatic storage rings and with mixed electric and magnetic fields are increasingly used not only in atomic physics, biology and chemistry [1], but also in proposed experiments to search for the electric dipole moment [2]. Presumably, the most successful experiment to search for EDM can be based on measuring spin precession to study EDM. The spin precession frequency is measured with the electric field parallel and antiparallel to the magnetic field. A change in the measured spin precession frequency would be evidence for an EDM.

IH (Inter digital H-type) and SPR (Split Ring) structures are applied for ion acceleration at low energy range on relatively low frequencies. A procedure for selecting the Drift Tubes (DT) parameters to achieve high RF efficiency and simultaneous suppression of the parasitic dipole component of the electric field with given electrical strength is presented. With a modern software in the 3D electrostatic approximation database of DT options has been accumulated for six free geometric parameters. The choice of the final option is carried using sequential polynomial interpolation of the database. For the beam dynamics calculations Fourier coefficients of the accelerating field are carried.

The paper considers the design features of a 8 MeV linear electron accelerator related to the development of a two-sectional accelerating structure and MW power coupler devices. The electron beam dynamics was simulated using BEAMDULAC-BL code. The model of the accelerating structure with the couplers were adjusted using the simulation results. The desired values of the electrodynamic characteristics were obtained.

The Kurchatov Complex of Theoretical and Experimental Physics of the National Research Centre “Kurchatov Institute” is developing a multi-beam facility for performing experiments on express analysis of the irradiation resistance of structural materials of nuclear and fusion reactors. Reproduction of the processes occurring in the reactor requires irradiation of samples of structural materials with two or three ion beams [Fedin P.A. et al. // J. Phys.: Conf. Ser. 2020. V. 1686. P. 012073.]. Irradiation of one type of heavy ions (Fe²⁺, Ti²⁺, Co²⁺, etc.) and one type of light ions (H⁺/He⁺) of the target will occur in the same chamber simultaneously. To generate beams of light ions, a compact ion source with a discharge chamber based on an extremity waveguide, installed on a high-voltage platform, is being developed. The paper contains a description of the design of a light ion source and preliminary results on the generation of a helium ion beam.

This work is devoted to the determination of the tissue optical properties of the organs of the human gastrointestinal tract in the spectral range of 400-620 nm. The diffuse reflection and transmission spectra were measured using a Hitachi U-3400 integrating sphere spectrophotometer. The absorption and reduced scattering coefficients were determined using the inverse adding-doubling method. The obtained results of optical properties were compared with the available literature data.

The article analyzes the effectiveness of using spherical gold nanoparticles (AuNPs) with a size of 50 nm in combination with proton irradiation at a dose of 30 Gy (energy 150 MeV) in order to enhance the cytotoxic effect of binary therapy. The analysis was carried out in vivo experiments using the model invertebrate animal Daphnia magna. The biodistribution of AuNPs in the animal body was studied and the biochemical effect of the separate and combined action of the AuNPs with irradiation was analyzed. Accumulation of AuNPs in the intestine as well as in the eggs and embryos of the next generation was detected. Analysis of the level of free radicals and malondialdehyde revealed an increase in the cytotoxic effect of irradiation with nanoparticles.

Results are presented from studying physicochemical characteristics and radiosensitizing properties of a new type of lutetium fluoride (LuF₃) nanoparticle as a promising nanoradiosensitizer for X-ray irradiation of B16/F10 melanoma cells. A comprehensive analysis is performed of functional characteristics of synthesized LuF₃ nanoparticles, their cytotoxicity, and their radiosensitizing effect in vitro. It is shown that LuF₃ nanoparticles have a hydrodynamic diameter of less than 200 nm. Colloidal sol obtained on their basis is highly stable as a result of using the biocompatible stabilizer ammonium citrate. LuF₃ nanoparticles have a cytotoxic and radiosensitizing effect on melanoma cells in concentrations of 116 mg/mL and higher by reducing their metabolic activity and membrane mitochondrial potential while initiating apoptosis. Such nanomaterial can form the basis of promising modern approaches to increasing the effectiveness of radiation therapy.

