Electron collision effects on the bremsstrahlung emission in Lorentzian plasmas

International Nuclear Information System (INIS)

Jung, Young-Dae; Kato, Daiji

2009-06-01

The electron-electron collision effects on the electron-ion bemsstranhlung process are investigated in warm Lorentzian plasmas. The effective electron-ion interaction potential is obtained by including the far-field terms caused by the electron-electron collisions with the effective Debye length in Lorentzian plasmas. The bremsstranhlung radiation cross section is obtained as a function of the electron energy, photon energy, collision frequency, spectral index, and Debye length using the Born approximation for the initial and final states of the projectile electron. It is shown that the non-Maxwellian character suppresses the bremsstrahlung radiation cross section. It is also shown that the electron-electron collision effect enhances the bremsstrahlung emission spectrum. In addition, the bremsstrahlung radiation cross section decreases with an increase of the plasma temperature. (author)

Newly appreciated roles for electrons in ion-atom collisions

International Nuclear Information System (INIS)

Sellin, I.A.

1990-01-01

Since the previous Debrecen workshop on High-Energy Ion-Atom Collisions there have been numerous experiments and substantial theoretical developments in the fields of fast ion-atom and ion- solid collisions concerned with explicating the previously largely underappreciated role of electrons as ionizing and exciting agents in such collisions. Examples to be discussed include the double electron ionization problem in He; transfer ionization by protons in He; double excitation in He; backward scattering of electrons in He; the role of electron-electron interaction in determining beta parameters for ELC; projectile K ionization by target electrons; electron spin exchange in transfer excitation; electron impact ionization in crystal channels; resonant coherent excitation in crystal channels; excitation and dielectronic recombination in crystal channels; resonant transfer and excitation; the similarity of recoil ion spectra observed in coincidence with electron capture vs. electron loss; and new research on ion-atom collisions at relativistic energies

Electronic transport coefficients in plasmas using an effective energy-dependent electron-ion collision-frequency

Science.gov (United States)

Faussurier, G.; Blancard, C.; Combis, P.; Decoster, A.; Videau, L.

2017-10-01

We present a model to calculate the electrical and thermal electronic conductivities in plasmas using the Chester-Thellung-Kubo-Greenwood approach coupled with the Kramers approximation. The divergence in photon energy at low values is eliminated using a regularization scheme with an effective energy-dependent electron-ion collision-frequency. Doing so, we interpolate smoothly between the Drude-like and the Spitzer-like regularizations. The model still satisfies the well-known sum rule over the electrical conductivity. Such kind of approximation is also naturally extended to the average-atom model. A particular attention is paid to the Lorenz number. Its nondegenerate and degenerate limits are given and the transition towards the Drude-like limit is proved in the Kramers approximation.

Geometric and electronic structures of molecular ions from high energy collisions

International Nuclear Information System (INIS)

Groeneveld, K.O.

1983-01-01

This chapter examines the characteristics of heavy ion collision and of beam foil spectroscopy. It discusses the kinematic consequences of the high energies and presents results from ''Coulomb explosion'' and structure determination of molecular ions. It demonstrates that studies of molecular ions with accelerators can provide electronic and geometric structure information of molecules or molecular ions and points out that the understanding of the microscopic processes at such high energies is incomplete and needs further experimental and theoretical efforts

Electron-molecule collisions

International Nuclear Information System (INIS)

Shimamura, I.; Takayanagi, K.

1984-01-01

The study of collision processes plays an important research role in modern physics. Many significant discoveries have been made by means of collision experiments. Based on theoretical, experimental, and computational studies, this volume presents an overview detailing the basic processes of electron-molecule collisions. The editors have collected papers-written by a group of international experts-that consider a diverse range of phenomena occurring in electronmolecule collisions. The volume discusses first the basic formulation for scattering problems and then gives an outline of the physics of electron-molecule collisions. The main topics covered are rotational transitions, vibrational transitions, dissociation of molecules in slow collisions, the electron-molecule collision as a spectroscopic tool for studying molecular electronic structures, and experimental and computational techniques for determining the cross sections. These well-referenced chapters are self-contained and can be read independently or consecutively. Authoritative and up-to-date, Electron-Molecule Collisions is a useful addition to the libraries of students and researchers in the fields of atomic, molecular, and chemical physics, and physical chemistry

Electron capture in ion-molecule collisions at intermediate energy

International Nuclear Information System (INIS)

Kumura, M.

1986-01-01

Recent progress of theoretical charge transfer study in ion-molecule collisions at the intermediate energy is reviewed. Concept of close and distant collisions obtained from extensive ion-atom collision studies is identified so that it can be utilized to model two distinct collision processes. For a close collision, explicit representation of the whole collision complex is necessary to describe collision dynamics correctly, while a model potential approach for molecule is appropriate for a distant collision. It is shown that these two distinct models are indeed capable of reproducing experimental charge transfer cross sections. Some remarks for further theoretical study of ion-molecule collisions are also given. 21 refs., 8 figs

Collisions of low-energy multicharged ions

International Nuclear Information System (INIS)

Phaneuf, R.A.; Crandall, D.H.

1981-01-01

Experimental measurements of cross sections for collisions of multiply charged ions with atoms at the lowest attainable collision energies are reported. Emphasis is on electron capture from hydrogen atoms by multiply charged ions at energies below 1 keV/amu. The principal effort is the development of a merged-ion-atom-beams apparatus for studies down to 1 eV/amu relative energy

Electron loss from multiply protonated lysozyme ions in high energy collisions with molecular oxygen

DEFF Research Database (Denmark)

Hvelplund, P; Nielsen, SB; Sørensen, M

2001-01-01

We report on the electron loss from multiply protonated lysozyme ions Lys-Hn(n)+ (n = 7 - 17) and the concomitant formation of Lys-Hn(n+1)+. in high-energy collisions with molecular oxygen (laboratory kinetic energy = 50 x n keV). The cross section for electron loss increases with the charge state...... of the precursor from n = 7 to n = 11 and then remains constant when n increases further. The absolute size of the cross section ranges from 100 to 200 A2. The electron loss is modeled as an electron transfer process between lysozyme cations and molecular oxygen....

Projectile Coulomb center effects on low-energy electron emission from H[sup +][yields]Ne collisions

Energy Technology Data Exchange (ETDEWEB)

Suarez, S. (Centro Atomico Bariloche e Inst. Balseiro, Comision Nacional de Energia Atomica, S.C. de Bariloche, Rio Negro (Argentina)); Garibotti, C. (Centro Atomico Bariloche e Inst. Balseiro, Comision Nacional de Energia Atomica, S.C. de Bariloche, Rio Negro (Argentina) Consejo Nacional de Investigaciones Cientificas y Tecnicas (CONICET) (Argentina)); Bernardi, G. (Centro Atomico Bariloche e Inst. Balseiro, Comision Nacional de Energia Atomica, S.C. de Bariloche, Rio Negro (Argentina) Consejo Nacional de Investigaciones Cientificas y Tecnicas (CONICET) (Argentina)); Focke, P. (Centro Atomico Bariloche e Inst. Balseiro, Comision Nacional de Energia Atomica, S.C. de Bariloche, Rio Negro (Argentina)); Meckbach, W. (Centro Atomico Bariloche e Inst. Balseiro, Comision Nacional de Energia Atomica, S.C. de Bariloche, Rio Negro (Argentina) Consejo Nacional de Investigaciones Cientificas y Tecnicas (CONICET) (Argentina))

1994-03-01

We present doubly differential energy distributions of low-energy electrons emitted in collisions of 106 keV H[sup +] on Ne atoms. We find a relevant dependence of the measured distribution of low-energy electrons on the physical extension of the gas target and discuss a correction procedure. Our measurements enable a quantitative analysis of the shape of the soft electron peak, which is clearly evidenced by measured contour lines. Present results indicate that ''two center effects'' must be considered in order to account for the strong asymmetry of the soft electron peak observed experimentaly. (orig.)

Multiple-electron processes in fast ion-atom collisions

International Nuclear Information System (INIS)

Schlachter, A.S.

1989-03-01

Research in atomic physics at the Lawrence Berkeley Laboratory Super-HILAC and Bevalac accelerators on multiple-electron processes in fast ion-atom collisions is described. Experiments have studied various aspects of the charge-transfer, ionization, and excitation processes. Examples of processes in which electron correlation plays a role are resonant transfer and excitation and Auger-electron emission. Processes in which electron behavior can generally be described as uncorrelated include ionization and charge transfer in high-energy ion-atom collisions. A variety of experiments and results for energies from 1 MeV/u to 420 MeV/u are presented. 20 refs., 15 figs

Single-electron capture in low-energy Ar6+-He collisions

International Nuclear Information System (INIS)

Akguengoer, K.; Kamber, E.Y.; Ferguson, S.M.

1997-01-01

Double differential cross sections for state-selective single-electron capture processes in Ar 6+ -He collisions have been measured at laboratory energies between 75 and 900 eV and scattering angles between 0 and 8 . At the lowest energy, the zero-angle spectrum shows capture into Ar 5+ (4p) to be the most important channel. However, as the scattering angle is increased, a second peak appears at angles ≥2 and becomes more pronounced relative to the 4p capture channel. The energy spectra are interpreted qualitatively in terms of the reaction windows, which are calculated using the single-crossing Landau-Zener model. Total and differential cross sections are also measured and compared with available measurements and calculations. (orig.)

Electron transfer, ionization, and excitation in atomic collisions

International Nuclear Information System (INIS)

Winter, T.G.; Alston, S.G.

1992-01-01

The research being carried out at Penn State by Winter and Alston addresses the fundamental processes of electron transfer, ionization, and excitation in ion-atom (and ion-ion) collisions. The focus is on intermediate- and higher-energy collisions, corresponding to proton energies of about 25 kilo-electron-volts (keV) or larger. At intermediate energies, where the transition probabilities are not small, many states must be coupled in a large calculation, while at higher energies, perturbative approaches may be used. Several studies have been carried out in the current three-year period; most of these treat systems with only one or two electrons, so that fewer approximations need be made and the basic collisional mechanisms can be more clearly described

Removal of nonorthogonality in the Born theory used for study of electron capture in high energy ion-atom collisions

International Nuclear Information System (INIS)

Kimura, M.

1989-01-01

We show the complete removal of the nonorthogonality of wave functions between initial and final states in the Born theory. Hence, this treatment offers more realistic electron capture cross sections in high energy ion-atom collisions. Representative results for resonant electron capture in H + + H collision are discussed in conjunction with other perturbative results. 10 refs., 1 fig

Electronic stopping in ion-fullerene collisions

NARCIS (Netherlands)

Schlathölter, T.A.; Hadjar, O.; Hoekstra, R.A.; Morgenstern, R.W.H.

The electronic friction experienced by a multiply charged ion interacting with the valence electrons of a single fullerene is an important aspect of the collision dynamics. It manifests itself in a considerable loss of projectile kinetic energy transferred to the target, resulting in excitation. The

Electron detachment by H- + H- collisions

International Nuclear Information System (INIS)

Chibisov, M.I.; Yavlinskii, Yu.N.

1994-01-01

The autoionization channels for electrons detachment in collisions of two negative hydrogen ions in the energy range 300 - 500 eV and > 500 eV are investigated. In small energy range at large inter-ion distances the asymptotic approximation is used; at high energies - perturbation theory and classical motion are used. 18 refs., 3 figs

ELECTRON-CAPTURE IN HIGHLY-CHARGED ION-ATOM COLLISIONS

NARCIS (Netherlands)

MORGENSTERN, R

1993-01-01

An attempt is made to identify the most important mechanisms responsible for the rearrangement of electrons during collisions between multiply charged ions and atoms at keV energies. It is discussed to which extent the influence of binding energy, angular momentum of heavy particles and electrons,

Electron emission and energy loss in grazing collisions of protons with insulator surfaces

International Nuclear Information System (INIS)

Gravielle, M. S.; Miraglia, J. E.; Aldazabal, I.; Arnau, A.; Ponce, V. H.; Aumayr, F.; Lederer, S.; Winter, H.

2007-01-01

Electron emission from LiF, KCl, and KI crystal surfaces during grazing collisions of swift protons is studied using a first-order distorted-wave formalism. Owing to the localized character of the electronic structure of these surfaces, we propose a model that allows us to describe the process as a sequence of atomic transitions from different target ions. Experimental results are presented for electron emission from LiF and KI and energy loss from KI surfaces. Calculations show reasonable agreement with these experimental data. The role played by the charge of the incident particle is also investigated

Single electron capture differential cross section in H+ + He collisions at intermediate and high collision energies

International Nuclear Information System (INIS)

Abufager, P N; Fainstein, P D; MartInez, A E; Rivarola, R D

2005-01-01

The generalized continuum distorted wave-eikonal initial state (CDW-EIS II) approximation is employed to study differential cross sections (DCS) for single electron capture in H + + He collisions at intermediate and high energies. Present results are compared with theoretical calculations obtained using the previous CDW-EIS formulation in order to show the importance of the description of the bound and continuum target states in the entrance and exit channels, respectively. Both DCS are also shown together with other theoretical results and with experimental data

High-resolution electron collision spectroscopy with multicharged ions in merged beams

Energy Technology Data Exchange (ETDEWEB)

Lestinsky, M.

2007-04-18

The Heidelberg ion storage ring Tsr is currently the only ring equipped with two independent devices for the collinear merging of a cold electron beam with stored ions. This greatly improves the potential of electron-ion collision experiments, as the ion beam can be cooled with one electron beam, while the other one is used as a dedicated target for energy-resolved electron collision processes, such as recombination. The work describes the implementation of this system for rst electron collision spectroscopy experiments. A detection system has been realized including an ion detector and specroscopic beam-control software and instrumentation. Moreover, in order to improve the spectroscopic resolution systematical studies of intrinsic relaxation processes in the electron beam have been carried out. These include the dependence on the electron beam density, the magnetic guiding eld strength, and the acceleration geometry. The recombination measurements on low-lying resonances in lithiumlike Sc{sup 18+} yield a high-precision measurement of the 2s-2p{sub 3/2} transition energy in this system. Operation of the two-electron-beam setup at high collision energy ({approx}1000 eV) is established using resonances of hydrogenlike Mg{sup 11+}, while the unique possibility of modifying the beam-merging geometry con rms its importance for the electron-ion recombination rate at lowest relative energy, as demonstrated on F{sup 6+}. (orig.)

High-resolution electron collision spectroscopy with multicharged ions in merged beams

International Nuclear Information System (INIS)

Lestinsky, M.

2007-01-01

The Heidelberg ion storage ring Tsr is currently the only ring equipped with two independent devices for the collinear merging of a cold electron beam with stored ions. This greatly improves the potential of electron-ion collision experiments, as the ion beam can be cooled with one electron beam, while the other one is used as a dedicated target for energy-resolved electron collision processes, such as recombination. The work describes the implementation of this system for rst electron collision spectroscopy experiments. A detection system has been realized including an ion detector and specroscopic beam-control software and instrumentation. Moreover, in order to improve the spectroscopic resolution systematical studies of intrinsic relaxation processes in the electron beam have been carried out. These include the dependence on the electron beam density, the magnetic guiding eld strength, and the acceleration geometry. The recombination measurements on low-lying resonances in lithiumlike Sc 18+ yield a high-precision measurement of the 2s-2p 3/2 transition energy in this system. Operation of the two-electron-beam setup at high collision energy (∼1000 eV) is established using resonances of hydrogenlike Mg 11+ , while the unique possibility of modifying the beam-merging geometry con rms its importance for the electron-ion recombination rate at lowest relative energy, as demonstrated on F 6+ . (orig.)

Measurement of ejected electrons from collisions of He+ ions with He, Ne, and Ar at the intermediate energies

International Nuclear Information System (INIS)

Tokoro, Nobuhiro; Oda, Nobuo

1985-01-01

The doubly differential cross sections for electron production, differential in angle and energy of the electrons, for 5-25 keV He + impact on helium, neon and argon have been measured in the electron energy range of 2-200 eV at the ejection angles from 30 0 to 150 0 with respect to the incident ion beam. The characteristic features of continnum parts of ejected electron spectra are described for each collision system. (author)

Quantum mechanics of electronic-rotational energy transfer in F(2P) + H2 collisions

International Nuclear Information System (INIS)

Wyatt, R.E.; Walker, R.B.

1977-01-01

A theoretical study is made of electronic-rotational energy transfer in F( 2 P) + H 2 three-dimensional collisions, with electronic matrix elements from DIM theory. The quantum close-coupled equations are integrated via the R-matrix propagation method. Inelastic quenching probabilities are emphasized, with and without simulated open reaction channels. Interweaving patterns in the transition probability for even and odd nuclear parity vs. J (total angular momentum quantum number) are analyzed in terms of avoided crossing structure in the electrotational energy correlation diagrams. Localized regions where electronic quenching is dominant are identified in the correlation diagrams, and are confirmed in separate calculations which neglect interchannel mixing in local regions of the atom-molecule separation. Open reaction channels are found to have little influence on the quenching probabilities in these low energy calculations

Charge-transfer collisions involving few-electron systems

International Nuclear Information System (INIS)

Kirchner, T.

2016-01-01

Ion-atom collision systems that involve more than one electron constitute nonseparable few-body problems, whose full solution is difficult to say the least. At impact energies well below 1 keV/amu an expansion of the stationary scattering wave function in terms of a limited number of products of nuclear and molecular state wave functions (amended to satisfy scattering boundary conditions) is feasible and usually sufficient to obtain accurate charge-transfer cross sections provided the electronic wave functions include configuration interaction. At energies above 1 keV/amu this approach becomes inefficient and close-coupling methods within the semi classical approximation are better suited to treat the problem. For bare-ion collisions from helium target atoms explicit solutions of the two-electron time-dependent Schrödinger equation can be achieved, but are computationally costly and cannot be extended to problems which involve more than two electrons.

Ultra-low energy electrons from fast heavy-ion helium collisions: the `target Cusp`

Energy Technology Data Exchange (ETDEWEB)

Schmitt, W. [Freiburg Univ. (Germany)]|[Gesellschaft fuer Schwerionenforschung mbH, Darmstadt (Germany); Moshammer, R.; Kollmus, H.; Ullrich, J. [Freiburg Univ. (Germany); O`Rourke, F.S.C. [Queen`s Univ., Belfast, Northern Ireland (United Kingdom); Sarkadi, L. [Magyar Tudomanyos Akademia, Debrecen (Hungary). Atommag Kutato Intezete; Mann, R. [Gesellschaft fuer Schwerionenforschung mbH, Darmstadt (Germany); Hagmann, S. [Kansas State Univ., Manhattan, KS (United States). J.R. MacDonald Lab.; Olson, R.E. [Missouri Univ., Rolla, MO (United States). Dept. of Physics

1998-09-01

Doubly differential cross sections d{sup 2}{sigma}/dv {sub parallel} dv {sub perpendicular} {sub to} have been obtained by mapping the 3-dimensional velocity space of ultra-low and low-energy electrons (1.5 meV{<=} E{sub e}{<=}100 eV) emitted in singly ionizing 3.6 MeV/u Au{sup 53+} on helium collisions. A sharp ({Delta}E{sub e} {sub perpendicular} {sub to} {sup FWHM} {<=} 22 meV) asymmetric peak centered at vertical stroke anti {nu} vertical stroke =0 is observed to emerge at ultra-low energies from the strongly forward shifted low-energy electron velocity distribution. The shape of this ``target cusp``, which is very sensitive on the details of the two-center potential, is in excellent accord with theoretical CTMC and CDW-EIS predictions. (orig.)

Electron collisions and internal excitation in stored molecular ion beams

International Nuclear Information System (INIS)

Buhr, H.

2006-01-01

In storage ring experiments the role, which the initial internal excitation of a molecular ion can play in electron collisions, and the effect of these collisions on the internal excitation are investigated. Dissociative recombination (DR) and inelastic and super-elastic collisions are studied in the system of He + 2 . The DR rate coefficient at low energies depends strongly on the initial vibrational excitation in this system. Therefore changes in the DR rate coefficient are a very sensitive probe for changes in the vibrational excitation in He + 2 , which is used to investigate the effects of collisions with electrons and residual gas species. The low-energy DR of HD + is rich with resonances from the indirect DR process, when certain initial rotational levels in the molecular ion are coupled to levels in neutral Rydberg states lying below the ion state. Using new procedures for high-resolution electron-ion collision spectroscopy developed here, these resonances in the DR cross section can be measured with high energy sensitivity. This allows a detailed comparison with results of a MQDT calculation in an effort to assign some or all of the resonances to certain intermediate Rydberg levels. (orig.)

Electron collisions and internal excitation in stored molecular ion beams

Energy Technology Data Exchange (ETDEWEB)

Buhr, H.

2006-07-26

In storage ring experiments the role, which the initial internal excitation of a molecular ion can play in electron collisions, and the effect of these collisions on the internal excitation are investigated. Dissociative recombination (DR) and inelastic and super-elastic collisions are studied in the system of He{sup +}{sub 2}. The DR rate coefficient at low energies depends strongly on the initial vibrational excitation in this system. Therefore changes in the DR rate coefficient are a very sensitive probe for changes in the vibrational excitation in He{sup +}{sub 2}, which is used to investigate the effects of collisions with electrons and residual gas species. The low-energy DR of HD{sup +} is rich with resonances from the indirect DR process, when certain initial rotational levels in the molecular ion are coupled to levels in neutral Rydberg states lying below the ion state. Using new procedures for high-resolution electron-ion collision spectroscopy developed here, these resonances in the DR cross section can be measured with high energy sensitivity. This allows a detailed comparison with results of a MQDT calculation in an effort to assign some or all of the resonances to certain intermediate Rydberg levels. (orig.)

Energy transfer in diatom/diatom molecular collisions

International Nuclear Information System (INIS)

Sohlberg, K.W.

