M.V. Gorbunkov , D.B. Vorchik
№ 2 Compact Q-switching device for giant pulses generation of various duration
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A.V. Bagulya , V.M. Grishin , A.P. Kostin , S.K. Kotel»nikov , B.N. Lomonosov , M.A. Negodaev , S.V. Rusakov , H.-J.. Seidel
№ 12 MiCROSTRIP GAS CHAMBER FOR H1 FORWARD PROTON SPECTROMETER
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Microstrip gas chamber prototypes for H1 forward proton spectrometer were tested in T22 beam at DESY. The technology of the detector preparation and some test results are discussed.
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O.D. Dalkarov , A.Yu. Voronin
№ 17 Antiprotonic metastable clusters in light atoms
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The internal Auger de-excitation mechanism in the cluster (e~~p#e++) is examined in terms of the coupled channels ap?proach. An important feature of pHe+ atom is that there are two types of three-body clusters with drastically different Auger widths. The significant importance of virtual cascade Auger mechanism is shown, especially in case of multielectron atoms. The lifetime of 1% fraction of antiprotons, stopped in Li, is estimated to be no longer than 10 s. Several ex?periments to check the possible scenario of complex cluster formation, including several He atoms or ions are discussed.
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E.M. Kudriavtsev , V.V. Krivov , S.D. Zotov , M.. Autric
№ 20 DC ELECTRICAL FIELD INFLUENCE ON THE BEHAVIOR OF THE REFLECTION AND CONDUCTION WAVE IN POLYCRYSTAL HTSC SAMPLE NdCeCuO AT ROOM TEMPERATURE ВЛИЯНИЕ ПОСТОЯННОГО ЭЛЕКТРИЧЕСКОГО ПОЛЯ НА ПОВЕДЕНИЕ ВОЛНЫ ОТРАЖЕНИЯ И ПРОВОДИМОСТИ В ПОЛИКРИСТАЛЛИЧЕСКОМ ВТСП ОБРА
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The conductivity changes of HTSC ceramic NdCeCuO sample (associate to the reflection and conduction wave) under the IR pulse laser irradiation by 4-contact scheme were examined. The «map» construction method of velocity values for a wave propagation on the sample surface was designed. It was found that the velocity value under the action of electrical field on the sample was about constant within the range from the laser spot centre (on the sample surface centre) to 1 mm around. But a small displacement of the laser spot beyond this area, especially along the electrical field, causes the sharp velocity decrease, which increase away from the spot center. Actually, the wave vanishes at this conditions. Seen for the first time, this effect of the dc electrical field influence on the RCW propagation in conducting solids will help to develop an adequate RCW mechanism.
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S.F. Lukashev
№ 21 SOME ISSUES OF (U, V)-PLANE APPROXIMATION
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Statement of the problem and some ways ot solution ol trie (u,v)-piane approximation for VLBI observations are considered. Under the approximation of the (uyv)-plane we understand the procedures of weighting, gridding, and tapering. It is shown that the approximation problem may be considered from different formal points of view: local one, global one, and as ill-posed problem.
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S.F. Lukhachev
№ 22 DISTINCTIVE PROPERTIES OF SVLBI IMAGING
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Рассмотрены особенности синтеза изображений в системах космической РСДБ. Показано, что задача синтеза является классическим примером некорректной задачи. Рассмотрены основные особенности и принципы построения системы обработки данных в космическом РСДБ эксперименте. Показано, что система обработки данных может быть реализованана основе клиент/серверного подхода как система с распределенными объектами.
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S.V. Mitko , V.N. Ochkin , F.A. van Goor , W.J. Witteman
№ 25 STATE AND PROSPECTS OF THE XeF(C-A) OPTICALLY PUMPED LASER
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Experimental and theoretical results are presented of a XeF(C-A) blue green laser driven by 5kJ energy. The laser was pumped by a ferrite induced discharge of 90 си long. The output energy of 0.22 J has been obtained with a plane — parallel resonator. A code to simulate the laser has been developed, numerical results for a wide range of conditions are compared with experiments performed by us and other authors. It is found that the intracavity refractive losses limit the laser operation for XeF,, pressures above 3 Torr. The laser output depends strongly on the discharge-cavity length ratio. Possible ways to increase the laser power and efficiency are discussed.
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J.. Aherns , V.. Alekseyev , H.J. Arends , R.. Beck , S.. Cherpnya , D.. Drechsel , L.. Fil»kov , P.. Harty , V.. Kashevarov , B.. Krusche , C.. McGeorge , V.. Metag , J.. Peise , H.. Stroher , Th.. Walcher
№ 32 MEASUREMENT OF THE П+ MESON POLARIZABILITY
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We study a possibility of investigation of the radiative pion photoproduction from the proton at the microtron MAMI-f) with the aim to obtain an experimental information about the тг+ meson polarizabililies. It is shown that an exposition time about ,’il) days will allow to determine the ж+ meson polarizability with quite high accuracy.
