Препринты / Preprints

The effect of doping of Cherenkov radiator NaBi{WO^)2 (NBW) with Sc ions on radiation hardness and optical prop?erties of this crystal has been studied. The radiation hardness of NBW:Sc is about 3 times higher than that of pure NBW.

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We propose to use observations of the time delay of pulses from pulsars in globular dusters to detect iensing objects located close to the line of the sight, in order to study the distribution of dark matter In globular clusters and in our Galaxy, In general, and to explain some distortions of the observed timeof-arrival of pulsar’s pulses. We have calculated a microlensing probabilities for pulsars in globular clusters in case of rather large impact parameters. In particular, 47 Tuc (NGC 104) and M15 (NGC 7078) were examined.

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It is shown for the first time that when a plane wave illuminates a certain type of bicomponent optical system, consisting of two plane screens with circular apertures on a given optical axis, a multifocal diffractive focusing effect can appear. Here, the diffraction picture in the focal planes represents the circular nonlocal bands of a Fresnel zone with a bright narrow peak at the center, whose intensity can exceed by six to ten times tlie value of the incident wave intensity. The detected optical effect is observed over a wide range of wavelengths, Л = 0.4 ? 10s /urn, and ratios of the aperture uiameters a\ г: ла.2 = 25 ? wuO A, and it is also insensitive to changes in the medium of the wave propagation. For large diameters of the input holes, a’y = 2d2 > 100A, or for wavelengths in the radiofrequency region of the spectrum, the bicomponent diffraction system acts like a long-focus lens with a high-intensity Gaussian distribution of radiation, at times exceeding the initial intensity, persisting at large distances (z = 1 -100 cm) from the diffraction system. Key words: wave diffraction, diffractive focussing of radiation, bicomponent diffracting system.

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The goal of the current work was estimation of the energy resolution of a matrix made of PWO CMS End Gap type crys?tals with vacuum phototriodc (VPT) readout. A stand alone light collection program simulating propagation of the emission photon inside PbWOi (PWO) crystal was developed. Spectral sensitivity of the VPT photodetector was included into the calculations. The matrix was studied by GEANT simulation program in the energy range of 30 — 200 GeV using the output of the light collection program. The developed program can be applied for further simulations of various scintillating crystal matrixes.

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We present the test for isotropy and the constrains on the halo subpopulation of gamma-ray bursts using the uniform GRBs catalog of Stern, Tikhpmii-oya (1999). The catalog is the result of the overall scan of BATSE 1024 ms data and includes non-trjggered bursts. The isotropy is confirmed for the sample with the largest statistics (376X bursts) and the lowest threshold (peak fluxes down to 0.1 ph cm-2 s»»1, which is lower then the BATSE trigger threshold by factor 2). Besides, we constrain the possible contribution of halo subpopulation into GRBs statistics by ru 60% of the total number of GRBs for the whole sample.

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The formulas for x-ray scattering diagram are deduced and analysed in the first order Distorted Wave Born Approximation (DWBA) without any sim?plified assumption about an unperturbed wave field nearby a rough interface. The comparison with other approaches described in literature is given. The possibilities of DWBA and the perturbation theory (FT) are discussed as applied to development of x-ray method of the surface roughness control. It is shown that just PT is the most natural and correct theoretical basis of x-ray testing method which permits one, in contrast to DWBA, to extract information from the scattering measurements by unambiguous manner. It is demonstrated that there is the optimum radiation wavelength lying in the sort x-ray anu liru V spectrai regions which proviues a means ?ог an cxuraction of the maximum amount of information about the surface microtopography from the scattering measurements. Application of existing EUV lasers for the study of the surface roughness is discussed.

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Resonant absorption of first-overtone (FO) CO laser radiation by atmospheric water vapor and various organic and nonorganic pollutants is discussed. Suitable ro-vibrational lines are selected for their potential use in traditional spectroscopic schemes of atmospheric pollution diagnostics. The tables containing FO CO spectral lines, which are most and least absorbed in the atmosphere are presented. Nonlinear atmospheric absorption of intense multiline FO CO laser radiation is simulated and laser-induced changes in absorption spectra are demonstrated. Absorption coefficients of a few substances on several FO CO ro-vibrational lines are experimentally measured. A comparative analysis of spectral characteristics of FO CO laser and FfF (DF) laser demonstrates that potential of FO CO laser applications for spectroscopic detection of various molecular trace gases is greater than that of HF and DF lasers.