1992-01-01

In a collision of two molecules, the translational energy of the collision may be redistributed into internal energy of rotation, vibration, or electron motion, in one or both of the colliding partners. In addition, internal energy in one or more of these modes may be open-quotes quenchedclose quotes into translation, leading to a superelastic collision. Such energy transfer may take place by a number of mechanisms. This energy transfer is of fundamental importance in understanding chemical reaction dynamics. Nearly all chemical reactions take place through a bimolecular collision process (or multiple bimolecular collisions) and the quantum state specificity of the reaction can have a major role in determining the kinetics of the reaction, In particular, the author has investigated vibrational energy transfer in collisions between two diatomic molecules. In addition to serving as models for all molecular collision process, gas phase collisions of these species are ubiquitous in atmospheric phenomena which are of critical importance in answering the current questions about the human induced degradation of the earth's atmospheric. Classical trajectory methods have been used to explore the excitation of vibrations in gas-phase collisions of the nitrogen molecular ion with its parent molecule. The near symmetry of the reactants is shown to result in a high probability that the two molecules are excited by an equal amount of energy. This provides a possible explanation of the molecular beam measurements which show that the total number of vibrational energy quanta excited in the collision is, with a high probability that the two molecules are excited by an equal amount of energy. This provides a possible explanation of the molecular beam measurements which show that the total number of vibrational energy quanta excited in the collision is, with a high probability, even

On the quantum Landau collision operator and electron collisions in dense plasmas

Energy Technology Data Exchange (ETDEWEB)

Daligault, Jérôme, E-mail: daligaul@lanl.gov [Theoretical Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States)

2016-03-15

The quantum Landau collision operator, which extends the widely used Landau/Fokker-Planck collision operator to include quantum statistical effects, is discussed. The quantum extension can serve as a reference model for including electron collisions in non-equilibrium dense plasmas, in which the quantum nature of electrons cannot be neglected. In this paper, the properties of the Landau collision operator that have been useful in traditional plasma kinetic theory and plasma transport theory are extended to the quantum case. We outline basic properties in connection with the conservation laws, the H-theorem, and the global and local equilibrium distributions. We discuss the Fokker-Planck form of the operator in terms of three potentials that extend the usual two Rosenbluth potentials. We establish practical closed-form expressions for these potentials under local thermal equilibrium conditions in terms of Fermi-Dirac and Bose-Einstein integrals. We study the properties of linearized quantum Landau operator, and extend two popular approximations used in plasma physics to include collisions in kinetic simulations. We apply the quantum Landau operator to the classic test-particle problem to illustrate the physical effects embodied in the quantum extension. We present useful closed-form expressions for the electron-ion momentum and energy transfer rates. Throughout the paper, similarities and differences between the quantum and classical Landau collision operators are emphasized.

On the quantum Landau collision operator and electron collisions in dense plasmas

Science.gov (United States)

Daligault, Jérôme

2016-03-01

The quantum Landau collision operator, which extends the widely used Landau/Fokker-Planck collision operator to include quantum statistical effects, is discussed. The quantum extension can serve as a reference model for including electron collisions in non-equilibrium dense plasmas, in which the quantum nature of electrons cannot be neglected. In this paper, the properties of the Landau collision operator that have been useful in traditional plasma kinetic theory and plasma transport theory are extended to the quantum case. We outline basic properties in connection with the conservation laws, the H-theorem, and the global and local equilibrium distributions. We discuss the Fokker-Planck form of the operator in terms of three potentials that extend the usual two Rosenbluth potentials. We establish practical closed-form expressions for these potentials under local thermal equilibrium conditions in terms of Fermi-Dirac and Bose-Einstein integrals. We study the properties of linearized quantum Landau operator, and extend two popular approximations used in plasma physics to include collisions in kinetic simulations. We apply the quantum Landau operator to the classic test-particle problem to illustrate the physical effects embodied in the quantum extension. We present useful closed-form expressions for the electron-ion momentum and energy transfer rates. Throughout the paper, similarities and differences between the quantum and classical Landau collision operators are emphasized.

Recent investigations on electronic capture in atomic collisions

International Nuclear Information System (INIS)

Rivarola, R.D.

1988-01-01

In this work, electron capture processes in ion-atom collisions at various impact energy ranges are dicussed: i) intermediate non-relativistic energy; ii) high energy; iii) high relativistic energy. Much attention is given to the development and use of distorted wave models. (A.C.A.S.) [pt

Electron collisions with biomolecules

International Nuclear Information System (INIS)

McKoy, V; Winstead, C

2008-01-01

We report on results of recent studies of collisions of low-energy electrons with nucleobases and other DNA constituents. A particular focus of these studies has been the identification and characterization of resonances that play a role in electron attachment leading to strand breaks in DNA. Comparison of the calculated resonance positions with results of electron transmission measurements is quite encouraging. However, the higher-lying π* resonances of the nucleobases appear to be of mixed elastic and core-excited character. Such resonant channel coupling raises the interesting possibility that the higher π*resonances in the nucleobases may promote dissociation of DNA by providing doorway states to triplet excited states.

Search for Fermi shuttle mechanisms in electron emission from atomic collision sequences

International Nuclear Information System (INIS)

Suarez, S.; Jung, M.; Rothard, H.; Schosnig, M.; Maier, R.; Clouvas, A.; Groeneveld, K.O.

1994-01-01

In electron spectra induced by slow heavy ion bombardment of solids a high energy tail can be observed, which is suggested to be explained by multiple collision sequences. In order to find those multiple collision effects like the ''Fermi shuttle'' acceleration mechanism we measured doubly differential electron emission cross sections for H + (33.5-700 keV) impact on different targets (He, Ne, C and Au) as a function of projectile energy and electron emission angle. We observed a surprising target dependence of the electron emission within the range of electron energies close to that of the binary encounter electrons for all observed angles of emission. (orig.)

Electron collision cross sections and radiation chemistry

International Nuclear Information System (INIS)

Hatano, Y.

1983-01-01

A survey is given of the cross section data needs in radiation chemistry, and of the recent progress in electron impact studies on dissociative excitation of molecules. In the former some of the important target species, processes, and collision energies are presented, while in the latter it is demonstrated that radiation chemistry is a source of new ideas and information in atomic collision research. 37 references, 4 figures

Correlated electron-ion collisions in a strong laser field; Korrelierte Elektron-Ion-Stoesse in starken Laserfeldern

Energy Technology Data Exchange (ETDEWEB)

Ristow, T.

2007-12-17

Electron-ion-collisions in plasmas in the presence of an ultra-short intensive laser pulse can cause high energy transfers to the electrons. During the collision the oscillation energy of the electron in the laser field is changed into drift energy. In this regime, multi-photon processes, known from the ionization of neutral atoms (Above-Threshold Ionization), and successive, so called correlated collisions, are important. The subject of the thesis is a study of binary Coulomb collisions in strong laser fields. The collisions are treated both in the context of classical Newtonian mechanics and in the quantum-mechanical framework by the Schroedinger equation. In the classical case a simplified instantaneous collision model and a complete dynamical treatment are discussed. Collisions can be treated instantaneously, if the ratio of the impact parameter to the quiver amplitude is small. The energy distributions calculated in this approximation show an elastic peak and a broad plateau due to rescattered electrons. At incident velocities smaller than the quiver velocity, correlated collisions are observed in the electron trajectories of the dynamical model. This effect leads to characteristic momentum distributions of the electrons, that are explicitly calculated and compared with the results of the instantaneous model. In addition, the time-dependence of the collisions is discussed in the framework of a singular perturbation theory. The complete description of the Coulomb scattering requires a quantum-mechanical description. A time-dependent method of wave-packet scattering is used and the corresponding time-dependent three-dimensional Schroedinger equation is solved by an implicit ADImethod on a spatial grid. The momentum and the energy distributions of the scattered electrons are calculated by the Fourier transformation of the wavefunction. A comparison of the scattering from a repulsive and an attractive potential is used to distinguish between simple collisions and

Fragmentation of molecular ions in slow electron collisions

International Nuclear Information System (INIS)

Novotny, Steffen

2008-01-01

The fragmentation of positively charged hydrogen molecular ions by the capture of slow electrons, the so called dissociative recombination (DR), has been investigated in storage ring experiments at the TSR, Heidelberg, where an unique twin-electron-beam arrangement was combined with high resolution fragment imaging detection. Provided with well directed cold electrons the fragmentation kinematics were measured down to meV collision energies where pronounced rovibrational Feshbach resonances appear in the DR cross section. For thermally excited HD + the fragmentation angle and the kinetic energy release were studied at variable precisely controlled electron collision energies on a dense energy grid from 10 to 80 meV. The anisotropy described for the first time by Legendre polynomials higher 2 nd order and the extracted rotational state contributions were found to vary on a likewise narrow energy scale as the rotationally averaged DR rate coefficient. Ro-vibrationally resolved DR experiments were performed on H 2 + produced in distinct internal excitations by a novel ion source. Both the low-energy DR rate as well as the fragmentation dynamics at selected resonances were measured individually in the lowest two vibrational and first three excited rotational states. State-specific DR rates and angular dependences are reported. (orig.)

Fragmentation of molecular ions in slow electron collisions

Energy Technology Data Exchange (ETDEWEB)

Novotny, Steffen

2008-06-25

The fragmentation of positively charged hydrogen molecular ions by the capture of slow electrons, the so called dissociative recombination (DR), has been investigated in storage ring experiments at the TSR, Heidelberg, where an unique twin-electron-beam arrangement was combined with high resolution fragment imaging detection. Provided with well directed cold electrons the fragmentation kinematics were measured down to meV collision energies where pronounced rovibrational Feshbach resonances appear in the DR cross section. For thermally excited HD{sup +} the fragmentation angle and the kinetic energy release were studied at variable precisely controlled electron collision energies on a dense energy grid from 10 to 80 meV. The anisotropy described for the first time by Legendre polynomials higher 2{sup nd} order and the extracted rotational state contributions were found to vary on a likewise narrow energy scale as the rotationally averaged DR rate coefficient. Ro-vibrationally resolved DR experiments were performed on H{sub 2}{sup +} produced in distinct internal excitations by a novel ion source. Both the low-energy DR rate as well as the fragmentation dynamics at selected resonances were measured individually in the lowest two vibrational and first three excited rotational states. State-specific DR rates and angular dependences are reported. (orig.)

Electron energy distribution function, effective electron temperature, and dust charge in the temporal afterglow of a plasma

International Nuclear Information System (INIS)

Denysenko, I. B.; Azarenkov, N. A.; Kersten, H.

2016-01-01

Analytical expressions describing the variation of electron energy distribution function (EEDF) in an afterglow of a plasma are obtained. Especially, the case when the electron energy loss is mainly due to momentum-transfer electron-neutral collisions is considered. The study is carried out for different EEDFs in the steady state, including Maxwellian and Druyvesteyn distributions. The analytical results are not only obtained for the case when the rate for momentum-transfer electron-neutral collisions is independent on electron energy but also for the case when the collisions are a power function of electron energy. Using analytical expressions for the EEDF, the effective electron temperature and charge of the dust particles, which are assumed to be present in plasma, are calculated for different afterglow durations. An analytical expression for the rate describing collection of electrons by dust particles for the case when the rate for momentum-transfer electron-neutral collisions is independent on electron energy is also derived. The EEDF profile and, as a result, the effective electron temperature and dust charge are sufficiently different in the cases when the rate for momentum-transfer electron-neutral collisions is independent on electron energy and when the rate is a power function of electron energy.

Energy distributions of H+ fragments ejected by fast proton and electron projectiles in collision with H2O molecules

International Nuclear Information System (INIS)

Barros, A. L. F. de; Lecointre, J.; Luna, H.; Montenegro, E. C.; Shah, M. B.

2009-01-01

Experimental measurements of the kinetic energy distribution spectra of H + fragment ions released during radiolysis of water molecules in collision with 20, 50, and 100 keV proton projectiles and 35, 200, 400, and 1000 eV electron projectiles are reported using a pulsed beam and drift tube time-of-flight based velocity measuring technique. The spectra show that H + fragments carrying a substantial amount of energy are released, some having energies well in excess of 20 eV. The majority of the ions lie within the 0-5 eV energy range with the proton spectra showing an almost constant profile between 1.5 and 5 eV and, below this, increasing gradually with decreasing ejection energy up to the near zero energy value while the electron spectra, in contrast, show a broad maximum between 1 and 3 eV and a pronounced dip around 0.25 eV. Beyond 5 eV, both projectile spectra show a decreasing profile with the electron spectra decreasing far more rapidly than the proton spectra. Our measured spectra thus indicate that major differences are present in the collision dynamics between the proton and the electron projectiles interacting with gas phase water molecules.

Coupled-Sturmian and perturbative treatments of electron transfer and ionization in high-energy p-He+ collisions

Science.gov (United States)

Winter, Thomas G.; Alston, Steven G.

1992-02-01

Cross sections have been determined for electron transfer and ionization in collisions between protons and He+ ions at proton energies from several hundred kilo-electron-volts to 2 MeV. A coupled-Sturmian approach is taken, extending the work of Winter [Phys. Rev. A 35, 3799 (1987)] and Stodden et al. [Phys. Rev. A 41, 1281 (1990)] to high energies where perturbative approaches are expected to be valid. An explicit connection is made with the first-order Born approximation for ionization and the impulse version of the distorted, strong-potential Born approximation for electron transfer. The capture cross section is shown to be affected by the presence of target basis functions of positive energy near v2/2, corresponding to the Thomas mechanism.

Coupled-Sturmian and perturbative treatments of electron transfer and ionization in high-energy p-He+ collisions

International Nuclear Information System (INIS)

Winter, T.G.; Alston, S.G.

1992-01-01

Cross sections have been determined for electron transfer and ionization in collisions between protons and He + ions at proton energies from several hundred kilo-electron-volts to 2 MeV. A coupled-Sturmian approach is taken, extending the work of Winter [Phys. Rev. A 35, 3799 (1987)] and Stodden et al. [Phys. Rev. A 41, 1281 (1990)] to high energies where perturbative approaches are expected to be valid. An explicit connection is made with the first-order Born approximation for ionization and the impulse version of the distorted, strong-potential Born approximation for electron transfer. The capture cross section is shown to be affected by the presence of target basis functions of positive energy near v 2 /2, corresponding to the Thomas mechanism

Effects of target plasma electron-electron collisions on correlated motion of fragmented H2+ protons

International Nuclear Information System (INIS)

Barriga-Carrasco, Manuel D.

2006-01-01

The objective of the present work is to examined the effects of plasma target electron-electron collisions on H 2 + protons traversing it. Specifically, the target is deuterium in a plasma state with temperature T e =10 eV and density n=10 23 cm -3 , and proton velocities are v p =v th , v p =2v th , and v p =3v th , where v th is the electron thermal velocity of the target plasma. Proton interactions with plasma electrons are treated by means of the dielectric formalism. The interactions among close protons through plasma electronic medium are called vicinage forces. It is checked that these forces always screen the Coulomb explosions of the two fragmented protons from the same H 2 + ion decreasing their relative distance. They also align the interproton vector along the motion direction, and increase the energy loss of the two protons at early dwell times while for longer times the energy loss tends to the value of two isolated protons. Nevertheless, vicinage forces and effects are modified by the target electron collisions. These collisions enhance the calculated self-stopping and vicinage forces over the collisionless results. Regarding proton correlated motion, when these collisions are included, the interproton vector along the motion direction overaligns at slower proton velocities (v p =v th ) and misaligns for faster ones (v p =2v th , v p =3v th ). They also contribute to a great extend to increase the energy loss of the fragmented H 2 + ion. This later effect is more significant in reducing projectile velocity

Electron loss from hydrogen-like highly charged ions in collisions with electrons, protons and light atoms

Science.gov (United States)

Lyashchenko, K. N.; Andreev, O. Yu; Voitkiv, A. B.

2018-03-01

We consider electron loss from a hydrogen-like highly charged ion (HCI) in relativistic collisions with hydrogen and helium in the range of impact velocities v min ≤ v ≤ v max (v min and v max correspond to the threshold energy ε th for electron loss in collisions with a free electron and to ≈5 ε th, respectively) where any reliable data for loss cross sections are absent. In this range, where the loss process is characterized by large momentum transfers, we express it in terms of electron loss in collisions with equivelocity protons and electrons and explore by performing a detailed comparative study of these subprocesses. Our results, in particular, show that: (i) compared to equivelocity electrons protons are more effective in inducing electron loss, (ii) the relative effectiveness of electron projectiles grows with increase in the atomic number of a HCI, (iii) collisions with protons and electrons lead to a qualitatively different population of the final-state-electron momentum space and even when the total loss cross sections in these collisions become already equal the spectra of the outgoing electrons still remain quite different in almost the entire volume of the final-state-electron momentum space, (iv) in collisions with hydrogen and helium the contributions to the loss process from the interactions with the nucleus and the electron(s) of the atom could be rather well separated in a substantial part of the final-state-electron momentum space.

Electron capture and energy-gain spectroscopy

Energy Technology Data Exchange (ETDEWEB)

Taulbjerg, K.

1989-01-01

The applicability of translation energy spectroscopy as a tool to determine individual reaction cross sections in atomic collisions is analyzed with special emphasis on the electron capture process in highly charged ion collisions. A condition is derived to separate between higher collision energies where translation energy spectroscopy is problem free and lower energies where strong overlap of individual spectra features prohibits an analysis of the total translation energy spectrum by means of a simple deconvolution procedure. 8 refs., 6 figs.

Electron acceleration during streamer collisions in air

DEFF Research Database (Denmark)

Köhn, Christoph; Chanrion, Olivier; Neubert, Torsten

2017-01-01

charge fields, with a Monte Carlo scheme accounting for collisions and ionization. We present the electron density, the electric field, and the velocity distribution as functions of space and time. Assuming a background electric field 1.5 times the breakdown field, we find that the electron density......High-voltage laboratory experiments show that discharges in air, generated over a gap of one meter with maximal voltage of 1 MV, may produce X-rays with photon energies up to 1 MeV. It has been suggested that the photons are bremsstrahlung from electrons accelerated by the impulsive, enhanced field...... during collisions of negative and a positive streamers. To explore this process, we have conducted the first self-consistent particle simulations of streamer encounters. Our simulation model is a 2-D, cylindrically symmetric, particle-in-cell code tracing the electron dynamics and solving the space...

Collision dynamics probed by convoy electron emission

International Nuclear Information System (INIS)

Seliger, M.; Burgdoerfer, J.; Toekesi, K.; Reinhold, C.O.; Takabayashi, Y.; Ito, T.; Komaki, K.; Azuma, T.; Yamazaki, Y.; RIKEN, Saitama

2002-01-01

The description of the collision mechanisms was examined by the emission of convoy electrons as a result of the transport of an Ar 17+ ion with an energy of 390 MeV/amu through self-supporting amorphous carbon foils of thickness varying from 25 to 9190 μg/cm 2 . A classical trajectory Monte Carlo (CTMC) simulation of the random walk of the electron initially attached to the relativistic hydrogenic Argon ion was performed. Measurements were made of the final kinetic energy of the emitted convoy electrons at the Heavy Ion Medical Accelerator in Chiba (HIMAC). (R.P.)

Failure of single electron descriptions of molecular orbital collision processes. [Electron promotion mechanism

Energy Technology Data Exchange (ETDEWEB)

Elston, S.B.

1978-01-01

Inner-shell excitation occurring in low and moderate (keV range) energy collisions between light atomic and ionic systems is frequently describable in terms of molecular promotion mechanisms, which were extensively explored both theoretically and experimentally. The bulk of such studies have concentrated on processes understandable through the use of single- and independent-electron models. Nonetheless, it is possible to find cases of inner-shell excitation in relatively simple collision systems which involve nearly simultaneous multiple-electron transitions and transitions induced by inherently two-electron interactions. Evidence for these many- and nonindependent-electron phenomena in inner-shell excitation processes and the importance of considering such effects in the interpretation of collisionally induced excitation spectra is discussed. 13 references.

Quantum-mechanical theory for electronic-vibrational-rotational energy transfer in atom--diatom collisions: Analysis of the Hamiltonian

International Nuclear Information System (INIS)

Bellum, J.C.; McGuire, P.

1983-01-01

We investigate forms of the molecular system Hamiltonian valid for rigorous quantum-mechanical treatments of inelastic atom--diatom collisions characterized by exchange of energy between electronic, vibrational, and rotational degrees of freedom. We analyze this Hamiltonian in terms of various choices of independent coordinates which unambiguously specify the electronic and nuclear positions in the context of space-fixed and body-fixed reference frames. In particular we derive forms of the Hamiltonian in the context of the following four sets of independent coordinates: (1) a so-called space-fixed set, in which both electronic and nuclear positions are relative to the space-fixed frame; (2) a so-called mixed set, in which nuclear positions are relative to the body-fixed frame while electronic positions are relative to the space-fixed frame; (3) a so-called body-fixed set, in which both electronic and nuclear positions are relative to the body-fixed frame; and (4) another mixed set, in which nuclear positions are relative to the space-fixed frame while electronic positions are relative to the body-fixed frame. Based on practical considerations in accounting for electronic structure and nonadiabatic coupling of electronic states of the collision complex we find the forms of the Hamiltonian in the context of coordinate sets (3) and (4) above to be most appropriate, respectively, for body-fixed and space-fixed treatments of nuclear dynamics in collisional transfer of electronic, vibrational, and rotational energies

Non-Maxwellian electron velocity distribution as a result of electron-attachment collisions in ionized gases

International Nuclear Information System (INIS)

Schmidt, R.; Stiller, W.

1981-01-01

The effects of electron-attachment collisions on the velocity distribution of electrons is studied on the basis of Boltzmann kinetic equations governing the energetic balance of electrons (e), atoms of a carrier gas (c), and SF 6 -molecules (m) capturing electrons. Under the assumption that 1) the densities of the particles fulfill the conditions nsub(e) << nsub(c), nsub(m), nsub(m) << nsub(c), and that 2) only the electron-attachment process is in competition with the elastic collision process between electrons and the atoms of the carrier gas, the time behaviour of the energetic balance of the electrons is investigated. The calculations lead to non-Maxwellian forms of the electron velocity distribution changing the mean electron energy. (author)

Investigation of the dynamics of dissipative U+Au collisions with δ-electron spectroscopy

International Nuclear Information System (INIS)

Stroth, J.; Dahlinger, M.; Konen, W.; Stiebing, K.

1997-01-01

δ-electron emission in elastic and dissipative collisions of U+Au at E/A=8.65 MeV has been investigated. The velocity vectors of the reaction products were measured in coincidence with electrons of energies up to 3.2 MeV. The δ-electron yield measured for elastic collisions is in good agreement with coupled-channel calculations. The δ-electron spectra of dissipative reactions show a clear dependence on the violence of the collision, i.e. the total kinetic energy loss (TKEL). The shape of the spectra are analysed with an atomic model by a fitting procedure using phenomenological trajectories. The results indicate an increasing contact time of the united system with increasing total kinetic energy loss reaching 1.16(4) x 10 -21 s at left angle TKEL right angle =375 MeV. (orig.). With 2 figs

Electron-molecule collisions

CERN Document Server

Takayanagi, Kazuo

1984-01-01

Scattering phenomena play an important role in modern physics. Many significant discoveries have been made through collision experiments. Amongst diverse kinds of collision systems, this book sheds light on the collision of an electron with a molecule. The electron-molecule collision provides a basic scattering problem. It is scattering by a nonspherical, multicentered composite particle with its centers having degrees of freedom of motion. The molecule can even disintegrate, Le., dissociate or ionize into fragments, some or all of which may also be molecules. Although it is a difficult problem, the recent theoretical, experimental, and computational progress has been so significant as to warrant publication of a book that specializes in this field. The progress owes partly to technical develop­ ments in measurements and computations. No less important has been the great and continuing stimulus from such fields of application as astrophysics, the physics of the earth's upper atmosphere, laser physics, radiat...

