DARK MATTER

Yu.L. Bolotin

Full Text :  (1860 kB, Rus.)

Abstract
One of the most mysterious results to come out of recent cosmological observations is that about 90% of the mass of the Universe is not made from baryons and electrons, or any other known particles, but of something unknown that does not shine. For this reason this substance got the name "dark matter". We summarize the theoretical and observational status of study of the dark matter. Particle candidates for dark matter are briefly considered, and detection strategies for cosmological observations and collider experiments are discussed. We demonstrate that weakly-interacting massive particle with mass around 100 GeV the observed dark matter relic density emerges naturally. It should be particularly emphasized that to resolve problem of dark matter and related questions we will need information both from the particle physics and from astrophysics. Specifically, we discuss implications of cosmology for supersymmetry and vice versa.

KEY WORDS: Dark energy, dark matter, relic radiation, particle candidates, supersymmetry, detection of dark matter.

DIFFRACTION, EXTRACTION AND FOCUSING OF PARAMETRIC X-RAY RADIATION, CHANNELING RADIATION AND CRYSTAL UNDULATOR RADIATION

A.V. Shchagin

Full Text :  (1830 kB, Eng)

Abstract
The paper describes the possibility of producing a focused parametric X-ray radiation (PXR) without applying any special X-ray optics. The PXR is emitted by relativistic charged particles that are channeling along a bent crystal. The PXR emitted from the whole length of the bent crystal is brought into focus. Some properties of focused PXR are estimated for typical experimental conditions, its possible applications are discussed. Besides, the feasibility of diffraction of parametric X-ray radiation emitted by relativistic particles in a bent crystal is described for the first time. The PXR generated at one set of crystallographic planes may be diffracted by another set of crystallographic planes in the same bent crystal. In the example being, the PXR is emitted in the backward direction and undergoes diffraction at a right angle. After diffraction, the PXR escapes from the thin crystal and becomes focused. Some properties of the diffracted focused PXR are estimated for typical experimental conditions. The experiment for observation of focused non-diffracted and diffracted PXR is proposed. Application of focused PXR for online control of the bent crystal and paricle beam state and the bent crystal alignment is proposed. Besides, possibilities for diffraction, extraction and focusing of crystal undulator radiation, as well as focusing of channeling radiation from a bent crystal are proposed. The installation of X-ray detector(s) in the vicinity of Bragg direction(s) is proposed in forthcoming experiments with crystalline undulator for observation of undulator radiation and online control of the undulator and particle beam state and also undulator alignment.

KEY WORDS: parametric X-ray radiation, channeling radiation, crystal undulator radiation, diffraction of X-rays, bent crystal, channeling particles, focusing of X-rays, virtual images, focusing of channeling radiation, focusing of crystal undulator radiation.

ELECTRON-POSITRON ANNIHILATION INTO KAON PAIR IN AN EXTENDED VECTOR-MESON-DOMINANCE FRAMEWORK

S.A. Ivashyn, A.Yu. Korchin

Full Text :  (310 kB, Eng)

Abstract
A model is developed for electromagnetic form factors of the charged and neutral mesons. The form factors, calculated without fitting parameters, are in a good agreement with experiment for space-like and time-like photon momentum. Contribution of the two-kaon channels to the muon anomalous magnetic moment is calculated.

KEY WORDS: chiral Lagrangians, vector-meson dominance, electromagnetic form factors.

THE ION CYCLOTRON INSTABILITIES OF INHOMOGENEOUS PLASMA WITH MAGNETIC-FIELD-ALIGNED FLOW AND TRANSVERSE VELOSITY SHEAR

V. S. Mikhailenko, D. V. Chibisov

Full Text :  (300 kB, Rus.)

Abstract
The influence of plasma inhomogeneity on ion cyclotron instabilities in magnetic-field-aligned plasma flow with transverse velocity shear is investigated. In this plasma hydrodynamic and two kinetic ion cyclotron instabilities are exited. One of kinetic instability is a modification of the ion cyclotron instability of plasma with parallel current. The cause of the second kinetic instability branch is a transverse to magnetic field velocity shear. It was shown, that plasma inhomogeneity to increase the range of longitudinal wave number where hydrodynamic ion cyclotron instability is exited. The inhomogeneity of plasma density also reduces the threshold of kinetic ion cyclotron instabilities.

