NUCLEAR REACTIONS INDUCED BY 3HE ON 19F NUCLEUS AT LOW ENERGIES

V.D. Sarana, N.S. Lutsay, N.A. Shlyahov

Full Text :   (3170 kB, Rus.) 

Abstract
This work deal with experimental investigation cross sections of the elastic scattering ³Не on ¹⁹F and nuclear reactions ¹⁹F (³Не,р) ²¹Ne and ¹⁹F (³Не,α)¹⁸F with energies between 2.3 and 4,2 MeV. Excitation functions and angular distributions for transitions to ground and first two excite states of ²¹Ne and to ground, 5, 6, 7 excite states of ¹⁸F are measured. From a fluctuation analysis and comparison of experimental cross sections with expected on the theory of Hauser-Feshbach upper Г_exp = 135 ± 23 кeV and lower Г_еxp = 70 кeV limits of values of widths levels of compound nucleus ²²Na at energy excitation 21 MeV are deduced, correspondingly. Rough estimations of form of the angular distributions of cross section in the framework DWBA, show that, if there is a direct single-stage transition of np-pair of nucleons, then it takes place transitions with the transfers of mainly next orbital angular momentum - in transition to the ground-state of (3/2⁺) - L = 2, to the 1-th excited states of (5/2⁺ or with one L = 2, or with L = 2 + 4 and with L = 4 for transfer to the 2-th excited states (7/2⁺). In view of the strong contribution of compound nucleus mechanism, for legality of these values L are required experiments with more high energies.

KEY WORDS: nuclear reactions with 3-helium, nucleus-target are a fluorine, transitions to the 18-fluorine and 21-neon, cross sections, excitation function, angular distribution, mechanism of reaction, theory of Hauser-Feshbach, distorted waves method.

MECHANISMS OF HEAVY QUARKS PRODUCTION IN PROTON-PROTON COLLISIONS AT HIGH ENERGIES

N.V. Krupina, A.Yu. Korchin

Full Text :   (860 kB, Rus.) 

Abstract
Production of heavy quarks c, b, t in the proton-proton collisions at high energies is considered. Various mechanisms of quark production are studied in framework of Quantum Chromodynamics (QCD). The cross sections for these mechanisms are analytically calculated. The color factors corresponding to each mechanism are explicitly kept in the formulas in order to further investigate the QCD color group in the cross sections of proton-proton collisions which will be measured in CERN on large hadron collider LHC.

KEY WORDS: heavy quark, proton-proton collision, color factor, QCD color group

ADDITIONAL TERMS FOR DESCRIPTION OF NONLOCAL INTERACTIONS IN QED

Yu.A. Kasatkin, A.P. Korzh

Full Text :   (1280 kB, Rus.) 

Abstract
Article summarizes the cycle of the works, published in the magazine of "Letter in ECHAYa" on construction and ground of alternative approach of description within the framework of quantum electrodynamics both local and nonlocal fields of matter simultaneously. Additional use of properties of inseparability of notion about an electric charge from notion of mass for fundamental particles and indifference of electromagnetic forces in relation to structure-formative interactions, allow saving in an unchanging kind the structure of group of gauge symmetries for the nonlocal fields and provide a correct output limits for local theory. A structural limit to local consideration is explored, not violating the here before got results within the framework of local theory. A common property of regular part of the generalized pole amplitude is discussing.

KEY WORDS: local Lagrangian, nonlocal interactions, gauge invariance, Green's function, momentum distributions

OPTIMIZATION OF THE TARGET ARRANGEMENT FOR THE NEUTRON SOURCE FOR THE BEST PRODUCING 99MO

V.A. Tsymbal, N.D.Masalitin, S.A. Pismenetskiy, V.G. Rudychev, Y.V. Rudychev, A.F.Stoyanov

Full Text :   (780 kB, Rus.) 

Abstract
With computer simulation using a version of the target structure has been analyzed for the Be(d,n) neutron generator aimed to produce ⁹⁹Mo along the reaction ⁹⁸Mo(n,γ)⁹⁹Mo. It was shown the biggest neutron density and the needed transformation of their spectrum in the limited volume the beryllium moderator can provide, which in addition realizes the neutrons multiplication in (n,2n) reaction. The parameters of polyethylene and beryllium moderators have been compared. The technique is proposed for the determination of the geometrical point and the form of the irradiated spacemen for the maximal producing of ⁹⁹Mo. The calculations have been executed with MCNP code on the base of geometrical model of the target arrangement. Absolute values of ⁹⁹Mo output have been determined and were compared from analytic and digital estimations.

KEY WORDS: Monte-Carlo simulation, target for neutron generator, neutron moderation, beryllium, polyethylene, output of radioactive molybdenum, optimization.

THE CONTRIBUTION OF RESONANT NEUTRONS TO MOLYBDENUM ACTIVATION IN THE NEUTRON GENERATOR

A.N. Dovbnja, V.A. Tsymbal, N.D. Masalitin, S.A. Pismenetskiy, A.F. Stoyanov, D.Y. Shahov

Full Text :   (490 kB, Rus.) 

