| 2016 |
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2016-9 (3.003.816)
Brief Review of Topmost Scientific Results Obtained in 2015 at the Joint Institute for Nuclear Research
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P15-2016-1 (14221.520)
Didyk A. Yu., Gulbekyan G. G., Myshinskiy G. V.
Anomalies on the Inner Surfaces of the Xenon High-Pressure Chamber
XeHPC 250 Bar with the Synthesis of Microparticles of Complex Composition
under Irradiation with Bremsstrahlung Threshold
Energy of 10 MeV
Natural xenon at an initial pressure of 250 bar in a special chamber (XeHPC)
was irradiated for 60 h 16 min (2.17· 105 s) by braking γ-rays with
a threshold energy of 10 MeV at the electron accelerator MT-25 at an average
intensity of the beam of 20–22 µA. With increase in temperature the
pressure in the steady
state at the beginning of exposure grew up to 270 bar. After opening of the XeHPC both internal chambers
with all the structures and particles, but without gas, were measured using
a γ-germanium detector.
Visual inspection of the inner chambers showed visible dense greenish-yellow
coating of
significant thickness formed on their
surfaces.
X-ray microprobe analysis (RMPA) and SEM studies allowed us to determine the composition of the synthesized particles.
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P11-2016-4 (255.5)
Amirkhanov I.V. et al.
Investigation of Quasi-Stationary States in the Double-Barrier Open Well
In this paper an investigation of solutions of quasi-stationary states in
the framework of the Schroedinger equation with complex energies with
piecewise constant potentials for various values of the parameters of the
potential is conducted. Quasi-levels are found for the under- and
above-barrier cases. For the given potential barrier heights the number of
under-barrier quasi-levels for the double-barrier potential is more than for
the single-barrier potential. The calculations show that the real part of
the energy varies smoothly and the imaginary part of the energy changes
irregularly when changing the parameters of the potential.
|
P9-2016-6 (927.7)
Nozdrin M.A. et al.
Diagnostics at JINR LHEP Photogun Bench
The photoinjector electron beam quality dramatically depends on the laser driver beam quality. For laser beam diagnostics a "virtual cathode"
system was realized at the JINR LHEP photogun bench. The system allows one to image laser beam profile at the cathode. The AVINE software complex developed in
DESY Zeuthen is being used for imaging. Equipment for emittance measurement using the slit method was installed. The original emittance calculation software
EmCa was created and tested with the laser beam.
|
E17-2016-8 (116.0)
Bogolubov N.N. (Jr.), Soldatov A.V.
Variational Master Equation Approach to Dynamics of Magnetic Moments
Non-equilibrium properties of a model system comprised of a
subsystem of magnetic moments strongly coupled to a selected Bose
field mode and weakly coupled to a heat bath made of a plurality
of Bose field modes were studied on the basis of non-equilibrium
master equation approach combined with the approximating
Hamiltonian method. A variational master equation derived within
this approach is tractable numerically and can be readily used to
derive a set of ordinary differential equations for various
relevant physical variables belonging to the subsystem of magnetic
moments. Upon further analysis of the thus obtained variational
master equation, an influence of the macroscopic filling of the
selected Bose field mode at low enough temperatures on the
relaxation dynamics of magnetic moments was revealed.
|
P13-2016-10 (405.9)
Pepelyshev Yu.N., Tsogtsaikhan Ts.
Prediction of the Thermal Dynamic Parameters Fluctuation of Coolant System of the IBR-2M Reactor Using Neural Networks
This paper presents an artificial neural network method for long-term
prediction of the thermal dynamic parameters of primary coolant circuit of
the IBR-2M reactor. The main goal is to predict the temperature and liquid
sodium flow rate through the core and thermal power. It is shown that the
prediction can reduce three times the effects of slow reactivity
fluctuations in power and decrease the requirements for the automatic power
stabilization system. Nonlinear autoregressive neural network (NAR) with
local feedback connection has been considered. The results of prediction
error ~ 5% coincide with the experimental ones.
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P11-2016-14 (1.859.0)
Batgerel B., Nikonov E.G., Puzynin I.V.
A Procedure for Constructing Symplectic Numerical Schemes for Solving Hamiltonian Systems of Equations
A new procedure for constructing symplectic numerical schemes for solving the Hamiltonian systems of equations is proposed.
