469 research outputs found

    Secondary electron emission yield in the limit of low electron energy

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    Secondary electron emission (SEE) from solids plays an important role in many areas of science and technology.1 In recent years, there has been renewed interest in the experimental and theoretical studies of SEE. A recent study proposed that the reflectivity of very low energy electrons from solid surface approaches unity in the limit of zero electron energy2,3,4, If this was indeed the case, this effect would have profound implications on the formation of electron clouds in particle accelerators,2-4 plasma measurements with electrostatic Langmuir probes, and operation of Hall plasma thrusters for spacecraft propulsion5,6. It appears that, the proposed high electron reflectivity at low electron energies contradicts to numerous previous experimental studies of the secondary electron emission7. The goal of this note is to discuss possible causes of these contradictions.Comment: 3 pages, contribution to the Joint INFN-CERN-EuCARD-AccNet Workshop on Electron-Cloud Effects: ECLOUD'12; 5-9 Jun 2012, La Biodola, Isola d'Elba, Ital

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    The present paper features the publication of an unedited manuscript by the Soviet linguist E.D. Polivanov, submitted in November 1927 by its author not for publication but just as a contribu- tion to the discussion around the so-called Abkhaz Analytical Alphabet. is graphic system was devised by the academician Nikolay Yakovlevich Marr on the basis of the Latin alphabet for the representation of all Japhetic (Caucasian) languages. In the rst section of the introduction, the main characteristics of Marr\u2019s Analytical Alphabet are presented; the second section addresses the linguistic discussion that followed its introduction in Abkhazia as the o cial alphabet in 1926 and its replacement two years later by a Latin-based alphabet. e third section gives comment on some questions of Abkhaz phonetics and transcription; the fourth is devoted to textual and editorial is- sues. e edition of the Russian text is accompanied by an English translation, prepared by Grazia Giannetta (Macerata)

    Representations of solutions of the wave equation based on relativistic wavelets

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    A representation of solutions of the wave equation with two spatial coordinates in terms of localized elementary ones is presented. Elementary solutions are constructed from four solutions with the help of transformations of the affine Poincar\'e group, i.e., with the help of translations, dilations in space and time and Lorentz transformations. The representation can be interpreted in terms of the initial-boundary value problem for the wave equation in a half-plane. It gives the solution as an integral representation of two types of solutions: propagating localized solutions running away from the boundary under different angles and packet-like surface waves running along the boundary and exponentially decreasing away from the boundary. Properties of elementary solutions are discussed. A numerical investigation of coefficients of the decomposition is carried out. An example of the field created by sources moving along a line with different speeds is considered, and the dependence of coefficients on speeds of sources is discussed.Comment: submitted to J. Phys. A: Math. Theor., 20 pages, 6 figure

    Detectability of non-differentiable generalized synchrony

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    Generalized synchronization of chaos is a type of cooperative behavior in directionally-coupled oscillators that is characterized by existence of stable and persistent functional dependence of response trajectories from the chaotic trajectory of driving oscillator. In many practical cases this function is non-differentiable and has a very complex shape. The generalized synchrony in such cases seems to be undetectable, and only the cases, in which a differentiable synchronization function exists, are considered to make sense in practice. We show that this viewpoint is not always correct and the non-differentiable generalized synchrony can be revealed in many practical cases. Conditions for detection of generalized synchrony are derived analytically, and illustrated numerically with a simple example of non-differentiable generalized synchronization.Comment: 8 pages, 8 figures, submitted to PR

    Hard loss of stability in Painlev\'e-2 equation

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    A special asymptotic solution of the Painlev\'e-2 equation with small parameter is studied. This solution has a critical point tt_* corresponding to a bifurcation phenomenon. When t<tt<t_* the constructed solution varies slowly and when t>tt>t_* the solution oscillates very fast. We investigate the transitional layer in detail and obtain a smooth asymptotic solution, using a sequence of scaling and matching procedures

    Measurements of production and inelastic cross sections for p+C, p+Be, and p+Al at 60  GeV/c and p+C and p+Be at 120  GeV/c