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The new optical effect of a diffractive multifocal focusing of radiation, predicted earlier by theory in the first part of this paper, on a bicomponent diffraction system with small Fresnel numbers, consisting of two plane screens with circular apertures on given optical axes, is confirmed experimentally. It is shown that the diffraction picture in the focal planes of such a system represents the circular nonlocal bands of the Fresnel zones with a bright narrow peak at the center, whose intensity in the experiment can exceed by six to ten times the value of the incident plane wave intensity. Experimentally it is established that the diffractive multifocal focusing of radiation on real screens with axial circular apertures, whose diameters exceed the radiation wavelength, is insensitive to the «rough» external conditions: thickness of the screens, irregularities of the edges and non-ideal form of the apertures, heterogeneity of the initial distribution of the incident wave intensity, and changes in the medium of the wave propagation.

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In the first part of this paper has been detected theoretically a new optical effect of diffractive multifocal focusing of the radiation (DMFR) on a certain type of bicomponent optical system, consisting of two plane screens with circular apertures on a given optical axis. Such relatively simple bicomponent diffraction system enables to focus the beams without using classical refraction elements such as lenses and prisms. As example of prospective application of the DMFR effect, in the present paper we offer to initiate of high-power HF- lasers and amplifiers by an external power radiation, which is focused by the proposed bicomponent diffraction system. The focusing of input signal ensures the minimization of the initially excited volume of a laser active medium and appropriate sharp lowering of the necessary energy of the input pulse up to ~ 10~6 J. This enables the laser system to reach a huge value of the energy gain of 10 . The huge laser energy gain allows us to use a master oscillator in the form of a small microjoule laser powered by an accumulator, and consequently, makes it possible to construct a completely self-contained compact pulsed chemical HF- laser. Key words: diffractive focussing of radiation, bicomponent diffracting system, chemical lasers and amplifiers, photon-branched chain reaction, auto-wave amplification regime, self-contained compact laser.

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The Project of upgrading of two currently operating experimental setups, i.e. the Pamir and the Hadron setups, located at high mountain altitudes is proposed for comprehensive investigations of the primary cosmic rays (PCR) in the energy range 1-1000 PeV. The main goals of the Project are the research of PCR energy spectrum peculiarities, i.e, the breaks of the spectrum, and its mass composition as well as the revealing the nature of some new phenomena in cosmic rays recently observed in mountain altitude experiments. An important component of the upgraded Hadron-M setup at the Tien Shan is a radically new detector, i.e., an ionization neutron calorimeter (INCA) of large area which will essentially increase the information productivity of the setup. The study of anomalous events at the Pamirs will be prolonged by means of two new types of X-ray emulsion chambers specially designed for solving specific problems.

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The neutron matter of high density in the Minkowski space — time is considered (the model problem). The relativistic Lagrangian de?scribes the interaction of » bare» nucleons in the framework of Yukawa theory, and besides an exchange by the scalar mesons ensures an at?traction character of nuclear forces, and an exchange by the massive vector mesons — a repulsion. The formula of correlation energy is calculated by the method of external Schwinger sources in the high density limit, under the effective — zero temperature. The obtained result for the correlation energy formula does not contain the scalar — vector polarization (muxure) operator, that is the consequence of covariance of the massive neutral vector field equation and condition of the current conservation. Of course, this model is far from the real situation. And in such a form, it can not pretend for describing of the true neutron matter of pulsar, but is important (primary) stage under investigating of pulsars or neutron stars and in the technique (the Schwinger method of external sources) of solution of the relativistic many — particle problem for strong — interacting matter, because such a technique is not sufficient — well elaborating so far.

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The high density neutron matter is considered in the Minkowski space — time (the model problem). The gauge — invariance of equation of the neutral massive vector meson field is investigated. It is shown, that the scalar — vector (mixed) polarization operator does not give the contribution in correlation energy of neutron matter.

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The HI detector at HERA has been upgraded by the addition of a new electromag?netic calorimeter. This is installed in the HERA tunnel close to the electron beam line at a position ~ 8 m from the interaction point in the electron beam direction. The new calorimeter extends the acceptance for tagged photoproduction events to the high у range, 0.85 < у < 0.95, and thus significantly improves the capability of Hi to study high energy т-р processes. The calorimeter design, performance and first results obtained during the 1996-1998 HERA running are described.

