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.
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.
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.
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.
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.
Pepelyshev Yu.N., Popov �.�., 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
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
Periodically repeated in the process of exploitation, estimation of the PFB
parameters is one of the methods to ensure safety operation of the reactor.
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
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
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.
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.