2017-1 (1.257.218)
Brief Review of Topmost Scientific Results Obtained in 2016 at the Joint Institute for Nuclear Research
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E2-2017-2 (182.901)
Tokarev M., Zborovský I.
Top-Quark ρT -Spectra at CMS and Flavor Independence of z-Scaling
We present new results of the analysis of top-quark differential cross sections obtained by the CMS Collaboration in ρρ collisions
within the z-scaling approach. The spectra are measured over a wide range of collision energy √s=7, 8, 13 TeV
and transverse momentum ρT = 30–500 GeV/c of top-quark using leptonic and jet decay modes. Flavor independence of the scaling function ψ(z)
is verified in the new kinematic range. The results of analysis of the top-quark spectra obtained at the LHC are compared with
similar spectra measured in ρρ collisions at the Tevatron energy √s = 1,96 TeV. A tendency to saturation of ψ(z) for the process at low z and
a power-law behavior of ψ(z) at high z is observed. The measurements of high ρT spectra of the top-quark production at the highest LHC energy
is of interest for verification of self-similarity of particle production, understanding the flavor origin, and search for new physics symmetries with
top-quark probe.
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P2-2017-3 (337.191)
Dedovich T. G., Tokarev M. V.
Reconstruction of Fractals in the Presence of Background Events
Analysis of samples containing fractal and background events is performed using
the method of systems of equations of P-adic coverages (SePaC)
and Box Counting (BC) method.
The features of these methods are studied.
The procedures to indicate the existence of fractals in the combined sample,
reconstruct fractals, estimate a fraction of fractals
and estimate background in the extracted sample are suggested.
The results of a comparative analysis of combined fractal samples
using these methods are presented.
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P13-2017-4 (519.460)
Pepelyshev Yu. N., Tsogtsaikhan Ts.
Investigation of the Dynamics of Pulse Energy Noise at the IBR-2M
Reactor in the Fuel Burnup
In this paper, we present the results of a study on pulse energy noise
dynamics of the IBR-2M in the fuel burnup for a significant period of the
reactor operation, starting from the date of its commissioning in
2011 and until the end of 2016. It is shown that the pulse energy noise
during operation of the IBR-2M with burnup to about
∼1100 MW·day changes significantly by both the spectral component and the level. The
standard deviation of the random power fluctuations did not exceed 5% and
was less than allowable. In addition, the low level of low-frequency
noise (∼1,6%) indicates the absence of sign of
vibrational instability of the reactor and a substantial margin of burnup
until instability.
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E19-2017-5 (386.497)
Koltovaya N. et al.
Kinetics of Gene and Chromosome Mutations Induced by UV-C in Yeast Saccharomyces cerevisiae
The systematic study of the kinetics of UV-induced gene and structural mutations in eukaryotic cells was carried out on the basis
of model yeast S. cerevisiae. A variety of genetic assays (all types of base pair substitutions, frameshifts, forward mutations
canl, chromosomal and plasmid rearrangements) in haploid strains were used. Yeast cells were treated by UV-C light of fluence of energy
up to 200 J/m2. The kinetics of the induced gene and structural mutations is represented
by a linear-quadratic and exponential functions. The slope of curves in log-log plots was not constant,
had the value 2-4 and depended on the interval of doses. It was suggested that it is the superposition
and dynamics of different pathways form the mutagenic responses of eukaryotic cells to UV-C light that cause the high-order curves.
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P19-2017-11 (125.300)
Kiselev Yu.F.
Analytical Model of Active and Passive Transport in Biological Membranes
A formula is obtained for calculating the ion concentration profile in biological membranes. It is assumed that spherical ions move in an aqueous solution under the influence of an electric field and a concentration gradient. The friction force follows the Stokes law. The ions are covered with hydrate shells consisting of a dipole of water molecules which change their effective radius and friction.
It is shown that if the friction force at the membrane inlet is stronger than at its outlet, then the ions can move by active transport.
Analysis of the hydration allows the development of an analytical model of active and passive ion transport in membranes.
The calculations are consistent with the concentration profile of Na+1, K+1 and Cl-1 measured in frog and squid cells.
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E3-2017-12 (1.674.130)
Aksenov V. L.
A 15-year Forward Look at Neutron Facilities in JINR
The service life of the IBR-2 reactor, one of the leading pulse neutron
sources in the world, is expected to end in 2032. Modern trends in sciences
where neutrons are used, possible variants of a concept for a new neutron
source and its potential position in the world neutron landscape are
discussed. The flagship experiments for a new neutron source in the fields
of condensed matter research, fundamental and nuclear physics are proposed.