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High-pressure tritium facilities refer to the support equipment used for the fuel supplies of fusion targets; they are typically required to be very near the power facility (laser, accelerator, etc) in an environment not specialized for tritium handling. This paper discusses a general approach to the design of such systems that would meet radiation safety requirements. In presented part of work the principles of laser fusion and basic physical features on plasma compression. These allow to state the requirements to the sizes and accuracy of fabrication of spherical shells — laser targets. The main attention was paid to the prognosis that we worked out in the beginning of activity on the program » Laser thermonuclear targets «. The prospects for development of there research direction for the coming 15 years, in-depth study of main problems faced by the researchers and engineers were analyzed then. Experimental works differ essentially in comparison with theoretical mathematical modeling (simulation) of heating and compression of thermonuclear targets or concepts of hybrid nuclear reactor. In theoretical approach the majority of physical processes is taken into account and the exterior conditions only do vary (form of the energy input, degree of fuel burn-out and so on). The unknown parameters are introduced as the average estimated value, and then it is updated, investigated. For laser targets fabrication development, if a single link is absent then it is impossible to supply the necessary targets for experiment or honestly to describe the future of target factory. And to develop the absent part of a process engineering can take 5 to 10 years, and all this time is lost for experiments or for development of the national program. Therefore in the national programs of different countries (USA, Japan, France etc.) the basic elements of reactor-size targets are present (various, but of a definite structure in different projects). Technology developments follow the logic of target main structures, having the concrete elements. The targets for current experiments are subdivided on the same base according to various technological works — specialization. The methods and techniques adopted from the other technological disciplines of microproducts manufacture had helped us to create the equipment complex which has completely ensured and now ensures making the basic set of spherical shell targets, their monitoring and issuing passport of target parameters. The technology developments require a lot of time, and in our conditions only their early beginning allowed to keep at a level of world achievements. With smaller forces and small expenditures but having thus reserve of time, we got competitive scientific outcomes. The paper considers a variety of compression devices allowing pressures up to 500 MPa. Design requirements on high-pressure work chambers are described. The radiation safety problem in application to high-pressure tritium facilities is discussed. In this work we are going to analyze the technological and technical solutions, which were obtained at the development of methods of targets filling by DT-mixture up to the high pressure in miniature installations, comparing results with those from USA and Japan laboratories.

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In presented work the principles of laser fusion and basic physical features on plasma compression. I’hese allow to state the requirements to the sizes and accuracy of fabrication of spherical shells — laser targets. The main attention was paid to the prognosis that we worked out in the beginning of activity on the program » Laser thermonuclear targets «. The prospects for development of there research direction for the coming 15 years, in-depth study of main problems faced by the researchers and engineers were analyzed then. To our mind and deep conviction confirmed by experience, the best variants of target designs realizable in experiment should be born in acute disputes (battles) of the theorists — the target designers and target fabricators. The paper is result of this battle between theorist — Prof. S. Yu. Guskov and experimenter — Dr. Yu. A. Merkul’ev. Experimental works differ essentially in comparison with theoretical mathematical modeling (simulation) of heating and compression of thermonuclear targets or concepts of hybrid nuclear reactor. In theoretical approach the majority of physical processes is taken into account and the exterior conditions only do vary (form of the energy input, degree of fuel burn-out and so on). The unknown parameters are introduced as the average estimated value, and then it is updated, investigated. For laser targets fabrication development, if a single link is absent then it is impossible to supply the necessary targets for experiment or honestly to describe the future of target factory. And to develop the absent part of a process engineering can take 5 to 10 years, and all this time is lost for experiments or for development of the national program. Therefore in the national programs of different countries (USA, Japan, France etc.) the basic elements of reactor-size targets are present (various, but of a definite structure in different projects). Technology developments follow the logic of target main structures, having the concrete elements. The targets for current experiments are subdivided on the same base according to various technological works — specialization. With little resources the methods and techniques adopted from the other technological disciplines of microproducts manufacture had helped us to create the equipment complex which has completely ensured and now ensures making the basic set of spherical shell targets, their monitoring and issuing passport of target parameters. The technology developments require a lot of time, and in our conditions only their early beginning allowed to keep at a level of world achievements. With smaller forces and small expenditures but having thus reserve of time, we got competitive scientific outcomes.

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