Study of post-collision effect on autoionisation electron spectra in He+-He collision

International Nuclear Information System (INIS)

Ioannis, K.

1981-11-01

Energy spectra of electrons ejected by autoionisation of the helium atom have been measured at low collision energy (3-20 keV) in the He + -He collision system. Perturbations of the line shapes due to the Coulomb field of the spectator ion are studied. Our results are compared with the semi classical model of MORGENSTERN et al. Only for small (or great) emission angles relative phases as well as moduli of transition amplitudes towards the Msub(L)=0 sublevel of the 2p 2 1 D and 2s2p 1 P states are deduced. Near the 2s 2 1 S line, strong discrepancies with the model are observed (at thetasub(Lab)=11 0 ) which are attributed to a contribution of autoionisation in the quasimolecule. Angular distributions have also been measured which seem to be not perturbed by the Coulomb field. An unexplained oscillatory behaviour of the singly differential cross section, when plotted against the collision energy has also been observed [fr

Electron-positron pair creation in heavy ion collisions

International Nuclear Information System (INIS)

Kienle, P.

1987-01-01

The authors review the status of experiments to study the electron positron pair creation in heavy ion atom collisions at bombarding energies close to the Coulomb barrier. The disentanglement and characterization of various sources of positrons observed in such collisions are described with a focus on the monoenergetic electron positron pairs observed. They seem to originate from the two-body decay of a family of neutral particles with masses of about 3m and lifetimes in the range of 6 x 10 - 14 s, produced by high Coulomb fields. First attempts were made to create these particles by resonant Bhabha scattering

Correlation effects in electron-atom collisions

International Nuclear Information System (INIS)

Water, W. van de.

1981-01-01

This thesis deals with correlation effects occurring in the outer region of configuration space after an ionising collision. The motion of both escaping electrons in the external region is then fully determined by the long-range Coulomb forces. Firstly the threshold ionisation of hydrogen-like targets is studied. In that case two slow electrons attempt to escape from the Coulomb attraction of the residual ion. Secondly ionising collisions, with the formation of an autoionising state as an intermediate step, are considered. Such an autoionising state is in fact a quasi bound state of the neutral atom which lies imbedded in the ionisation continuum. The state decays after a certain lifetime by emission of an electron. Of all states to be formed in the reaction region only the autoionising state(s) under consideration is then relevant for this type of ionisation process. The energy positions of autoionising states usually are such that the electron to be ionised is ejected with a rather large velocity. The correlation in the outer region of configuration space then consists of the interaction of a fast ejected electron and, in case of threshold excitation of the autoionising state, a slow scattered electron. (Auth.)

Electron transfer, ionization, and excitation atomic collisions

International Nuclear Information System (INIS)

Winter, T.G.; Alston, S.G.

1990-01-01

Basic atomic-collision processes at intermediate and high energies are being studied theoretically at Penn State by Alston and Winter. In the high velocity regime, single-electron capture is treated using a high order multiple-scattering approach; extensive comparison with experiment and analysis of mechanisms have been made. Fitting the calculated amplitude with a simple analytic form, the asymptotic velocity dependence of the cross section is obtained. The effect on the capture amplitude of altering the inner part of the internuclear potential has also been explored. In the intermediate velocity regime, earlier work on collisions between protons and hydrogenic-ion targets using a coupled-state approach is being extended to the two-electron helium target. 29 refs

Electron energy distribution from intense electron beams in the upper mesosphere and lower thermosphere

International Nuclear Information System (INIS)

Martinez-Sanchez, M.; Cheng, Wai; Dvore, D.; Zahniser, M.S.

1992-01-01

A model was developed to calculate the electron energy spectrum created by an electron beam in the upper atmosphere. A significant feature of the model is the inclusion of the effects of electron-electron collisions which are important at high beam intensity when the ratio of the electron to ambient gas density is high. Comparing the calculated results for a 2.6-kV, 20-A beam at 110-km altitude from models with and without the electron-electron collision term, the electron-electron collisions have the effect of smoothing out the electron spectrum in the low-energy region ( 2 and O 2 are filled in, resulting in an increase in the calculated production rate of these species compared with model calculations that neglect this effect

Experimental and theoretical study of very-low-energy inelastic processes in electron-molecule collisions. Progress report, March 20, 1982-March 20, 1983

International Nuclear Information System (INIS)

Golden, D.E.; Morrison, M.

1983-01-01

Objectives of this research are: to determine accurate integrated and differential cross sections for low energy electron-molecule elastic scattering, excitation and ionization; to develop, implement, and test new experimental and theoretical procedures for studying low energy collision processes; and to contribute to basic understanding of a fundamental problem in atomic collision physics, the interaction of a charged particle with a non-spherical target that is rich in structure

Double electron transfer in ion-atom collisions

International Nuclear Information System (INIS)

Martinez, A.E

1990-01-01

Continuum distorted wave (CDW) and CDW-EIS (electron-ion scattering) approximations are used to study the resonant double capture by collision of alpha particles on He targets for intermediate and high energies. Calculations of total cross-sections based on the Independent Event Approximation are presented. A good agreement with experimental results was found, even without the inclusion of the dynamic and angular correlation of captured electrons. (Author). 11 refs., 1 fig

Electron-positron pair creation in heavy ion collisions

International Nuclear Information System (INIS)

Kienle, P.

1987-08-01

We review here the status of experiments to study the electron positron pair creation in heavy ion atom collisions at bombarding energies close to the Coulomb barrier. The disentanglement and characterisation of various sources of positrons observed in such collisions are described with a focus on the monoenergetic electron positron pairs observed. They seem to originate from the two-body decay of a family of neutral particles with masses of about 3 m e and life times in the range of 6x10 -14 s -10 s, produced by high Coulomb fields. First attempts were made to create these particles by resonant Bhabha scattering. First we present some experimental methods for high efficiency positron spectroscopy in heavy ion collisions. Then we describe the discovery of positron creation induced by strong time changing Coulomb fields. (orig./HSI)

Electroweak Measurements in Electron-Positron Collisions at W-Boson-Pair Energies at LEP