Cancer, a major global cause of death, requires more selective treatments to minimize side effects. Immunotherapy that uses antibodies targeting immune checkpoints is a promising approach, but it has limitations, mainly related with poor tumor penetration and consequent treatment resistance. Biocompatible and biodegradable calcium carbonate microparticles offer a solution to this problem due to the possibilities of encapsulation and controlled release of these biomolecules, which increase their therapeutic efficacy while reducing adverse effects. This study focuses on optimizing the synthesis of these microparticles and improving protein loading with the use of the coprecipitation approach, with bovine serum albumin as a model protein. The procedures developed make it possible to obtain protein carriers with improved morphological characteristics and a loading efficiency of more than 90%.

This work is devoted to modern methods for studying the three-dimensional nanostructure of biomaterials and biological objects based on scanning probe nanotomography—a combination of probe microscopy and ultamicrotomy, and fluorescence microscopy. The paper presents the results of experiments on studying the three-dimensional nanostructure of composite scaffolds based on Bombyx Mori silk fibroin and extracellular matrix microparticles obtained from decellularized liver tissue. Such scaffolds have significant potential for use in regenerative medicine. It has been shown that probe nanotomography methods make it possible to effectively analyze the three-dimensional nanostructure of microinclusions and their morphological parameters that affect the biological activity of scaffolds.

Plastic scintillators based on polystyrene and other polymers of the vinyl aromatic row (polyvinyltoluene, polyvinylxylene, etc.) have long been used in scintillation detectors because of their short fluorescence lifetimes, low cost, and relative ease of fabrication. On the other hand, such materials have a small light output. Plastic scintillators are usually doped with fluorescent organic dyes to impart scintillation properties to the polymer matrix and increase the light yield. In recent years, considerable interest has been aroused by studies aimed at the use of semiconductor nanocrystals-quantum dots—as dopants for plastic scintillators based on polymer matrices. One of the most promising materials for this purpose are considered to be CsPbBr₃ perovskite nanocrystals and CdSe/ZnS quantum dots of core/shell type. These materials demonstrate high quantum yield values, have high effective atomic number and can be effectively integrated into polymer matrices while preserving their structural and optical properties. Thus, it can be hypothesized that doping plastic scintillators with quantum dots can significantly improve their light yield and increase their radiation resistance. Here, we propose an approach to the chemical design of plastic scintillators doped with quantum dots, investigate their radioluminescence and describe the optimal parameters for the fabrication of such composite scintillators by radical polymerization of para-methylstyrene.

Porous silicon (pSi) based resonators are of interest as a basis of hybrid photoluminescent (PL) systems in terms of both fundamental and applied research. One of the most promising types of luminophores for creating such hybrid systems are semiconductor quantum dots (QDs) due to their narrow PL spectrum along with a broad absorption spectrum. The formation of polariton states and modification of PL properties of the luminophore may occur depending on the structure and parameters of the hybrid system. Here, we demonstrate a 4.4-fold narrowing of the PL spectrum of CdSe/ZnS QDs and a 3.7-fold acceleration of spontaneous emission in a pSi microcavity (MC) compared to QD in solution. The observed changes in the PL properties of QDs are due to the light-matter interaction between the MC eigenmode and QD excitons. The obtained results open the way to the development of new photonic, optoelectronic and sensing devices.

In this paper, the regularities of laser heating of iron oxide nanoparticles depending on their size, shape, and aggregation at the subcellular level were investigated. The temperature was measured using time-resolved fluorescence thermometry based on rhodamine B dye. The obtained temperature estimates are over 100°C, which creates favorable conditions for initiation of programmed cell death of tumor cells at laser hyperthermia.