A method for symmetrization of the obtained symplectic numerical schemes is suggested. The numerical schemes constructed by the above procedure conserve the energy
of a system on the large interval of numerical integration for relatively large integration step in comparison with the Verlet method which is usually used for
solving equations of motion in molecular dynamics. Results of numerical experiments are given. These results show the main advantages of the obtained symmetric
symplectic numerical schemes of the third order of accuracy for the integration step for the Hamiltonian systems of equations in comparison with numerical schemes
of the Verlet method of the second order of accuracy.
|
P16-2016-16 (241.610)
Mokrov Yu. V., Morozova S. V.
The Research of the Correspondence of the Indication of the Neutron
Dosimeter Based on 10Â Counter with Moderator to the Ambient
Dose in the Fields of U-400M at LNR
The calculated results of the research correspondence of the indication of
dosimeter based on the 10Â counter with polyethylene moderator to the
ambient dose equivalent behind the U-400M are presented. It was shown that
the instrument can be used to measure the ambient dose with the uncertainty
25 % in radiation monitoring at LNR cyclotrons. Value of correction
coefficient for this dosimeter behind the cyclotron shield is 0.9.
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P13-2016-17 (156.5)
Pepelyshev Yu.N., Popov A. K., Sumkhuu D.
Estimation of Power Feedback Parameters of the IBR-2M Reactor by Square Wave Reactivity
Parameters of the IBR-2M reactor power feedback (PFB) are estimated based on
the analysis of power transients caused by deliberate square wave reactivity
when the pulsed reactor operates in the self-regulation mode.
The PFB of the IBR-2M is described by three linear first-order differential
equations.
Two components of the PFB are responsible for the negative feedback and one,
for the positive. The overall feedback is negative, i.e., it has a
stabilizing effect for the operation of the reactor.
The slowest negative component of the PFB is probably caused by heating of
the fuel.
Periodically repeated in the process of exploitation, estimation of the PFB
parameters is one of the methods to ensure safety operation of the reactor.
|
P15-2016-19 (1.423.912)
Didyk A. Yu. et al.
Synthesis of Microparticles with Complex Compositions in a Xenon High-Pressure Chamber (550 bar)
under Irradiation by Braking Radiation with a Maximum Energy of 10 MeV
Natural xenon at a pressure of 550 bar
in a high pressure chamber (XeHPC) was irradiated by 2,59 · 105 s
bremsstrahlung with a maximum energy of 10 MeV at the electron accelerator
MT-25 microtron with an electron beam intensity of 20–22μA. The final electron
fluence was 4,74 · 1019 electrons. The growth of pressure versus temperature
during the stationary exposure mode grew at first
up to 620 bar and then dropped to 550 bar.
After opening of the XeHPC both of the internal chambers with all the structures, but without gas,
were measured using a γ-germanium detector (Canberra) during 15 h each for measurement of the background and short-lived isotopes.
During a visual inspection of the interior surfaces of the XeHPC inner assembly, a visible coating of substantial thickness and greenish-yellowish
color was observed. The research carried out by scanning electron microscopy (SEM) and X-ray micro-probe analysis (XMPA)
allowed us to determine the elemental composition of synthesized particles.
|
P13-2016-20 (1.004.3)
Pepelyshev Yu.N. et al.
Application of the Properties of Toeplitz Matrices of the Noise Correlation Characteristics to the Diagnostics of the IBR-2M Pulsed Reactor
The safeguarding of a nuclear reactor during the operation process is one of
the most significant tasks. The difficulty is in the necessity to use
nondestructive methods. One of such perspective methods is the neutron noise
diagnostics of a nuclear reactor.
Possibility of the noise diagnostics by the new method of norms of positive
definite Toeplitz correlation matrices is studied. The advantage of this
method is its purely mathematical nature; no model of the process is
employed.
The neutron noise analysis of the IBR-2M pulse energy has been carried out
by the represented method. Both the static state and dynamic
state of the reactor have been studied.
Frequency analysis of unstable components of the reactor noise has been
carried out. The main unstable components of the neutron noise are
frequencies of 0.8 and 1.6 Hz, which are conditional on the vibration of the
movable reflector blades of the reactivity modulator. The results of this
diagnostics have been compared with the results of the classical spectral
analysis.
|
E7-2016-21 (292.6)
Volkov V.V., Cherepanov E.A., Kalandarov Sh.A.
Interpretation of the Mechanism of Spontaneous Fission of Heavy Nuclei in the Framework of Dinuclear System Conception
A new approach to the interpretation of the process of spontaneous fission
of heavy nuclei is suggested. It is based on nuclear physics data which are
obtained in heavy ion collisions. The process of spontaneous fission
consists of three sequential stages: clusterization of the valent nucleons
of a heavy nucleus into a light nucleus-cluster, which leads to the
formation of a dinuclear system; evolution of the dinuclear system which
proceeds by nucleon transfer from the heavy to light nucleus; and decay of
the dinuclear system from the equilibrium configuration into two fragments.
|
E18-2016-22 (201.921)
Yamauchi Yu., Apel P. Yu.