CERN Document Server

Schael, S.; Bruneliere, R.; Buskulic, D.; De Bonis, I.; Decamp, D.; Ghez, P.; Goy, C.; Jezequel, S.; Lees, J.P.; Lucotte, A.; Martin, F.; Merle, E.; Minard, M.N.; Nief, J.Y.; Odier, P.; Pietrzyk, B.; Trocme, B.; Bravo, S.; Casado, M.P.; Chmeissani, M.; Comas, P.; Crespo, J.M.; Fernandez, E.; Fernandez-Bosman, M.; Garrido, Ll.; Grauges, E.; Juste, A.; Martinez, M.; Merino, G.; Miquel, R.; Mir, Ll. M.; Orteu, S.; Pacheco, A.; Park, I.C.; Perlas, J.; Riu, I.; Ruiz, H.; Sanchez, F.; Colaleo, A.; Creanza, D.; De Filippis, N.; De Palma, M.; Iaselli, G.; Maggi, G.; Maggi, M.; Nuzzo, S.; Ranieri, A.; Raso, G.; Ruggieri, F.; Selvaggi, G.; Silvestris, L.; Tempesta, P.; Tricomi, A.; Zito, G.; Huang, X.; Lin, J.; Ouyang, Q.; Wang, T.; Xie, Y.; Xu, R.; Xue, S.; Zhang, J.; Zhang, L.; Zhao, W.; Abbaneo, D.; Bazarko, A.; Becker, U.; Boix, G.; Bird, F.; Blucher, E.; Bonvicini, B.; Bright-Thomas, P.; Barklow, T.; Buchmuller, O.; Cattaneo, M.; Cerutti, F.; Ciulli, V.; Clerbaux, B.; Drevermann, H.; Forty, R.W.; Frank, M.; Greening, T.C.; Hagelberg, R.; Halley, A.W.; Gianotti, F.; Girone, M.; Hansen, J.B.; Harvey, J.; Jacobsen, R.; Hutchcroft, D.E.; Janot, P.; Jost, B.; Knobloch, J.; Kado, M.; Lehraus, I.; Lazeyras, P.; Maley, P.; Mato, P.; May, J.; Moutoussi, A.; Pepe-Altarelli, M.; Ranjard, F.; Rolandi, L.; Schlatter, D.; Schmitt, B.; Schneider, O.; Tejessy, W.; Teubert, F.; Tomalin, I.R.; Tournefier, E.; Veenhof, R.; Valassi, A.; Wiedenmann, W.; Wright, A.E.; Ajaltouni, Z.; Badaud, F.; Chazelle, G.; Deschamps, O.; Dessagne, S.; Falvard, A.; Ferdi, C.; Fayolle, D.; Gay, P.; Guicheney, C.; Henrard, P.; Jousset, J.; Michel, B.; Monteil, S.; Montret, J.C.; Pallin, D.; Pascolo, J.M.; Perret, P.; Podlyski, F.; Bertelsen, H.; Fernley, T.; Hansen, J.D.; Hansen, J.R.; Hansen, P.H.; Kraan, A.C.; Lindahl, A.; Mollerud, R.; Nilsson, B.S.; Rensch, B.; Waananen, A.; Daskalakis, G.; Kyriakis, A.; Markou, C.; Simopoulou, E.; Siotis, I.; Vayaki, A.; Zachariadou, K.; Blondel, A.; Bonneaud, G.; Brient, J.C.; Machefert, F.; Rouge, A.; Rumpf, M.; Swynghedauw, M.; Tanaka, R.; Verderi, M.; Videau, H.; Ciulli, V.; Focardi, E.; Parrini, G.; Zachariadou, K.; Corden, M.; Georgiopoulos, C.; Antonelli, A.; Antonelli, M.; Bencivenni, G.; Bologna, G.; Bossi, F.; Campana, P.; Capon, G.; Cerutti, F.; Chiarella, V.; Felici, G.; Laurelli, P.; Mannocchi, G.; Murtas, G.P.; Passalacqua, L.; Picchi, P.; Colrain, P.; ten Have, I.; Hughes, I.S.; Kennedy, J.; Knowles, I.G.; Lynch, J.G.; Morton, W.T.; Negus, P.; O'Shea, V.; Raine, C.; Reeves, P.; Scarr, J.M.; Smith, K.; Thompson, A.S.; Turnbull, R.M.; Wasserbaech, S.; Buchmuller, O.; Cavanaugh, R.; Dhamotharan, S.; Geweniger, C.; Hanke, P.; Hansper, G.; Hepp, V.; Kluge, E.E.; Putzer, A.; Sommer, J.; Stenzel, H.; Tittel, K.; Werner, W.; Wunsch, M.; Beuselinck, R.; Binnie, D.M.; Cameron, W.; Davies, G.; Dornan, P.J.; Goodsir, S.; Marinelli, N.; Martin, E.B.; Nash, J.; Nowell, J.; Rutherford, S.A.; Sedgbeer, J.K.; Thompson, J.C.; White, R.; Williams, M.D.; Ghete, V.M.; Girtler, P.; Kneringer, E.; Kuhn, D.; Rudolph, G.; Bouhova-Thacker, E.; Bowdery, C.K.; Buck, P.G.; Clarke, D.P.; Ellis, G.; Finch, A.J.; Foster, F.; Hughes, G.; Jones, R.W.L.; Keemer, N.R.; Pearson, M.R.; Robertson, N.A.; Sloan, T.; Smizanska, M.; Snow, S.W.; Williams, M.I.; van der Aa, O.; Delaere, C.; Leibenguth, G.; Lemaitre, V.; Bauerdick, L.A.T.; Blumenschein, U.; van Gemmeren, P.; Giehl, I.; Holldorfer, F.; Jakobs, K.; Kasemann, M.; Kayser, F.; Kleinknecht, K.; Muller, A.S.; Quast, G.; Renk, B.; Rohne, E.; Sander, H.G.; Schmeling, S.; Wachsmuth, H.; Wanke, R.; Zeitnitz, C.; Ziegler, T.; Aubert, J.J.; Benchouk, C.; Bonissent, A.; Carr, J.; Coyle, P.; Curtil, C.; Ealet, A.; Etienne, F.; Fouchez, D.; Motsch, F.; Payre, P.; Rousseau, D.; Tilquin, A.; Talby, M.; Thulasidas, M.; Aleppo, M.; Antonelli, M.; Ragusa, F.; Buscher, V.; David, A.; Dietl, H.; Ganis, G.; Huttmann, K.; Lutjens, G.; Mannert, C.; Manner, W.; Moser, H.G.; Settles, R.; Seywerd, H.; Stenzel, H.; Villegas, M.; Wiedenmann, W.; Wolf, G.; Azzurri, P.; Boucrot, J.; Callot, O.; Chen, S.; Cordier, A.; Davier, M.; Duflot, L.; Grivaz, J.F.; Heusse, Ph.; Jacholkowska, A.; Le Diberder, F.; Lefrancois, J.; Mutz, A.M.; Schune, M.H.; Serin, L.; Veillet, J.J.; Videau, I.; Zerwas, D.; Azzurri, P.; Bagliesi, G.; Bettarini, S.; Boccali, T.; Bozzi, C.; Calderini, G.; Dell'Orso, R.; Fantechi, R.; Ferrante, I.; Fidecaro, F.; Foa, L.; Giammanco, A.; Giassi, A.; Gregorio, A.; Ligabue, F.; Lusiani, A.; Marrocchesi, P.S.; Messineo, A.; Palla, F.; Rizzo, G.; Sanguinetti, G.; Sciaba, A.; Sguazzoni, G.; Spagnolo, P.; Steinberger, J.; Tenchini, R.; Vannini, C.; Venturi, A.; Verdini, P.G.; Awunor, O.; Blair, G.A.; Cowan, G.; Garcia-Bellido, A.; Green, M.G.; Medcalf, T.; Misiejuk, A.; Strong, J.A.; Teixeira-Dias, P.; Botterill, D.R.; Clifft, R.W.; Edgecock, T.R.; Edwards, M.; Haywood, S.J.; Norton, P.R.; Tomalin, I.R.; Ward, J.J.; Bloch-Devaux, B.; Boumediene, D.; Colas, P.; Emery, S.; Fabbro, B.; Kozanecki, W.; Lancon, E.; Lemaire, M.C.; Locci, E.; Perez, P.; Rander, J.; Renardy, J.F.; Roussarie, A.; Schuller, J.P.; Schwindling, J.; Tuchming, B.; Vallage, B.; Black, S.N.; Dann, J.H.; Kim, H.Y.; Konstantinidis, N.; Litke, A.M.; McNeil, M.A.; Taylor, G.; Booth, C.N.; Cartwright, S.; Combley, F.; Hodgson, P.N.; Lehto, M.; Thompson, L.F.; Affholderbach, K.; Barberio, E.; Bohrer, A.; Brandt, S.; Burkhardt, H.; Feigl, E.; Grupen, C.; Hess, J.; Lutters, G.; Meinhard, H.; Minguet-Rodriguez, J.; Mirabito, L.; Misiejuk, A.; Neugebauer, E.; Ngac, A.; Prange, G.; Rivera, F.; Saraiva, P.; Schafer, U.; Sieler, U.; Smolik, L.; Stephan, F.; Trier, H.; Apollonio, M.; Borean, C.; Bosisio, L.; Della Marina, R.; Giannini, G.; Gobbo, B.; Musolino, G.; Pitis, L.; He, H.; Kim, H.; Putz, J.; Rothberg, J.; Armstrong, S.R.; Bellantoni, L.; Berkelman, K.; Cinabro, D.; Conway, J.S.; Cranmer, K.; Elmer, P.; Feng, Z.; Ferguson, D.P.S.; Gao, Y.; Gonzalez, S.; Grahl, J.; Harton, J.L.; Hayes, O.J.; Hu, H.; Jin, S.; Johnson, R.P.; Kile, J.; McNamara, P.A., III; Nielsen, J.; Orejudos, W.; Pan, Y.B.; Saadi, Y.; Scott, I.J.; Sharma, V.; Walsh, A.M.; Walsh, J.; Wear, J.; von Wimmersperg-Toeller, J.H.; Wiedenmann, W.; Wu, J.; Wu, S.L.; Wu, X.; Yamartino, J.M.; Zobernig, G.; Dissertori, G.; Abdallah, J.; Abreu, P.; Adam, W.; Adzic, P.; Albrecht, T.; Alemany-Fernandez, R.; Allmendinger, T.; Allport, P.P.; Amaldi, U.; Amapane, N.; Amato, S.; Anashkin, E.; Andreazza, A.; Andringa, S.; Anjos, N.; Antilogus, P.; Apel, W-D.; Arnoud, Y.; Ask, S.; Asman, B.; Augustin, J.E.; Augustinus, A.; Baillon, P.; Ballestrero, A.; Bambade, P.; Barbier, R.; Bardin, D.; Barker, G.J.; Baroncelli, A.; Battaglia, M.; Baubillier, M.; Becks, K-H.; Begalli, M.; Behrmann, A.; Belous, K.; Ben-Haim, E.; Benekos, N.; Benvenuti, A.; Berat, C.; Berggren, M.; Berntzon, L.; Bertrand, D.; Besancon, M.; Besson, N.; Bloch, D.; Blom, M.; Bluj, M.; Bonesini, M.; Boonekamp, M.; Booth, P.S.L.; Borisov, G.; Botner, O.; Bouquet, B.; Bowcock, T.J.V.; Boyko, I.; Bracko, M.; Brenner, R.; Brodet, E.; Bruckman, P.; Brunet, J.M.; Bugge, L.; Buschbeck, B.; Buschmann, P.; Calvi, M.; Camporesi, T.; Canale, V.; Carena, F.; Castro, N.; Cavallo, F.; Chapkin, M.; Charpentier, Ph.; Checchia, P.; Chierici, R.; Chliapnikov, P.; Chudoba, J.; Cieslik, K.; Collins, P.; Contri, R.; Cosme, G.; Cossutti, F.; Costa, M.J.; Crawley, B.; Crennell, D.; Cuevas, J.; D'Hondt, J.; Dalmau, J.; da Silva, T.; Da Silva, W.; Della Ricca, G.; De Angelis, A.; De Boer, W.; De Clercq, C.; De Lotto, B.; De Maria, N.; De Min, A.; De Paula, L.; Di Ciaccio, L.; Di Simone, A.; Doroba, K.; Drees, J.; Dris, M.; Duperrin, A.; Eigen, G.; Ekelof, T.; Ellert, M.; Elsing, M.; Espirito Santo, M.C.; Fanourakis, G.; Fassouliotis, D.; Feindt, M.; Fernandez, J.; Ferrer, A.; Ferro, F.; Flagmeyer, U.; Foeth, H.; Fokitis, E.; Fulda-Quenzer, F.; Fuster, J.; Gandelman, M.; Garcia, C.; Gavillet, Ph.; Gazis, E.; Gele, D.; Gokieli, R.; Golob, B.; Gomez-Ceballos, G.; Goncalves, P.; Graziani, E.; Grosdidier, G.; Grzelak, K.; Guy, J.; Haag, C.; Hallgren, A.; Hamacher, K.; Hamilton, K.; Haug, S.; Hauler, F.; Hedberg, V.; Hennecke, M.; Herr, H.; Hoffman, J.; Holmgren, S-O.; Holt, P.J.; Houlden, M.A.; Hultqvist, K.; Jackson, J.N.; Jarlskog, G.; Jarry, P.; Jeans, D.; Johansson, E.K.; Johansson, P.D.; Jonsson, P.; Joram, C.; Jungermann, L.; Kapusta, F.; Katsanevas, S.; Katsoufis, E.; Kernel, G.; Kersevan, B.P.; Kerzel, U.; Kiiskinen, A.; King, B.T.; Kjaer, N.J.; Kluit, P.; Kokkinias, P.; Kostioukhine, V.; Kourkoumelis, C.; Kouznetsov, O.; Krumstein, Z.; Kucharczyk, M.; Lamsa, J.; Leder, G.; Ledroit, F.; Leinonen, L.; Leitner, R.; Lemonne, J.; Lepeltier, V.; Lesiak, T.; Libby, J.; Liebig, W.; Liko, D.; Lipniacka, A.; Lopes, J.H.; Lopez, J.M.; Loukas, D.; Lutz, P.; Lyons, L.; MacNaughton, J.; Malek, A.; Maltezos, S.; Mandl, F.; Marco, J.; Marco, R.; Marechal, B.; Margoni, M.; Marin, J-C.; Mariotti, C.; Markou, A.; Martinez-Rivero, C.; Masik, J.; Mastroyiannopoulos, N.; Matorras, F.; Matteuzzi, C.; Mazzucato, F.; Mazzucato, M.; Nulty, R.Mc; Meroni, C.; Meyer, W.T.; Migliore, E.; Mitaroff, W.; Mjoernmark, U.; Moa, T.; Moch, M.; Moenig, K.; Monge, R.; Montenegro, J.; Moraes, D.; Morettini, P.; Mueller, U.; Muenich, K.; Mulders, M.; Mundim, L.; Murray, W.; Muryn, B.; Myatt, G.; Myklebust, T.; Nassiakou, M.; Navarria, F.; Nawrocki, K.; Nemecek, S.; Nicolaidou, R.; Nikolaenko, V.; Nikolenko, M.; Oblakowska-Mucha, A.; Obraztsov, V.; Olshevski, A.; Onofre, A.; Orava, R.; Osterberg, K.; Ouraou, A.; Oyanguren, A.; Paganoni, M.; Paiano, S.; Palacios, J.P.; Palka, H.; Papadopoulou, Th. D.; Pape, L.; Parkes, C.; Parodi, F.; Parzefall, U.; Passeri, A.; Passon, O.; Perepelitsa, V.; Perrotta, A.; Petrolini, A.; Piedra, J.; Pieri, L.; Pierre, F.; Pimenta, M.; Podobnik, T.; Poireau, V.; Pol, M.E.; Polok, G.; Poropat, P.; Pozdniakov, V.; Pukhaeva, N.; Pullia, A.; Radojicic, D.; Rames, J.; Ramler, L.; Read, A.; Rebecchi, P.; Rehn, J.; Reid, D.; Reinhardt, R.; Renton, P.; Richard, F.; Ridky, J.; Ripp-Baudot, I.; Rivero, M.; Rodriguez, D.; Romero, A.; Ronchese, P.; Rosenberg, E.; Roudeau, P.; Rovelli, T.; Ruhlmann-Kleider, V.; Ryabtchikov, D.; Sadovsky, A.; Salmi, L.; Salt, J.; Sander, C.; Savoy-Navarro, A.; Schwickerath, U.; Segar, A.; Sekulin, R.; Siebel, M.; Simard, L.; Sisakian, A.; Smadja, G.; Smirnova, O.; Sokolov, A.; Sopczak, A.; Sosnowski, R.; Spassov, T.; Stanitzki, M.; Stocchi, A.; Strauss, J.; Stugu, B.; Szczekowski, M.; Szeptycka, M.; Szumlak, T.; Tabarelli, T.; Taffard, A.C.; Tegenfeldt, F.; Terranova, F.; Thomas, J.; Timmermans, J.; Tkatchev, L.; Tobin, M.; Todorovova, S.; Tome, B.; Tonazzo, A.; Tortosa, P.; Travnicek, P.; Treille, D.; Tristram, G.; Trochimczuk, M.; Troncon, C.; Turluer, M-L.; Tyapkin, I.A.; Tyapkin, P.; Tzamarias, S.; Uvarov, V.; Valenti, G.; Van Dam, P.; Van Eldik, J.; Van Lysebetten, A.; van Remortel, N.; Van Vulpen, I.; Vegni, G.; Veloso, F.; Venus, W.; Verbeure, F.; Verdier, P.; Verzi, V.; Vilanova, D.; Vitale, L.; Vrba, V.; Wahlen, H.; Washbrook, A.J.; Weiser, C.; Wicke, D.; Wickens, J.; Wilkinson, G.; Winter, M.; Witek, M.; Yushchenko, O.; Zalewska, A.; Zalewski, P.; Zavrtanik, D.; Zhuravlov, V.; Zimine, N.I.; Zintchenko, A.; Achard, P.; Adriani, O.; Aguilar-Benitez, M.; Alcaraz, J.; Alemanni, G.; Allaby, J.; Aloisio, A.; Alviggi, M.G.; Anderhub, H.; Andreev, V.P.; Anselmo, F.; Arefiev, A.; Azemoon, T.; Aziz, T.; Bagnaia, P.; Bajo, A.; Baksay, G.; Baksay, L.; Baldew, S.V.; Banerjee, S.; Banerjee, Sw.; Barczyk, A.; Barillere, R.; Bartalini, P.; Basile, M.; Batalova, N.; Battiston, R.; Bay, A.; Becker, U.; Behner, F.; Bellucci, L.; Berbeco, R.; Berdugo, J.; Berges, P.; Bertucci, B.; Betev, B.L.; Biasini, M.; Biglietti, M.; Biland, A.; Blaising, J.J.; Blyth, S.C.; Bobbink, G.J.; Bohm, A.; Boldizsar, L.; Borgia, B.; Bottai, S.; Bourilkov, D.; Bourquin, M.; Braccini, S.; Branson, J.G.; Brochu, F.; Burger, J.D.; Burger, W.J.; Cai, X.D.; Capell, M.; Cara Romeo, G.; Carlino, G.; Cartacci, A.; Casaus, J.; Cavallari, F.; Cavallo, N.; Cecchi, C.; Cerrada, M.; Chamizo, M.; Chang, Y.H.; Chemarin, M.; Chen, A.; Chen, G.; Chen, G.M.; Chen, H.F.; Chen, H.S.; Chiefari, G.; Cifarelli, L.; Cindolo, F.; Clare, I.; Clare, R.; Coignet, G.; Colino, N.; Costantini, S.; de la Cruz, B.; Cucciarelli, S.; De Asmundis, R.; D'eglon, P.; Debreczeni, J.; Degre, A.; Dehmelt, K.; Deiters, K.; della Volpe, D.; Delmeire, E.; Denes, P.; DeNotaristefani, F.; De Salvo, A.; Diemoz, M.; Dierckxsens, M.; Dionisi, C.; Dittmar, M.; Doria, A.; Dova, M.T.; Duchesneau, D.; Duda, M.; Echenard, B.; Eline, A.; El Hage, A.; El Mamouni, H.; Engler, A.; Eppling, F.J.; Extermann, P.; Falagan, M.A.; Falciano, S.; Favara, A.; Fay, J.; Fedin, O.; Felcini, M.; Ferguson, T.; Fesefeldt, H.; Fiandrini, E.; Field, J.H.; Filthaut, F.; Fisher, P.H.; Fisher, W.; Forconi, G.; Freudenreich, K.; Furetta, C.; Galaktionov, Yu.; Ganguli, S.N.; Garcia-Abia, P.; Gataullin, M.; Gentile, S.; Giagu, S.; Gong, Z.F.; Grenier, G.; Grimm, O.; Gruenewald, M.W.; Gupta, V.K.; Gurtu, A.; Gutay, L.J.; Haas, D.; Hatzifotiadou, D.; Hebbeker, T.; Herve, A.; Hirschfelder, J.; Hofer, H.; Hohlmann, M.; Holzner, G.; Hou, S.R.; Jin, B.N.; Jindal, P.; Jones, L.W.; de Jong, P.; Josa-Mutuberria, I.; Kaur, M.; Kienzle-Focacci, M.N.; Kim, J.K.; Kirkby, J.; Kittel, W.; Klimentov, A.; Konig, A.C.; Kopal, M.; Koutsenko, V.; Kraber, M.; Kraemer, R.W.; Kruger, A.; Kunin, A.; Ladron de Guevara, P.; Laktineh, I.; Landi, G.; Lebeau, M.; Lebedev, A.; Lebrun, P.; Lecomte, P.; Lecoq, P.; Le Coultre, P.; Le Goff, J.M.; Leiste, R.; Levtchenko, M.; Levtchenko, P.; Li, C.; Likhoded, S.; Lin, C.H.; Lin, W.T.; Linde, F.L.; Lista, L.; Liu, Z.A.; Lohmann, W.; Longo, E.; Lu, Y.S.; Luci, C.; Luminari, L.; Lustermann, W.; Ma, W.G.; Malgeri, L.; Malinin, A.; Mana, C.; Mans, J.; Martin, J.P.; Marzano, F.; Mazumdar, K.; McNeil, R.R.; Mele, S.; Merola, L.; Meschini, M.; Metzger, W.J.; Mihul, A.; Milcent, H.; Mirabelli, G.; Mnich, J.; Mohanty, G.B.; Muanza, G.S.; Muijs, A.J.M.; Musy, M.; Nagy, S.; Natale, S.; Napolitano, M.; Nessi-Tedaldi, F.; Newman, H.; Nisati, A.; Novak, T.; Nowak, H.; Ofierzynski, R.; Organtini, G.; Palomares, C.; Paolucci, P.; Paramatti, R.; Passaleva, G.; Patricelli, S.; Paul, T.; Pauluzzi, M.; Paus, C.; Pauss, F.; Pedace, M.; Pensotti, S.; Perret-Gallix, D.; Piccolo, D.; Pierella, F.; Pieri, M.; Pioppi, M.; Pirou'e, P.A.; Pistolesi, E.; Plyaskin, V.; Pohl, M.; Pojidaev, V.; Pothier, J.; Prokofiev, D.; Rahal-Callot, G.; Rahaman, M.A.; Raics, P.; Raja, N.; Ramelli, R.; Rancoita, P.G.; Ranieri, R.; Raspereza, A.; Razis, P.; Rembeczki, S.; Ren, D.; Rescigno, M.; Reucroft, S.; Riemann, S.; Riles, K.; Roe, B.P.; Romero, L.; Rosca, A.; Rosemann, C.; Rosenbleck, C.; Rosier-Lees, S.; Roth, S.; Rubio, J.A.; Ruggiero, G.; Rykaczewski, H.; Sakharov, A.; Saremi, S.; Sarkar, S.; Salicio, J.; Sanchez, E.; Schafer, C.; Schegelsky, V.; Schopper, H.; Schotanus, D.J.; Sciacca, C.; Servoli, L.; Shevchenko, S.; Shivarov, N.; Shoutko, V.; Shumilov, E.; Shvorob, A.; Son, D.; Souga, C.; Spillantini, P.; Steuer, M.; Stickland, D.P.; Stoyanov, B.; Straessner, A.; Sudhakar, K.; Sultanov, G.; Sun, L.Z.; Sushkov, S.; Suter, H.; Swain, J.D.; Szillasi, Z.; Tang, X.W.; Tarjan, P.; Tauscher, L.; Taylor, L.; Tellili, B.; Teyssier, D.; Timmermans, C.; Ting, S.C.C.; Ting, S.M.; Tonwar, S.C.; Toth, J.; Tully, C.; Ulbricht, J.; Valente, E.; Van de Walle, R.T.; Vasquez, R.; Vesztergombi, G.; Vetlitsky, I.; Viertel, G.; Vivargent, M.; Vlachos, S.; Vodopianov, I.; Vogel, H.; Vogt, H.; Vorobiev, I.; Vorobyov, A.A.; Wadhwa, M.; Wang, Q.; Wang, X.L.; Wang, Z.M.; Weber, M.; Wynhoff, S.; Xia, L.; Xu, Z.Z.; Yamamoto, J.; Yang, B.Z.; Yang, C.G.; Yang, H.J.; Yang, M.; Yeh, S.C.; Zalite, An.; Zalite, Yu.; Zhang, Z.P.; Zhao, J.; Zhu, G.Y.; Zhu, R.Y.; Zhuang, H.L.; Zichichi, A.; Zimmermann, B.; Zoller, M.; Abbiendi, G.; Ackerstaff, K.; Ainsley, C.; Akesson, P.F.; Alexander, G.; Allison, J.; Altekamp, N.; Ametewee, K.; Anagnostou, G.; Anderson, K.J.; Anderson, S.; Arcelli, S.; Asai, S.; Ashby, S.F.; Axen, D.; Azuelos, G.; Ball, A.H.; Bailey, I.; Barberio, E.; Barillari, T.; Barlow, R.J.; Bartoldus, R.; Batley, R.J.; Baumann, S.; Bechtle, P.; Bechtluft, J.; Beeston, C.; Behnke, T.; Bell, K.W.; Bell, P.J.; Bella, G.; Bellerive, A.; Benelli, G.; Bentvelsen, S.; Berlich, P.; Bethke, S.; Biebel, O.; Boeriu, O.; Blobel, V.; Bloodworth, I.J.; Bloomer, J.E.; Bobinski, M.; Bock, P.; Bonacorsi, D.; Bosch, H.M.; Boutemeur, M.; Bouwens, B.T.; Braibant, S.; Bright-Thomas, P.; Brigliadori, L.; Brown, R.M.; Burckhart, H.J.; Burgard, C.; Burgin, R.; Cammin, J.; Campana, S.; Capiluppi, P.; Carnegie, R.K.; Carter, A.A.; Carter, J.R.; Chang, C.Y.; Charlton, D.G.; Chrisman, D.; Ciocca, C.; Clarke, P.E.L.; Clay, E.; Cohen, I.; Conboy, J.E.; Cooke, O.C.; Couchman, J.; Couyoumtzelis, C.; Coxe, R.L.; Csilling, A.; Cuffiani, M.; Dado, S.; Dallapiccola, C.; Dallavalle, M.; Dallison, S.; de Jong, S.; De Roeck, A.; Dervan, P.; De Wolf, E.A.; del Pozo, L.A.; Desch, K.; Dienes, B.; Dixit, M.S.; do Couto e Silva, E.; Donkers, M.; Doucet, M.; Dubbert, J.; Duchovni, E.; Duckeck, G.; Duerdoth, I.P.; Edwards, J.E.G.; Estabrooks, P.G.; Etzion, E.; Evans, H.G.; Evans, M.; Fabbri, F.; Fanti, M.; Fath, P.; Feld, L.; Ferrari, P.; Fiedler, F.; Fierro, M.; Fischer, H.M.; Fleck, I.; Folman, R.; Fong, D.G.; Ford, M.; Foucher, M.; Frey, A.; Furtjes, A.; Futyan, D.I.; Gagnon, P.; Gary, J.W.; Gascon, J.; Gascon-Shotkin, S.M.; Gaycken, G.; Geddes, N.I.; Geich-Gimbel, C.; Geralis, T.; Giacomelli, G.; Giacomelli, P.; Giacomelli, R.; Gibson, V.; Gibson, W.R.; Gingrich, D.M.; Giunta, M.; Glenzinski, D.; Goldberg, J.; Goodrick, M.J.; Gorn, W.; Graham, K.; Grandi, C.; Gross, E.; Grunhaus, J.; Gruwe, M.; Gunther, P.O.; Gupta, A.; Hajdu, C.; Hamann, M.; Hanson, G.G.; Hansroul, M.; Hapke, M.; Harder, K.; Harel, A.; Hargrove, C.K.; Harin-Dirac, M.; Hart, P.A.; Hartmann, C.; Hauke, A.; Hauschild, M.; Hawkes, C.M.; Hawkings, R.; Hemingway, R.J.; Hensel, C.; Herndon, M.; Herten, G.; Heuer, R.D.; Hildreth, M.D.; Hill, J.C.; Hillier, S.J.; Hilse, T.; Hobson, P.R.; Hocker, A.; Hoffman, K.; Homer, R.J.; Honma, A.K.; Horvath, D.; Hossain, K.R.; Howard, R.; Hughes-Jones, R.E.; Huntemeyer, P.; Hutchcroft, D.E.; Igo-Kemenes, P.; Imrie, D.C.; Ingram, M.R.; Ishii, K.; Jacob, F.R.; Jawahery, A.; Jeffreys, P.W.; Jeremie, H.; Jimack, M.; Joly, A.; Jones, C.R.; Jones, G.; Jones, M.; Jones, R.W.L.; Jost, U.; Jovanovic, P.; Junk, T.R.; Kanaya, N.; Kanzaki, J.; Karapetian, G.; Karlen, D.; Kartvelishvili, V.; Kawagoe, K.; Kawamoto, T.; Keeler, R.K.; Kellogg, R.G.; Kennedy, B.W.; Kim, D.H.; King, B.J.; Kirk, J.; Klein, K.; Klier, A.; Kluth, S.; Kobayashi, T.; Kobel, M.; Koetke, D.S.; Kokott, T.P.; Kolrep, M.; Komamiya, S.; Kowalewski, R.V.; Kramer, T.; Krasznahorkay, A., Jr.; Kress, T.; Krieger, P.; von Krogh, J.; Kuhl, T.; Kupper, M.; Kyberd, P.; Lafferty, G.D.; Lahmann, R.; Lai, W.P.; Landsman, H.; Lanske, D.; Lauber, J.; Lautenschlager, S.R.; Lawson, I.; Layter, J.G.; Lazic, D.; Lee, A.M.; Lefebvre, E.; Leins, A.; Lellouch, D.; Letts, J.; Levinson, L.; Lewis, C.; Liebisch, R.; Lillich, J.; List, B.; List, J.; Littlewood, C.; Lloyd, A.W.; Lloyd, S.L.; Loebinger, F.K.; Long, G.D.; Losty, M.J.; Lu, J.; Ludwig, A.; Ludwig, J.; Macchiolo, A.; Macpherson, A.; Mader, W.; Mannelli, M.; Marcellini, S.; Marchant, T.E.; Markus, C.; Martin, A.J.; Martin, J.P.; Martinez, G.; Mashimo, T.; Matthews, W.; Mattig, P.; McDonald, W.J.; McKenna, J.; Mckigney, E.A.; McMahon, T.J.; McNab, A.I.; McPherson, R.A.; Mendez-Lorenzo, P.; Meijers, F.; Menges, W.; Menke, S.; Merritt, F.S.; Mes, H.; Meyer, N.; Meyer, J.; Michelini, A.; Mihara, S.; Mikenberg, G.; Miller, D.J.; Mir, R.; Mohr, W.; Montanari, A.; Mori, T.; Morii, M.; Muller, U.; Mutter, A.; Nagai, K.; Nakamura, I.; Nanjo, H.; Neal, H.A.; Nellen, B.; Nijjhar, B.; Nisius, R.; O'Neale, S.W.; Oakham, F.G.; Odorici, F.; Ogren, H.O.; Oh, A.; Okpara, A.; Oldershaw, N.J.; Omori, T.; Oreglia, M.J.; Orito, S.; Pahl, C.; Palinkas, J.; Pasztor, G.; Pater, J.R.; Patrick, G.N.; Patt, J.; Pearce, M.J.; Petzold, S.; Pfeifenschneider, P.; Pilcher, J.E.; Pinfold, J.; Plane, D.E.; Poffenberger, P.; Polok, J.; Poli, B.; Pooth, O.; Posthaus, A.; Przybycien, M.; Przysiezniak, H.; Quadt, A.; Rabbertz, K.; Rees, D.L.; Rembser, C.; Renkel, P.; Rick, H.; Rigby, D.; Robertson, S.; Robins, S.A.; Rodning, N.; Roney, J.M.; Rooke, A.; Ros, E.; Rosati, S.; Roscoe, K.; Rossi, A.M.; Rosvick, M.; Routenburg, P.; Rozen, Y.; Runge, K.; Runolfsson, O.; Ruppel, U.; Rust, D.R.; Rylko, R.; Sachs, K.; Saeki, T.; Sahr, O.; Sarkisyan, E.K.G.; Sasaki, M.; Sbarra, C.; Schaile, A.D.; Schaile, O.; Scharff-Hansen, P.; Schenk, P.; Schieck, J.; Schmitt, S.; Schorner-Sadenius, T.; Schroder, M.; Schultz-Coulon, H.C.; Schulz, M.; Schumacher, M.; Schutz, P.; Schwick, C.; Scott, W.G.; Seuster, R.; Shears, T.G.; Shen, B.C.; Shepherd-Themistocleous, C.H.; Sherwood, P.; Siroli, G.P.; Sittler, A.; Skillman, A.; Skuja, A.; Smith, A.M.; Smith, T.J.; Snow, G.A.; Sobie, R.; Soldner-Rembold, S.; Spagnolo, S.; Spano, F.; Springer, R.W.; Sproston, M.; Stahl, A.; Steiert, M.; Stephens, K.; Steuerer, J.; Stockhausen, B.; Stoll, K.; Strom, D.; Strohmer, R.; Strumia, F.; Stumpf, L.; Surrow, B.; Szymanski, P.; Tafirout, R.; Talbot, S.D.; Tanaka, S.; Taras, P.; Tarem, S.; Taylor, R.J.; Tasevsky, M.; Teuscher, R.; Thiergen, M.; Thomas, J.; Thomson, M.A.; von Torne, E.; Torrence, E.; Towers, S.; Toya, D.; Trefzger, T.; Trigger, I.; Trocsanyi, Z.; Tsukamoto, T.; Tsur, E.; Turcot, A.S.; Turner-Watson, M.F.; Ueda, I.; Ujvari, B.; Utzat, P.; Vachon, B.; Van Kooten, R.; Vannerem, P.; Vertesi, R.; Verzocchi, M.; Vikas, P.; Vincter, M.; Vokurka, E.H.; Vollmer, C.F.; Voss, H.; Vossebeld, J.; Wackerle, F.; Wagner, A.; Waller, D.; Ward, C.P.; Ward, D.R.; Ward, J.J.; Watkins, P.M.; Watson, A.T.; Watson, N.K.; Wells, P.S.; Wengler, T.; Wermes, N.; Wetterling, D.; White, J.S.; Wilkens, B.; Wilson, G.W.; Wilson, J.A.; Wolf, G.; Wotton, S.; Wyatt, T.R.; Yamashita, S.; Yekutieli, G.; Zacek, V.; Zer-Zion, D.; Zivkovic, L.

2013-01-01

Electroweak measurements performed with data taken at the electron-positron collider LEP at CERN from 1995 to 2000 are reported. The combined data set considered in this report corresponds to a total luminosity of about 3~fb$^{-1}$ collected by the four LEP experiments ALEPH, DELPHI, L3 and OPAL, at centre-of-mass energies ranging from $130~GeV$ to $209~GeV$. Combining the published results of the four LEP experiments, the measurements include total and differential cross-sections in photon-pair, fermion-pair and four-fermion production, the latter resulting from both double-resonant WW and ZZ production as well as singly resonant production. Total and differential cross-sections are measured precisely, providing a stringent test of the Standard Model at centre-of-mass energies never explored before in electron-positron collisions. Final-state interaction effects in four-fermion production, such as those arising from colour reconnection and Bose-Einstein correlations between the two W decay systems arising ...

Exact analytical solutions of continuity equation for electron beams precipitating in Coulomb collisions

Energy Technology Data Exchange (ETDEWEB)

Dobranskis, R. R.; Zharkova, V. V., E-mail: valentina.zharkova@northumbria.ac.uk [Department of Mathematics and Information Sciences, University of Northumbria, Newcastle upon Tyne NE1 2XP (United Kingdom)

2014-06-10

The original continuity equation (CE) used for the interpretation of the power law energy spectra of beam electrons in flares was written and solved for an electron beam flux while ignoring an additional free term with an electron density. In order to remedy this omission, the original CE for electron flux, considering beam's energy losses in Coulomb collisions, was first differentiated by the two independent variables: depth and energy leading to partial differential equation for an electron beam density instead of flux with the additional free term. The analytical solution of this partial differential continuity equation (PDCE) is obtained by using the method of characteristics. This solution is further used to derive analytical expressions for mean electron spectra for Coulomb collisions and to carry out numeric calculations of hard X-ray (HXR) photon spectra for beams with different parameters. The solutions revealed a significant departure of electron densities at lower energies from the original results derived from the CE for the flux obtained for Coulomb collisions. This departure is caused by the additional exponential term that appeared in the updated solutions for electron differential density leading to its faster decrease at lower energies (below 100 keV) with every precipitation depth similar to the results obtained with numerical Fokker-Planck solutions. The effects of these updated solutions for electron densities on mean electron spectra and HXR photon spectra are also discussed.

Pauli blocking and laser manipulation of the electron dynamics in atomic collisions

International Nuclear Information System (INIS)

Kirchner, T.

2004-01-01

Full text: The dynamics of ion-atom collisions are governed primarily by the Coulomb interactions between the active electrons and the projectile and target nuclei. This contribution is devoted to the question whether and how other phenomena can modify the outcome of atomic scattering experiments. Firstly, the role of the Pauli exclusion principle on electronic transitions will be considered. Supported by experimental data it will be argued that Pauli blocking may have an important influence on electron transfer processes if collision systems with electrons on target and projectile in the initial channel are addressed [1]. Secondly, it will be discussed to which extent the electron dynamics can be modified and manipulated by an external interaction, namely by a suitable laser field [2]. The prototype scattering system He 2+ -H will be considered in the framework of the semiclassical approximation, i.e., projectile and laser interactions are described in terms of time-dependent external potentials which govern the quantum dynamics of the electron. The focus will be on slow collisions, in which electron transfer dominates, and on relatively short wavelengths such that both time dependent potentials vary on comparable time scales. A strong enhancement of laser-assisted electron transfer is found at collision energies below 1 keV/amu [3]. Its origin and its disappearance at higher energies as well as implications for planned experiments will be discussed

Correlation effects on double electron capture in highly-charged, low-energy ion-atom collisions

International Nuclear Information System (INIS)

Meyer, F.W.; Griffin, D.C.; Havener, C.C.; Huq, M.S.; Phaneuf, R.A.; Swenson, J.K.; Stolterfoht, N.

