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Vol 88, No 1 (2025)
ЯДРА. Эксперимент
THE REVISION OF CUMULATIVE SPECTRA OF BETA PARTICLES FROM 235U, 239Pu AND 238U FISSION PRODUCTS BASED ON THE UPDATED MEASUREMENTS OF THE RATIO OF SPECTRA 235U/239Pu
Abstract
Based on new measurements of the ratio of cumulative spectra of β-particles 235U/239Pu, performed at the Kurchatov Institute (KI), the cumulative spectra of β-particles fission products of 235U, 239Pu and 238U isotopes have been updated. The presented β-particles spectra 235U, 239Pu and 238U KI are compared with similar spectra measured at the Institute Laue–Langevin (ILL), and the spectrum of β-particles 238U KI – with the measurements performed at the Technical University of Munich (TUM). It is shown that the ILL ratio of β-particles spectra 235U/239Pu is mistakenly overestimated by ≈5.4%.
Physics of Atomic Nuclei. 2025;88(1):5-9
5-9
NEW DATA ON PHOTONEUTRON REACTION CROSS SECTIONS FOR 68Zn
Abstract
New data on cross sections of the (γ, 1n) and (γ, 2n) reactions on the 68Zn nucleus, for which the neutron yield cross sections of σexp(γ, xn) = σ(γ, 1n) + 2σ(γ, 2n) and the total photoneutron reaction σexp(γ, sn) = σ(γ, 1n) + σ(γ, 2n) have been obtained in two experiments on the beams of bremsstrahlung, were determined using the possibilities of the experimental-theoretical method for the evaluation of cross sections of partial photoneutron reactions based on objective physical criteria. The contributions of partial reaction cross sections σeval(γ, in) = Ftheor i × σexp(γ, xn) for i = 1 and 2 to the neutron yield cross section were evaluated using the ratios Ftheor i × σ = = σtheor(γ, in) / σtheor(γ, xn) calculated within the combined photonuclear reaction model (CPNRM).
Physics of Atomic Nuclei. 2025;88(1):10–18
10–18
THE RESEARCH OF THE APPLICATION OF 3D PRINTING FOR THE MANUFACTURE OF A SCINTILLATION DETECTOR CASE
Abstract
The paper considers the possibility of using 3D printing technology to manufacture structural elements of ionizing radiation detectors in low-background conditions. The results of measurements carried out using a scintillation detector with a housing made of PETG plastic are presented.
Physics of Atomic Nuclei. 2025;88(1):19–23
19–23
ЯДРА. Теория
NUCLEOSYNTHESIS OF TRANSURANIUM ELEMENTS IN THERMONUCLEAR EXPLOSIONS
Abstract
Artificial rapid nucleosynthesis (r-process) in high intensive neutron fluxes of thermonuclear explosions (∼1024 n/cm2 during the time ∼10–6 s) is investigated within the developed dynamic model. Creation of transuranium nuclides is studied taking into account the time dependence of parameters and processes accompanying the beta-decays of neutron-rich nuclei. The probabilities of beta-delayed processes are calculated basing on the finite Fermi systems theory. Calculations of the transuranium nuclides’ yields Y (A) were carried out for five large-scale explosiveUSA experiments (“Mike”, “Anacostia”, “Par”, “Barbel” and “Vulcan”). It was obtained good or satisfactory agreement with experimental data. Even-odd anomaly in the observed transuranium yields at A > 250 is explained by the effect of processes accompanying the betadecays of heavy neutron-rich isotopes.
Physics of Atomic Nuclei. 2025;88(1):24–32
24–32
ЭЛЕМЕНТАРНЫЕ ЧАСТИЦЫ И ПОЛЯ. Эксперимент
THE UNUSUAL EVENTS IN X-RAY EMULSION CHAMBER EXPERIMENTS
Abstract
The article considers events recorded in an experiment with X-ray emulsion chambers (XREC) to study the cores of extensive air showers (EAS) with energies of nuclei of primary cosmic radiation (PCR) E0 > 100TeV, which currently have no explanation within the Standard Model of nuclear interactions (SM). The XRECmethod is the only one that allows studying EAS cores with a high coordinate resolution of about 100 microns. EAS cores contain the most complete information about primary acts of nuclear interactions, as a result of which all unusual events recorded by the XREC method are of great scientific interest. Several types of unusual events recorded by the XREC method were explained within the SM.