Abstract
Interaction of the neutrons created by neutron Be (d, n) - generator and special target device from beryllium , with the sample from molybdenum is considered. Quantitative estimations are executed on the basis of the decision of the equation of age for a dot source of fast neutrons, energy and sections of resonances of radiating capture by molybdenum. Influence of temperature of the Mo-target on the form of resonances (Doppler broadening) is considered. On the basis of calculations the contribution of resonant neutrons to a full exit (n,γ) reactions on 98Мо which in the considered conditions makes about 35 % is estimated. Such influence of resonant neutrons is caused by dependence (n,γ) - sections ⁹⁸Мо from energy, and the spectrum of neutrons formed by massive Be-moderator from fast neutrons.

KEY WORDS: the generator of neutrons, a target- moderator, beryllium, radiating capture, the contribution of resonances, the age equation, broadening of resonances.

TRIGGERING OF LONG-LIVED ISOMER ^178M2HF BY 50 KEV ELECTRON IRRADIATION

A.N. Dovbnya, S.S. Kandybei, V.I. Kirischuk, Yu.N. Ranyuk, V.M. Azhazha, K.V. Kovtun, M.P. Starolat

Full Text :   (1500 kB, Rus.) 

Abstract
The results of experiments on long-lived isomer ^178M2Hf (T_1/2 = 31 y) triggering when an isomeric target produced by 1.2 GeV Kharkov linear electron accelerator about 30 years ago has been irradiated at the electron microscope by 50 keV electrons are presented. It is shown that at low electron currents ^178M2Hf isomer triggering is not observed. At the same time, when the currents have been increased by more than an order of magnitude, there are apparent effects indicating indirectly the possible triggering. In addition, conducted experiments clearly demonstrated that the existing measurement geometry cannot allow registering adequately the investigated phenomenon and requires substantial improvements.

KEY WORDS: ^178M2Hf isomer, electron beam, HPGe detector, triggering, NEET process, quantum Zeno effect

SIMULATION OF SIGNALS OF MAGNETIC INDUCTION SENSORS AND MONITORS OF CHARGED PARTICLE BEAMS

V.I. Trotsenko, N.I. Mocheschnikov, V.Е. Ivashchenko

Full Text :   (1270 kB, Rus.) 

Abstract
The formulas are deduced for the description of signals of magnetic inductive pickups and monitors of charged particle beams. The pickups sensitive to a radial and angular component of magnetic induction of a beam are considered. The pickups based on cylindrical ring cores with μ = μ_о and μ > μ_о were simulated. Linearity and sensitivity of various types of pickups and monitors are investigated for a wide range of geometrical parameters of core and coils, parameters of the electric circuit formed by pickups, duration of a beam current pulse.

KEY WORDS: simulations, pickups and monitors, accelerators of particles.

NORMAL MODE OF THE DC DISCHARGE IN LOW PRESSURE NITROGEN

V.A. Lisovskiy, N.D. Kharchenko, R.N. Fateev

Full Text :   (1200 kB, Rus.) 

Abstract
This work is devoted to investigation of the normal mode of DC glowing discharge in nitrogen. As a result of the experiments we made by two different methods it is shown that the transition area of the nitrogen pressure exist (from the threshold pressure of the normal mode appearance р » 0.3 - 0.4 Тоrr to р » 2 Тоrr) where the normal current density divided to the squared gas pressure j_n/p² doesn't remain constant and decreases with the discharge current increasing. Magnitudes j_n/p² for different cathode materials and gas pressures were obtained experimentally. The experiments on the investigation of the radial current density distribution across the cathode area in normal and abnormal modes were made. It is obtained that radial current density profile in normal mode has a form of a bell and possesses a maximum in the center of the discharge spot. Thickness of the cathode sheath changes in the radial direction of the discharge spot. It takes maxima values near the spot boarders; at the same time in this area lower current density compared to the center of the discharge spot is observed.

KEY WORDS: DC discharge, normal mode, radial structure, low pressure, nitrogen.

THERMOMODIFICATION OF NANOPOWDER NATURAL CLINOPTILOLITE

N.P. Dikiy, E.P. Medvedeva, I.D. Fedorets, N.P. Khlapova, N.S. Lutsay, Yu.V. Lyashko, D.V. Medvedev, A.P. Gavrik

Full Text :   (680 kB, Rus.) 

Abstract
Methods of gamma activation analysis, X-ray diffraction analysis and Ik-spectroscopy study element composition, crystallinity and character of an intermolecular interaction in samples of a natural and thermomodified nanoklinoptilolite. In received klinoptilolite ? - spectrum observed γ - the lines matching to radionuclides ⁴⁰K and from families ²³⁸U, ²³⁵U, ²³²Th. On intensity of spectrum lines estimates of content Th and U are executed and is shown that their concentration in a klinoptilolite (Th - 1.06•10^-5 and U - 2.75•10^-6 г/г) approximately coincides with abundance of these devices in earth crust. By results of radiographic and IR-spectroscopic examinations it is positioned that in the modified samples the high level of crystallinity and klinoptilolite phases is conserved. Minor alterations intesity of lines of the diffraction reflexions 2θ = 9,93° and 26,60° and conversion of absorption bands of hydroxyl groups (OН, Si- OН, K- OН and Nа-ОН) testify to reorganisation in the vodno-cationic subsystem of a klinoptilolite which are not mentioning its basic alumosilicic carcase.