Adsorption of Anionic Surfactant on Porous and Nonporous Polyethylene Terephthalate Films
We study the adsorption of anionic surfactant, sodium dodecyl diphenyloxide disulfonate (SDDD)
on three types of polyethylene terephthalate (PET) substrates from aqueous solutions of SDDD of different concentrations.
Neutral electrolyte (KCl) was added to the solutions to vary the ionic strength. Three types of substrates were used:
1) original PET film; 2) etched nonporous film, obtained from pristine film by chemical etching and bearing negative charge on the surface;
3) etched porous membranes, fabricated from pristine film by ion irradiation and subsequent chemical etching. The membranes have negative charge
on the flat surface and on the inner pore walls. The comparison shows that the negative charge on the flat surface
has weak effect on adsorption of the anionic surfactant, and the SDDD adsorption on the inner walls of pores is much
weaker than on flat surface, even if the pore radius is significantly larger than the Debye length. This «exclusion»
effect strongly depends on ionic strength of solution.
|
P13-2016-23 (543.803)
Tsulaia M. I. et al.
Upgraded Experimental Setup KOLHIDA Designed to Study Interactions of Polarized Neutrons with Polarized Nuclei
We study the adsorption of anionic surfactant, sodium dodecyl diphenyloxide disulfonate (SDDD) on three types of polyethylene terephthalate (PET)
substrates from aqueous solutions of SDDD of different concentrations. Neutral electrolyte (KCl) was added to the solutions to vary the ionic strength.
Three types of substrates were used: 1) original PET film; 2) etched nonporous film, obtained from pristine film by chemical etching and bearing negative charge
on the surface; 3) etched porous membranes, fabricated from pristine film by ion irradiation and subsequent chemical etching.
The membranes have negative charge on the flat surface and on the inner pore walls.
The comparison shows that the negative charge on the flat surface has weak effect on adsorption of the anionic surfactant,
and the SDDD adsorption on the inner walls of pores is much weaker than on flat surface, even if the pore radius is significantly larger than the
Debye length. This “exclusion” effect strongly depends on ionic strength of solution.
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E14-2016-24 (664.7)
Nyamdavaa E. et al.
Preparation and Characterization of La1-xCexCoO3 Perovskite Oxides for Energy Materials
Cerium-doped lanthanum cobaltite perovskites (La1-xCexCoO3
with x = 0, 0.2, 0.4) were prepared by the sol-gel method (calcined for 5 h at
750ºC) and characterized by X-ray diffraction (XRD), X-ray absorption
(XAS), energy-dispersive X-ray spectroscopy (EDS), and BET surface area
analysis. The results showed that the cerium doping promoted the structural
transformation of LaCoO3 from rhombohedral into the cubic structure.
High specific surface area and small crystallite size are achieved at x = 0.2.
The XAS results confirmed the formation of compound La1-xCexCoO3.
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P14-2016-26 (691.931)
Artoshina O. V. et al.
Structure and Phase Composition of the Titanium Dioxide Thin Films
Deposited on the Surface of the Metallized Track Membranes from
Polyethyleneterephthalate by Reactive Magnetron Sputtering
Thin films of TiO2, Ag, Ag-TiO2, Cu-TiO2 deposited on the
surface of polyethyleneterephthalate track membranes (TM) were investigated.
Metals and oxide deposition was carried out by the method of vacuum reactive
sputtering with application of a planar magnetron. The microstructure of
samples was studied by the scanning and transmission electron microscopy
(TEM) techniques. The elemental composition of coatings was investigated
using energy-dispersive spectroscopy. For the identification of phase
structure, X-ray diffraction phase analysis was used at various
temperatures, and the XRD crystal structure patterns of the samples were
obtained by the selected area electron diffraction (SAED) in TEM analysis.
It was found that titanium dioxide on the TM surface can be present in three forms: nanocrystals of tetragonal anatase with impurity
of rhombic brookite and the so-called X-ray amorphous TiO2. Cubical Cu2O was identified in TM metallized by copper.
Optical properties of composite
membranes and films were investigated by the method of absorption
spectroscopy. Calculation of energies of the direct and indirect allowed
optical transitions was carried out based on the analysis of absorption
spectra of the studied composite membranes.
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P6-2016-29 (231.164)
Gustova M. V., Maslov O. D., Sabelnikov A. V.
