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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.
| 2022 |
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E3-2022-43 (1.179.334)
Sukhovoj A. M., Mitsyna L. V.
A Possibility of Simultaneous Obtaining of the Nuclear Level Density and Radiative Strength Functions When Analyzing (n,2γ) Reaction
For 43 compound nuclei from the 40 ⩽ A ⩽ 200 mass region,the most probable nuclear-physical parameters
(the radiative strength functions and nuclear level density) were accumulated obtained by the empirical method of analysis of precise experimental
intensities of the two-step γ cascades in nucleus decaying after thermal neutron capture. The method allows obtaining the strongly correlated
nuclear-physical parameters from indirect experiment simultaneously which enables to investigate the intranuclear processes. The results of the empirical
analysis are presented for all investigated nuclei when testing versions of model representations of energy dependences of the required nuclear-physical parameters.
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P13-2022-40 (396.114)
Avdeev S. P. et al.
Detector for Setting Up Beam Convergence and Determining Luminosity at the
Interaction Point on the MPD NICA
A detector for adjusting the convergence of beams at the point of
interaction of the MPD (Multi-Purpose Detector) installation at the NICA
collider (Nuclotron-based Ion Collider fAcility) is discussed. Simulation of
the detector operation for Au + Au collisions at √SNN = 11 GeV is performed. It is shown
that background events from scattering on residual gas give a negligible
contribution to the detector's samples. The question of how to use a detector to
adjust beam alignment is discussed. The calibration procedure for obtaining absolute
luminosity in the MPD interaction zone with the help of this detector is
considered.
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P13-2022-33 (537.588)
Artukh A. G. et al.
Precision High Voltage Sources for Nuclear Radiation Detectors on POL-12012
(KST-POL-12012) Transformers
Precision high-voltage sources have been developed for nuclear radiation
detectors (semiconductor detectors, based on photomultipliers, etc.). Instead of
a specialized high-voltage source, an AC line voltage transformer (∾220 V)
POL-12012 together with a voltage multiplier was used. Electrical parameters
of the units: range 0...+/–2,5 kV, power ⪯10 W, efficiency 77%, ripple
factor (2 kV/1 mA) – 1 mV, conversion frequency 80–150 kHz, temperature drift
⪯004%/°Ñ, operating temperature –40...+ 60°Ñ, manual/external control,
smooth rise/fall of voltage, shutdown during overload.
Structurally, the blocks are made in two versions: Euromechanics 3U or
stand-alone module 80x80x40 mm. They are used in a number of experiments
and industrial installations, where they provide quality, reliability, temperature
range and the necessary functionality.
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P11-2022-32 (301.110)
Amirkhanov I. V. et al.
Numerical Investigation of the Influence of Finite Sample Thickness on Laser
Ablation of Materials
In previous works, numerical simulations of laser ablation of materials that
occurs under the action of ultrashort laser pulses in semi-constrained
samples were carried out.
In the present work, a similar numerical study was carried out in samples of
a finite size. The action of the laser is taken into account through the
source functions in the heat conduction equation, setting the coordinate and
time dependences of the laser source. During laser ablation of the material,
the thickness of the sample changes. By passing to the moving coordinate
system, the problem with moving boundaries is transferred to the problem
with fixed boundaries. In this case, in the heat conduction equation, along
with the diffusion term, a convective heat transfer term arises.
The effective speed of the convective term involves the speeds of displacements of the first and second boundaries, as well as the variable thickness of the sample.
In our new formulation of the problem, the variable thickness of the
sample affects not only the convective term, but it affects the diffusion
term, the source functions, and the boundary conditions of the heat
equation. These influences are visible from the mathematical formulation of
the problem itself.
Other effects are established by numerical simulation.
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P11-2022-31 (797.241)
Amirkhanov I. V., Sarkhadov I., Tukhliev Z. K.
Simulation of Thermal Processes Appearing in Materials under the Action of
Laser Pulses within the Hyperbolic Thermal Peak Model
The paper proposes a modification of the thermal spike model (TSM) based on
a system of two coupled hyperbolic heat conduction equations. The action of
the laser in the electron gas is taken into account through the source
function, which was chosen in the form of a double femtosecond laser pulse.
In the hyperbolic TSM, in contrast to the parabolic TSM, there are
additional parameters that characterize the relaxation times of the heat
flux in the electron gas and the crystal lattice. In addition, there are
additional terms in the sources of the hyperbolic TSM — derivatives from the
sources of parabolic equations and from the temperatures difference between
the electron gas and the crystal lattice. This means that the temperatures
of the electron gas and the crystal lattice are influenced not only by the
sources, but also by their rates of change.