KEY WORDS: nanoklinoptilolite, gamma - activation analysis, X-ray diffraction analysis, IR-spectroscopy, thermoprocessing, crystallinity.

TEMPERATURE INTERVALS OF HELIUM AND HYDROGEN RETENTION IN FERRITIC-MARTENSITIC STEELS EI-852 AND EP-450

V.V. Ruzhytskyi, S.O. Karpov, V.O. Sanik, G.D. Tolstolutska, V.M. Voyevodin

Full Text :   (1680 kB,  Ukr.) 

Abstract
The behaviour of hydrogen (deuterium) and helium in ferritic-martensitic steels EI-852 and EP-450 were studied. Using complex of experimental methods such as ion implantation, thermal desorption spectrometry and transmission electron microcopy it was established that preliminary helium implantation lead to shifting of the temperature interval of hydrogen release from steels on 100…200 K to high temperatures.

KEY WORDS: ferritic-martensitic steel, hydrogen, helium, implantation, thermal desorption.

DETERMINATION OF EFFECTIVE RATE OF ELECTRON-IMPACT IONIZATION OF MULTICOMPONENT GAZ- AND GAZ-VAPOR MIXTURES

Yu.V. Kovtun, E.I. Skibenko, A.I. Skibenko, V.B. Yuferov

Full Text :   (605 kB, Rus.) 

Abstract
The paper describes a simple method for determination of effective rates of gas and gas-vapor mixtures by the electron impact. The media investigated were the following mixtures: H₂+ Ti, Ar+Ti, Kr+Xe+N₂+O₂, (Kr+Xe+N₂+O₂)+Ti. The experiments on the ionization of these media were carried out using the plasma of a pulsed reflecting discharge. A Ti concentration in the discharge was varying within 0-50%. A comparison between the calculated values of the effective rate of multicomponent gas-vapor mixture ionization with experimental data is made.

KEY WORDS: ionization, elementary process, electron impact, multicomponent mixture, impurity concentration, electron temperature

THE FEATURES OF STRUCTURE OF NANOMETRIC GRAPHITE SURFACE LAYERS

V.G. Kirichenko, E.S. Melnikova

Full Text :   (2400 kB, Rus.) 

Abstract
The results of research of graphite surface by scanning tunneling electron microscopy and by computer simulation of cell structure of monoatomic surface layers are presented. Simulation was carried on the base of created sectioning technique of experimental values of surface electron density. Thy tetragonal structure features in graphite surface cells which connected with influence of second and third neighbors carbon atoms was found.

KEY WORDS: graphite, surface, graphene, multiscale structures, graphane.

EFFECT OF DOPING BY PRAZEODIMOM ON TEMPERATURE DEPENDENCE OF PSEUDOGAP IN Y_1-ZPR_ZBa₂Cu₃O_7-δ SINGLE CRYSTALS

A.V. Samoylov, A.A. Zavgorodniy, R.V. Vovk, M.A. Obolenskii, K.A. Kotvitskaya, V.Yu. Gres’

Full Text :   (700 kB, Ukr.) 

Abstract
In present work we have investigated the conductivity in the basis plane of the doped by Pr and of YBaCuO single crystals. It is shown, that the excess conductivity for the analyzed samples shows dependence Δσ~(1-Т/Т*)exp(Δ*_ab/T) in a wide temperature range T_f < Т < T*, where Т* is the mean field temperature of superconducting transition. The temperature dependence of the pseudogap can be satisfactorily described in terms of the BCS-BEC crossover theoretical model.

KEY WORDS: excess conductivity, doping, YВaCuO single crystals, high temperature superconductivity, crossover, pseudogap state.

SYNCHRONIZATION SYSTEM FOR EXPERIMENTS RESEARCH INSTALLATION "URAGAN-2М"

V.N. Lyashchenko, F.I. Ozherel'ev, S.N. Reva, D.A. Tsibliev

Full Text :   (840 kB, Rus.) 

Abstract
A system of synchronizing the operation of technology systems, diagnostic equipment and instrumentation for carrying out physical experiments in plasma physics and controlled thermonuclear fusion (CTF) on a major research facility "Uragan-2М" (Institute of Plasma Physics, NSC KIPT, Kharkov) are considered. The system is assembled on the basis of modules in the CAMAC standard. It comprises a CC02 controller crate, MC01 launcher and six modules MD01 of programmable timers. Synchronization System is connected to a personal computer using a galvanically isolated serial communication channel operating at data rates 10 Mbaud. Adapter for serial communication with the controller is installed in the computer on the bus PCI and manages crate, which can be removed from the computer to a distance of 300 meters.

KEY WORDS: plasma, torsatron, computer, synchronizing, CAMAC, software