Physics of Atomic Nuclei最新文献

The DECOR coordinate-tracking detector is designed to register charged cosmic ray particles in wide zenith angles. Measurements by the installation are currently analyzed manually, affecting its performance. The use of deep machine learning allows automated processing and larger samples of processed data. The artificial neural network (ANN) architectures considered in this work have displayed high accuracy in counting the multiplicity of muons in data from the DECOR facility. Estimates are given of ANN performance for events with different muon multiplicities. The accuracy is 1 track for 5–6 particles and 7 tracks for more than 100 particles.

The results of mechanical testing and fractography of the ring samples, made of the model Zr–Nb–Sn–Fe alloy, are presented. The most reliable macro- and micro- parameters to quantify the fracture surface are defined. The correlations of some hydride microstructure metrics with fracture parameters are investigated. The advantages and disadvantages of individual metrics are revealed. Threshold stress for the near-surface radial hydride fracture at room temperature is obtained.

The possibility of using an atmospheric optical communication line at nuclear power facilities of the Russian Federation as a backup communication channel as well as for regular use has been analyzed. Using the existing methodology for assessing the feasibility of this type of communication and long-term meteorological observations in all location areas of nuclear power facilities on the territory of the Russian Federation, it has been shown that the use of existing modern Russian atmospheric communication terminals will allow high-speed data exchange within each perimeter of these facilities and will ensure high year-round availability of such a communication channel. A map of applicability of the atmospheric optical line has been developed, emphasizing the high efficiency of application of various communication terminals at nuclear power facilities on the territory of Russia.

In modern practice, collimators are employed in electron beam therapy to shape the irradiation field into standard configurations. However, tumors often have complex shapes, requiring the use of collimators with individually created collimation windows typically made of metal alloys. The production of such devices is time-consuming, limiting their widespread use. A promising approach to collimator manufacturing is three-dimensional printing, using fused filament fabrication that allows the production of three-dimensional objects quickly and accurately. The polymer materials used today allow the 3D printing of products with densities up to 1.3 g/cm³, requiring the use of a relatively thick collimator. This work proposes using plastics infused with metal impurities for 3D printing collimators created for electron beam therapy. Monte Carlo numerical simulation is performed to calculate the collimator thickness required for the effective absorption of electron beams in the range of therapeutic energies. A modular collimator is therefore designed and created by 3D printing that offering the possibility of varying the diameter of the collimation window from 0.5 to 6 cm. Based on experimental data obtained for a medical electron beam with an energy of 6 MeV, it is found that the 3D printed device can effectively shape a radiation field corresponding to the chosen diameter of the collimation window. Features of using a plastic collimator to shape the field of an electron beam when planning electron beam treatment must be considered.

In the last few years, lead halide nanocrystals with perovskite mineral structures (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 photostability 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 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.

The design of a large-scale installation is being considered—a large ring laser gyroscope (RLG)—with record sensitivity to variations in the rotation speed and angular inclinations of the laboratory base surface, as well as to the rotational asymmetry of the refractive index of the optical medium, including vacuum. Using such an instrument, located in an underground observatory, it is possible to obtain information relevant to particle physics, quantum field theory, laser physics, astrometry, global geodynamics and seismology. An applied solution could be the early forecast of global cataclysms such as earthquakes. As a practical step to support the project, the results of trial experiments with a small-sized laser gyroscope (LG) are presented.

The authors describe a way of calibrating the URAN array with thin scintillation detectors using joint events of registration of extensive air showers with the NEVOD-EAS array. Results are presented from reconstructing parameters of extensive air showers based on data from the URAN array with allowance for coefficients of calibration.

The scientific and technological base of muography researches using emulsion detectors, including the equipment and software, is developed and actively used in Russia by the MISIS, NRU MEPhI, SINP MSU and LPI RAS collaboration. The article presents a number of experiments performed with the emulsion muography and illustrates the major stages of the method development and improvement.

An experiment was carried out at the RADEX neutron channel of the Institute for Nuclear Research, Russian Academy of Sciences, at neutron energies of 40–60 MeV to investigate the cluster structure ({}^{3}textrm{He}+t) of ({}^{6})Li nucleus in the reaction ({}^{6})Li((n); ({}^{3})He (n))(t). The excitation energy spectrum of ({}^{6})Li was obtained in the range (E_{x}=16{-}50) MeV. At an excitation energy of (E_{x}=16.6) MeV a resonance with (Gamma=0.7) MeV was observed, and in the interval (E_{x}=30{-}50) MeV two broad resonances were found at (E_{x}=35.9) and (43.1) MeV with (Gamma=8.4) and (5.4) MeV, respectively. All levels are observed for the first time.