ABOUT THE PROBLEM OF PARAMETRIC X-RADIATION OF RELATIVISTIC ELECTRONS IN BRAGG SCATTERING GEOMETRY

S.V. Blazhevich, A.V. Noskov

Full Text :   (420 kB, Rus.) 

Abstract
The parametric x-radiation (PXR) of relativistic electrons crossing a single crystal plate in Bragg scattering geometry is considered. On the base of the dynamic diffraction theory analytical expressions describing the spectral-angular distribution of PXR are derived taking into account the asymmetrical reflection in the plate. It was revealed that by changing the reflection asymmetry the width of PXR spectrum changes essentially as well. The contribution of each of the two branches of solution of the dispersion equation for X- waves in the crystal to PXR yield is shown.

KEY WORDS: relativistic electron, single crystal, parametric x-radiation, dynamical diffraction theory.

RECRYSTALLIZATION OF BERYLLIUM

I.I. Papirov, P.I. Stoev, A.A. Nikolaenko

Full Text :   (3700 kB, Rus.) 

Abstract
The recrystallization of beryllium high-purity 99,9% deformed by different methods in correlation with features of structure evolution are investigated during of annealing. Energy parameters and middle rates of grain growth at stages of an primary and collective recrystallization are defined. It is determined that cellular structure and an amount of defects which is entered in a material during its preliminary deformation renders major influence on rates of growth grain.

KEY WORDS: beryllium, rolling of a beryllium, hydroextrude of a beryllium, extrusion of a beryllium, a beryllium wire, a fine grain size Be, rate growth of grains, an activation energy of recrystallization.

X-RAY SOURCE WITH VARIABLE PHOTON’S ENERGY FOR MEDICINE APPLICATIONS

I.E. Vnukov, Yu.V. Zhandarmov, R.A. Shatokhin

Full Text :   (520 kB, Rus.) 

Abstract
The prospect creation of the X-ray source with variable photon's energy on the basis of the average energy accelerator (E_e≤50 МeV) and mosaic crystals is analyzed. It is shown, that due to the contribution of diffracted bremsstrahlung, the mosaic crystals provide the essentially greater yield of hard radiation (ω≥20 keV), than perfect crystals. It is shown that using a scheme with one crystal for X-ray generation practically isn't acceptable for medicine applications due to the contribution of background bremsstrahlung in the location of irradiated object. Double- crystal scheme is offered and analyzed, in which one crystal located directly on the electrons beams, and another used, for monochromatization and parallel moving of the X-ray beam. It provides almost full suppression of background bremsstrahlung which gives harmful doze loading, and there is no need to move the object when change the photons energy.

KEY WORDS: parametric X-ray radiation, crystal, mosaicity, radiation yield, diffracted bremsstrahlung, diffraction.

COMBINED FOCUSING BY RF-FIELD FOR ION LINEAR ACCELERATORS

S.S. Tishkin

Full Text :   (810 kB, Rus.) 

Abstract
Combined RFQ-focusing, a spatial 3d version of the alternating-phase focusing method for an ion linear accelerator, is presented. CRFQ is a modified alternating-phase focusing (MAPF) with rf-quadruples introduced into a focusing period. It is proposed to use the method based on a "local stability" of non-equilibrium particles to calculate parameters of an accelerator with RFQ. Presented is interactive software APFRFQ that allows step-by-step simulation of linear accelerator sections. The pre-stripping section of the multi-charge ion linear accelerator is used for comparative analysis of both focusing methods, MAPF and CRFQ. Using APFRFQ code, the accelerating-focusing section of the powerful medium energy proton accelerator with CRFQ included is simulated. Also, a possibility of applying the CRFQ-method for heavy ion (mass-to-charge ratio being 65) is considered.

KEY WORDS: ion linear accelerator, beam current, beam emittance, alternating-phase focusing, RFQ focusing, electronuclear technologies.