Application of TEVA Resin for the Separation of the Products of
Photonuclear Reaction 237Np(γ, n) 236mNp → (β–)236Pu
The paper reports on the possibility of using TEVA resin (TRISKEM company),
made on the basis of the Aliquat-336 extractant (a quaternary ammonium
salt), for the isolation and concentration of 236Pu. The 236Pu
isotope was produced as a result of the photonuclear reaction
237Np(γ, n) 236mNp → (β–)236Pu using the linebreak
MT-25 microtron at FLNR, JINR. Plutonium-236 was separated on the TEVA
resin from 237Np target. Products of (γ, f) photonuclear reactions,
daughter products of 236Pu and 237Np, fragments of 237Np(γ, n) (237Np, 232U,
228Th, 233Pa, 137Cs, etc.) induced fission were also separated. The content of the
actinide elements in 236Pu was less than 10-6 Bq/Bq.
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P13-2016-33 (500.863)
Azorskii N. I. et al.
New Type of Drift Tubes for Gas-Discharge Detectors Operating in Vacuum: Production Technology and Quality Control
A device for fabricating thin-wall (straw) drift tubes
using polyethylene terephthalate film 36 µm thick by ultrasonic welding is described together with the technique for controlling their quality.
The joint width amounts to 0.4–1.0 mm. The joint breaking strength is 31.9 kg/mm2
The argon leakage from a tube of volume 188.6 cm3 under a pressure gradient of 1.0 atm does not exceed 0.3 · 10-3cm3min,
which is mainly related to the absence of metallization in the joint vicinity.
The high strength, the low tensile creep due to the absence of glued layers,
and the small value of gas leakage make the new tubes capable of reliable and long-term operation in vacuum,
which is confirmed by the operation of 7168 straw tubes for two years in the NA62 experiment.
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P13-2016-37 (653.4)
Babkin V. A. et al.
Setup for Testing of Detectors at the Nuclotron “MPD Test Beam”
A new specialized setup “MPD test beam” was created at the extracted beam
of the Nuclotron to carry out methodical research and testing detectors for
the MPD experiment at the NICA collider. The setup is described in detail.
Results of the test of fast detectors for the MPD TOF system are presented
as an example of the setup operation.
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P3-2016-39 (514.3)
Êiselev Ì. À., Zemlyanaya Å. V.
Dehydration of the Intermembrane Space in the Multilamellar Membranes of Dipalmitoylphosphatidylcholine under the Influence of Dimethyl
Sulfoxide. Neutron and Synchrotron Study
On the basis of the separated form factors method (SFF), the analysis of
data on the small-angle neutron scattering (SANS) on polydispersed
population of unilamellar vesicles of dipalmitoylphosphatidylcholine (DPPC)
in heavy water with dimethyl sulfoxide (DMSO) is carried out. It is shown
that the growth of DMSO molar fraction in water from 0 to 15% leads to
increase of thickness of the bilayer to values of the repeat distance of
multilamellar membranes of DPPC, which means a dehydration of the
intermembrane space and steric contact of the neighbor bilayers of DPPC at a
DMSO molar fraction of 15%.
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P13-2016-42 (456.7)
Omelyanenko M. M. et al.
Low-Noise Pulse-Mode Current Power Supply for Magnetic Field Measurements of Magnets for Accelerators
The described pulse-mode current power supply has been designed and fabricated for the magnetic field
measurement system of superconducting magnets for accelerators. The power supply is based on a current regulator with pass transistor bank
in linear mode. The output current pulses (0–100 A) are produced by using the energy of preliminary charged capacitor bank (5–40 V),
which is charged additionally after each pulse. There is no AC-line frequency and harmonics ripple in the output current,
the relative noise level is less than –100 dB (or 10–5 of RMS value (it is defined as the ratio of output RMS noise current
to the maximal output current 100 A within the operating bandwidth, expressed in dB).
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E3-2016-43 (1.532.519)
Vu D. C. et al.
Representation of the Radiative Strength Functions in the Practical
Model of Cascade Gamma Decay
The developed in Dubna practical model of the cascade gamma decay of
neutron resonance allows one, from the fitted intensities of the two-step
cascades, to obtain parameters both of level density and of partial widths of
emission of nuclear reaction products. In the presented variant of the model a part
of phenomenological representations is minimized. Analysis of new results
confirms the previous finding that dynamics of interaction between Fermi- and
Bose-nuclear states depends on the form of the nucleus. It also follows from the
ratios of densities of vibrational and quasi-particle levels that this
interaction exists at least up to the binding neutron energy and probably differs
for nuclei with varied parities of nucleons.
|
P15-2016-44 (219.4)
Kabdrakhimova G. D. et al.