1987-01-01

The method of zero-degree Auger electron spectroscopy has been used to study two-electron excited states populated in slow double capture collisions of highly charged ions with He and H 2 . The focus of this study is on production of autoionization electrons originating from the non-equivalent 1s 2 2pnl electron configurations in comparison with electron production resulting from the Auger decay of (near) equivalent 1s 2 nln'l' (with n∼n') configurations. It is shown that production of non-equivalent electron configurations is significant and involves electron-electron correlation effects whose analysis leads beyond the independent-particle model. Recent results that include a measurement at non-zero angles are presented to illustrate the angular dependence of electron emission from non-equivalent electron configurations, as well as the dependence on projectile charge state and target species. Comparison of high resolution scans over two lines of the 1s 2 2pnl sequence for the O 6+ + He system with accurate transition energy calculations shows preferential population of high angular momentum substation

Soft electromagnetic bremsstrahlung in inelastic hadronic collisions at high and intermediate energies

International Nuclear Information System (INIS)

Rueckl, R.

1978-01-01

Electromagnetic bremsstrahlung in hadronic collisions was studied extensively at low and intermediate energies. It was found that the infrared divergent term of the cross section describes the data well up to surprisingly large photon energies. Using essentially the same soft photon approximation, production of low mass-low energy electron pairs via internal conversion of soft virtual bremsstrahlung accompanying the production of charged hadrons in hadron-hadron collisions at very high and intermediate energies. The resulting electron yields explain, at least in part, the direct electrons with small transverse momenta seen at the ISR, and are in no contradiction to the rates observed at LAMPF

Double electron transfer in H- + H+ collisions

International Nuclear Information System (INIS)

Braeuning, H; Helm, H; Briggs, J S; Salzborn, E

2007-01-01

Absolute cross sections for double electron transfer in H - + H + collisions have been measured for center-of-mass energies from 0.5 keV to 12 keV. Clear oscillations in the cross section are observed which are in excellent agreement with earlier measurements at lower energies by Brouillard et al (1979) as well as Peart and Dolder (1979). After an oscillation maximum at 3 keV center-of-mass energy the cross section decreases for increasing energy with no indication of further oscillations

Laser-assisted electron-atom collisions

International Nuclear Information System (INIS)

Mason, N.J.

1989-01-01

New developments in our understanding of the electron-atom collision process have been made possible by combining the use of highly monochromatic electron beams and intense CO 2 lasers. This paper reviews such experiments and discusses possible future progress in what is a new field in atomic collision physics. (author)

Studies of collision mechanisms in electron capture by slow multiply charged ions

International Nuclear Information System (INIS)

Gilbody, H B; McCullough, R W

2004-01-01

We review measurements based on translational energy spectroscopy which are being used to identify and assess the relative importance of the various collision mechanisms involved in one-electron capture by slow multiply charged ions in collisions with simple atoms and molecules

Coincident Auger electron and recoil ion momentum spectroscopy for low-energy ion-atom collisions

International Nuclear Information System (INIS)

Laurent, G.; Tarisien, M.; Flechard, X.; Jardin, P.; Guillaume, L.; Sobocinski, P.; Adoui, L.; Bordenave-Montesquieu, A.; Bordenave-Montesquieu, D.; Chesnel, J.-Y.; Fremont, F.; Hennecart, D.; Lienard, E.; Maunoury, L.; Moretto-Capelle, P.; Cassimi, A.

2003-01-01

The recoil ion momentum spectroscopy (RIMS) method combined with the detection of Auger electrons has been used successfully to analyse double electron capture following O 6+ + He collisions at low impact velocities. Although RIMS and Auger spectroscopies are known to be efficient tools to obtain details on the primary processes occurring during the collision, the conjunction of both techniques provides new insights on the electron capture process. In the present experiment, triple coincidence detection of the scattered projectile, the target recoil ion and the Auger electron allows for a precise identification of the doubly excited states O 4+ (1s 2 nln ' l ' ) populated after double electron-capture events

Failure of single electron descriptions of molecular orbital collision processes

International Nuclear Information System (INIS)

Elston, S.B.

1978-01-01

Inner-shell excitation occurring in low and moderate (keV range) energy collisions between light atomic and ionic systems is frequently describable in terms of molecular promotion mechanisms, which were extensively explored both theoretically and experimentally. The bulk of such studies have concentrated on processes understandable through the use of single- and independent-electron models. Nonetheless, it is possible to find cases of inner-shell excitation in relatively simple collision systems which involve nearly simultaneous multiple-electron transitions and transitions induced by inherently two-electron interactions. Evidence for these many- and nonindependent-electron phenomena in inner-shell excitation processes and the importance of considering such effects in the interpretation of collisionally induced excitation spectra is discussed. 13 references

Dissipation and energy balance in electronic dynamics of Na clusters

Science.gov (United States)

Vincendon, Marc; Suraud, Eric; Reinhard, Paul-Gerhard

2017-06-01

We investigate the impact of dissipation on the energy balance in the electron dynamics of metal clusters excited by strong electro-magnetic pulses. The dynamics is described theoretically by Time-Dependent Density-Functional Theory (TDDFT) at the level of Local Density Approximation (LDA) augmented by a self interaction correction term and a quantum collision term in Relaxation-Time Approximation (RTA). We evaluate the separate contributions to the total excitation energy, namely energy exported by electron emission, potential energy due to changing charge state, intrinsic kinetic and potential energy, and collective flow energy. The balance of these energies is studied as function of the laser parameters (frequency, intensity, pulse length) and as function of system size and charge. We also look at collisions with a highly charged ion and here at the dependence on the impact parameter (close versus distant collisions). Dissipation turns out to be small where direct electron emission prevails namely for laser frequencies above any ionization threshold and for slow electron extraction in distant collisions. Dissipation is large for fast collisions and at low laser frequencies, particularly at resonances. Contribution to the Topical Issue "Dynamics of Systems at the Nanoscale", edited by Andrey Solov'yov and Andrei Korol.

Cross sections for collisions of subexcitation electrons with molecules

International Nuclear Information System (INIS)

Itikawa, Y.

1983-01-01

A short review is given on the present knowledge about the collision processes of subexcitation electrons (i.e., electrons whose energy is below the threshold of the first electronically excited state) with molecules. The processes considered are: vibrational and rotational excitations and elastic scattering. As an example, stopping cross sections for those processes (and electronic excitation and ionization, for comparison) are shown graphically for N 2 and H 2 O. 21 references, 2 figures

n l -> n' l' transition rates in electron and proton - Rydberg atom collision

Science.gov (United States)

Vrinceanu, Daniel

2017-04-01

Electrons and protons drive the recombination dynamics of highly excited Rydberg atoms in cold rarefied plasmas found in astrophysical conditions such as primordial recombination or star formation in H-II clouds. It has been recognized that collisions induce both energy and angular momentum transitions in Rydberg atoms, although in different proportions, depending on the initial state, temperature and the given species considered in the collision (electron or proton). Most studies focused on one collision type at a time, under the assumption that collision types are independent or their effects are not competing. The classical Monte-Carlo trajectory simulations presented in this work calculate the rates for both energy and angular momentum transfers and show their interdependence. For example, energy transfer with small angular momentum change are more efficient for target states with initial large angular momentum. The author acknowledges support received from the National Science Foundation through a Grant for the Center for Research on Complex Networks (HRD-1137732).

Coincident Auger electron and recoil ion momentum spectroscopy for low-energy ion-atom collisions

Energy Technology Data Exchange (ETDEWEB)

Laurent, G. E-mail: glaurent@ganil.fr; Tarisien, M.; Flechard, X.; Jardin, P.; Guillaume, L.; Sobocinski, P.; Adoui, L.; Bordenave-Montesquieu, A.; Bordenave-Montesquieu, D.; Chesnel, J.-Y.; Fremont, F.; Hennecart, D.; Lienard, E.; Maunoury, L.; Moretto-Capelle, P.; Cassimi, A

2003-05-01

The recoil ion momentum spectroscopy (RIMS) method combined with the detection of Auger electrons has been used successfully to analyse double electron capture following O{sup 6+} + He collisions at low impact velocities. Although RIMS and Auger spectroscopies are known to be efficient tools to obtain details on the primary processes occurring during the collision, the conjunction of both techniques provides new insights on the electron capture process. In the present experiment, triple coincidence detection of the scattered projectile, the target recoil ion and the Auger electron allows for a precise identification of the doubly excited states O{sup 4+} (1s{sup 2}nln{sup '}l{sup '}) populated after double electron-capture events.

Electron Linacs for High Energy Physics

International Nuclear Information System (INIS)

Wilson, Perry B.

2011-01-01

The purpose of this article is to introduce some of the basic physical principles underlying the operation of electron linear accelerators (electron linacs). Electron linacs have applications ranging from linacs with an energy of a few MeV, such that the electrons are approximately relativistic, to future electron-positron linear colliders having a collision energy in the several-TeV energy range. For the most part, only the main accelerating linac is treated in this article.

Electron-positron collision physics: 1 MeV to 2 TeV

International Nuclear Information System (INIS)

Perl, M.L.

1988-07-01

An overview of electron-positron collision physics is presented. It begins at 1 MeV, the energy region of positronium formation, and extends to 2 TeV, the energy region which requires an electron- positron linear collider. In addition, the concept of searching for a lepton-specific forces is discussed. 18 refs., 15 figs., 1 tab

Electron collision cross sections and transport parameters in Cl2

International Nuclear Information System (INIS)

Pinhao, N.; Chouki, A.

1995-01-01

Molecular chlorine, Cl 2 , is a widely used gas with important application in gas discharge physics, namely in plasma etching, UV lasers and gas-filled particle detectors. However, due to experimental difficulties and to a complicated electronic spectrum, only some of the electron collision cross section have been measured and only recently the electronic structure has been resolved. This situation hampered the theoretical analysis of chlorine mixtures by a lack of relevant transport parameters. To our best knowledge there is only one published measurement of electron drift velocity and characteristic energy. Regrettably these data are considered of doubtful quality. There is also only one measurement of attachment and ionisation coefficients and one published set of cross sections. However those authors used the transport data from a He-Cl 2 mixture (80/20) where chlorine's effect can be hidden by the other component. Consequently that set is not completely consistent with the measurements in pure chlorine. This paper presents a new proposal of a consistent set of electron collision cross sections and the corresponding transport parameters and collision frequencies

New parameter-free polarization potentials in low-energy positron collisions

Science.gov (United States)

Jain, Ashok

1990-01-01

The polarization potential plays a decisive role in shaping up the cross sections in low energy positron collisions with atoms and molecules. However, its inclusion without involving any adjustable parameter, is still a challenge. Various other techniques employed so far for positron collisions are summarized, and a new, nonadjustable and very simple form of the polarization potential for positron-atom (molecule) collisions below the threshold of positronium formation is discussed. This new recently proposed potential is based on the correlation energy of a single positron in a homogeneous electron gas. The correlation energy was calculated by solving the Schrodinger equation of the positron-electron system and fitted to an analytical form in various ranges of the density parameter. In the outside region, the correlation energy is joined smoothly with the correct asymptotic form. This new positron correlation polarization (PCOP) potential was tested on several atomic and molecular targets such as the Ar, CO, and CH4. The results on the total and differential cross sections on these targets are shown along with the experimental data where available.

Resonance effects in projectile-electron loss in relativistic collisions with excited atoms

International Nuclear Information System (INIS)

Voitkiv, A B

2005-01-01

The theory of electron loss from projectile-ions in relativistic ion-atom collisions is extended to the case of collisions with excited atoms. The main feature of such collisions is a resonance which can emerge between electron transitions in the ion and atom. The resonance becomes possible due to the Doppler effect and has a well-defined impact energy threshold. In the resonance case, the ion-atom interaction is transmitted by the radiation field and the range of this interaction becomes extremely long. Because of this the presence of other atoms in the target medium and the size of the space occupied by the medium have to be taken into account and it turns out that microscopic loss cross sections may be strongly dependent on such macroscopic parameters as the target density, temperature and size. We consider both the total and differential loss cross sections and show that the resonance can have a strong impact on the angular and energy distributions of electrons emitted from the projectiles and the total number of electron loss events

Theory of low-energy electron-molecule collision physics in the coupled-channel method and application to e-CO2 scattering

International Nuclear Information System (INIS)

Morrison, M.A.

1976-08-01

A theory of electron-molecule scattering based on the fixed-nuclei approximation in a body-fixed reference frame is formulated and applied to e-CO 2 collisions in the energy range from 0.07 to 10.0 eV. The procedure used is a single-center coupled-channel method which incorporates a highly accurate static interaction potential, an approximate local exchange potential, and an induced polarization potential. Coupled equations are solved by a modification of the integral equations algorithm; several partial waves are required in the region of space near the nuclei, and a transformation procedure is developed to handle the consequent numerical problems. The potential energy is converged by separating electronic and nuclear contributions in a Legendre-polynomial expansion and including a large number of the latter. Formulas are derived for total elastic, differential, momentum transfer, and rotational excitation cross sections. The Born and asymptotic decoupling approximations are derived and discussed in the context of comparison with the coupled-channel cross sections. Both are found to be unsatisfactory in the energy range under consideration. An extensive discussion of the technical aspects of calculations for electron collisions with highly nonspherical targets is presented, including detailed convergence studies and a discussion of various numerical difficulties. The application to e-CO 2 scattering produces converged results in good agreement with observed cross sections. Various aspects of the physics of this collision are discussed, including the 3.8 eV shape resonance, which is found to possess both p and f character, and the anomalously large low-energy momentum transfer cross sections, which are found to be due to Σ/sub g/ symmetry. Comparison with static and static-exchange approximations are made

Effects of external field on elastic electron-ion collision in a plasma

International Nuclear Information System (INIS)

Na, Sang-Chul; Jung, Young-Dae

2008-01-01

The field effects on elastic electron-ion collision are investigated in a plasma with the presence of the external field. The eikonal method and effective interaction potential including the far-field term caused by the external field is employed to obtain the eikonal phase shift and eikonal cross section as functions of the field strength, external frequency, impact parameter, collision energy, thermal energy and Debye length. The result shows that the effect of the external field on the eikonal cross section is given by the second-order eikonal phase. In addition, the external field effects suppress the eikonal cross section as well as eikonal phase for the elastic electron-ion collision. The eikonal phase and cross section are found to be increased with an increase of the frequency of the external field. It is also shown that the eikonal cross section increases with an increase of the thermal energy and Debye length.

Electron capture in collisions of Si3+ ions with atomic hydrogen from low to intermediate energies

Science.gov (United States)

Liu, C. H.; Liu, L.; Wang, J. G.

2014-07-01

The electron capture process for the Si3+(3s) + H(1s) collisions is investigated by the quantum-mechanical molecular orbital close-coupling (MOCC) method and by the two-center atomic orbital close-coupling (AOCC) method in the energy range of 10-5-10 keV/u and 0.8-200 keV/u, respectively. Total and state-selective cross sections are presented and compared with the available theoretical and experimental results. The present MOCC and AOCC results agree well with the experimental measurements, but show some discrepancy with the calculations of Wang et al. [Phys. Rev. A 74, 052709 (2006), 10.1103/PhysRevA.74.052709] at E > 40 eV/u because of the inclusion of rotational couplings, which play important roles in the electron capture process. At lower energies, the present results are about three to five times smaller than those of Wang et al. due to the difference in the molecular data at large internuclear distances. The energy behaviors of the electron capture cross sections are discussed on the basis of identified reaction mechanisms.

Low energy electron capture in collisions of C3+ with He

International Nuclear Information System (INIS)

Wu, Y.; Qi, Y.Y.; Yan, J.; Wang, J.G.; Li, Y.; Buenker, R.J.; Kato, D.

2009-06-01

Charge transfer processes due to collisions of ground state C 3+ (1s 2 2s 2 S) ions with He atom are investigated using the quantum-mechanical molecular-orbital close-coupling (QMOCC) method for energies between 10 -4 eV/u and 10 3 eV/u. The ab initio adiabatic potential and radial coupling utilized in the QMOCC calculations are obtained from the multi-reference single- and double-excitation configuration interaction (MRD-CI) approach. Total and state-selective single electron capture (SEC) cross sections and rate coefficients are obtained and compared with the available experimental and theoretical data. Good agreement between the measured SEC cross sections and the present calculation is found, but the previous calculation of total rate coefficient using the Landau-Zener model is one or two orders of magnitude smaller than the present result. (author)

Resonant inelastic collisions of electrons with diatomic molecules

International Nuclear Information System (INIS)

Houfek, Karel

2012-01-01

In this contribution we give a review of applications of the nonlocal resonance theory which has been successfully used for treating the nuclear dynamics of low-energy electron collisions with diatomic molecules over several decades. We give examples and brief explanations of various structures observed in the cross sections of vibrational excitation and dissociative electron attachment to diatomic molecules such as threshold peaks, boomerang oscillations below the dissociative attachment threshold, or outer-well resonances.

Resonant inelastic collisions of electrons with diatomic molecules

Energy Technology Data Exchange (ETDEWEB)

Houfek, Karel, E-mail: karel.houfek@gmail.com [Institute of Theoretical Physics, Faculty of Mathematics and Physics, Charles University, V Holesovickach 2, 180 00 Prague 8 (Czech Republic)

2012-05-15

In this contribution we give a review of applications of the nonlocal resonance theory which has been successfully used for treating the nuclear dynamics of low-energy electron collisions with diatomic molecules over several decades. We give examples and brief explanations of various structures observed in the cross sections of vibrational excitation and dissociative electron attachment to diatomic molecules such as threshold peaks, boomerang oscillations below the dissociative attachment threshold, or outer-well resonances.

Consequences of the collision symmetry on the observed electron spectra produced by autoionisation

International Nuclear Information System (INIS)

Gleizes, A.; Bordenave-Montesquieu, A.; Benoit-Cattin, P.

1980-01-01

Some properties of symmetrical collisions observed in the decay of the helium autoionising states by electron emission are reported. They have been seen in the He + on He and the He on He collisional systems within the 7 to 140 keV energy range. Comparison of the excitation processes for the fast and slow atoms is made through the measurement of ejected-electron line shape and angular distributions for various autoionising states. At low energy the symmetry of the two systems is well verified; discrepancies from the symmetry requirements are observed in the angular distributions for the neutral-neutral system at high collision energy. (author)

Shifts in electron capture to the continuum at low collision energies: Enhanced role of target postcollision interactions

International Nuclear Information System (INIS)

Shah, M. B.; McGrath, C.; Luna, H.; Crothers, D.S.F.; O'Rourke, S.F.C.; Gilbody, H.B.; Illescas, Clara; Riera, A.; Pons, B.

2003-01-01

Measurements of electron velocity distributions emitted at 0 deg. for collisions of 10- and 20-keV H + incident ions on H 2 and He show that the electron capture to the continuum cusp formation, which is still possible at these low impact energies, is shifted to lower momenta than its standard position (centered on the projectile velocity), as recently predicted. Classical trajectory Monte Carlo calculations reproduce the observations remarkably well, and indicate that a long-range residual interaction of the electron with the target ion after ionization is responsible for the shifts, which is a general effect that is enhanced at low nuclear velocities

Precession mechanism of spin relaxation at frequent electron-electron collisions

CERN Document Server

Glazov, M M

2002-01-01

It is shown that the spin relaxation mechanism in the two-dimensional electron gas, is controlled not only through the electron pulse relaxation processes, determining the mobility, but through the electron-electron collisions as well. It is decided to use the kinetic equation, describing the electron spin mixing in the k-space, for determining the spin relaxation time tau sub s at frequent electron-electron collisions. The tau sub s time is calculated for the nondegenerated electron gas both with an account and with no account of the exchange interaction

Sixteenth International Conference on the physics of electronic and atomic collisions

Energy Technology Data Exchange (ETDEWEB)

Dalgarno, A.; Freund, R.S.; Lubell, M.S.; Lucatorto, T.B. (eds.)

1989-01-01

This report contains abstracts of papers on the following topics: photons, electron-atom collisions; electron-molecule collisions; electron-ion collisions; collisions involving exotic species; ion- atom collisions, ion-molecule or atom-molecule collisions; atom-atom collisions; ion-ion collisions; collisions involving rydberg atoms; field assisted collisions; collisions involving clusters and collisions involving condensed matter.

Sixteenth International Conference on the physics of electronic and atomic collisions

International Nuclear Information System (INIS)

Dalgarno, A.; Freund, R.S.; Lubell, M.S.; Lucatorto, T.B.

1989-01-01

This report contains abstracts of papers on the following topics: photons, electron-atom collisions; electron-molecule collisions; electron-ion collisions; collisions involving exotic species; ion- atom collisions, ion-molecule or atom-molecule collisions; atom-atom collisions; ion-ion collisions; collisions involving rydberg atoms; field assisted collisions; collisions involving clusters and collisions involving condensed matter

Future directions in electron--ion collision physics

International Nuclear Information System (INIS)

Reed, K.J.; Griffin, D.C.

1992-01-01

This report discusses the following topics: Summary of session on synergistic co-ordination of theory and experiment; synergism between experiment and theory in atomic physics; comparison of theory and experiment for electron-ion excitation and ionization; summary of session on new theoretical and computational methods; new theoretical and computational methods-r-matrix calculations; the coulomb three-body problem: a progress report; summary of session on needs and applications for electron-ion collisional data; electron-ion collisions in the plasma edge; needs and applications of theoretical data for electron impact excitation; summary of session on relativistic effects, indirect effects, resonance, etc; direct and resonant processes in electron-ion collisions; relativistic calculations of electron impact ionization and dielectronic recombination cross section for highly charged ions; electron-ion recombination in the close-coupling approximation; modified resonance amplitudes with strongly correlated channels; a density-matrix approach to the broadening of spectral lines by autoionization, radiative transitions and electron-ion collisions; towards a time-dependent description of electron-atom/ion collisions two electron systems; and comments on inclusion of the generalized bright interaction in electron impact excitation of highly charged ions

Absorption effects in electron-sulfur-dioxide collisions

Energy Technology Data Exchange (ETDEWEB)

Machado, L. E.; Sugohara, R. T.; Santos, A. S. dos [Departamento de Fisica, UFSCar, 13565-905 Sao Carlos-SP (Brazil); Lee, M.-T.; Iga, I.; Souza, G. L. C. de [Departamento de Quimica, UFSCar, 13565-905 Sao Carlos-SP (Brazil); Homem, M. G. P.; Michelin, S. E. [Departamento de Fisica, UFSC, 88040-970 Florianopolis-SC (Brazil); Brescansin, L. M. [Instituto de Fisica ' ' Gleb Wataghin' ' , UNICAMP, 13083-970 Campinas-SP (Brazil)

2011-09-15

A joint experimental-theoretical study on electron-SO{sub 2} collisions in the low and intermediate energy range is reported. More specifically, experimental elastic differential, integral, and momentum transfer cross sections in absolute scale are measured in the 100-1000 eV energy range using the relative-flow technique. Calculated elastic differential, integral, and momentum transfer cross sections as well as grand-total and total absorption cross sections are also presented in the 1-1000 eV energy range. A complex optical potential is used to represent the electron-molecule interaction dynamics, whereas the Schwinger variational iterative method combined with the distorted-wave approximation is used to solve the scattering equations. Comparison of the present results is made with the theoretical and experimental results available in the literature.