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    This paper presents measurements of production cross sections and inelastic cross sections for the following reactions: 60 GeV=c protons with C, Be, Al targets and 120 GeV=c protons with C and Be targets. The analysis is performed using the NA61/SHINE spectrometer at the CERN Super Proton Synchrotron. First measurements are obtained using protons at 120 GeV=c, while the results for protons at 60 GeV=c are compared with previously published measurements. These interaction cross section measurements are critical inputs for neutrino flux prediction in current and future accelerator-based long-baseline neutrino experiments.Authors:A. Aduszkiewicz,15 E. V. Andronov,21 T. Antićić,3 V. Babkin,19 M. Baszczyk,13 S. Bhosale,10 A. Blondel,23 M. Bogomilov,2 A. Brandin,20 A. Bravar,23 W. Bryliński,17 J. Brzychczyk,12 M. Buryakov,19 O. Busygina,18 A. Bzdak,13 H. Cherif,6 M. Ćirković,22 M. Csanad,7 J. Cybowska,17 T. Czopowicz,17 A. Damyanova,23 N. Davis,10 M. Deliyergiyev,9 M. Deveaux,6 A. Dmitriev,19 W. Dominik,15 P. Dorosz,13 J. Dumarchez,4 R. Engel,5 G. A. Feofilov,21 L. Fields,24 Z. Fodor,7,16 A. Garibov,1 M. Gaździcki,6,9 O. Golosov,20 M. Golubeva,18 K. Grebieszkow,17 F. Guber,18 A. Haesler,23 S. N. Igolkin,21 S. Ilieva,2 A. Ivashkin,18 S. R. Johnson,26 K. Kadija,3 E. Kaptur,14 N. Kargin,20 E. Kashirin,20 M. Kiełbowicz,10 V. A. Kireyeu,19 V. Klochkov,6 V. I. Kolesnikov,19 D. Kolev,2 A. Korzenev,23 V. N. Kovalenko,21 K. Kowalik,11 S. Kowalski,14 M. Koziel,6 A. Krasnoperov,19 W. Kucewicz,13 M. Kuich,15 A. Kurepin,18 D. Larsen,12 A. László,7 T. V. Lazareva,21 M. Lewicki,16 K. Łojek,12 B. Łysakowski,14 V. V. Lyubushkin,19 M. Maćkowiak-Pawłowska,17 Z. Majka,12 B. Maksiak,11 A. I. Malakhov,19 A. Marchionni,24 A. Marcinek,10 A. D. Marino,26 K. Marton,7 H.-J. Mathes,5 T. Matulewicz,15 V. Matveev,19 G. L. Melkumov,19 A. O. Merzlaya,12 B. Messerly,27 Ł. Mik,13 G. B. Mills,25 S. Morozov,18,20 S. Mrówczyński,9 Y. Nagai ,26 M. Naskręt,16 V. Ozvenchuk,10 V. Paolone,27 M. Pavin,4,3 O. Petukhov,18 R. Płaneta,12 P. Podlaski,15 B. A. Popov,19,4 B. Porfy,7 M. Posiadała-Zezula,15 D. S. Prokhorova,21 D. Pszczel,11 S. Puławski,14 J. Puzović,22 M. Ravonel,23 R. Renfordt,6 E. Richter-Wąs,12 D. Röhrich,8 E. Rondio,11 M. Roth,5 B. T. Rumberger,26 M. Rumyantsev,19 A. Rustamov,1,6 M. Rybczynski,9 A. Rybicki,10 A. Sadovsky,18 K. Schmidt,14 I. Selyuzhenkov,20 A. Yu. Seryakov,21 P. Seyboth,9 M. Słodkowski,17 A. Snoch,6 P. Staszel,12 G. Stefanek,9 J. Stepaniak,11 M. Strikhanov,20 H. Ströbele,6 T. Šuša,3 A. Taranenko,20 A. Tefelska,17 D. Tefelski,17 V. Tereshchenko,19 A. Toia,6 R. Tsenov,2 L. Turko,16 R. Ulrich,5 M. Unger,5 F. F. Valiev,21 D. Veberič,5 V. V. Vechernin,21 A. Wickremasinghe,27 Z.Włodarczyk,9 A.Wojtaszek-Szwarc,9 K. Wójcik,14 O.Wyszyński,12 L. Zambelli,4 E. D. Zimmerman,26 and R. Zwaska24 (NA61/SHINE Collaboration) 1National Nuclear Research Center, Baku, Azerbaijan 2Faculty of Physics, University of Sofia, Sofia, Bulgaria 3Rud¯er Bošković Institute, Zagreb, Croatia 4LPNHE, University of Paris VI and VII, Paris, France 5Karlsruhe Institute of Technology, Karlsruhe, Germany 6University of Frankfurt, Frankfurt, Germany 7Wigner Research Centre for Physics of the Hungarian Academy of Sciences, Budapest, Hungary 8University of Bergen, Bergen, Norway 9Jan Kochanowski University in Kielce, Poland 10Institute of Nuclear Physics, Polish Academy of Sciences, Cracow, Poland 11National Centre for Nuclear Research, Warsaw, Poland 12Jagiellonian University, Cracow, Poland 13AGH—University of Science and Technology, Cracow, Poland 14University of Silesia, Katowice, Poland 15University of Warsaw, Warsaw, Poland 16University of Wrocław, Wrocław, Poland 17Warsaw University of Technology, Warsaw, Poland 18Institute for Nuclear Research, Moscow, Russia 19Joint Institute for Nuclear Research, Dubna, Russia 20National Research Nuclear University (Moscow Engineering Physics Institute), Moscow, Russia 21St. Petersburg State University, St. Petersburg, Russia 22University of Belgrade, Belgrade, Serbia 23University of Geneva, Geneva, Switzerland 24Fermilab, Batavia, Illinois, USA 25Los Alamos National Laboratory, Los Alamos, New Mexico, USA 26University of Colorado, Boulder, Colorado, USA 27University of Pittsburgh, Pittsburgh, Pennsylvania, US
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