THE ELECTRIC FIELD DISTRIBUTION REGULATION IN THE INTERDIGITAL ACCELERATING STRUCTURE WITH HIGH-FREQUENCY QUADRUPOLES

A.F. Dyachenko

Full Text :   (920 kB, Rus.) 

Abstract
Results of experimental research of the electric field distribution regulation in the model interdigital accelerating structure with alternating phase and high-frequency quadrupole focusing a beam are discussed. Two most simple variants of high-frequency quadrupoles (in the form of «horns») and various schemes of their use are considered. Regulation of the electric field distribution is carried out by a change of a corner of an arrangement of the basic or intermediate stems of the quadrupole drift tubes in an azimuthal plane.

KEY WORDS: linear accelerator, interdigital accelerating structure, high-frequency quadrupole, distribution of an electric field, corner of an arrangement stems of the drift tubes, cell, doublet.

ANALYSIS OF EXTERNAL GAMMA-RAY FROM A CYLINDER TANK FILLED WITH RADIOACTIVE WASTE

S.A. Pismenetskiy, V.G. Rudychev, E.V. Rudychev, O.K. Tutunik

Full Text :   (520 kB, Rus.) 

Abstract
Dose field outside of a volume cylindrical source has been investigated both Monte-Carlo and volume-integration numerical methods. It was shown the exceeding of calculated dose from a cylindrical source with approximately equilateral cross-section (2Rsh) can be reduced within 10% at the expense of adding an adjust multiplier to the buildup factor. Shaping of dose rate spatial distribution which is the nearest to isotropic takes place under the condition 2R/h≈0.9-1.0. Those effect is depended weakly on the cylinder volume and on the material density inside the source. The effect of a lateral dose reduction is near 15% compared to 200 liter conventional barrel if radius to altitude ratio is optimized and grows if one steps back from the barrel.

KEY WORDS: cylindrical source, scattered radiation, buildup factors, barrel filled with radioactive waste, external radiation, shape optimization.

POSSIBILITY OF GENERAL DESCRIPTION OF LOCAL AND NONLOCAL ELECTROMAGNETIC INTERACTIONS

Yu.A. Kasatkin

Full Text :   (370 kB, Rus.) 

Abstract
It is shown, that expansion of local gauge symmetry of lagrangian free fermions and scalar fields in QED can be attained on the basis of wave functions taking into account the structure of configuration space as direct multiply of spatio-temporal variety and space of internal symmetries. Is possibility of alternative introduction of interactions on the basis of the QCD analogue - the gauge EM "string" providing description of interactions identical with QED and not requiring bring in consideration of lagrangian approach. The calibrate EM "star" allows by a no alternative method to enter interactions with the nonlocal field, not requiring constructing of unknown lagrangian and introduction of some additional parameters. Invariant character of structure of amplitude in relation to hieratic evolution structure of generate forces and structural elements of the nonlocal field, allows its uses in an unchanging type for description of processes of EM of interactions in different scales the structure of matter. In the generalized gauge amplitude a continuous limit in transition from consideration of the nonlocal fields to local is well-to-do.

KEY WORDS: vertex function, Green's function, gauge invariance, form factor, asymptotic of sections, regular part of the amplitude.

THE PECULIARITIES OF THE FORMATION OF LASER IMPULSES' FINE STRUCTURE UNDER INDUCED INTERFERENCE

V.M. Kuklin, A.S. Petrenko

Full Text :   (290 kB, Rus.) 

Abstract
Conditions of wave pulses formation, as a result of mode interference, arising from the development of instabilities in the case of a small excess of thresholds threshold crossing are reviewed in the paper. Under these conditions, in the developed instability regime one can see slow dynamics of mode amplitudes. At the same time spectrum energy does not change. In the mode of developed volatility a slow change in amplitude of modes is observed, and the excitation spectrum energy remains constant. The main physical phenomenon in the developed instability regime in the mode of developed volatility is so named forced interference. Features of the forced interference dynamic are studied. Conditions of the large peaks arising and also their distribution in the space are discussed clarified. An ability of applying the forced interference phenomenon for describing a fine structure formation of the fine structure of laser radiation is examined discussed.