Electron-positron pair production in Coulomb collisions at ultrarelativistic energies

International Nuclear Information System (INIS)

Vane, C.R.; Datz, S.; Dittner, P.F.; Krause, H.F.; Bottcher, C.; Strayer, M.; Schuch, R.; Gao, H.; Hutton, R.

1993-01-01

We have measured angular and momentum distributions for electrons and positrons created as pairs in peripheral collisions of 6.4 TeV bare sulfur ions with fixed targets of Al, Pd, and Au. Singly- and doubly-differential cross sections have been determined for 1--17 MeV/c electrons and positrons detected independently and in coincidence as pairs. Integrated yields for pair production are found to vary as the square of the target nuclear charge. Relative angular and momentum differential cross sections are effectively target independent. Probability distributions for the pair total momentum, the positron fraction of the pair momentum, and the pair traverse momentum have been derived from the coincident electron-positron data

Identification of very low energy projectile autoionizing transitions in high velocity collisions using zero-degree Auger electron spectroscopy

International Nuclear Information System (INIS)

Zouros, T.J.M.; Liao, C.; Montenegro, E.C.; Hagmann, S.; Richard, P.; Grabbe, S.; Bhalla, C.P.; Wong, K.L.

1995-01-01

The unusual looking ''mesa''-shaped cusp observed in O 3+ collisions with He [N. Stolterfoht et al., Proc. 2nd US-Mexico Symp. on Atomic and Molecular Phy. eds. A. Cisneros and T. Morgan (Instituto de Fysica, Cuernavaca, Mexico, 1986) p. 51.], has been investigated using zero-degree electron spectroscopy, in both high resolution singles measurements and lower resolution electron-projectile coincidence measurements at 10, 15 and 23 MeV. The high resolution studies indicate the ''mesa'' peak to be actually composed of primarily two (other than the cusp) very strong autoionizing peaks corresponding to energies of 60 and 100 meV in the emitter frame. The coincidence studies, indicate these lines to originate from excitation of the O 3+ ion followed by autoionization. Ongoing Hartree-Fock-Slater calculations, severely tested at these extremely small transition energies, indicate that these lines can indeed result from the autoionization of t he O 3+ (1s 2 2s2p5l) Rydberg states produced during the collision. Furthermore, the unusually sharp edges of these lines giving rise to the characteristic ''mesa''-shape look, can be explained in terms of the kinematic constraints imposed by the energy and angular acceptance range of the spectrometer. (orig.)

Two-electron excitation to Rydberg levels in fast I6+ on hydrogen collisions

International Nuclear Information System (INIS)

Liao, C.; Hagmann, S.; Zouros, T.J.M.; Montenegro, E.C.; Toth, G.; Richard, P.; Grabbe, S.; Bhalla, C.P.

1995-01-01

The emission of electrons in the forward direction in collisions of 0.3 MeV/u I 6+ with H 2 has been studied, and strong autoionization peaks are observed on the shoulder of the cusp peak. The energies of these autoionization lines in the projectile rest frame are determined by high-resolution electron spectroscopy. Using the electron projectile final charge state coincidence technique, we probe different collision mechanisms, which create continuum electrons that are slow in the projectile rest frame. We conclude that the observed autoionization lines are due to two electron excitation to projectile Rydberg levels. (orig.)

Delta electron spectroscopy for the study of the inner-shell excitation in heavy ion collisions

International Nuclear Information System (INIS)

Trollmann, G.

1981-01-01

In this thesis energy and angular differential cross sections of delta electrons from ion-atom collisions are measured and compared with different perturbation theories. Shell specific cross sections were obtained from electron-X-ray coincidences. Contradicting theoretical statements concerning the angular distribution of the electrons can be experimentally clarified, other predictions are verified. Starting from fast, strongly asymmetric collisions until to slow, more symmetric collisions the question of the disturbance of the stationary target state by the projectile and the formation of intermediate molecular state is studied. With the results of the measurement of the delta electrons it can be contributed to the clarification of the question for the physical origin of the continuous X-radiation in the energy range beyond the K-line of the heavier collision partner. It is shown that the secondary electron bremsstrahlung discussed as radiation source besides the molecular orbital (MO) radiation is in its intensity about more than one order of magnitude weaker than the measured X-radiation and is therefore excluded as dominant radiation. In the framework of this work an apparature was developed, which allows the electron spectroscopy in the energy range between 10 keV and 150 keV and the angular range between 5 degrees and 180 degrees for the absolute determination of double differential cross sections. (orig./HSI) [de

PARTON SATURATION, PRODUCTION, AND EQUILIBRATION IN HIGH ENERGY NUCLEAR COLLISIONS

International Nuclear Information System (INIS)

VENUGOPALAN, R.

1999-01-01

Deeply inelastic scattering of electrons off nuclei can determine whether parton distributions saturate at HERA energies. If so, this phenomenon will also tell us a great deal about how particles are produced, and whether they equilibrate, in high energy nuclear collisions

Spin-flip processes in low-energy Fe17+ + He collisions

International Nuclear Information System (INIS)

Bruch, R.; Altick, P.L.; Rauscher, E.; Wang, H.; Schneider, D.

1993-01-01

Spin-nonconserving electron transfer processes violating the ''Wigner rule'' have been studied for slow multiply charged ion-atom collisions. Experimentally a strong population of highly metastable sodium-like quartet states in low energy Fe 17+ + He single collision events has been observed. The possibility of double-electron capture plus spin-flip mechanisms has been discussed experimentally and theoretically, Our theoretical model using time dependent perturbation theory predicts that spin-flip processes are as likely as no spin flip under the conditions of our experiment

Fine structures of atomic excited states: precision atomic spectroscopy and electron-ion collision process

International Nuclear Information System (INIS)

Gao Xiang; Cheng Cheng; Li Jiaming

2011-01-01

Scientific research fields for future energies such as inertial confinement fusion researches and astrophysics studies especially with satellite observatories advance into stages of precision physics. The relevant atomic data are not only enormous but also of accuracy according to requirements, especially for both energy levels and the collision data. The fine structure of high excited states of atoms and ions can be measured by precision spectroscopy. Such precision measurements can provide not only knowledge about detailed dynamics of electron-ion interactions but also a bench mark examination of the accuracy of electron-ion collision data, especially incorporating theoretical computations. We illustrate that by using theoretical calculation methods which can treat the bound states and the adjacent continua on equal footing. The precision spectroscopic measurements of excited fine structures can be served as stringent tests of electron-ion collision data. (authors)

[Electron transfer, ionization, and excitation in atomic collisions]. Final technical report, June 15, 1986 - June 14, 1998

International Nuclear Information System (INIS)

1998-01-01

The research on theoretical atomic collisions that was funded at The Pennsylvania State University's Wilkes-Barre Campus by DOE from 1986 to 1998 was carried out by Winger from 1986 to 1989 and by Winter and Alston from 1989 to 1998. The fundamental processes of electron transfer, ionization, and excitation in ion-ion, ion-atom, and, more recently, ion-molecule collisions were addressed. These collision processes were treated in the context of simple one-electron, quasi-one-electron, or two-electron systems in order to provide unambiguous results and reveal more clearly the collisional mechanisms. Winter's work generally focused on the intermediate projectile-energy range corresponding to proton energies from about ten to a few hundred keV. In this velocity-matching energy range, the electron-transfer cross section reaches a peak, and many states, including electron-transfer and ionization states, contribute to the overall electron-cloud distribution and transition probabilities; a large number of states are coupled, and therefore perturbative approaches are generally inappropriate. These coupled-state calculations were sometimes also extended to higher energies to join with perturbative results. Alston concentrated on intermediate-energy asymmetric collision systems, for which coupling with the projectile is weaker, but many target states are included, and on high energies (MeV energies). Thus, while perturbation theory for electron transfer is valid, it is not adequate to first order. The studies by Winter and Alston described were often done in parallel. Alston also developed formal perturbative approaches not tied to any particular system. Materials studied included He + , Li 2+ , Be 3+ , B 4+ , C 5+ , and the H + + Na system

Simultaneous electron capture and excitation in ion-atom collisions

International Nuclear Information System (INIS)

Tanis, J.A.; Bernstein, E.M.; Graham, W.G.; Clark, M.; Shafroth, S.M.; Johnson, B.M.; Jones, K.; Meron, M.

1982-01-01

A review of recent efforts to observe simultaneous electron capture-and-K-shell excitation in ion-atom collisions is presented. This process which has been referred to as resonant-transfer-and-excitation (RTE), is qualitatively analogous to dielectronic recombination (inverse Auger transition) in free-electron-ion collisions, and, hence, is expected to be resonant. Experimentally, events having the correct signature for simultaneous capture-and-excitation are isolated by detecting projectile K x rays in coincidence with ions which capture a single electron. In a recent experiment involving 70-160 MeV S 13+ ions incident on Ar, a maximum was observed in the yield of projectile K x rays associated with electron capture. This maximum is attributed to simultaneous capture - and excitation. The position (120 MeV) and width (60 MeV) of the observed maximum are in good agreement with theoretical calculations. The data indicate that RTE is an important mechanism for inner-shell vacancy production in the energy range studied

Kinetic parameters, collision rates, energy exchanges and transport coefficients of non-thermal electrons in premixed flames at sub-breakdown electric field strengths

KAUST Repository

Bisetti, Fabrizio; El Morsli, Mbark

2014-01-01

The effects of an electric field on the collision rates, energy exchanges and transport properties of electrons in premixed flames are investigated via solutions to the Boltzmann kinetic equation. The case of high electric field strength, which

Inner-shell excitation in heavy ion collisions up to intermediate incident energies

International Nuclear Information System (INIS)

Reus, T. de.

1987-04-01

Electronic excitations in collisions of very heavy ions with a total nuclear charge Z greater than 1/α ≅ 137 at bombarding energies reaching from 3.6 MeV/n up to 100 MeV/n are the subject of this thesis. The dynamical behaviour of the electron-positron-field is described within a semiclassical model, which is reviewed and extended to include electronic interactions via a mean field. A detailed comparison with experimental data of K-vacancy formation, δ-electron and positron emission shows an improved agreement compared with former calculations. Structures in spectra of positrons emitted in sub- and supercritical collision are discussed in two respects: Firstly as a signal of the vacuum decay in supercritical electromagnetic fields which evolve in the vicinity of long living giant nuclear molecules. Secondly as an atomic effect, which might be related to an instaneous formation of molecular 1sσ- and 2p 1/2 σ- levels. However, beyond this speculation the emission spectra of electrons and positrons in deep inelastic reactions have proven to be a powerful tool for measuring nuclear reaction or delay times in the order of 10 -21 s. This property was transfered to the domain of intermediate energy collisions. In first order perturbation theory we derived a scaling law, exhibiting how nuclear stopping times could be extracted from the emission spectra of high energetic δ-electrons. Quantitative calculations within a coupled channel code have been carried out for the system Pb+Pb, yielding cross sections of up to 20 nb for the emission of electrons with a kinetic energy of 50 MeV in 60 MeV/n-collisions. (orig./HSI)

Studies of collision dynamics in electron capture processes

International Nuclear Information System (INIS)

Hansen, J.P.

1990-12-01

This thesis presents some recent development in time-dependent coupled channel methods for one- and two-electron systems. The methods have been applied to detailed studies on several different aspects of charge transfer processes in ion-atom collisions at intermediate to low energies. Measurable quantities, such as partial and total cross sections, partial cross sections in projectile energy gain, orientation and alignment fractions, have been calculated. Confrontation with experiments has in general given good agreement. 29 refs

Studies of collision dynamics in electron capture processes

International Nuclear Information System (INIS)

Hansen, J.P.

1989-12-01

The thesis presents some recent development in time-dependent coupled channel methods for one- and two-electron systems. The methods have been applied to detailed studies on several different aspects of charge transfer processes in ion-atom collisions at intermediate to low energies. Measurable quantities, such as partial and total cross sections, partial cross sections in projectile energy gain, orientation and alignment fractions, have been calculated. Confrontation with experiments has in general given good agreement. 14 refs., 2 figs

Transverse-energy distribution in proton-nucleus collisions at high energy

International Nuclear Information System (INIS)

Liu, F.H.

2001-01-01

Based on the model of nuclear-collision geometry, the independent N - N collision picture and participant contribution picture are used to describe the transverse-energy distribution in p-A collisions at high energy. In the independent N - N collision picture, the energy loss of leading proton in each p-N collision is considered. The calculated results are in agreement with the experimental data of p-Al, p-Cu, p-U collisions at 200 GeV/c. (author)

The electron transport problem sampling by Monte Carlo individual collision technique

International Nuclear Information System (INIS)

Androsenko, P.A.; Belousov, V.I.

2005-01-01

The problem of electron transport is of most interest in all fields of the modern science. To solve this problem the Monte Carlo sampling has to be used. The electron transport is characterized by a large number of individual interactions. To simulate electron transport the 'condensed history' technique may be used where a large number of collisions are grouped into a single step to be sampled randomly. Another kind of Monte Carlo sampling is the individual collision technique. In comparison with condensed history technique researcher has the incontestable advantages. For example one does not need to give parameters altered by condensed history technique like upper limit for electron energy, resolution, number of sub-steps etc. Also the condensed history technique may lose some very important tracks of electrons because of its limited nature by step parameters of particle movement and due to weakness of algorithms for example energy indexing algorithm. There are no these disadvantages in the individual collision technique. This report presents some sampling algorithms of new version BRAND code where above mentioned technique is used. All information on electrons was taken from Endf-6 files. They are the important part of BRAND. These files have not been processed but directly taken from electron information source. Four kinds of interaction like the elastic interaction, the Bremsstrahlung, the atomic excitation and the atomic electro-ionization were considered. In this report some results of sampling are presented after comparison with analogs. For example the endovascular radiotherapy problem (P2) of QUADOS2002 was presented in comparison with another techniques that are usually used. (authors)

Observation of the two-electron cusp in atomic collisions. Evidence for strong electron-electron correlation

International Nuclear Information System (INIS)

Sarkadi, L.; Orban, A.

2007-01-01

Complete text of publication follows. In this report we present experimental data for a process when two electrons with velocity vectors equal to that of the projectile are emitted from collisions. By observing the two electron cusp the study of the threshold phenomenon for two-electron break-up is possible. It is a particularly interesting question whether the outgoing charged projectile can attract the two repulsing electrons so strongly that the two-electron cusp is formed. If it is so, a further question arises: Are the two electrons correlated in the final state as it is predicted by the Wannier theory? The experiments have been done at the 1 MeV VdG accelerator of ATOMKI using our TOF spectrometer. The first measurements clearly showed the formation of the two-electron cusp and signature of the electron correlation in 200 keV He 0 +He collisions. These promising results motivated us to carry out the experiment at 100 keV beam energy where the coincidence count rate is still reasonable but the energy resolution is better. For an acceptable data acquisition time we improved our data acquisition and data processing system for triple coincidence measurements. In Fig. 1a we present our measured relative fourfold differential cross section (FDCS) that shows strong electron correlation. For a comparison, in Fig. 1b we displayed the contour plot for uncorrelated electron pair emission. These latter data were synthesized artificially, generating the energies of the electron pairs from two independent double coincidence experiments. In both figures the distributions are characterized by two ridges. In Fig. 1b the ridges are perpendicular straight lines (E 1 = E 2 .13.6 eV). As a result of the correlation, the ridges in Fig. 1a are distorted in such a way that they have a joint straight-line section following the line E 1 + E 2 = 27.2 eV. This means that the electron pairs in the vicinity of the cusp maximum are emitted with a center of- mass velocity equal to that of

Electron Capture in Proton Collisions with CO.

Science.gov (United States)

Stancil, P. C.; Schultz, D. R.; Kimura, M.; Gu, J.-P.; Hirsch, G.; Buenker, R. J.; Li, Y.

1999-10-01

Electron capture by protons following collisions with carbon monoxide is studied with a variety of theoretical approaches including quantal and semiclassical molecular-orbital close-coupling (MOCC) and classical trajectory Monte Carlo (CTMC) techniques. The MOCC treatments utilize potential surfaces and couplings computed for a range of H^+-CO orientation angles and C-O separations. Results including integral, differential, electronic state-selective, and vibrational state-selective cross sections will be presented for low- to intermediate-energies. Comparison with experiment will be made where possible and the relevance of the reaction in astrophysics and atmospheric physics will be discussed.

Differential electron emission in multi-charged ion atom collisions: Systematics for distant and close collisions

International Nuclear Information System (INIS)

DuBois, R.D.; Toburen, L.H.; Middendorf, M.E.; Jagutzki, O.

1992-09-01

Absolute doubly differential cross sections for electron emission are presented for 0.5 MeV/u multi-charged ion impact on helium, neon, and argon targets. For the helium target, Bq+, Cq+ (q = 2--5) and Oq+, Fq+ (q = 3--6) projectiles were studied; for neon and argon, only Cq+ (q = 2--5) projectiles were used. Electron emission for 10 degrees ≤ Θ ≤ 60 degrees was studied. The measured cross sections were assumed to scale as the square of an effective projectile charge, Z eff , which was determined as a function of emitted electron energy and angle. For distant collisions (low emitted electron energies), we find that Z eff ∼ q for small q and Z eff eff > Z and increases as q decreases. This is true for all angles and targets investigated

Electron-ion collisions

International Nuclear Information System (INIS)

Crandall, D.H.

1982-01-01

This discussion concentrates on basic physics aspects of inelastic processes of excitation, ionization, and recombination that occur during electron-ion collisions. Except for cases of illustration along isoelectronic sequences, only multicharged (at least +2) ions will be specifically discussed with some emphasis of unique physics aspects associated with ionic charge. The material presented will be discussed from a primarily experimental viewpoint with most attention to electron-ion interacting beams experiments

Effective collision frequency of electrons in noble gases

International Nuclear Information System (INIS)

Baille, P.; Chang, J.-S.; Claude, A.; Yau, A.W.; Hobson, R.M.; Ogram, G.L.

1981-01-01

The electron-neutral collision frequency in the noble gases has been calculated using recent numerical results for momentum transfer cross sections by assuming a Maxwellian distribution of electron velocities. In all these gases, except for argon, good agreement is obtained with most previously published experimental and theoretical data. Mean free path, mobilities and diffusion coefficients are also calculated from the resulting effective collision frequencies. The empirical formulae are presented for an electron temperature dependence of the electron-neutral collision frequency for all noble gases up to Tsub(e) < approximately 25.000 K. (author)

Double electron capture by protons in collisions with H2

International Nuclear Information System (INIS)

Salazar-Zepeda, M.H.; Gleason, Cristian; Gonzalez, Eduardo; Gonzalez-Magana, O.; Hinojosa, Guillermo

2010-01-01

Double electron capture of protons in collisions with molecular hydrogen in the energy range 1.5-10 keV was studied by measuring the resulting H - velocity distributions. In this paper, a technique that provides experimental evidence about double capture mechanisms is proposed. In addition, cross-sections for this process were measured in the energy range of 1-5 keV.

Unpolarised and spin-change collisions between He/sup +/ and H at low energies

Energy Technology Data Exchange (ETDEWEB)

Falcon, C; Opradolce, L [Instituto de Astronomia y Fisica del Espacio, Buenos Aires (Argentina); Piacentini, R D

1978-09-14

He/sup +/-H collisions are studied for energies lower than the electron excitation threshold. Unpolarised cross sections having resonances and values greater than 4000 a/sup 2//sub 0/ and spin-change cross sections showing high structures are obtained. Comparisons with the corresponding H-H collision cross sections are displayed. The sensitivity of the cross sections to the potential energy curves is discussed.

Multiple electron capture in close ion-atom collisions

International Nuclear Information System (INIS)

Schlachter, A.S.; Stearns, J.W.; Berkner, K.H.

1989-01-01

Collisions in which a fast highly charged ion passes within the orbit of K electron of a target gas atom are selected by emission of a K x-ray from the projectile or target. Measurement of the projectile charge state after the collision, in coincidence with the K x-ray, allows measurement of the charge-transfer probability during these close collisions. When the projectile velocity is approximately the same as that of target electrons, a large number of electrons can be transferred to the projectile in a single collision. The electron-capture probability is found to be a linear function of the number of vacancies in the projectile L shell for 47-MeV calcium ions in an Ar target. 18 refs., 9 figs

Cross-sections for dissociative excitation of lead atom in collisions of slow electrons with PbI2 molecules

International Nuclear Information System (INIS)

Smirnov, Yu.M.

2006-01-01

The dissociative excitation of the lead atom in e-PbI 2 collisions has been studied experimentally. 27 excitation cross-sections are measured at an exciting-electron energy of 100 eV. Nine optical excitation functions are recorded at the electron energy varying in the 0-100 eV range. The most possible reaction channels at low electron energies along with the relation of the dissociative-excitation cross-sections of the lead atom both in e-PbI 2 and e-PbCl 2 collisions are discussed. (authors)

Inelastic collisions of medium energy atomic elements. Qualitative model of energy losses during collisions

International Nuclear Information System (INIS)

Pustovit, A.N.

2006-01-01

A new approach to the theoretical description of energy losses of atomic particle of medium energy during their interaction with the substance is proposed. The corner-stone of this approach is the supposition that all of the collision processes have inelastic nature during particle movement through the substance, while the calculation of the atomic particles braking is based on the law of their dispersion and the laws of energy and momentum conservation at the inelastic collisions. It is shown that inelastic atomic collision there are three dispersion zones for the only potential interaction with different laws, which characterize energy losses. The application conditions of this approach are determined [ru

High energy hadron-hadron collisions

International Nuclear Information System (INIS)

Chou, T.T.

