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Preprints and Communications
 Here you can find JINR preprints and communications in pdf format starting from 1999. File size is given in bytes in round brackets.
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E4-2024-61 (338.351)
Efimov A. D. et al.
Moments of Inertia in IBM
For more convenient visualization of the character of the spectrum in the band, as well as the quality of reproduction of experimental energies in various
models, it is convenient to move from energies to effective moments of inertia J depending on the square of the rotation frequency ω2. In this regard, it is found out
what character of J (ω2) can be reproduced by various limiting cases of IBM, as well as what are the variations in the behavior of J (ω2) for arbitrary values
of the IBM Hamiltonian parameters. This can provide additional information on
the change in the nature of states in the bands as the spin increases.
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P18-2024-60 (4.048.625)
Litvak I. L. et al.
Operating Principles of a Device for Producing Dispersed Moderating Material in the Form of Balls for Cryogenic Neutron Moderators
A study of the main physical effects occurring during the production of dispersed moderating substance for cryogenic neutron moderators of the IBR-2M research pulsed
reactor (JINR, Dubna) was conducted. The results of the study can be used as a basis for developing a more advanced dispersed moderating substance that will increase
the safety of operation of the cryogenic moderator complex and improve its performance characteristics.
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P11-2024-57 (1.956.780)
Palii Yu.G., Bogolubskaya A. A., Yanovich D.A.
Modeling of the Operation of the Algorithm QAOA with the Software Library Cirq
We discuss the problem of finding the lowest energy state in the Ising model with a longitudinal magnetic field on a quantum computer using the quantum approximation
optimization algorithm (QAOA). The base states of the quantum computer register correspond to spin configurations on a spatial lattice. The Hamiltonian of the model is represented
by a set of quantum gates. The average energy value can be effectively measured using the Hadamard test. Increasingly complex examples are used to simulate the operation of the
quantum algorithm QAOA by means of the software library Cirq. The main arguments in favor of the efficiency of using a quantum computer in this problem are presented.
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E11-2024-56 (927.077)
Chervyakov A.M.
FEM-Based Approaches to Modeling the Resource-Demanding Magnetostatic Problems with Magnetic Scalar Potential
The paper aims to improve the computational efficiency of 3D finite-element
method for modeling the resource-demanding magnetization problems in the
presence of steady currents and nonlinear magnetic materials. For this purpose,
new approaches based on the use of magnetic scalar potential for numerical
analysis of Maxwell’s equations and modeling the inductive effect of conductors
using both the scalar potential discontinuities of thin cuts and the magnetizations
of linear and nonlinear permanent magnets are proposed and validated. Compared
to the computationally expensive standard approach for modeling magnetic fields
in dipole magnet with magnetic vector potential and the current-carrying coil,
the novel approaches allow us to obtain the expected results with similar
accuracy at much lower computational cost.
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P7-2024-50 (1.565.878)
Kuznetsova A. A. et al.
Properties of Radioactive Decay of the New Nucleus 227Pu
A new isotope 227Pu was discovered by complete fusion reactions
26Mg+204Pb and 26Mg+206Pb. The experiment was carried out at the GRAND
separator of the SHE Factory at FLNR, JINR. For the nucleus 227Pu, an
α-particle energy of Eα = (8156 ± 26) keV and a half-life of T1/2 = 2.2+0.5–0.3 s were
measured. A single event with Eα = (8754 ± 24) keV and an estimated lower
limit half-life of 1 ms from the measured lifetime, which is probably attributed
to the new isotope 226Pu, was identified by chains with 222U.
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P11-2024-49 (5.348)
Batmunkh M., Bayarchimeg L., Bugay A.N.
Mathematical Modeling of Radiation-Induced Effects in Central Nervous System Structures Following Exposure to Heavy Accelerated Charged Particles
Theoretical research is presented on the basic mechanisms of action of accelerated heavy charged particles on the structures of the central nervous
system, taking into account their complex geometry. Analysis was conducted on
the spatial distribution patterns of absorbed dose and the probability of particle hits in various parts of a cell (body, axon, dendrites, spines) following exposure
to charged particles — from protons to iron ions with the energy ranging from 10 to 1000 MeV/nucleon. Mechanisms of the formation of both direct and
indirect molecular damage in the genetic apparatus and synapses of neurons were considered, involving physical processes that lead to bond breakage as well as
chemical reactions with products of water radiolysis. Key modeling parameters necessary for verifying the calculations against experimental results are also
discussed. The data obtained can be used for further analysis radiation risks during interplanetary missions, evaluating the side effects of hadron therapy.
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E4-2024-27 (1.257.216)
Efimov A. D., Izosimov I. N.
Advanced Microscopic IBM1 Version. Description of the Crossing of Bands in Xe and Th Isotopes
The boson representation of fermion operators is used. A
method is described for calculating the parameters of boson operators based
on consideration of matrix elements between phonon states with a minimum
number of the latter. The configuration space of bosons is expanded up to
bosons with multipole J = 14+. Within the framework of this method, the
effect of backbending in even isotopes 112–128Xe is considered, where
it is clearly manifested. In even 220–236Th isotopes, where backbending
is observed only for the lightest of these nuclei, the intersection of bands
is obtained only for two nuclei. Moreover, for 222Th it is so smooth
that it does not appear through the moment of inertia. Among the properties,
the energies of the yrast bands and the values of B(E2) are considered.
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P13-2024-22 (6.474.596)
Pepelyshev Yu. N. et al.