Physics of Atomic Nuclei. 2025;88(1):33–41
33–41
ANALYZING POWER MEASUREMENTS OF QUASI-ELASTIC PROTON-PROTON SCATTERING AT THE INTERMEDIATE ENERGIES AT THE NUCLOTRON INTERNAL TARGET
Abstract
Obtaining new data on the polarization observables is the important part of the nucleon-nucleon scattering models’ development. For this purpose, the polarized deuteron beam and the detection setup at the Nuclotron internal target station were used. Counters were mounted in according to pp-elastic scattering kinematics. Relevant events were selected using time and amplitude information from the counters. The polyethylene target was used as the main target. Auxiliary carbon target was used to remove the background. This article presents the results of the vector analyzing power measurement for the proton-proton quasielastic scattering at the deuteron beam energies of 200, 500, 550, 650 MeV/nucleon. The obtained results are in a good accordance with the data of other experiments and the partial wave analyzis SP07 SAID predictions.
Physics of Atomic Nuclei. 2025;88(1):42–53
42–53
MEASUREMENT OF THE e+e− →π+π−2π0η CROSS SECTION BELOW √s = 2 GeV
Abstract
The cross section for the process e+e− → π+π−2π0η is measured in the center-of-mass energy region 1.55–2 GeV for integrated luminosity 146 pb−1 collected by the SND detector at the VEPP-2000 e+e− collider. The obtained cross section is fitted with theVMDmodel with the ρ(1700) and ρ(2150) resonances.
Physics of Atomic Nuclei. 2025;88(1):54–63
54–63
ANALYSIS OF THE SEARCH RESULTS FOR PENTAQUARKS IN THE ZEUS EXPERIMENT
Abstract
The results of the search for the pentaquarks Θ+ and ¯Θ+ in the ZEUS experiment are analyzed within the framework of the model of formation of five-quark states. The criteria for selecting pentaquarks, leading to different results of observing the resonant signal, are considered. Possible reasons for the negative results of the search for pentaquarks are identified.
Physics of Atomic Nuclei. 2025;88(1):64-72
64-72
SENSITIVITY OF THE CP-VIOLATION PHASE MEASUREMENT IN THE LEPTON SECTOR IN THE P2O EXPERIMENT
Abstract
In the scope of the P2O (Protvino-to-ORCA) experiment it is planned to carry out experiments to determine the neutrino mass hierarchy and to search for the CP-violation in the lepton sector. Previously, various variants of neutrino channels at the U-70 accelerator were considered for these experiments. In this paper, the neutrino beams formed in these channels are considered; their characteristics are compared. Different types of uncertainties in the experiment are considered and their contributions to the measurement error of the CP-violation phase and their comparative analysis has been carried out. This will make it possible to further shape the optimal architecture of planned long-baseline experiments (i.e., to determine the type and characteristics of the beam, detectors, and the required integral intensity of the experiment) at the qualitative level. Also in this work, we calculate the sensitivity of the P2O experiment to the measurement of the CP-violation phase using each of the neutrino beams considered earlier. The choice of the optimal channel variant, which allows us to ensure the maximum sensitivity of the P2O experiment to the planned measurements, is carried out.
Physics of Atomic Nuclei. 2025;88(1):73–80
73–80
OPTICAL SCHEME OF THE NEUTRINO CHANNEL WITH MAGNETIC HORNS AND DIPOLES AT THE U–70 ACCELERATOR COMPLEX
Abstract
The optical scheme of the channel based on two magnetic horns for the formation of neutrino beams with a narrow energy spectrum at the U–70 accelerator complex for the P2O experiment is considered, the far detector of which is located at a distance of 2595kmfromthe end of the decay channel.To select the required momentum interval of π-mesons two dipole magnets with opposite polarity is proposed to use. The decay part of the channel is rotated relative to the direction of the primary proton beam to the target. The main calculated characteristics of neutrino beams at the far detector of the P2O experiment at an energy of the primary proton beam of 60 GeV are discussed.