The development of innovative fluorescence detection methods based on optically encoded microspheres of different colors and sizes is an important direction of multiparameter detection and diagnostics of a wide range of diseases. Thus, the xMAP technology of the American company Luminex is based on the use of polystyrene microspheres colored with two or three organic fluorophores in different ratios, each of which has unique spectral characteristics. Despite the ability to detect up to 80 proteins or DNA sequences in a single test system, the need to use special equipment only from this company for multiplex analysis and the characteristic disadvantages of organic fluorophores (large Stokes shift, photo-bleaching under laser excitation) limit the application of this technology. The objectives of the present study consisted of the design and fabrication of microspheres encoded with semiconducting quantum dots. Carboxylated melamine-formaldehyde microspheres of two sizes were optically encoded with quantum dots of two colors immobilized on the surface of the microspheres by layer-by-layer adsorption of oppositely charged polyelectrolytes. As a result, six populations of microspheres with different sizes and/or unique optical codes were obtained with stability and homogeneity in aqueous solutions for a long time. Analysis of the obtained microspheres by dynamic light scattering, epifluorescence microscopy and flow cytometry methods showed their suitability for multiparameter analysis. At the same time, the use of quantum dots for optical encoding made it possible to exclude photodegradation of the signal and provided the possibility of excitation of all populations by the same wavelength of radiation with effective separation of signals from microspheres in different channels of a standard flow cytometer.

Radiopharmaceuticals, which are targeted prostate-specific membrane antigen (PSMA), are highly promising for radioligand therapy of prostate cancer. The aim of this work was to study the general toxic properties of radiopharmaceutical ²²⁵Ac-DOTA-PSMA after its single intravenous administration to animals (“acute” toxicity). It was shown that administration of ²²⁵Ac-DOTA-PSMA to mice and rats (male and female) at doses 100, 200 and 500 kBq/kg was adequately undergone by the animals. No significant signs of intoxication or animal death were observed. No pathomorphological changes of organs and tissues were revealed at autopsy of animals. In mice treated with ²²⁵Ac-DOTA-PSMA at doses of 200 and 500 kBq/kg a decrease of salivary gland weight by 8–15% was observed when compared with the control group (p > 0.05).

In the last few years, lead halide nanocrystals with perovskite mineral structure (PNСs) have attracted increasing attention due to their excellent optical and physical properties, which make them promising for liquid crystal displays, light-emitting diodes, solar concentrators and basic elements of quantum computing systems. Initially, the synthesis of PNСs was carried out using oleic acid and oleylamine as organic surface ligands, and the materials obtained in this way did not have sufficient colloidal and photo-stability for practical applications. This problem was partially overcome by the use of phosphonic acids and other types of molecules as ligands, but in this case, the reaction is often incomplete, resulting in some of the metal precursors remaining in the product, which in turn leads to a gradual degradation of the optical properties of PNСы. Here, we demonstrate the effective application of a method of additional purification of CsPbBr₃ PNC solutions obtained by colloidal synthesis using tetradecylphosphonic acid as a ligand by gel permeation chromatography. As a result of this procedure, we were able to remove the excess of unreacted precursors from the synthesized nanocrystals, which allowed us to achieve the preservation of a high value of the quantum yield of PNCs fluorescence within 6 months from the moment of their synthesis. The obtained results open perspectives for creation of more efficient material for application in the fields of quantum technologies and, in particular, for creation of single photon sources.

In the present work several series of thin tantalum nanocluster films deposited on a quartz crystal were obtained, and their masses were measured using a quartz mass sensor. In each series the films had a characteristic particle size from 1.5 to 6.5 nm. The result of the mass measurement showed that the ratio of the deposited mass to the incident volume of clusters differs for different sizes. A physical model of the particle deposition process was also proposed and studied to explain the observed effect. According to the simulation results, it turned out that the focusing of particles practically does not change with size, and also is very weakly dependent on the initial velocity of the particles. It was concluded that the main reason for the above-described effect may be the difference in the adhesion coefficient of particles of different sizes. It has been proposed to test this assumption through additional experiments.