KEY WORDS: laser pulses generation, forced interference, small threshold crossing small excess of threshold, instability near threshold supported by external source, modes competition.

ELECTROMAGNETIC DIFFRACTION BY METAL CYLINDER COATED WITH INHOMOGENEOUS MAGNETOACTIVE PLASMA SHEATH. I

N.A. Azarenkov, V.K. Galaydych

Full Text :   (250 kB, Eng.) 

Abstract
This paper is devoted to the problem of diffraction of low frequency electromagnetic waves incident from a homogeneous magnetoactive plasma by a metal circular cylinder surrounded by radially inhomogeneous plasma sheath. The external magnetic field is parallel to a cylinder axis; the wavevector of incident plane wave is perpendicular to this axis. It is assumed that plasma is cold and perturbations in it are governed by Maxwell's and two-liquid hydrodynamic equations. The exact solutions for fields in both linear and power plasma sheath profile are obtained. The cross-sections for backward and forward scattering as a function of incident wave vector are derived for various parameters of task. The dependences of these cross- sections upon these parameters are analyzed. The inhomogeneous plasma sheath enhances the oscillation amplitude of the back scattering cross-section and changes in several times the value of the forward scattering cross-section.

KEY WORDS: electromagnetic wave, diffraction, magnetoactive plasma, non-uniform plasma, cross-section.

DISTINCTION OF MICROSTRUCTURAL DIFFRACTION EFFECTS BY HALF-WIDTH OF X-RAY LINES

D.G. Malychin, V.V. Kornyeyeva,  T.Y. Gural'nik

Full Text :   (200 kB, Rus.) 

Abstract
This work concerns an X-ray diffraction line shape analysis based on a method of approximation. It is proposed a method of separation of line shape components relevant to diffraction on microstrains and domain sizes where half-width of lines is used. The numerical computations and anlytical studies of parameters of Voigt function which is used for approximation of line shape is carried out. Dependence of half-width of Voigt function from values of half-width of its components - Cauchy and Gauss function is investigated. Optimum analytical expression of this dependence is received. The algorithm of use of the received expression for modelling experimental α₁-singlet line is offered.

KEY WORDS: X-ray diffraction analysis, an approximation method, broadening of X-ray lines, half-width, domain size, particle size.

MODELLING OF ELECTRON BUNCH DYNAMICS IN RESONATOR STRUCTURES OF CONTINUOUS ACTION 100 KW POWER KLYSTRON

V.E. Balakin, S.V. Berezovskiy, I.M. Karnauhov, V.P. Olefir, V.E. Teryaev, V.P. Tsiova

Full Text :   (270 kB, Rus.) 

Abstract
The article presents the results of numeral modeling of electronic bunch dynamics in the multiresonator systems of powerful flight continuous action klystron of 100 kW power. The electron bunch with accelerating voltage 30 kV, current 7A and operating frequency 700 MHz is used in numerical calculations. The comparison of klystron parameters, obtained as a result of numeral modeling, with experimentally obtained results show their good accordance.

KEY WORDS: numerical modeling, electron bunch, resonator, klystron, efficiency, frequency characteristic.

MEASUREMENT OF BEAM ELECTRON DENSITY DISTRIBUTION ON AN ELECTRON LINEAR ACCELERATOR OF “KIPT” NSC

A.N. Dovbnya, V.V. Zakutin, N.G. Reshetnyak, V.A. Popenko, V.P. Yefimov, N.A. Dovbnya, T.A. Kovalenko

Full Text :   (540 kB, Rus.) 

Abstract
The results of exprimental research on electron density distribution of nonunfolded and unfolded beams carried out on the targets of EPOS and KUT-30 linear accelerators of the National Science Center, Kharkiv Institute of Physics & Technology are given below. The measurements were conducted at different distances from the output foil under standard modes of the electron accelerator operation. The irradiation zone width was determined in its vertical and horizontal planes.

KEY WORDS: electron beam, beam sweep, irradiation, accelerated electrons, electron density distribution.