Physics of Atomic Nuclei. 2025;88(1):81–88
81–88
ЭЛЕМЕНТАРНЫЕ ЧАСТИЦЫ И ПОЛЯ. Теория
INFLUENCE OF INVERSE GLUON EMISSION ON FORWARD–BACKWARD ASYMMETRY IN DILEPTON PRODUCTION PROCESS AT LHC
Abstract
Inverse gluon emission in the dilepton production process in hadron collisions for Large Hadron Collider (LHC) experimental program aimed is estimated in details. Numerical analysis of inverse emission effects on observable quantities (cross sections and, in more details, forward–backward asymmetry) is performed in a wide kinematical region including the CMS LHC experiment in Run3/HL regime which corresponds to ultra-high energies and dilepton invariant masses. Effective technics for analysis of the influence of different radiative contributions on forward–backward asymmetry using two additive relative corrections is suggested.
Physics of Atomic Nuclei. 2025;88(1):89–101
89–101
PROCEEDINGS OF 74TH INTERNATIONAL CONFERENCE ON NUCLEAR PHYSICS “NUCLEUS-2024: FUNDAMENTAL PROBLEMS AND APPLICATIONS”, 1–5 JULY 2024, DUBNA, RUSSIA. Nuclei. Experiment
CORRELATION CHARACTERISTICS OF THE 20Ne(2+, 1.634 MeV) NUCLEUS, FORMED IN THE 19F(α, t)20Ne REACTION AT 𝐸α = 30.3 MeV
Abstract
The differential cross sections of the 19F(α, t)20Ne(g. s., 2+, 4+) reaction studied at the cyclotron of the MSU Institute of Nuclear Physics, tg-angular correlations in the reaction 19F(α, t)20Ne(2+) at the energy Eα = 30.3 MeVand the tensors of the orientation of the multipole moments and the alignments Fk(θt) of the 20Ne(2+) nucleus reconstructed on their basis are compared with the calculated ones under the assumption of a direct mechanism of proton stripping taking into account the coupling of channels using the Coupled Сhannels Born approximation. A set of calculation parameters necessary for such a reaction mechanism is established and their specific values are determined. The calculated differential cross sections of the reaction 19F(α, t)20Ne for all states of the rotational band agree with the experimental ones at θt < 120∘, where the direct mechanism makes the main contribution. In the same region of θt the calculated F2(θt) and F4(θt) of the 20Ne(2+) nucleus agree satisfactorily with the experimental ones. It was found that their value at θt < 120∘ is small, so the isotropy of the spin distribution in 20Ne(2+) is not violated. At large angles θt both the experimental and calculated values of F4 are about 0.5, that indicates a partial violation of this isotropy.
Physics of Atomic Nuclei. 2025;88(1):102–109
102–109
INVESTIGATION OF (γ, xn)-REACTIONS ON NATURAL IRIDIUM AT 55 MeV BREMSSTRAHLUNG END-POINT ENERGY
Abstract
The paper presents the results of a study of the flux-weighted average cross sections of 185–190Ir and 192Ir nuclei production in (γ, xn)-reactions under irradiation of a natural mixture of iridium isotopes by Bremsstrahlung with an end-point energy of 55 MeV. For the first time experimental data on the weighted average cross-sections of photoneutron reactions with the emission of up to 6 particles have been compared with theoretical weighted average cross-sections calculated in the framework of the Fermi model with a constant temperature and the Gogni–Hartree–Fock–Bogoliubov nuclear mass model using the TALYS1.96 software. It is demonstrated that the cross sections of the investigated reactions can be accurately described by the Fermi model with a constant temperature, which incorporates pre-equilibrium processes.
Physics of Atomic Nuclei. 2025;88(1):110–115
110–115
DETERMINATION OF EXCITATION ENERGY SPECTRUM OF 6Li IN THE n + 6Li REACTION
Abstract
An experiment on the study of the 3He + t cluster structure of the 6Li nucleus in the reaction 6Li(n; 3He n)t was carried out on the RADEX neutron channel of the INR RAS at a neutron energy of 40–60 MeV. The excitation energy spectrum of 6Li was obtained in the range Ex = 16–50 MeV. At the excitation energy Ex = 16.6 MeV a resonance with Γ = 0.7 MeV was detected, and in the range Ex = 30–50 MeV two broad resonances Ex = 35.9 MeV with Γ = 8.4 MeV and Ex = 43.1 MeV with Γ = 5.4 MeV were detected. All levels are observed for the first time.