Preliminary Computations for the Pulsed Reactor IBR-4. Optimization of the Neutron Flux
The IBR-4 pulsed reactor with a power of 4 MW and a pulse repetition
frequency of 10 s–1 is considered as a pulsed neutron source to replace the
IBR-2M reactor, which will be decommissioned by the end of the thirties. The
design of the IBR-4 is based on the MBIR reactor with some rearrangement of
the core. The core, with the changes made, ensures the nuclear safety of the
reactor and minimizes the low-frequency fluctuations in pulse energy
inherent in periodic pulse reactors. The optimal design of the IBR-4 core is
based on the basic design with the addition of beryllium reflectors and
small volume water moderators. The IBR-4 reactor, with a relatively small
average power of 4 MW, makes it possible to obtain thermal neutron flux
densities on the surface of the water moderator for the derived neutron
beams at the level of 1.2 · 1014 cm–2 · s–1, and in
the area close to the surface —
3.0 · 1014 cm–2 · s–1.
Therefore, IBR-4 is a powerful pulsed source of thermal neutrons.
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E11-2024-17 (469.408)
Gordeev I. S., Bugay A. N.
Computer Modeling of a New Type Galactic Cosmic Rays Simulator
A new type of a galactic cosmic rays (GCR) simulator, provided at the JINR Laboratory of Radiation Biology,
is potentially capable of generating a complex radiation field with inclusions of a variety of ions with a wide energy range
and with required abundance at the charged particle accelerators. This complex multicomponent radiation field simulates radiation
environment inside a spacecraft during an interplanetary flight, for example, to Mars. The paper provides an analytical description
of the GCR simulator as well as a description of a specially developed software that enables selection of necessary parameters of a simulator model
for creating relevant mixed radiation conditions. The software implements processing of data obtained with Monte Carlo-based FLUKA and PHITS programs,
fitting and optimization of model parameters as well as data visualization tools.
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D17-2024-16 (43.002.580)
Shukrinov Yu. M., Botha A. E.
JINR-UNISA Results of Collaboration on Theoretical Study of Josephson Nanostructures
An overview of the results obtained within the framework of the JINR—UNISA collaboration in the field of theoretical study
of Josephson nanostructures is presented. In particular, our work has involved studies of a wide variety of nonlinear
dynamic effects in various systems of coupled Josephson junctions, including superconductor/ferromagnet/superconductor junctions,
which are currently being investigated intensively due to the potential applications in superconducting electronics and spintronics.
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E6-2024-14 (177.455)
Izosimov I. N.
Manifestations of the Intermediate Structure
in the γ Decay of Non-Analog Resonances
The angular distributions of γ radiation during
the decay of non-analog resonances in reactions 58, 60, 62Ni (p, γ ) 59,61,63Cu are analyzed. The coefficients of decomposition of angular
distributions by Legendre polynomials, the correlation of widths and the
distribution function of a mixture of multipoles δ for M1+E2 γ decays of non-analog resonances are analyzed. Unambiguous evidence of the
non-statistical nature of the studied resonances has been obtained. A possible reason for the manifestation of non-statistical effects in
(p, γ ) reactions is discussed.
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E4-2024-13 (177.455)
Kuz'min V. A., Tetereva T. V.
Formation of Superconducting Pair Correlations in Spherical Even-Even Nuclei
The appearance of like nucleon pair correlations in the ground state of spherical even-even nuclei is considered within
the special Bogoliubov transformation. It is confirmed that in closed subshell nuclei, superconducting pair correlations appear if the
coupling constant G exceeds a certain threshold value. Rough upper and lower estimates are obtained for the threshold value.
It is shown that superconducting correlations exist in open subshell nuclei at any positive G. In this case, nucleon pairs are distributed
over all subshells participating in the pairing interaction.
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P13-2024-7 (3.929.070)
Pepelyshev Yu. N. et al.
Preliminary Computations for the Pulsed Reactor IBR-4. Basic Composition
By the end of the thirties, the IBR-2M reactor will be decommissioned.
The authors suggested that after the decommissioning of the reactor, they should not create an absolutely new neutron source,
which would require significant development work, but use positive technical solutions tested at other fast neutron nuclear facilities,
for example, IBR-2, IBR-2M, MBIR, BOR-60, BN-1200 and others. This is a conceptual vision of a new source, called IBR-4. Special attention
in IBR-4 was devoted to the issues of stable reactor dynamics. The article is based on calculations for the so-called basic composition
of the IBR-4, which considers the fundamental possibility of implementing positive technical solutions. In the next work, based on the basic composition,
the IBR-4 core and its immediate environment — all that makes it possible to increase the density of the thermal neutron flux on the extracted
neutron beams and at the same time fully ensure the reliability and safety of the reactor — will be considered. It is expected that the parameters
of the IBR-4 will be significantly higher than the parameters of the IBR-2M.
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P11-2024-5 (683.575)
Bureš M. et al.
Application of the Hopfield Network to SPD Track Reconstruction
One of the key stages of processing data from particle physics experiments is the reconstruction
of trajectories (tracks) of interacting particles from measurement data. In the SPD experiment planned at the NICA collider,
a special difficulty will be caused by the extremely high frequency of interactions (3 MHz), which leads to overlapping of events during
the data acquisition in the time-slice mode, as well as by the strong contamination of data by fake measurements due to the specifics of
the track detectors. This makes track reconstruction (tracking) algorithms very complicated.
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