1990-01-01

Results of a study on high energy collision with the geometrical model are summarized in three parts: (i) the elastic hadron-hadron collision, (ii) the inelastic hadron-hadron collision, and (iii) the e + e - annihilation. The geometrical description of high-energy elastic scattering developed earlier is still in general agreement with experiments at the CERN-S bar ppS energies. A simple one-parameter expression for the blackness of bar pp system has been proposed recently which describes very well all existing data from ISR to S bar ppS energies. The geometrical description has also been extended to include processes of fragmentation and diffraction dissociation and other phenomena. In the past five years, a unified physical picture for multiparticle emission in hadron-hadron and e + e - collisions was developed. It focuses on the idea of the wide range of values for the total angular momentum in hadron-hadron collisions. An extension of this consideration yields a theory for the momentum distribution of the outgoing particles which agrees with bar pp and e + e - collision experiments. The results and conclusions of this theory have been extrapolated to higher energies and yielded many predictions which can be experimentally tested. 37 refs

Physics of ep collisions in the TeV energy range

International Nuclear Information System (INIS)

Altarelli, G.; Mele, B.; Rueckl, R.

1984-01-01

We study the physics of electron-proton collisions in the range of centre-of-mass energies between √s approx.= 0.3 TeV (HERA) and √s approx.= (1-2) TeV. The latter energies would be achieved if the electron or positron beam of LEP [Esub(e) approx.= (50-100) GeV] is made to collide with the proton beam of LHC [Esub(p) approx.= (5-10) TeV]. (orig.)

Electron correlation in highly-charged-ion collisions

International Nuclear Information System (INIS)

Hansen, J.P.; Taulbjerg, K.

1992-01-01

We have used the coupled-channel method to study the significance of electron correlation in the reaction mechanism for two-electron capture in C 5+ -He collisions. Two different sets of calculations were performed. While the static correlation energy was generally included in the calculations, further correlation effects were ignored in the first set of calculations. In the second set of calculations the so-called doubly excited symmetry basis (DESB) states were used to model the spatial electron correlation. The difference between the two sets of results is so profound that we can conclude that electron correlation plays an essential role in the reaction mechanism. The results of the DESB-based calculations are in good agreement with experimental data [Holt et al., Phys. Rev. A 43, 607 (1991)

Electron Capture in Slow Collision of He^2++H : Revisited

Science.gov (United States)

Krstic, Ps

2003-05-01

Very early experimental data (Fite et al. al., Proc. R. Soc. A 268, 527 (1962)) for He^2++H, recent ORNL measurements for Ne^2+ + H and our theoretical estimates suggest that the electron capture cross sections for these strongly exoergic collision systems drop slower toward low collision energies than expected from previous theories. We perform a theoretical study to establish and understand the true nature of this controversy. The calculations are based on the Hidden Crossings MOCC method, augmented with rotational and turning point effects.

Positron-electron pairs produced in heavy-ion collisions

International Nuclear Information System (INIS)

Ahmad, I.; Austin, Sam. M.; Back, B. B.; Betts, R. R.; Calaprice, F. P.; Chan, K. C.; Chishti, A.; Conner, C. M.; Dunford, R. W.; Fox, J. D.

1999-01-01

The production of positron-electron pairs in collisions of 238 U+ 232 Th at 5.95 MeV/nucleon, and of 238 U+ 181 Ta at 5.95, 6.1, and 6.3 MeV/nucleon, has been studied with the APEX spectrometer at Argonne National Laboratory. Several analyses have been performed to search for sharp structures in sum-energy spectra for positron-electron pairs. Such features have been reported in previous experiments. No statistically convincing evidence for such behavior is observed in the present data. (c) 1999 The American Physical Society

Production and decay of exotic fermions in high energy collisions

International Nuclear Information System (INIS)

Queiroz Filho, Pedro Pacheco de

1995-05-01

In this work, we investigate the production and decay of exotic fermions predicted by some extensions of the standard model. We select for our study the more popular models: vector singlet, vector doublet and Fermion Mirror-Fermion. We want to establish the differences between these models and also in relation to the Standard Model. We make investigations by Monte Carlo simulations, to study the phenomenology of the particles expected in these models, particularly the exotic fermions. These studies were done for electron-proton collisions at DESY HERA energies. We considered the investigation of exotic quark production, electron-positron collisions in LEP II and NLC energies in order to study the production of exotic leptons, and virtual exotic lepton contribution in the specific process e + e - → ιν-bar ι W + . (author)

The electron transport problem sampling by Monte Carlo individual collision technique

Energy Technology Data Exchange (ETDEWEB)

Androsenko, P.A.; Belousov, V.I. [Obninsk State Technical Univ. of Nuclear Power Engineering, Kaluga region (Russian Federation)

2005-07-01

The problem of electron transport is of most interest in all fields of the modern science. To solve this problem the Monte Carlo sampling has to be used. The electron transport is characterized by a large number of individual interactions. To simulate electron transport the 'condensed history' technique may be used where a large number of collisions are grouped into a single step to be sampled randomly. Another kind of Monte Carlo sampling is the individual collision technique. In comparison with condensed history technique researcher has the incontestable advantages. For example one does not need to give parameters altered by condensed history technique like upper limit for electron energy, resolution, number of sub-steps etc. Also the condensed history technique may lose some very important tracks of electrons because of its limited nature by step parameters of particle movement and due to weakness of algorithms for example energy indexing algorithm. There are no these disadvantages in the individual collision technique. This report presents some sampling algorithms of new version BRAND code where above mentioned technique is used. All information on electrons was taken from Endf-6 files. They are the important part of BRAND. These files have not been processed but directly taken from electron information source. Four kinds of interaction like the elastic interaction, the Bremsstrahlung, the atomic excitation and the atomic electro-ionization were considered. In this report some results of sampling are presented after comparison with analogs. For example the endovascular radiotherapy problem (P2) of QUADOS2002 was presented in comparison with another techniques that are usually used. (authors)

Kinetic parameters, collision rates, energy exchanges and transport coefficients of non-thermal electrons in premixed flames at sub-breakdown electric field strengths

KAUST Repository

Bisetti, Fabrizio

2014-01-02

The effects of an electric field on the collision rates, energy exchanges and transport properties of electrons in premixed flames are investigated via solutions to the Boltzmann kinetic equation. The case of high electric field strength, which results in high-energy, non-thermal electrons, is analysed in detail at sub-breakdown conditions. The rates of inelastic collisions and the energy exchange between electrons and neutrals in the reaction zone of the flame are characterised quantitatively. The analysis includes attachment, ionisation, impact dissociation, and vibrational and electronic excitation processes. Our results suggest that Townsend breakdown occurs for E/N = 140 Td. Vibrational excitation is the dominant process up to breakdown, despite important rates of electronic excitation of CO, CO2 and N2 as well as impact dissociation of O2 being apparent from 50 Td onwards. Ohmic heating in the reaction zone is found to be negligible (less than 2% of peak heat release rate) up to breakdown field strengths for realistic electron densities equal to 1010 cm-3. The observed trends are largely independent of equivalence ratio. In the non-thermal regime, electron transport coefficients are insensitive to mixture composition and approximately constant across the flame, but are highly dependent on the electric field strength. In the thermal limit, kinetic parameters and transport coefficients vary substantially across the flame due to the spatially inhomogeneous concentration of water vapour. A practical approach for identifying the plasma regime (thermal versus non-thermal) in studies of electric field effects on flames is proposed. © 2014 Taylor & Francis.

Band-structure-based collisional model for electronic excitations in ion-surface collisions

International Nuclear Information System (INIS)

Faraggi, M.N.; Gravielle, M.S.; Alducin, M.; Silkin, V.M.; Juaristi, J.I.

2005-01-01

Energy loss per unit path in grazing collisions with metal surfaces is studied by using the collisional and dielectric formalisms. Within both theories we make use of the band-structure-based (BSB) model to represent the surface interaction. The BSB approach is based on a model potential and provides a precise description of the one-electron states and the surface-induced potential. The method is applied to evaluate the energy lost by 100 keV protons impinging on aluminum surfaces at glancing angles. We found that when the realistic BSB description of the surface is used, the energy loss obtained from the collisional formalism agrees with the dielectric one, which includes not only binary but also plasmon excitations. The distance-dependent stopping power derived from the BSB model is in good agreement with available experimental data. We have also investigated the influence of the surface band structure in collisions with the Al(100) surface. Surface-state contributions to the energy loss and electron emission probability are analyzed

Measurements of Pair Production and Electron Capture from the Continuum in Heavy Particle Collisions

CERN Multimedia

2002-01-01

% WA99 \\\\ \\\\ Large transient Coulomb fields, which are generated in collisions of high-Z systems at sufficiently high energies, lead to copious production of electron-positron pairs. It has been suggested that these lepton pairs might mask signals arising from plasma phase interaction. Pair-production cross-sections have been calculated by several authors with results that differ significantly from each other. For very heavy ions and high energies, multiple pairs are expected to be formed even in single peripheral collisions. Perturbative and nonperturbative treatments lead to various predictions for the fractions of multiple pair formation out of the total cross-sections. Some of the electrons produced will be captured into bound states of the ion, thereby, reducing its charge state by one unit. This process which has been termed $^{\\prime\\prime}$Electron Capture from Pair Production$^{\\prime\\prime}$, represents the only electron capture process which increases with energy, and as such, will dominate all oth...

Two-electron excitation in slow ion-atom collisions: Excitation mechanisms and interferences among autoionizing states

International Nuclear Information System (INIS)

Kimura, M.; Rice Univ., Houston, TX

1990-01-01

The two-electron capture or excitation process resulting from collisions of H + and O 6+ ions with He atoms in the energy range from 0.5 keV/amu to 5 keV/amu is studied within a molecular representation. The collision dynamics for formation of doubly excited O 4+ ions and He** atoms and their (n ell, n'ell ') populations are analyzed in conjunction with electron correlations. Autoionizing states thus formed decay through the Auger process. An experimental study of an ejected electron energy spectrum shows ample structures in addition to two characteristic peaks that are identified by atomic and molecular autoionizations. These structures are attributable to various interferences among electronic states and trajectories. We examine the dominant sources of the interferences. 12 refs., 5 figs

Electron emission following collisions between multi-charged ions and D2 molecules

International Nuclear Information System (INIS)

Laurent, G.

2004-05-01

Dissociative ionisation mechanisms induced in collisions involving a highly charged ion (S 15+ , 13.6 MeV/u) and a molecular deuterium target, have been studied through momentum vector correlations of both the D + fragments and the electrons produced. An experimental apparatus has been developed in order to detect in coincidence all the charged particles produced during the collision. The measurement of their momentum vectors, which allows one to determine both their kinetic energy and direction of emission with respect to the projectile one, combines Time of Flight, Position Sensitive Detection, and multi-coincidence techniques. The correlation of the fragment and electron kinetic energies enables not only to determine branching ratios between the dissociative ionisation pathways, but also to separate unambiguously kinetic energy distributions of fragments associated to each process. Finally, the angular distributions of ejected electrons, as a function of the orientation of the molecular axis with respect to the projectile direction, are deduced from the spatial correlation. Measurements are compared to theoretical angular distributions obtained using the CDW-EIS (Continuum Distorted Wave-Eikonal Initial State) method. (author)

Emission of low-energetic electrons in collisions of heavy ions with solid targets

International Nuclear Information System (INIS)

Lineva, Natallia

2008-07-01

At the UNILAC accelerator, we have initiated a project with the objective to investigate lowenergy electrons, emitted from solid, electrically conductive targets after the impact of swift light and heavy ions. For this purposes, we have installed, optimized, and put into operation an electrostatic toroidal electron spectrometer. First, investigations of electrons, emitted from solid-state targets after the bombardment with a monochromatic electron beam from an electron gun, has been carried out. The proposed method combines the results of the measurements with the results of dedicated Monte Carlo simulations. The method has been elaborated in a case study for carbon targets. The findings have been instrumental for the interpretation of our measurements of electrons emitted in collisions of swift ions with the same carbon targets. Our investigations focused on following ion beams: protons and (H + 3 )-molecules of the same energy, as well as on carbon ions with two different energies. Thin carbon, nickel, argon and gold foils has been used as targets. Electrons in the energy range between 50 eV and 1 keV have been investigated. The measured electron distributions, both integral as well as differential with respect to the polar angle, have been compared to simple standard theories for gases as well as to the results of TRAX simulations, the latter being based on data from gaseous targets. Dedicated TRAX simulations have been performed only for the carbon targets, applying the method mentioned above. Within our experimental uncertainties, we observe a good agreement of the measured and TRAX simulated data. That leads us to the conclusion that - as a first order approximation - the electron emission pattern from ion-atom collisions in solid-state targets and the one from single collisions in gases are similar. (orig.)

Forward electron production in heavy ion-atom and ion-solid collisions

International Nuclear Information System (INIS)

Sellin, I.A.

1984-01-01

A sharp cusp in the velocity spectrum of electrons, ejected in ion-atom and ion-solid collisions, is observed when the ejected electron velocity vector v/sub e/ matches that of the emergent ion vector v/sub p/ in both speed and direction. In ion-atom collisions, the electrons originate from capture to low-lying, projectile-centered continuum states (ECC) for fast bare or nearly bare projectiles, and from loss to those low-lying continuum states (ELC) when loosely bound projectile electrons are available. Most investigators now agree that ECC cusps are strongly skewed toward lower velocities, and exhibit full widths half maxima roughly proportional to v/sub p/ (neglecting target-shell effects, which are sometimes strong). A close examination of recent ELC data shows that ELC cusps are instead nearly symmetric, with widths nearly independent on v/sub p/ in the velocity range 6 to 18 a.u., a result only recently predicted by theory. Convoy electron cusps produced in heavy ion-solid collisions at MeV/u energies exhibit approximately velocity-independent widths very similar to ELC cusp widths. While the shape of the convoy peaks is approximately independent of projectile Z, velocity, and of target material, it is found that the yields in polycrystalline targets exhibit a strong dependence on projectile Z and velocity. While attempts have been made to link convoy electron production to binary ECC or ELC processes, sometimes at the last layer, or alternatively to a solid-state wake-riding model, our measured dependences of cusp shape and yield on projectile charge state and energy are inconsistent with the predictions of available theories. 10 references, 8 figures, 1 table

Multiple electron capture in close ion-atom collisions

International Nuclear Information System (INIS)

Schlachter, A.S.

1987-10-01

Multiple electron capture is reported for Ca 17+ in Ar. Close collisions are defined by the observation of a coincident Ca K or Ar K x-ray. A large number of electrons is transferred to the projectile in a single close collision when the Ca ion projectile is of the order of the Ar L-shell electron velocity. The cross section for electron capture is reported

Determination of equilibrium electron temperature and times using an electron swarm model with BOLSIG+ calculated collision frequencies and rate coefficients

International Nuclear Information System (INIS)

Pusateri, Elise N.; Morris, Heidi E.; Nelson, Eric M.; Ji, Wei

2015-01-01

Electromagnetic pulse (EMP) events produce low-energy conduction electrons from Compton electron or photoelectron ionizations with air. It is important to understand how conduction electrons interact with air in order to accurately predict EMP evolution and propagation. An electron swarm model can be used to monitor the time evolution of conduction electrons in an environment characterized by electric field and pressure. Here a swarm model is developed that is based on the coupled ordinary differential equations (ODEs) described by Higgins et al. (1973), hereinafter HLO. The ODEs characterize the swarm electric field, electron temperature, electron number density, and drift velocity. Important swarm parameters, the momentum transfer collision frequency, energy transfer collision frequency, and ionization rate, are calculated and compared to the previously reported fitted functions given in HLO. These swarm parameters are found using BOLSIG+, a two term Boltzmann solver developed by Hagelaar and Pitchford (2005), which utilizes updated cross sections from the LXcat website created by Pancheshnyi et al. (2012). We validate the swarm model by comparing to experimental effective ionization coefficient data in Dutton (1975) and drift velocity data in Ruiz-Vargas et al. (2010). In addition, we report on electron equilibrium temperatures and times for a uniform electric field of 1 StatV/cm for atmospheric heights from 0 to 40 km. We show that the equilibrium temperature and time are sensitive to the modifications in the collision frequencies and ionization rate based on the updated electron interaction cross sections

Low-energy electron scattering from molecules, biomolecules and surfaces

CERN Document Server

Carsky, Petr

2011-01-01

Since the turn of the 21st century, the field of electron molecule collisions has undergone a renaissance. The importance of such collisions in applications from radiation chemistry to astrochemistry has flowered, and their role in industrial processes such as plasma technology and lighting are vital to the advancement of next generation devices. Furthermore, the development of the scanning tunneling microscope highlights the role of such collisions in the condensed phase, in surface processing, and in the development of nanotechnology.Low-Energy Electron Scattering from Molecules, Biomolecule

Collisions of low-energy antiprotons and protons with atoms and molecules

International Nuclear Information System (INIS)

Luehr, Armin

2010-01-01

Antiproton (anti p) collisions have evolved to a powerful tool for the testing of dynamic electron correlations in atoms and molecules. While advances in the understanding of anti p collisions with the simplest one- and two-electron atoms, H and He, have been achieved experiment and theory did not agree for low-energy anti p+He collisions ( 2 despite its fundamental role in representing the simplest two-electron molecule. The obtained results may be useful for the anti p experiments at CERN (e.g., antihydrogen production) and in particular for the facility design of low-energy anti p storage rings (e.g., at FLAIR) where a precise knowledge of the anti p interaction with the dominant residual-gas molecule H 2 is needed. In this work a nonperturbative, time-dependent numerical approach is developed which describes ionization and excitation of atoms or molecules by either anti p or p impact based on the impact-parameter method. A spectral close-coupling method is employed for solving the time-dependent Schroedinger equation in which the scattering wave function is expanded in (effective) one- or two-electron eigenstates of the target. This includes for the first time a full two-electron, two-center description of the H 2 molecule in anti p collisions. The radial part of the one-electron eigenstates is expanded in B splines while the two-electron basis is obtained with a configurationinteraction approach. Calculations are performed for anti p collisions with H, H 2 + , and H 2 as well as with He and alkali-metal atoms Li, Na, K, and Rb. Additionally, data are obtained for p collisions with H 2 , Li, Na, and K. The developed method is tested and validated by detailed comparison of the present findings for p impacts and for anti p+He collisions with literature data. On the other hand, total and differential cross sections for ionization and excitation of the targets by anti p impact complement the sparse literature data of this kind. Results gained from different targets

Energy dependence of the ionization of highly excited atoms by collisions with excited atoms

International Nuclear Information System (INIS)

Shirai, T.; Nakai, Y.; Nakamura, H.

1979-01-01

Approximate analytical expressions are derived for the ionization cross sections in the high- and low-collision-energy limits using the improved impulse approximation based on the assumption that the electron-atom inelastic-scattering amplitude is a function only of the momentum transfer. Both cases of simultaneous excitation and de-excitation of one of the atoms are discussed. The formulas are applied to the collisions between two excited hydrogen atoms and are found very useful for estimating the cross sections in the wide range of collisions energies

Electron-Atom Collisions in Gases

Science.gov (United States)

Kraftmakher, Yaakov

2013-01-01

Electron-atom collisions in gases are an aspect of atomic physics. Three experiments in this field employing a thyratron are described: (i) the Ramsauer-Townsend effect, (ii) the excitation and ionization potentials of xenon and (iii) the ion-electron recombination after interrupting the electric discharge.

Fragmentation of the C60 molecule in collision with light ions studied by a multi-correlation technique. Cross-sections, electron spectroscopy

International Nuclear Information System (INIS)

Rentenier, A.

2004-04-01

A quantitative study of the C60 fullerenes fragmentation in collision with light ions (H n + with n=1,2,3, He q+ with q=1,2) in the velocity range 0,1 - 2,3 u.a.) is presented. The multi-correlation technique, developed between fragment ions and electrons with well defined energy, has enlightened some of the dependences and properties of fragmentation mechanisms (cross sections, electron spectroscopy, size distributions, kinetic energy of fragment ions, Campi's scatter plot, activation energies). The deposited energy hence appeared as an important parameter. Cross sections have been measured, for the first time, for all the collisional processes. Ionisation and capture only depends on the collision velocity. On the other hand, scaling laws with the deposited energy have been observed for the cross sections of multifragmentation, which depends on the collision energy and the nature of the projectile. The deposited energy has also been found as an essential parameter to understand the evolution of the charged fragment size distributions. The electron spectroscopy, achieved at an emission angle of 35 degrees, showed spectra peaked at important energies (from 5 to 20 eV). The spectra shape depends on the collision velocity. A first theoretical analysis points out the link between the observed energy distribution and the presence of a centrifugal potential barrier. Finally, correlation experiments between produced ions and electron energy reveal that electron energy increases with internal energy. (author)

Collisions of low-energy antiprotons and protons with atoms and molecules

Energy Technology Data Exchange (ETDEWEB)

Luehr, Armin

2010-02-18

Antiproton (anti p) collisions have evolved to a powerful tool for the testing of dynamic electron correlations in atoms and molecules. While advances in the understanding of anti p collisions with the simplest one- and two-electron atoms, H and He, have been achieved experiment and theory did not agree for low-energy anti p+He collisions (<40 keV), stimulating a vivid theoretical activity. On the other hand, only very few theoretical anti p studies can be found considering molecular as well as other atomic targets, in contrast to proton (p) collisions. This is in particular true for anti p impacts on H{sub 2} despite its fundamental role in representing the simplest two-electron molecule. The obtained results may be useful for the anti p experiments at CERN (e.g., antihydrogen production) and in particular for the facility design of low-energy anti p storage rings (e.g., at FLAIR) where a precise knowledge of the anti p interaction with the dominant residual-gas molecule H{sub 2} is needed. In this work a nonperturbative, time-dependent numerical approach is developed which describes ionization and excitation of atoms or molecules by either anti p or p impact based on the impact-parameter method. A spectral close-coupling method is employed for solving the time-dependent Schroedinger equation in which the scattering wave function is expanded in (effective) one- or two-electron eigenstates of the target. This includes for the first time a full two-electron, two-center description of the H{sub 2} molecule in anti p collisions. The radial part of the one-electron eigenstates is expanded in B splines while the two-electron basis is obtained with a configurationinteraction approach. Calculations are performed for anti p collisions with H, H{sub 2}{sup +}, and H{sub 2} as well as with He and alkali-metal atoms Li, Na, K, and Rb. Additionally, data are obtained for p collisions with H{sub 2}, Li, Na, and K. The developed method is tested and validated by detailed

Collisions of carbon and oxygen ions with electrons, H, H2 and He: Volume 5

International Nuclear Information System (INIS)

Phaneuf, R.A.; Janev, R.K.; Pindzola, M.S.