Investigation of the Total Cross Sections in the Interactionsof 6He and 4He Nuclei with Si Nuclei at 5–50 MeV/A
The analysis of the experimental excitation functions of the total cross sections of nuclear
reactions 6He+Si and 4He+Si in the energy range 5–50 MeV/A and a
brief overview of the techniques by which experimental data were obtained have been presented.
Detailed attention is given to the description of experiments conducted with beams of radioactive nuclei
of the accelerators of FLNR JINR. Analysis of experimental data was performed using the semi-microscopic optical model.
|
P9-2016-47 (700.824)
Alexandrov V. S. et al.
Influence of Errors of a Solenoidal Magnetic Field of the First
Accelerating Section of LUE-200 Accelerator on Electron Beam Dynamics
The analysis of results of the magnetic measurements executed on a
breadboard model of the focusing solenoid of accelerating section of
accelerator LUE-200, and results of numerical modelling of dynamics of a
beam in accelerating system of the linear accelerator with the account of
the possible errors admitted in focusing fields of the linac are presented.
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P9-2016-48 (538.141)
Sumbaev A. P., Kukarnikov S. I.
The Focusing Solenoid of the First Accelerating Section of LUE-200 Accelerator
Results of designing and manufacturing of the focusing solenoid of
the first accelerating section of the electron linear accelerator with a S-band traveling
wave — the driver of the the IREN facility, a pulse resonant neutrons source, are considered.
Requirements to parametres of the solenoid with the account of necessity of minimisation of
heterogeneity of a magnetic field at edges and in the area occupied with an electron beam are formulated.
Results of calculations, a design and results of measurements of magnetic fields of the solenoid after
its installation on a regular place on the linac are presented.
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P13-2016-49 (439.069)
Aksenov V. L. et al.
High-Flux Pulsed Neutron Source on the Base of Cascade Booster
A physical model of high-flux neutron source based on subcritical (kef = 0,96)
two-stage booster, managed by proton accelerator with energy of 600 MeV
and 0.3 MW beam power, is offered. It is shown that the thermal neutron flux will be
comparable to the flux density in the European Spallation Source (ESS),
proton beam power of which is 5 MW. Due to a short pulse the neutron diffraction experiments on
the proposed source will be almost an order of
magnitude more efficient than in ESS.
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P4-2016-50 (251.6)
Pupyshev V. V.
The Amplitude Functions Method in the Theory of Two-Dimensional Scattering
In the present work, we formulate and give the mathematical foundation of the amplitude functions method. This method is adopted
for solving the radial problem of two-dimensional scattering of a quantum particle by the sum of the Coulomb potential and a central
short- or long-range potential.
|
P13-2016-51 (724.647)
Morozov V. A., Morozova N. V.
Autocorrelation Method for Determination of Scintillator Decay Time
An autocorrelation method is developed for determining the composition and
decay time of scintillators. It also allows studying the spatial distribution of nuclear radiation and controlling the amount
of the admixture introduced in the scintillators. The decay time is measured in the range from a few nanoseconds to microseconds.
It is found that the decay time increases in plastic scintillators with a wave shifter and a Gd admixture.
|
E1-2016-54 (185.621)
Baatar Ts. et al.
Thermodynamic Characteristics of the Secondary Particles Produced in π–C Interactions at 40 GeV/ñ as a Function of Cumulative Number nc
The multiparticle production process in π–C interactions at 40 GeV/ñ has been studied on cumulative number nc. Local
values of temperature, pressure, volume, and energy density in the interaction region are determined as a function of the cumulative number.
This analysis gives us an opportunity of studying a space-time picture and the phase transition process at high energies.
|
P4-2016-58 (297.178)
Pupyshev V. V.
Two-Dimensional Nuclear-Coulomb Scattering
of a Slow Quantum Particle
The two-dimensional scattering of a slow quantum particle
by the superposition of the Coulomb and short-range potential is
studied. The analysis of low-energy asymptotics of all radial
wave-functions, partial phase-shifts and cross-sections is given.
Two methods for calculation of the scattering length and effective
radius are proposed.
|
E6-2016-62 (378.210)
Khushvaktov J. H. et al.
Interactions of Secondary Particles with Thorium Samples in the Setup QUINTA Irradiated with 6-GeV Deuterons
The natural uranium assembly, QUINTA, was irradiated with 6-GeV deuterons.
The 232Th samples were placed at the central axis of the setup QUINTA.
The spectra of gamma rays emitted by the activated 232Th samples have been analysed,
and more than one hundred nuclei produced have been identified. For each of those products,
reaction rates have been determined. The ratio of the weight of produced 233U to that of 232Th is presented.