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O.M. Krokhin , E.R. Koresheva , I.V. Aleksandrova , L.E. Osipov
№ 34 PRESENT STATUS AND NEAR-TERM GOAL OF THE LPI IN ICF- CRYOGENICS
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Pellet injection is the research area which has long been explored at the Lebedev Physical Institute. Outstanding contributions to inertial confinement fusion, covering the period of 1984-1996, are presented in this issue. Highlights of the research are: ? Scientific considerations that support the concept of ciyogenic target transport by means of injection. ? Creation and testing of two types of injectors: gravitational and electromagnetic one. ? Target hacking. ? Target trajectory correction. ? A new method for cryogenic layer formation based on keeping a rapid cooling of initially the gas-filled target during its downward fall inside a cryogenic layering channel. ? The results on crystalline layer homogenization demonstrated with hydrogen at 4.2K. ? Permeability-temperature and strength-temperature behavior of polystyrene capsules within the range of 300-140 K. ? Conceptual design of the fill system capable of 1000 atm. A broad program for large target fabrication and their delivery at the center of the target chamber of a MJ-class laser facility were set up at LPI in 1993. The program underlines still further the dominant role of the injection principle for target transport among basic units, namely fill system => layering module => target chamber. Picking such a strategy for future developments, we provide a unique avenue (a) for modeling an operational cycle of cryogenic target fabrication and delivery, and (b) for investigating a large amount of fuel filled microspheres in one cryogenic experiment, in other words, for making the research statistically. The final goal of the program is to design and construct a prototype of the factory that can mass produce targets.
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Yu.. Shibata , E.G. Bessonov
№ 35 LONG WAVELENGTH BROADBAND SOURCES OF COHERENT RADIATION
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Some considerations of long v/avelength and broadband radiation sources based on the emission of the coherent radiation by a train of short relativistic electron bunches moving in an open resonator along an arc-like or undulator trajectories and some new versions of the transition radiation sources and long wavelength sources based on storage rings are presented.
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A.. Lebedev , L.. Sinclair , E.. Strickland , J.. Vazdik
№ 40 COLOUR COHERENCE IN PHOTON INDUCED REACTIONS
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Colour coherence in hard photoproduction is considered using the Monte Carlo event generators PYTHIA and HERWIG. Sig?nificant effects in the parton shower are found using multijet observ-ables for direct and resolved photon induced reactions. The particle flow in the interjet region of direct processes show’s a strong influence of string fragmentation effects.
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L.A. Vanshtein , V.P. Shevelko
№ 43 PROGRAM «ATOM»
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The ATOM Program was developed by L.A.Vainshtein in laboratory for spectroscopy at the Lebedev Physical Institute (FIAN). The first description of ATOM was given in [1, 2]. The present version contains additional sub?programs and corrections. The Program is written on the FORTRAN for VAX computers and PC 386 or higher with MSFortran ver.5.0 or higher.
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A.A. Berezin , P.P. Gariaev , S.A. Reshetniak , K.V. Shaitan , V.A. Shechglov
№ 49 TO THE PROBLEM OF POSSIBLE DEVELOPMENT AT A BIOLASER WORKING ON FROLICH MODES
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The idea about possible development of a biological laser (BL) on Frolich modes (FM) has been stated. The two-level quantum system, simulating FM has been used as an initial model. Within the framework of the approach, using method of matrix of density, it has been shown, that in case of resonant interaction amplitude modulated electromagnetic radiation with FM the system can exist in the overexcited state. It is a necessary for creation the inverse population of theBL.
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V.N. Ochkin , S.N. Tskhai , I.V. Kochetov , W.J. Witteman , P.J..M.. Peters , Yu.B. Udalov , F.J. Blok
№ 51 GAIN IN A CW RF EXCITED Ar-He-Xe LASER
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Small signal gain values obtained from a rectangular RF Ar-TTe-Xe discharge are presented. Maximum space-averaged gains of 0.22 cm»1 and 0.37 cm»1 for the 2.03 um and 2.65 um xenon transitions have been measured respectively. Electrode-to electrode space resolved gain measurements have been performed. The gain distributions are essentially inliomogeneous with maxima near the electrodes and a dip at the discharge centre. A preliminary theoretical analysis shows that the spatial gain profile can be attributed to the temperature dependence of the inversion mechanism rate constants.
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V.M. Alekseyev , S.N. Cherepnya , L.V. Fil»kov , V.L. Kashevarov
№ 52 POSSIBILITY OF OBSERVATION OF SUPER NARROW DIBARYONS WITH SYMMETRIC WAVE FUNCTION IN yd -+ n? + yNN REACTIONS
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We study the possibility of observation of supernarrow dibaryons with a symmetric wave function in reactions -yd ?? ir+ + 77m and yd ?> jr~ + -ypp. The method of a dibaryon masses reconstruction over the dibaryon decay products (jnn) and (ypp) is analysed. The Monte Carlo simulation is used to choose the the optimal location of the detectors, to estimate the contribution of the main background processes and to calculate the expected yields of the dibaryon production. It is shown that 100 hours of the exposition time at the microtron MAMI (Main?) is quite enough to determine whether or not the supernarrow dibaryons with symmetric wave function exist.
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P.S. Baranov , A.S. Belousov , A.I. Lebedev , E.I. Malinovski
№ 53 RADIATIVE RESISTANCE OF MATERIAL USED IN SCINTILLATION AND CERENKOV COUNTERS
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Radiation hardness of plexiglass light guides, scintillating plastic fibers and tiles used in scintillation and Cerenkov counters for high energy physics is studied. Optical transparency and scintillator pulse height spectra for material samples and photon attenuation length in the fiber are measured before and after irradiation by bremsstrahlung beam of IGeV electron synchrotron with the dose of several Mrad.
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