Vol 87, No 8 (2023)

We presented the results of the series of experiments on the synthesis of Mc isotopes in the ²⁴³Am + ⁴⁸Ca reaction performed at the new separator DGFRS-2 and cyclotron DC280 of the SHE Factory at FLNR JINR. There were registered 110 new ²⁸⁸Mc decay chains, 10 ²⁸⁹Mc chains, and 4 ²⁸⁷Mc chains. Alpha decay of ²⁶⁸Db with an energy of 7.6–8.0 MeV, half-life \(16_{{ - 4}}^{{ + 6}}\) h and α-branch \(51_{{ - 12}}^{{ + 14}}\% \) was registered for the first time together with a new spontaneously fissioning isotope ²⁶⁴Lr with a half-life of \(4.8_{{ - 1.3}}^{{ + 2.2}}\,\,{\text{h}}.\) The measured cross section of the ²⁴³Am(⁴⁸Ca, 3n)²⁸⁸Mc reaction was \(17.1_{{ - 4.7}}^{{ + 6.3}}\) pb, which is the largest for known superheavy nuclei. A new isotope ²⁸⁶Mc was synthesized with a half-life of \(20_{{ - 9}}^{{ + 98}}\) ms and an α-particle energy of 10.71 ± 0.02 MeV. Spontaneous fission of ²⁷⁹Rg was first observed in one of the four new decay chains of ²⁸⁷Mc. The reaction excitation function was measured at six ⁴⁸Ca energies in the range of 239–259 MeV, which led to the first observation of the 5n channel with a cross section of \(0.5_{{ - 0.4}}^{{ + 1.3}}\) pb. The decay properties of 20 previously known isotopes have been determined with higher accuracy.

The yields of (γ, p)-reactions for bremsstrahlung γ-quanta with boundary energies of 20, 40, and 55 MeV on a natural mixture of molybdenum isotopes targets were measured as well as the activity of the resulting ^{91m, 95mg, 96, 97}Nb isotopes. The weighted average yields of these isotopes formed in (γ, p)-reactions on molybdenum were measured for the first time. The experimental values were compared with the theoretical yields calculated using the TALYS1.96 program code and the method of the consideration of the giant dipole resonance isospin splitting.

Recent results on heavy-ion physics at the LHC (CERN) by the Compact Muon Solenoid (CMS) collaboration are analyzed. The tests of quark-gluon plasma carried out with the CMS detector provide valuable information about the behavior of matter in the extreme regime of very high energy nucleus-nucleus collisions.

The spectra of protons were measured at the absorption of stopped π^–-mesons in “live” target—analog of the ²⁸Si target. Based on the data obtained, it was possible to isolate the process without secondary interactions and obtain the spectrum of primary protons from the act of pion absorption on an intranuclear pp pair.

It is expected that charmed particles will be copiously produced at Future Circular Collider (FCC). Due to relatively large lifetime of the particles, it will be needed to account their interactions with surrounded materials and detector’s materials. To satisfy the requirements, charmed particle production in soft interactions has been implemented in QGS and FTF models of the Geant4 package. Some details of the implementations are considered.

The latest data by the NA61/SHINE collaboration on inclusive distributions of K*⁰ and ϕ meson’s, Ξ^– and anti-Ξ⁺ hyperon’s production in pp interactions at P_lab from 40 up to 158 GeV/c are considered. As it was shown before in experimental papers, Monte Carlo models – EPOS 1.99, UrQMD 3.4 and Pythia 6, cannot describe reasonably well the data. In the presented paper, the yields of the particles are analyzed within the framework of the Geant4 FTF model. A good description of the experimental data has been reached.

The features and stages of simulation of triple GEM detector for the first physics run in the BM@N experiment in 2022 are presented. We described the procedure for electrostatic field map calculation based on the current configuration of the GEM detector. We also consider tool set required for detailed simulation of physics processes inside the GEM chamber and give some results obtained.

The hydrodynamic approach was used to find an analytical solution of the hydrodynamic equations in the soliton approximation for layer collisions in the one- and two-dimensional cases. The compression stage, the decompression stage, and the expansion stage are considered within the framework of a single formula for layers with energies on the order of ten MeV per nucleon. Our generalization to the two-dimensional case leads to the idea of the formation of a rarefied bubble region at the stage of expansion. The approach can be used in other fields for calculations of the nonlinear dynamics of oscillations of complex systems.

Reliability of (γ, 1n) and (γ, 2n) reactions cross sections for ^{58, 60}Ni obtained in experiments carried out on the beams of bremsstrahlung and quasimonoenergetic annihilation photons was investigated using objective physical criteria. It was found that data of the first type experiment do not satisfy those criteria and definitely are not reliable. At the same time there are serious doubts in reliability of the data obtained in the second type experiment. New partial photoneutron reaction cross sections on ^{58, 60}Ni satisfying physical criteria of data reliability were used for analysis of characteristics of both isotope photodisintegration processes. It was obtained that for neighboring (differ in two neutrons) isotopes because of various type systematic uncertainties there are significant disagreements between evaluated and experimental cross sections of various reactions which for isotopes ⁵⁸Ni and ⁶⁰Ni are of significant different character. It was shown that the reasons are not only the differences in energy thresholds and absolute values of cross sections of the (γ, 1n), (γ, 1n1p) and (γ, 2n) reactions on ⁵⁸Ni and ⁶⁰Ni but significant differences in specific features of neighboring isotopes shell structure also.

Recently, the existence of a special class of atomic nuclei, local magic nuclei, has been discovered. In the present paper, evidence for the existence of a new local magic nucleus, ¹⁴⁶Gd, is presented on the base of experimental data. This nucleus has a magic pair of nucleons (N, Z) = (82, 64). The shell evolution scheme leading to this phenomenon was obtained. It is shown that the tensor proton-neutron force plays a crucial role in this evolution.

We discussed nuclear technologies to produce radioactive isotopes, with a focus on radionuclides used as radiopharmaceuticals in novel methods of cancer diagnosis and radionuclide therapy—theranostics. New target materials and nuclear reactions to produce these radionuclides were considered. The experimental and theoretical results of excitation functions of reactions (p, xn) studies in energy range 6–80 MeV for medium mass nuclear systems to produce radionuclides: scandium, technetium, antimony, terbium are presented. These radionuclides are promising for their use in nuclear medicine methods for diagnostics, therapy and theranostics.

A new approach to the analysis of the intensity of the muon flux from different azimuthal directions is considered, which makes it possible to detect waves in the atmosphere from large-scale atmospheric phenomena (fronts, thunderstorm cells).