Physics of Atomic Nuclei. 2025;88(1):116–123
116–123
CURRENT STATE AND PROSPECTS OF USING IONIZING RADIATION SOURCES IN RUSSIA
Abstract
An analysis of the status and use of various types of ionizing radiation sources in science and industries of the national economy of Russia for 15 (2007–2022) years is presented. The review is based on objective data from scientific journals, printed/online sources of the IAEA and some governmental structures of our country. Availability and use of ionizing radiation sources in Russia and in the world are compared. The state and prospects of application of installations based on ionizing radiations both in fundamental science and in industry, agriculture and medicine are considered. The correlation of high-tech installations and devices is studied: accelerators (on counter beams, high, medium and low energies), reactors (power, industrial and research), thermonuclear installations, X-ray equipment, isotope devices and instruments. Trends of application of ionizing radiation sources in science and economy of Russia are studied. Effective measures to create conditions for technological independence of our country’s economy are proposed.
Physics of Atomic Nuclei. 2025;88(1):124–136
124–136
PROCEEDINGS OF 74TH INTERNATIONAL CONFERENCE ON NUCLEAR PHYSICS “NUCLEUS-2024: FUNDAMENTAL PROBLEMS AND APPLICATIONS”, 1–5 JULY 2024, DUBNA, RUSSIA. Nuclei. Theory
EVOLUTION OF NEUTRON SHELL STRUCTURE OF N = 14, 16 ISOTONES
Abstract
The evolution of the single-particle characteristics of neutron and proton-excess isotones with the new magic numbers N = 14, 16 in the Z range from 8 to 20 in the dispersive optical model was traced. The calculated energy gaps N = 14 and 16 widened with the increase in excess of protons and neutrons respectively. At the same time, the deviation of half-sum of the single-particle energies of the last predominantly occupied and the first predominantly unoccupied states from the Fermi energy decreased. The widening of the gaps enhanced under the assumption of an increase in the diffuseness of the Hartree–Fock component of the dispersive optical model potential with an increase in the neutron excess over the range of Z numbers considered. The bubble structure manifests clearly in the neutron density distribution of the proton-unstable nucleus 34Са.
Physics of Atomic Nuclei. 2025;88(1):137–144
137–144
THEORETICAL STUDY OF THE TRANSFER REACTIONS IN THE D–D SYSTEM
Abstract
In this work, the transfer reactions proceeding in the d–d system, such as D(d, p)T and D(d, n)3He, are studied by means of the microscopic multichannel cluster approach in the oscillator representation. Both reactions are of great interest for pure and applied physics. Their total and partial astrophysical S factors are calculated at low energies. The contributions of the different channels are discussed, the most important ones are carefully analyzed. Manifestations of the nuclear tensor force in dynamics of the studied transfer processes are considered. A comparison of the obtained results with experimental data demonstrates a good agreement.
Physics of Atomic Nuclei. 2025;88(1):145–150
145–150
MACHINE LEARNING IN THE PROBLEM OF NO CORE SHELL MODEL RESULT EXTRAPOLATIONS
Abstract
A method for extrapolating the results of variational calculations to the case of the infinite basis using an ensemble of artificial neural networks is proposed. Extrapolations of the no-core shell model results obtained with nucleon-nucleon interaction Daejeon16 for the ground state energies, as well as for the rootmean-square point-proton, point-neutron and point-nucleon (matter) radii of the 6Li and 6He nuclei, are performed.
Physics of Atomic Nuclei. 2025;88(1):151–160
151–160
PROCEEDINGS OF 74TH INTERNATIONAL CONFERENCE ON NUCLEAR PHYSICS “NUCLEUS-2024: FUNDAMENTAL PROBLEMS AND APPLICATIONS”, 1–5 JULY 2024, DUBNA, RUSSIA. Elementary particles and fields. Experiment
POSITION-SENSITIVE CHERENKOV MONITOR OF HIGH-INTENSITY PROTON BEAMS
Abstract
The results of the study of the Cherenkov monitor of proton beams with a high pulse current are presented. For proton beams with an energy of 160 MeV and a pulse current of 4 mA, good agreement was obtained between the monitor measurements and the data of the beam current transformer. Bench measurements of the position coordinate of the light flux simulating the light image of the proton beam in the radiator of the 2-coordinate monitor were carried out. An analysis of the algorithms for restoring the position coordinate of the light beam with the results of the monitor simulation is presented.
Physics of Atomic Nuclei. 2025;88(1):161–166
161–166