Experimental results were compared with the results of Monte Carlo simulations by the FLUKA code.
|
P12-2016-63 (32.057)
Molokanova L. G. et al.
Effect of Ultraviolet Radiation on Polyethylene Naphthalate Films Irradiated with High Energy Heavy Ions
The effect of UV radiation of a wide spectral range (λ = 100 – 400 nm)
on films of polyethylene naphthalate (PEN) was investigated. Changes in the optical absorption
spectra of PEN films after exposure to accelerated ions and UV radiation were studied.
Changes of the surface properties of PEN were studied and the depth of damaged polymer layer was
measured after high fluence UV-irradiation.
The depth of damage was found to range between 0.1 and 0.9 µm, depending on the length of treatment.
The rate of photoablation and the quantum yield of the removal of one monomer unit (∼0.7 ⋅ 10–4 molecules/
photon) of PEN films under the influence of UV radiation were evaluated.
The feasibility of production of asymmetric pores in PEN films via controlled photo-oxidative degradation was demonstrated.
|
P13-2016-65 (280.517)
Marachev A. A. et al.
Analysis of Dynamics of the IBR-2M Reactor with Statistically Optimal Automatic Regulator
For the IBR-2M pulsed reactor,
characterized by a high level of reactivity fluctuations and,
as a consequence, of a power pulse amplitude, two variants of an automatic regulator
(AR) are considered. Both variants satisfy the criterion of a minimum probable standard deviation
of the amplitude of the future pulse on the basis of information obtained in the previous momenta.
The difference between the AR variants is registered in the data. Since perturbations of reactivity
in the process of reactor operation contain random and regular components, transient processes in these
types of reactivity are considered for both AR variants. It is shown that the variant of AR accepted in the IBR-2M,
where earlier data is given less weight, is more preferable than the variant where the information obtained from a fixed
number of the last pulses is given the greatest weight, and the earlier information is not considered at all.
|
P13-2016-67 (29.202)
Pepelyshev Yu. N., Popov A. K., Sumkhuu D.
Power Feedback of the IBR-2 Pulsed Reactor and Its Modernized Version IBR-2M in Comparison
Based on the analysis of the power transient processes
caused by the intentional square-wave reactivity in the IBR-2 and IBR-2M
reactors with burnup of 800–900 MW · day, the fast power feedback
structure is substantiated. Due to the differences in the geometry of the reactor
cores and fuel structure, symmetrical oscillations of reactivity induced asymmetrical
power fluctuations in the IBR-2 reactor and symmetrical ones in the IBR-2M. The analysis
of the measured pulse response of the reactor feedback at a nominal power of 2 MW shows
that the IBR-2M is more stable in comparison with the IBR-2.
A margin of the perturbation amplitude to the stability boundary of the IBR-2M is almost twice
that at the IBR-2. A margin on the phase shift between the perturbing reactivity and power is large enough for both reactors.
It can be expected that the operation time of the IBR-2M in the existing nominal mode with a power of 2 MW
and a flow of coolant through the core of 100 m3/h before the oscillatory instability is longer than at the IBR-2.
|
P1-2016-71 (626.794)
Belyaev A. V. et al.
The Kinematical Fit
At measurements performed in experimental particle physics,
for every particle taking part in collision or decay, kinematical parameters such as momentum and
exit angles are fixed individually. Due to measurement errors the conservation laws of energy and
momentum are violated in this set of kinematical parameters. The procedure of ''kinematical fitting'',
which was developed as early as the sixties of the 20th century, makes values of kinematical parameters more precise,
eliminates violations of the conservation laws and makes smaller errors in parameters.
|
P1-2016-72 (542.178)
Belyaev A. V., Jerusalimov A. P., Troyan A. Ju.
Extraction of Channels in Particle Interactions Using Kinematical Fitting
At studying particle interactions we often have no particle identification. In this case the task of defining the true channel arises.
One of the important numerical instruments which is used to determine the true channel of a reaction is the procedure
of &quout;kinematical fitting&quout;, which for each of the tested combinations calculates the value of the functional χ2 (⩾ 0).
In this work it is proposed to use the obtained χ2 -values to attribute a specific weight to every combination.
Thus, in the proposed method all combinations (with their weight) which were successfully fitted take part in the forming of channels of a reaction.
The Kolmogorov criterion that has been applied to χ2-distributions, obtained with two described methods,
gives a better agreement between the experimental distributions and theoretical ones when the weight method is used.
|
E13-2016-73 (217.917)
Volkov A. D.