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P9-2017-13 (883.500)
Dolya S. N., Sarkhadov I.
Calculation of High-Current Linear Proton Accelerator
with an Energy of 80 MeV
This article considers the possibility of pulsed acceleration in a spiral
waveguide of a proton beam with the current Ib = 0,7 A. The accelerator
consists of three parts. The energy of the proton injection is 50 keV. In
the first part of the accelerator having the length
Lacc1 ≈ 1,4 m, the protons are accelerated up to
the energy ϵ 1fin = 0,8 MeV.
In this section of the accelerator, consumption of high-frequency power is
P1 = 0,8 MW. In the second part of the accelerator with the length
Lacc2 ≈ 2 m, the protons are accelerated up to the energy
ϵ 2fin = 5 MeV. Consumption of high-frequency power in the second
part of the accelerator is P2 = 4 MW. The third part of the
accelerator consists of 8 sections, each being 7 m long. Radial focusing of
the proton beam in this accelerator is carried out with the magnetic field
intensity H = 10 , generated by a superconducting solenoid.
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P13-2017-16 (431.772)
Agapov A. V., Mitsyn G. V.
Multichannel Magnetic Field Measuring System
Using Hall Sensors for Proton Therapy Beamline Elements ControlA 15-year Forward Look at Neutron Facilities in JINR
The article considers the design and construction of a multichannel magnetic field measuring system using
Hall sensors elaborated at the Medico-Technical Complex of the DLNP, JINR. The developed system allows
monitoring magnetic induction fluctuations of the bending electromagnets of the proton therapy beamline.
The thermostatic and power supply modules have been designed to solve the problem of thermal instability
of Hall sensors. The set-point temperature of working volume of the Hall sensors is about 40°C with
an accuracy of ± 0.05°Ñ; and the precision of supply voltage is ± 1 mV. The multichannel
magnetic field measuring system is routinely used in the proton therapy treatment sessions implementing
the “quality assurance” of treatment.
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P1-2017-17 (241.196)
Zinchenko Al. I. et al.
The Solenoid for the SPD Set-Up of the NICA Collider
Requirements were considered and recommendations were formulated for the
later technical design of the magnet for the SPD set-up. It has been shown
that to get magnetic field homogeneity in the 1% limits for the whole
inner solenoid volume, one has to use additional coils which must be placed
in the end faces of the solenoid. The superconducting magnet is preferred to
the warm version due to the lower weight and occupied volume of the coil,
and the absence of the heat evacuation problem also.
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P9-2017-18 (1.612.690)
Butenko A. V. et al.
Magnetic Field Errors Tolerance of Nuclotron Booster
Generation of magnetic field in the units of the booster synchrotron for the
NICA project is one of the most important conditions for getting the
required parameters and qualitative accelerator operation.
Research of linear and nonlinear dynamics of the 197Au31+ ion
beam in the booster was carried out with the MADX program. Analytical
estimation of magnetic field errors tolerance and numerical computation of
dynamic aperture of the booster DFO-magnetic lattice is presented. Closed
orbit distortion with random errors of magnetic fields and errors in layout
of the booster units was evaluated.
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E1-2017-20 (187.754)
Glonti L. et al.
Longitudinal Tension and Mechanical Stability of a Pressurized Straw Tube
When developing charged particle detectors based on straw tubes working in vacuum, a special technique
is needed for their mechanical properties evaluation. An experimental method of strained pressurized straw
tube mechanical properties study is presented. The performed measurement results are in agreement with the
approximate calculations taking into account the known uncertainties of the wall material parameters. It is shown that the difference between the tube wall longitudinal tension and the pressure force applied to the tube cross section area defines both the straw tube transverse stability and the lowest value of its oscillation frequency.
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P10-2017-21 (333.944)
Derenovskaya Î. Yu., Ivanov V. V., Ogorodnikova D. S.
J/ψ → e+e– Decays Selection Criteria for Au + Au Collisions at 10A GeV in the CBM Experiment
Currently the CBM experiment is being
developed in GSI (Darmstadt, Germany) at the FAIR accelerator complex of an international
collaboration with JINR. Measurements of the J/ψ → e+e– decays are the key objectives
of the CBM experiment, the registration of such decays is planned to be held in real-time experiment.
The current paper presents criteria that provide an effective selection of signal
events for Au + Au collisions at 10A GeV. This energy corresponds to the first stage of the CBM experiment.