Assuming that the thermophysical parameters of the sample material are
independent of temperatures, the hyperbolic TSM equations are linear.
Using this property of the equations in the present work, the contributions of each term of the common source in the electron
gas to the temperatures of the electron gas and the crystal lattice are established.
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D17-2022-30 (3.533.537)
Shukrinov Yu. M., Nashaat M.
JINR Collaboration with Scientific Institutions of Egypt in the Field of Theoretical Research of Superconducting Josephson Nanostructures
An overview of the results obtained in the framework of JINR collaboration with Egyptian scientific institutions
in the field of theoretical research and modeling of various superconducting Josephson nanostructures is presented. In particular,
systems of coupled Josephson junctions with various types of shunting are considered, and results are presented that reflect their
phase dynamics and current-voltage characteristics for various resonance phenomena. Much attention is paid to the study of superconducting structures
with ferromagnetic materials, which make it possible to control the magnetic properties of the system by a superconducting current.
An important place is occupied by joint studies of topological and chaotic phenomena in Josephson structures.
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E1-2022-29 (796.223)
Yurevich V. I.
Phenomenological Model of Nucleon-Induced Fission Cross Sections in High-Energy Region
A phenomenological model was developed for approximation and numerical estimation of fission cross sections
in interactions of high-energy nucleons with heavy nuclei. The model predictions are compared with the most reliable experimental data,
available estimations and theoretical calculations for different nuclei from 181Ta to 239Pu. The model reproduces
well the experimental results above 50 MeV and has good prediction potential.
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E1-2022-22 (287.247)
Sovd M. et al.
Thermodynamic Characteristics of Particles
Produced in π–C Interactions at 40 GeV/c as a Function of the Cumulative Number and the van der Waals Equation of State
In this paper we have determined constants a and b of the van der Waals equation of state using the experimentally obtained
critical parameters Tc, Vc and Pc for π–C mesons and protons from π–C interactions.
The P–V diagrams have also been analyzed.
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E1-2022-21 (267.611)
Sovd M. et al.
On the Possibility of Pion Condensation from π-C Interactions at 40 GeV/c
In this paper we consider an opportunity of observing the π–-meson condensation on the
basis of the dependence of temperature (T) on the target mass (mt )and chemical potential (μsec(μB,T)) obtained for π–+C interactions at 40 GeV/c.
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E1-2022-20 (267.611)
Baatar Ts. et al.
Two Different Distance Scales of q2 and VQCD Potential of Protons from π-C Interactions at 40 GeV/c
In this paper we have expressed the formula for the four-momentum
squared q2 as a function of two different distance scales r1 and r2. This procedure
necessitates taking into account an additional derivative from the formula for q2
(or the running coupling constant of αs(q2)). We have calculated the force using
the potential VQCD(r2). The impact of r2 parameter on the force has also been
studied.
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E6-2022-19 (270.279)
Efimov A. D., Izosimov I. N.
Extrapolation of the Energies of the 21+, 41+, 61+ States in the Superheavy Even–Even Nuclei
Based on the existing correlation between the
deformation energy and the lowest excitation energy, estimates were obtained
for energy of the 21+ states. The
considered systematics of the energy ratios in the rotational band also made
it possible to obtain estimates for the 41+ and 61+
states. A comparison with the results of other works was carried out.
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P3-2022-13 (496.940)
Dubois M. et al.
Enhanced Directional Extraction of Very Cold Neutrons Using a Diamond
Nanoparticle Powder Reflector
For more than a decade, Detonation NanoDiamond (DND) powders have been
actively studied as a material for efficient reflectors of Very Cold
Neutrons (VCNs) and Cold Neutrons (CNs). During this time, the storage of
VCNs in traps with walls made of DND powder and the quasi-specular
reflection of CNs from layers of DND powder have been experimentally
demonstrated. The quality of DND powder has been improved by reducing the
fraction of impurities causing neutron losses, as well as by choosing the
powder parameters that correspond to the most efficient reflection of
neutrons. Methods for calculating the transport of neutrons in real powders
have been developed. In this work, we experimentally demonstrate the
possibility of shaping a VCN beam using a reflector made of fluorinated DND
(F-DND) powder. With respect to the flux from an isotropic source located at
the bottom of the reflector cavity, the gain in the VCN flux density along
the beam axis is ∼ 10 for the neutron velocities of 57 m/s and
75 m/s. The gain in the total flux at the exit from the reflector cavity is
∼ 14 for the fastest VCNs from the interval 46—92 m/s
and increases with decreasing VCN velocity, reaching ∼ 33 for
the slowest VCNs.
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E7-2022-12 (413.769)
Isaev A. V. et al.