KEY WORDS: plasma shear flow, velocity flow shear, inhomogeneous plasma, ion cyclotron instability.

THE INFLUENCE OF DOPING ON THE MICROSTRUCTURE STABILITY AHD CORROSION OF ZIRCONIUM ALLOYS

V.G. Kirichenko, I.A. Petelguzov, A.I. Kirdin

Full Text :  (1720 kB, Rus.)

Abstract
By using Conversion Electron Mossbauer Spectroscopy and X-ray analysis the investigation of structure and phase composition of intermetallides in subsurface layers (0.3 μm thickness) of the zirconium-based alloys under corrosion in various mediums at the initial and annealed state was carried out. The conditions of stable microstructure formation were determined. The phase composition and structure of oxide films on surface of zirconium doped with Fe, Sn, Nb, V was investigated. It was revealed the oxide films formed on alloys were in hetero phase and had various composition determined by aggressive medium, temperature and time of oxidation.

KEY WORDS: zirconium alloys, intermetallic inclusions, migration, segregation, oxidation.

PECULARITIES OF INITIAL STAGE OF FORMATION OF STRUCTURE OF THIN COPPER FILMS IN TEMPERATURE DEPOSITION ZONE I

I.G. Marchenko, I.M. Neklyudov

Full Text :  (2500 kB, Rus.)

Abstract
In this work applying method of molecular dynamics the initial stage of growth of thin copper films is studied at low-temperature vacuum deposition. Change with time of the average size and quantity of FCC and HCP clusters at a surface of a substrate is investigated. It is established, that the effect of athermal coalescence plays an important role in the change of cluster distribution in sizes.

KEY WORDS: films, vacuum deposition, nanostructure, simulation, copper.

A WAY TO INCREASE THE SPECTRAL-ANGULAR DENSITY OF DIFFRACTED TRANSITION RADIATION OF THE RELATIVISTIC ELECTRON IN SINGLE CRYSTAL

S.V. Blazhevich, A.V. Noskov

Full Text :  (350 kB, Eng)

Abstract
Diffracted transition X-radiation (DTR) of relativistic electron crossing a single crystal plate of limited thickness is considered within the framework of x-ray diffraction dynamical theory in the geometry of Bragg. The analytical expression for spectral-angular characteristics of DTR is obtained with tacking to account the orientation of external surfaces relative to the diffracting atomic planes in the crystal. It is shown that under a fixed angle of electron incidence on the system of diffracting planes in the crystal the spectral-angular characteristics DTR significantly depend on the external surface orientation.

KEY WORDS: relativistic electron, transition radiation, dynamical diffraction, angle distribution, single crystal.

APPLICATION OF METHODS OF THE STATISTICAL PHYSICS FOR THE DESCRIPTION OF STATIONARY OPERATION OF INDUSTRIAL SYSTEMS

V.P. Demutsky, О.М. Pignasty, V.D. Khodusov, М.N. Аzаrеnкоvа

Full Text :  (330 kB, Rus.)

Abstract
The mathematical model of economic - industrial systems with mass production is constructed. The state of production system at any moment is set by a point in two-dimention phase space. The distribution function for a base product is introdused and for it the equation being analog of a rate equation in physics is noted. The engineering - industrial and generating functions are determined. In a zero approximation the closed system of the equations for the moments of a distribution function is written. For a closed system of equations of state of macroparameters of an industrial system the equations of a perturbed state are obtained. Stability conditions of operation of an industrial system are defined. The correlation between a reserve and rate of transition of base products along the technological line-up, providing stable operation of a process is determined.

KEY WORDS: synergetic, base product, the microscopic description, distribution function, engineering-production function, generating function, the balances equations.