Behavior of Welded Straws in Vacuum
The possibility of working
welded straw tubes in vacuum is considered.
The behavior of straw in a vacuum is considered
in the framework of the cylindrical shells theory. A solution
to the equilibrium state equation for a straw tube describing its behavior
under the effect of pre-tensioning and internal pressure is provided. The analysis of the
solution shows that the rotation of self-supporting straws is due to the moment acting on the unfixed ends.
The estimation of strain caused by the overpressure is made. An original technique of measurement of straw Poisson's
ratio is presented and its dependence on tension is investigated. The effect of the temperature and the deformation rate on
the mechanical properties of straw is considered with polybutylene terephthalate as an example. The optimum temperature range for the
long-term straw operation in the experiment is specified.
|
E4-2016-74 (160.597)
Arsenyev N. N. et al.
Effects of Phonon--Phonon Coupling on the Properties
of Pygmy Resonance in 40–48Ca
Starting from the Skyrme interaction SLy5, we study the effect of
phonon--phonon coupling on the low-energy electric dipole response
in 40–48Ca. This effect leads to the fragmentation of the
E1 strength to a low energy and improves the agreement with
available experimental data.
|
E4-2016-75 (99.648)
Sushenok E. O., Severyukhin A. P.
The Effect of the Unpaired Nucleons on the
β-Decay Properties of the Neutron-Rich Nuclei
Starting from the T45 Skyrme interaction with tensor terms, the
properties of the β-decay of 72-80Ni are studied. We
take into account the effect of unpaired neutron and proton on the
ground state properties of odd-odd and even-odd nuclei. It is
shown that the calculated Qβ values and the $\beta$-decay
half-lives are in a reasonable agreement with experimental data.
|
P4-2016-77 (131.057)
Sushenok E. O. et al.
The Simultaneous Inclusion of the Phonon-Phonon Coupling and
Effective Interactions in the Particle--Particle Channel
A finite rank separable approach(FRSA) based on the
quasiparticle random phase approximation with Skyrme
interactions has been extended to describe charge-exchange
excitation modes. The central and tensor residual interaction in
the both particle-hole and particle-particle channel and the
coupling between one- and two-phonon configurations are taken into
account in the framework of the FRSA model. The calculation scheme
of the β-delayed multi-neutron emission of the neutron-rich
nuclei is presented.
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P3-2016-81 (298.101)
Maslova V. A., Kiselev M. A.
The Structure of Sodium Cholate Micelles
Sodium cholate is a bile acid salt and is used as a biological detergent.
The mixed systems of sodium phospholipidcholate are used to study the
self-assembly process of the formation of micelles and micellar systems.
Micelles composed of a mixture of a phospholipidsodium cholate are used
as carriers of drugs through the skin.
We have studied the structure of micelles of sodium cholate by small-angle
neutron scattering. It was established that the average radius of sodium
cholate micelles was (10.14 ± 0.01) Å in the sodium
cholate concentration
range from 25 to 100 mM.
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D13-2016-82 (32.429)
Glonti L. N. et al.
Determination of the Anode Wire Position in a New Type
of Thin-Wall Drift Tubes (Straws)
for the NA62 Drift Chambers Using Visible Light.
I. Measurements in Transmitted Light
Microscope studies of thin-wall drift tubes (straws)
of a new type for the NA62 drift chambers have shown that under certain
conditions they are semitransparent and, when illuminated by directional light,
allow their anode wires to be observed in both transmitted and reflected light.
These tubes are supposed to be used in other experiments as well.
In this work, new results of the calibration measurements performed
with an accuracy of about ∼ ±1-2 μm using the
UIM-23 microscope are presented. It is also shown that the measurements
can in principle be automated. The first semiautomatic measurements accurate to about ∼ ±0.003 μm are reported,
which are made under the MBS-type microscope with a digital eyepiece.
The proposed method is much simpler than the methods based on radioactive or X-ray radiation.
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P4-2016-83 (237.254)
Pupyshev V. V.
Coulomb Scattering of a Slow Quantum Particle in a Space of Arbitrary Dimension
By assumption, a charged quantum particle moves in the space of dimension
d = 2,3,… and is scattered by a fixed Coulomb center. The expansions
of the wave-functions and all radial wave-functions of this particle over
integer powers of the wave number and the Bessel functions of real order
are derived. It is proven that the finite sums of these expansions are the
asymptotics of the wave-functions in the low-energy limit.
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P11-2016-85 (476.959)
Dikusar N. D.