Spontaneous Fission of 246Fm
An experiment on the study of the 246Fm spontaneous fission was conducted using the SHELS separator. The isotope was synthesized in the complete
fusion reaction of 40Ar beam ions and 208Pb target nuclei.
The neutron yields of 246Fm spontaneous fission (¯ν = 3,79±0,30, σ2nu = 2,1) were obtained using the SFiNx detector system.
The multiplicity distribution of emitted prompt neutrons was restored using the Tikhonov method of statistical regularisation (¯νr = 3,79 ± 0,20, σ2νr= 2,8).
The spontaneous fission branching ratio (bSF = 0,061 ± 0,005) and the half-life (T1/2 = 1,50+0,08-0,07 s) of the isotope were determined.
The experimental data were compared with scission point model predictions. Excellent convergence was observed in the average number of neutrons per spontaneous fission process.
However, the forms of the experimental and model prompt neutron multiplicity distributions differ significantly.
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Ð9-2022-10 (927.586)
Teterev Yu. G. et al.
Estimation of the Yield and Angular Distribution of Neutrons for
Calculating the Biological Protection of Reconstructed Heavy Ion
Accelerators with Energies from 1 to 6 MeV/nucleon
Simple analytical formulas are presented for the operational estimation of
the yield and angular distribution of neutrons, which are necessary for
calculating the biological protection of heavy ion accelerators with
energies from 1 to 6 MeV/nucleon. The results of the calculation were
compared with the results of calculations using the LIZE++ and FLUKA
programs and with the available experimental data in the literature. As a
result of the comparisons, it can be argued that the proposed method for
calculating the yield and angular distribution of neutrons from thick
targets can be used to quickly assess the necessary biological protection of
heavy ion accelerators under construction and reconstruction with energies
from 1 to 6 MeV/nucleon. The deviation of the results of these calculations from
the more accurate ones does not exceed a factor of two, which is comparable
with the results of deviations in the calculation of biological shielding
associated with a certain variety of spectra of produced neutrons and
deviations in the protective properties of the materials used or their
thickness.
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P10-2022-5 (496.940)
Kirilov A.S., Murashkevich S.M.
Adaptation of the Sonix+ Software Package to Work
with DAQ Controllers DeLiDAQ-2 and Digitizer N6730 by CAEN
Before the use of DeLiDAQ-2 controllers and Digitizer N6730 on the IBR-2
reactor instruments, the main form of DAQ output data was spectral
distributions of intensities in matrix form, which, in particular, was used
in the Sonix$+$ software package for online visualization. Due to the fact
that output data from considered controllers are available only in the
events list form, the construction of spectral distributions (histogramming)
must be done by programs.The work is devoted to adaptation of the complex
for use of the controllers specified, algorithms of data histogramming for
them, as well as to tests results carried out at the GRAINS instrument (beam 10 of the IBR-2) in October 2021 consideration.
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P10-2022-4 (496.940)
Kirilov A. S., Truntova L. A.
Enhancement of Experiment Control in the Sonix+ Software Package
The work is devoted to enhancing the Sonix+ software package at the IBR-2
instruments to minimize the loss of measurement time when including
mathematical operations (summing matrices, building spectral distributions
of intensity based on data from the list of events, etc.) directly in the
experimental procedure in the Python language (script). For this purpose,
the execution of all such operations was separated from the main script into
one or more background scripts. A special device class has been added to the
complex structure to execute background scripts. Besides this, the
checkpoint mechanism previously used to connect the user interface with the
script has been replaced by a new one — based on Python language decorators
and context managers. This significantly simplified the script, improved its
reliability, and reduced the time of its development or modification.
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2022-2 (20.032.428)
Brief Review of Topmost Scientific Results Obtained in 2021 at the Joint Institute for Nuclear Research
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Ð9-2022-1 (2.030.431)
Kozlov O. S. et al.
Actual Tasks of Beam Dynamics Analysis in the NICA Collider
The NICA project is under development at the Joint Institute for Nuclear Research
(Dubna). The accelerator complex is in the stage of step-by-step assembly and commissioning. The complex consists of two superconducting synchrotrons and
a superconducting ion collider. Numerous studies of beam dynamics, performed
at the design stage, formed the basis of R&D of the collider systems.
Most part of tasks was done in detail and totally completed. However, a
number of tasks are not finished and actual to date. Some of them, being
fundamental, need detailed analysis using
three-dimensional particle tracing with taking into account all the main
physical effects and nonlinearities of electromagnetic fields of the
structure. Key task in the NICA collider is study of collective phenomena,
to which this work is mainly devoted. The paper describes the current status of
numerical and analytical calculations of beam stability in the NICA collider
and possible plans of solution of noncompleted tasks.
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