THE ELECTRON MODEL OF DELAYD NEUTRON YIELD IN THE EXPERIMENT AT A PULSED LINEAR ACCELERATOR AND SOME OF ITS COROLLARIES

А.А. Khomich , V.I. Каsilоv,  V.V.  Кirichenko , S.S. Коchеtоv, К.S. Коchnyк, O.A. Shopen, V.I. Nоgа, R.P. Slabospitskij, K.А. Масhnenko

Full Text :  (370 kB, Rus.)

Abstract
Assuming six groups of delayed neutrons and pulsed accelerator regime and using the laws of radioactive decay, the relation for the delayed neutron yield has been obtained as a function of accelerator pulse frequency, number of pulses during the irradiation time and the width of temporal observation window. Test experiment has been carried out for the verification of the agreement between the model and the experiment. The model is adequate to the experiment. The model can be useful for the planning of experiments on pulsed linear electron accelerator aimed at the studies of delayed neutron yield and determination of such parameters as the relative yield of delayed neutrons. It can be also used for determination of the concentration of fissile materials in samples under the study. Based on this model, three methods of direct extraction of the average period of half-decay of delayed neutron predecessors have been obtained (i.e. without the assumption that relative contributions and half-decay periods of separate groups are known).

KEY WORDS: delayed neutrons, pulsed accelerator, delayed neutron predecessors.

INVESTIGATION OF BEAM PRODUCTION IN ELECTRON ACCELERATOR WITH SECONDARY-EMISSION SOURCE FOR MATERIAL SURFACE TREATMENT

A.N. Dovbnya, V.V. Zakutin, N.G. Reshetnyak, V.P. Romas’ko, I.А. Chertishcev, V.N. Boriskin,  N.A. Dovbnya, T.A. Kovalenko

Full Text :  (350 kB, Rus.)

Abstract
It was carried out research of beam production in electron accelerator with secondary-emission source. It was shown that such source produces electron beam with energy up to 100 keV, current 110 A, in pulse duratation 10…20 μs with frequency repetition 3…5 Hz with specific power on target surface ~3 mWt/cm². Target irradiation of different materials was carrird out.

KEY WORDS: electron beam, electron accelerator, secondary-emission source, surface modification.

INVESTIGATION OF THE DYNAMIC CHARACTERISTICS OF SILICON DOUBLE-SIDED MICROSTRIP DETECTORS

S.V. Naumov, L. Bosisio, N.I. Maslov, A.F. Starodubtsev

Full Text :  (310 kB, Eng)

Abstract
The energy resolution of both microstrip and pad detectors, fabricated on the same wafer, is investigated. Isotopic sources of gamma-radiation are used for energy resolution measurements. The active area of the planar detector is identical to the area of a single strip of the microstrip detector. Study of this pad detector gives the maximal possible energy resolution, since the influence of interstrip capacitance and other properties of the extended microstrip structure that decrease the energy resolution are excluded. Characteristics of the microstrip structure that diminish the energy resolution and methods of research of such characteristics are considered.

KEY WORDS: silicon microstrip detectors, energy resolution, signal-to-noise ratio.

EFFECTS OF g-IRRADIATION ON STRUCTURE-PHASE STATE OF TUFFS

E.P. Shevyakova, S.J. Sayenko, E.P. Bereznyak, L.A. Sayenko, E.A. Borts

Full Text :  (400 kB, Rus.)

Abstract
Еffects of g-irradiation on the structure-phase state of natural tuffs that could be used as matrix for placement of radioactive wastes was investigated by methods of crystallooptic (mineralogy-petrography) analysis and IR-spectroscopy. It was established, that increasing of dose g-irradiation (E=1,5 MeV, D_max=3·10⁸ Gy) cause reducing of mechanical strength and growth of secondary crystallization in feldspar-quarts bases mass. The degree of irradiation damage in tuffs lower than in full granular granites that connected with immediate contacts of phases in them.

KEY WORDS: g-irradiation, radiation-induced defects, nature tuffs, crystallooptic, IR-spectroscopy.