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E9-2017-23 (304.357)
Sabirov B. et al.
Recent Optimized Design of ILC Cryomodule with Explosion Welding Technology
This paper summarizes the test results of modified components
for the cryomodule of the International Linear Collider (ILC) obtained by the international
collaboration of JINR (Dubna, Russia), INFN (Pisa/Genova, Italy), and PWI (Kiev, Ukraine).Initially,
the baseline design for the superconducting RF cavities of the ILC is the TESLA 1.3 GHz cavity design
developed at DESY consisting of a 9-cell cavity structure of Nb sheet material and Ti for the surrounding helium
vessel and for the biphase He gas return pipe. To make the ILC project even cheaper, it is proposed to replace titanium
cryomodule components with stainless steel (SS) ones using a unique method based on explosion welding, opening up the possibility
to develop a new-generation of cryomodules for particle accelerators. These cryogenic system components operate at superlow temperatures,
as niobium cavities are contained in a stainless steel vessel filled with superfluid liquid helium at 1.8 K. Stepwise upgrading of these
components to the latest version of the Nb/Ti/SS transition element has led to an evolutionary improvement of the ILC cryomodule.
This new component resolves problems of residual stress, and its peculiar design prevents the possibility of a shift due to the difference
in the linear expansion coefficients of the constituent metals. He leak testing found no leaks at the background rate
of
≈ 0,4 · 10-10 àòì · cm3 · c–1
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E1-2017-24 (145.302)
Komarov V. I.
On the Possibility of Revealing the Transition of a Baryon Pair State to a Six-Quark Confinement State
Proton--proton collisions are considered to find favorable conditions for searching for the transition of a baryon pair state
to a hexa-quark confinement state
(3q) + (3q) → (6q)cnf. It is admitted that central pp collisions in a definite range
of the initial energy can lead to creation of an intermediate compound system where the hexa-quark dibaryon can be formed. Criteria
for the selection of central collision events and for manifestation of the quark-structure dibaryon production are proposed.
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P1-2017-26 (640.460)
Lenivenko V. V., Palichik V. V.
Reconstruction of Charged Particle Trajectories in Multiwire Proportional Chambers at the BM@N Experiment
The algorithm for track reconstruction in the multiwire proportional
chambers (MWPC) of the BM@N experiment is described. Beam tracks before the
interaction with the target and trajectories of charged particles after the
interaction are reconstructed using Nuclotron experimental data with
deuteron and carbon beams colliding with the carbon and copper targets.
Trajectories are extrapolated to the interaction point and to the drift
chambers. Efficiencies of MWPCs have been obtained. Beam parameters (transverse dimensions, the angular spread) have
been measured.
D13-2017-28 (225.935)
Chirikov-Zorin I.
New Method for Determining Avalanche Breakdown Voltage of Silicon Photomultipliers
The avalanche breakdown and Geiger mode of the silicon p–n junction is considered. A precise physically motivated method is proposed
for determining the avalanche breakdown voltage of silicon photomultipliers (SiPM). The method is based on measuring the dependence
of the relative photon detection efficiency (PDErel) on the bias voltage when one type of carriers (electron or hole)
is injected into the avalanche multiplication zone of the p–n junction. The injection of electrons or holes from the base region
of the SiPM semiconductor structure is performed using short-wave or long-wave light. At a low overvoltage (1–2 V) the detection
efficiency is linearly dependent on the bias voltage; therefore, extrapolation to zero PDErel value determines the SiPM avalanche
breakdown voltage with an accuracy within a few millivolts.
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P3-2017-32 (218.128)
Êiselev Ì. À. et al.
Analysis of Vesicular Structure of Nanoparticles in the Phospholipid Based Drug Delivery System using SAXS Data
Small-angle X-ray scattering has been used
to characterize the Phospholipid Transport Nanosystem (PTNS) at the PTNS concentrations in water
of 25%, 31.25%, and 37.5%. The vesicle's average radius, size polydispersity, bilayer thickness,
and internal structure were evaluated from the experiment via applications of two models for the photon scattering
density distribution. Two independent methods were used for the calculation of the SAXS spectra: the form factor of
the heterogeneous spherical shell and the method of separated form factors. Two methods of the spectra calculation
and two models for the approximation of the photon scattering length density evaluation provide coincident results,
which demonstrate the decrease in the vesicle radius, thickness of the bilayer, and thickness of the hydrocarbon chains
region at the increase in the maltose concentration in water.
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