Optimization of a Solution in Problems of Piecewise Polynomial Approximation
Piecewise polynomial approximation (PPA) is widely used in digital
technology and data processing. Within the framework of the Basic Element
Method (BEM), optimization of the solution of PPA problems is achieved on
the basis of the functional relationship between basis functions and
applying formulas to calculate the coefficients depending on parameters of
the three-point grid. The results of optimization and comparison with the
results of the respective Maple-procedures are illustrated by examples of
the 12th-order BEM-approximation.
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E18-2016-88 (935.626)
Dmitrieva S. O. et al.
Determination of the Origin of the Medieval Glass
Bracelets Discovered in Dubna (Moscow Region, Russia), Using
the Neutron Activation Analysis
The work is dedicated to the determination of the origin of archaeological
finds from medieval glass using the method of neutron activation
analysis(NAA). Among such objects we can discover things not only produced in
ancient Russian glassmaking workshops but also brought from Byzantium. The
authors substantiate the ancient Russian origin of the medieval glass
bracelets of pre-Mongol period, found on the ancient Dubna settlement. The
conclusions are based on the data about the glass chemical composition obtained
as a result of NAA of ten fragments of bracelets at the IBR-2 reactor, FLNP,
JINR.
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P16-2016-89 (131.036)
Mokrov Yu. V., Morozova S. V.
The Correction of Albedo Dosimeters DVGN-01 Readout at the Neutron Generator ING-27 with the Help of a Spherical Albedo System
The results of readout correction for albedo dosimeters DVGN-01 with
using of a spherical albedo system are presented. The measurements were carried out behind
the neutron generator ING-27. On the base of the presented results the correction coefficients
were recommended for individual radiation control at the neutron generator ING-27.
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P3-2016-90 (581.249)
Aksenov V. L. et al.
On Limit of Neutron Flux in Pulsed Neutron Sources Based on Fission
The upper limit of the thermal neutron flux density is obtained for fission pulsed sources for beam researches. Three types of possible configurations
are considered: multiplying target at a proton accelerator (booster), a booster with a reactivity modulation (superbooster), and a pulsed reactor.
Comparison with other high-flux sources, both operating and under construction, is done.
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P4-2016-91 (1.728.721)
Zaimidoroga O. A.
The Natural Law of Transition of a Charged Particle into a Compound State
under the Action of an Electroscalar Field
This article is the continuation of article [1] where the experimental
facts of observation of the electroscalar radiation in the spectrum of the Sun have been presented.
This radiation comes into the world having a long wavelength, being longitudinal and extraordinarily penetrating.
In accordance with the principle of least action, the Lagrangian of the electroscalar field and the energy-momentum
tensor are determined using variation of the potential and coordinates. The equation of motion of a charged particle
in the electroscalar field is determined where the energy of the particle has a negative sign with respect
to the particle’s mechanical energy and the energy of the electromagnetic field. So, this decreases
the electrical potential of the particle during the propagation. The electroscalar energy of the charged
particle and the field’s force acting on the particle during its motion change
the particle’s electrical status which, in its turn, may trigger the transition of the particle into a compound
state during an interaction with any object. Due to the continuity this process can lead the particle to the state where
it enters into a compound state with a negative energy at the particle’s different velocities. This state is the physical
vacuum state. Analysis of the solar spectrum demonstrates that scattering and absorption of the electroscalar wave occur
on the cavities of solids. The spreading out of the electroscalar field obeys the law of a plane wave, and the transfer
of energy and information can take place both in vacuum and in any medium.
The investigation has been performed at the Veksler and Baldin Laboratory of High Energy Physics, JINR.
Preprint of the Joint Institute for Nuclear Research. Dubna, 2016
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P7-2016-92 (427.701)
Lukyanov S. M. et al.
Cluster Structure 9Be and Mechanism of Transfer Nuclear Reaction
The study of inelastic scattering and multi-nucleon transfer reactions was
performed by bombarding a 9Be target with a 3He beam at the incident energy of 30 MeV.
Angular distributions for 9Be(3He, 4He) 8Be, 9Be(3He,
6Li) 6Li, 9Be(3He, 7Li)5Li,
and 9Be(3He, 7Be) 5He reaction channels were measured.
Experimental angular distributions for the corresponding ground states (g.s.)
were analyzed within the framework of the optical model,
the coupled-channel approach and the distorted-wave Born approximation.
The contributions of different exit channels have been determined confirming
that the (α + 5He) configuration plays an important role.
The configuration of 9Be consisting of two bound helium clusters
(3He + 6He) is significantly suppressed (less than 3%),
whereas the two-body configurations (𝓃 + 8Be) (69%) and (α + 5He) (25%) including unbound 8Be
and 5He are found more probable.
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