1987-02-01

This report provides a handbook for fusion research of recommended cross-section and rate-coefficient data for collisions of carbon and oxygen ions with electrons, hydrogen atoms and molecules, and helium atoms. Published experimental and theoretical data have been collected and evaluated, and recommended data are presented in tabular, graphical, and parametrized form. Processes considered include exciation, ionization, and charge exchange at collision energies appropriate to applications in fusion-energy research

Electron identification and hadron contamination studies in proton-proton collisions with ALICE

Energy Technology Data Exchange (ETDEWEB)

Dashi, Anisa [Technische Universitaet Muenchen (Germany); Collaboration: ALICE-Collaboration

2016-07-01

The continuum of electron-positron pairs, produced in heavy-ion collisions, provides an excellent probe of the quark-gluon plasma and a possible chiral symmetry restoration, since these particles do not undergo strong final state interactions and hence carry information about the in-medium properties of hadrons to the detectors. To extract possible signatures, it is important to work with an electron sample of high purity, i.e. not contaminated by other particles. Dielectrons are also studied in proton-proton collisions to provide a crucial reference for the measurement in heavy-ion collisions. This poster presents an analysis performed on a data set of pp collisions at √(s) = 7 TeV measured with the ALICE detector at the Large Hadron Collider. The aim of this work is to optimize the electron identification and to reduce the hadron contamination. For that, three different combinations of particle identification (PID) criteria are compared regarding the statistical significance S/σ{sub S} of their dielectron signals and their electron purities. The analysis shows that one can achieve good electron identification efficiencies and high electron purities by combining the specific energy loss signals measured in the Inner Tracking System and the Time Projection Chamber with the information of the Time of Flight detector. With such a PID selection one obtains a dielectron signal with a purity higher than 82% reaching up to 96%, depending on the invariant mass.

Second European study conference on molecular low energy collisions (MOLEC II)

Energy Technology Data Exchange (ETDEWEB)

1978-01-01

The conference contained 52 papers on molecular low energy collisions including nonadiabatic transitions and excited states, vibrational and rotational energy transfer, chemical reactions, dissociation and ionization, general methods, potential surfaces, electronic excitation and excited states, inelastic scattering and anisotropic potentials, chemical reactions, and Van der Waals molecules. (JFP)

Computer simulation of electronic excitation in atomic collision cascades

Energy Technology Data Exchange (ETDEWEB)

Duvenbeck, A.

2007-04-05

The impact of an keV atomic particle onto a solid surface initiates a complex sequence of collisions among target atoms in a near-surface region. The temporal and spatial evolution of this atomic collision cascade leads to the emission of particles from the surface - a process usually called sputtering. In modern surface analysis the so called SIMS technology uses the flux of sputtered particles as a source of information on the microscopical stoichiometric structure in the proximity of the bombarded surface spots. By laterally varying the bombarding spot on the surface, the entire target can be scanned and chemically analyzed. However, the particle detection, which bases upon deflection in electric fields, is limited to those species that leave the surface in an ionized state. Due to the fact that the ionized fraction of the total flux of sputtered atoms often only amounts to a few percent or even less, the detection is often hampered by rather low signals. Moreover, it is well known, that the ionization probability of emitted particles does not only depend on the elementary species, but also on the local environment from which a particle leaves the surface. Therefore, the measured signals for different sputtered species do not necessarily represent the stoichiometric composition of the sample. In the literature, this phenomenon is known as the Matrix Effect in SIMS. In order to circumvent this principal shortcoming of SIMS, the present thesis develops an alternative computer simulation concept, which treats the electronic energy losses of all moving atoms as excitation sources feeding energy into the electronic sub-system of the solid. The particle kinetics determining the excitation sources are delivered by classical molecular dynamics. The excitation energy calculations are combined with a diffusive transport model to describe the spread of excitation energy from the initial point of generation. Calculation results yield a space- and time-resolved excitation

Computer simulation of electronic excitation in atomic collision cascades

International Nuclear Information System (INIS)

Duvenbeck, A.

2007-01-01

The impact of an keV atomic particle onto a solid surface initiates a complex sequence of collisions among target atoms in a near-surface region. The temporal and spatial evolution of this atomic collision cascade leads to the emission of particles from the surface - a process usually called sputtering. In modern surface analysis the so called SIMS technology uses the flux of sputtered particles as a source of information on the microscopical stoichiometric structure in the proximity of the bombarded surface spots. By laterally varying the bombarding spot on the surface, the entire target can be scanned and chemically analyzed. However, the particle detection, which bases upon deflection in electric fields, is limited to those species that leave the surface in an ionized state. Due to the fact that the ionized fraction of the total flux of sputtered atoms often only amounts to a few percent or even less, the detection is often hampered by rather low signals. Moreover, it is well known, that the ionization probability of emitted particles does not only depend on the elementary species, but also on the local environment from which a particle leaves the surface. Therefore, the measured signals for different sputtered species do not necessarily represent the stoichiometric composition of the sample. In the literature, this phenomenon is known as the Matrix Effect in SIMS. In order to circumvent this principal shortcoming of SIMS, the present thesis develops an alternative computer simulation concept, which treats the electronic energy losses of all moving atoms as excitation sources feeding energy into the electronic sub-system of the solid. The particle kinetics determining the excitation sources are delivered by classical molecular dynamics. The excitation energy calculations are combined with a diffusive transport model to describe the spread of excitation energy from the initial point of generation. Calculation results yield a space- and time-resolved excitation

Studies of electron correlation effects in multicharged ion atom collisions involving double capture

International Nuclear Information System (INIS)

Stolterfoht, N.; Sommer, K.; Griffin, D.C.; Havener, C.C.; Huq, M.S.; Phaneuf, R.A.; Swenson, J.K.; Meyer, F.W.

1988-01-01

We review measurements of L-Coster Kronig and Auger electron production in slow, multicharged collision systems to study electron correlation effects in the process of double electron capture. The n/sup /minus/3/ law was confirmed for the production of the Coster-Kronig configurations 1s 2 2pn/ell/ (n ≥ 6) in O 6+ + He collisions. Enhancement of high angular momentum /ell/ in specific 1s 2 2pn/ell/ configurations was observed by means of high-resolution measurements of the Coster-Kronig lines. The importance of electron correlation effects in couplings of potential energy curves leading to the 1s 2 2pn/ell/ configurations is verified by means of Landau-Zener model calculations. 32 refs., 4 figs

On the relativistic and nonrelativistic electron descriptions in high-energy atomic collisions

International Nuclear Information System (INIS)

Voitkiv, A.B

2007-01-01

We consider the relativistic and nonrelativistic descriptions of an atomic electron in collisions with point-like charged projectiles moving at relativistic velocities. We discuss three different forms of the fully relativistic first-order transition amplitude. Using the Schroedinger-Pauli equation to describe the atomic electron we establish the correct form of the nonrelativistic first-order transition amplitude. We also show that the so-called semi-relativistic treatment, in which the Darwin states are used to describe the atomic electron, is in fact fully equivalent to the nonrelativistic consideration. The comparison of results obtained with the relativistic and nonrelativistic electron descriptions shows that the latter is accurate within 20-30% up to Z a ∼ a is the atomic nuclear charge

Energy deposition model for low-energy electrons (10-10 000 eV) in air

International Nuclear Information System (INIS)

Roldan, A.; Perez, J.M.; Williart, A.; Blanco, F.; Garcia, G.

2004-01-01

An energy deposition model for electrons in air that can be useful in microdosimetric applications is presented in this study. The model is based on a Monte Carlo simulation of the single electron scattering processes that can take place with the molecular constituents of the air in the energy range 10-10 000 eV. The input parameters for this procedure have been the electron scattering cross sections, both differential and integral. These parameters were calculated using a model potential method which describes the electron scattering with the molecular constituent of air. The reliability of the calculated integral cross section values has been evaluated by comparison with direct total electron scattering cross-section measurements performed by us in a transmission beam experiment. Experimental energy loss spectra for electrons in air have been used as probability distribution functions to define the electron energy loss in single collision events. The resulting model has been applied to simulate the electron transport through a gas cell containing air at different pressures and the results have been compared with those observed in the experiments. Finally, as an example of its applicability to dosimetric issues, the energy deposition of 10 000 eV by means of successive collisions in a free air chamber has been simulated

Electron collisions in gas switches

International Nuclear Information System (INIS)

Christophorou, L.G.

1989-01-01

Many technologies rely on the conduction/insulation properties of gaseous matter for their successful operation. Many others (e.g., pulsed power technologies) rely on the rapid change (switching or modulation) of the properties of gaseous matter from an insulator to a conductor and vice versa. Studies of electron collision processes in gases aided the development of pulsed power gas switches, and in this paper we shall briefly illustrate the kind of knowledge on electron collision processes which is needed to optimize the performance of such switching devices. To this end, we shall refer to three types of gas switches: spark gap closing, self-sustained diffuse discharge closing, and externally-sustained diffuse discharge opening. 24 refs., 15 figs., 2 tabs

Single-photon emission associated with double electron capture in F9+ + C collisions

CERN Document Server

Elkafrawy, Tamer; Tanis, John A; Warczak, Andrzej

2016-01-01

Radiative double electron capture (RDEC), the one-step process occurring in ion-atom collisions, has been investigated for bare fluorine ions colliding with carbon. RDEC is completed when two target electrons are captured to a bound state of a projectile simultaneously with the emission of a single photon. This work is a follow-up to our earlier measurement of RDEC for bare oxygen projectiles, thus providing a recipient system free of electron-related Coulomb fields in both cases and allowing for the comparison between the two collision systems as well as with available theoretical studies. The most significant mechanisms of x-ray emission that may contribute to the RDEC energy region as background processes are also addressed.

Angular differential studies of electron transfer in collisions of He-like ions with Na(3s) : The role of electron saddle crossings

NARCIS (Netherlands)

Blank, I.; Otranto, S.; Meinema, C.; Olson, R. E.; Hoekstra, R.

2013-01-01

We present a systematic experimental and theoretical study of angular differential cross sections of single-electron transfer in collisions of N5+, O6+, and Ne8+ with ground-state Na(3s) in the collision energy range from 1 to 8 keV/amu. Experiments were performed using recoil-ion momentum

Single-electron capture for 2-8 keV incident energy and direct scattering at 6 keV in He2+-He collisions

International Nuclear Information System (INIS)

Bordenave-Montesquieu, D.; Dagnac, R.

1992-01-01

We studied the single-electron capture as well as the direct processes occurring when a He 2+ ion is scattered by a He target. Doubly differential cross sections were measured for single-electron capture with a collision energy ranging from 2 to 8 keV and a scattering angle varying from 10' to 3 o 30' (laboratory frame). Single-electron capture into excited states of He + was found to be the dominant process, confirming a previous experimental study. Elastic scattering and ionization differential cross sections were measured for E = 6 keV. (Author)

Cusp electron production in 75--300 keV He+ + Ar collisions

International Nuclear Information System (INIS)

Plano, V.L.; Sarkadi, L.; Zavodszky, P.; Berenyi, D.; Palinkas, J.; Gulyas, L.; Takacs, E.; Toth, L.; Tanis, J.A.

1992-01-01

Cusp-electron production has been investigated in collisions of 75--300 keV He + with Ar. The relative contributions from electron capture to the continuum (ECC), transfer ionization (TI), and electron loss to the continuum (ELC) to the total cusp electron production were measured. Over the energy range investigated, ECC was found to decrease from about 86% to 80%, TI decreased from about 12% to 1%, and ELC increased from about 2% to 20%. The present results are consistent with earlier work for He + and O q+ projectiles

Uncertainties of Electron Capture Cross Sections In Be4+ + H(1s) Collisions

International Nuclear Information System (INIS)

Méndez, L.; Illescas, Clara; Jorge, Alba; Errea, L.F.; Rabadán, I.; Suárez, J.

2014-01-01

We have considered one-electron systems where the theoretical methods are well established. The use of different computational alternatives enables the accurate evaluation of nl-partial cross sections in a wide range of collision energies. In the presentation we have analyzed the uncertainties of n-partial charge exchange (CX) cross sections in Be 4+ + H(1s) collisions, which are relevant in tokamak plasmas and experimental data are not available.

Studies of electron correlation effects in multicharged ion atom collisions involving double capture

Energy Technology Data Exchange (ETDEWEB)

Stolterfoht, N.; Sommer, K.; Griffin, D.C.; Havener, C.C.; Huq, M.S.; Phaneuf, R.A.; Swenson, J.K.; Meyer, F.W.

1988-01-01

We review measurements of L-Coster Kronig and Auger electron production in slow, multicharged collision systems to study electron correlation effects in the process of double electron capture. The n/sup /minus/3/ law was confirmed for the production of the Coster-Kronig configurations 1s/sup 2/2pn/ell/ (n greater than or equal to 6) in O/sup 6 +/ + He collisions. Enhancement of high angular momentum /ell/ in specific 1s/sup 2/2pn/ell/ configurations was observed by means of high-resolution measurements of the Coster-Kronig lines. The importance of electron correlation effects in couplings of potential energy curves leading to the 1s/sup 2/2pn/ell/ configurations is verified by means of Landau-Zener model calculations. 32 refs., 4 figs.

Electron capture in very low energy collisions of multicharged ions with H and D in merged beams

International Nuclear Information System (INIS)

Havener, C.C.; Meyer, F.W.; Phaneuf, R.A.

1991-01-01

An ion-atom merged-beams technique is being used to measure total absolute electron-capture cross sections for multicharged ions in collisions with H (or D) in the energy range between 0.1 and 1000 eV/amu. Comparison between experiment and theory over such a large energy range constitutes a critical test for both experiment and theory. Total capture cross-section measurements for O 3+ H(D) and O 5+ + H(D) are presented and compared to state selective and differential cross section calculations. Landau-Zener calculations show that for O 5+ the sharp increase in the measured cross section below 1 eV/amu is partly due to trajectory effects arising from the ion-induced dipole interaction between the reactants. 20 refs., 8 figs

Single-electron capture in He2+-D2 collisions

International Nuclear Information System (INIS)

Bordenave-Montesquieu, D.; Dagnac, R.

1994-01-01

Doubly differential cross sections of single-electron capture were measured for He 2+ impinging on a molecular deuterium target. The investigated collision energies are 4, 6 and 8 keV and the scattering angles range from 10' to 2 o 30' (laboratory frame). The exothermic capture leading to He + (1s) + D 2 +* was found to be the most important process at low energies and angles, whereas the endothermic channels leading to dissociative capture become the main processes at high scattering angles, i.e. at small impact parameters. (author)

Electron distribution function in electron-beam-excited plasmas

International Nuclear Information System (INIS)

Brau, C.A.

1976-01-01

In monatomic plasmas excited by high-intensity relativistic electron beams, the electron secondary distribution function is dominated by elastic electron-electron collisions at low electron energies and by inelastic electron-atom collisions at high electron energies (above the excitation threshold). Under these conditions, the total rate of excitation by inelastic collisions is limited by the rate at which electron-electron collisions relax the distribution function in the neighborhood of the excitation threshold. To describe this effect quantitatively, an approximate analytic solution of the electron Boltzmann equation is obtained, including both electron-electron and inelastic collisions. The result provides a simple formula for the total rate of excitation

Monte Carlo simulation of energy deposition by low-energy electrons in molecular hydrogen

Science.gov (United States)

Heaps, M. G.; Furman, D. R.; Green, A. E. S.

1975-01-01

A set of detailed atomic cross sections has been used to obtain the spatial deposition of energy by 1-20-eV electrons in molecular hydrogen by a Monte Carlo simulation of the actual trajectories. The energy deposition curve (energy per distance traversed) is quite peaked in the forward direction about the entry point for electrons with energies above the threshold of the electronic states, but the peak decreases and broadens noticeably as the electron energy decreases below 10 eV (threshold for the lowest excitable electronic state of H2). The curve also assumes a very symmetrical shape for energies below 10 eV, indicating the increasing importance of elastic collisions in determining the shape of the curve, although not the mode of energy deposition.

Advances and challenges in electron-molecule scattering physics-A Report of the 14th International Symposium on Electron-Molecule Collisions and Swarms

Energy Technology Data Exchange (ETDEWEB)

Khakoo, M A [Department of Physics, California State University, Fullerton, CA 92831 (United States); Lima, M A P [Departamento de Eletronica Quantica, Instituto de Fisica ' Gleb Wataghin' -UNICAMP, Caixa Postal 6165, 13083-970 Campinas (Brazil); Tennyson, J [Department of Physics and Astronomy, University College, Gower Street, London WC1E 6BT (United Kingdom)

2006-07-15

A report is presented of the 13th International Symposium on Electron-Molecule Collisions Physics (Instituto de Fisica, Unicamp, Campinas, Brazil, 27-30 July 2005). This workshop covered low-energy electron interactions with atoms, molecules and condensed matter systems. Several important aspects of this symposium were to bring together theory and experimental advances in this field for gaseous targets as well as showcasing the increasing diversity of electron-molecule collision applications in condensed matter and biological applications. A summary session was held wherein were discussed aspects of the future of the field, including the development of new theoretical and experimental capabilities.

Energy-Aware RFID Anti-Collision Protocol.

Science.gov (United States)

Arjona, Laura; Simon, Hugo Landaluce; Ruiz, Asier Perallos

2018-06-11

The growing interest in mobile devices is transforming wireless identification technologies. Mobile and battery-powered Radio Frequency Identification (RFID) readers, such as hand readers and smart phones, are are becoming increasingly attractive. These RFID readers require energy-efficient anti-collision protocols to minimize the tag collisions and to expand the reader's battery life. Furthermore, there is an increasing interest in RFID sensor networks with a growing number of RFID sensor tags. Thus, RFID application developers must be mindful of tag anti-collision protocols. Energy-efficient protocols involve a low reader energy consumption per tag. This work presents a thorough study of the reader energy consumption per tag and analyzes the main factor that affects this metric: the frame size update strategy. Using the conclusion of this analysis, the anti-collision protocol Energy-Aware Slotted Aloha (EASA) is presented to decrease the energy consumption per tag. The frame size update strategy of EASA is configured to minimize the energy consumption per tag. As a result, EASA presents an energy-aware frame. The performance of the proposed protocol is evaluated and compared with several state of the art Aloha-based anti-collision protocols based on the current RFID standard. Simulation results show that EASA, with an average of 15 mJ consumed per tag identified, achieves a 6% average improvement in the energy consumption per tag in relation to the strategies of the comparison.

Investigation of the Direct Charge Transfer in Low Energy D2+ + H Collisions using Merged-Beams Technique

Science.gov (United States)

Romano, S. L.; Guillen, C. I.; Andrianarijaona, V. M.; Havener, C. C.

2011-10-01

The hydrogen - hydrogen (deuterium) molecular ion is the most fundamental ion-molecule two-electron system. Charge transfer (CT) for H2+ on H, which is one of the possible reaction paths for the (H-H2)+ system, is of special interest because of its contribution to H2 formation in the early universe, its exoergicity, and rich collision dynamics. Due to technical difficulty in making an atomic H target, the direct experimental investigations of CT for H2+ on H are sparse and generally limited to higher collision energies. The measurements of the absolute cross section of different CT paths for H2+ on H over a large range of collision energy are needed to benchmark theoretical calculations, especially the ones at low energies. The rate coefficient of CT at low energy is not known but may be comparable to other reaction rate coefficients in cold plasmas with H, H+, H2+, and H3+ as constituents. For instance, CT for H2+ on H and the following H3+ formation reaction H2+ + H2 → H + H3+ are clearly rate interdependent although it was always assumed that every ionization of H2 will lead to the formation of H3+. CT proceeds through dynamically coupled electronic, vibrational and rotational degrees of freedom. One can depict three paths, electronic CT, CT with nuclear substitution, and CT with dissociation. Electronic CT and CT with nuclear substitution in the H2+ on H collisions are not distinguishable by any quantum theory. Here we use the isotopic system (D2+ - H) to measure without ambiguity the electronic CT cross section by observing the H+ products. Using the ion-atom merged-beam apparatus at Oak Ridge National Laboratory, the absolute direct CT cross sections for D2+ + H from keV/u to meV/u collision energies have been measured. The molecular ions are extracted from an Electron-Cyclotron Resonance (ECR) ion source with a vibrational state distribution which is most likely determined by Frank-Condon transitions between ground state D2 and D2+. A ground-state H beam

Absolute single electron loss in collisions of Ar+ with various atoms

Science.gov (United States)

Reyes, P. G.; Martínez, H.; Castillo, F.

2001-07-01

Absolute differential and total cross sections for single electron loss were measured for Ar+ ions on various atoms in the energy range of 1.5 to 5.0 keV. The laboratory angular scan for the distributions ranged from -2.5 to 2.5 degrees. The measured differential cross sections have been integrated over the experimental angular range providing absolute total cross sections. The behavior of the total electron loss cross sections with the target atomic number, Zt, shows different dependences as the collision energy increases. In all cases it displays a saturation as Zt increases.

Nuclear energy release in hadron-nucleus collisions

International Nuclear Information System (INIS)

Strugalski, Z.; Strugalska-Gola, E.

1998-01-01

Energy release process in nuclear reactions induced by fast hadrons in hadron-nucleus collisions is discussed. Some portion of the internal nuclear energy is released when the locally damaged in a collision, and instable therefore, residual target nucleus transits itself into light nuclear fragments (nucleons, D, T) and a stable lighter final nucleus or some number of stable lighter nuclei. It is not excluded that in some of the collisions the induced intranuclear nuclear reactions may be energy overcompensating. Corresponding reconnaissance should be made - in analysing the nuclear reactions induced in hadron-nucleus collisions

Coincident detection of electrons ejected at large angles and target recoil ions produced in multiply ionizing collisions for the 1-MeV/u Oq++Ar collision system

International Nuclear Information System (INIS)

Gaither III, C.C.; Breinig, M.; Berryman, J.W.; Hasson, B.F.; Richards, J.D.; Price, K.

1993-01-01

The angular distributions of energetic electrons ejected at angles between 45 degree and 135 degree with respect to the incident-beam direction have been measured in coincidence with the charge states of the target recoil ions produced in multiply ionizing collisions for the 1-MeV/u O q+ (q=4,7)+Ar collision systems. These measurements have been made for ∼179-, ∼345-, and ∼505-eV electrons. Additionally, the energy distributions of electrons ejected into specific angular regions have been measured. Ar LMM satellite Auger electrons appear as a peak in the energy spectrum of electrons ejected at all large angles. The center of this peak is found at an electron energy of ∼179 eV. Electrons with ∼179 eV energy, ejected at large angles, are preferentially produced in coincidence with recoil ions of charge state 4+. Electrons with ∼345 eV energy and ∼505 eV energy ejected at large angles are preferentially produced in coincidence with recoil ions of charge state 3+. The angular distributions for these electrons are strongly peaked in the forward direction; essentially no electrons are observed at angles larger than 90 degree. These results are consistent with the dominant production mechanism for energetic electrons ejected at large angles being a binary-encounter process. Differential cross sections have been calculated from these angular distributions. They are on the order of 10 -21 cm 2 /(eV sr)

Electron-hole collision limited transport in charge-neutral bilayer graphene

Science.gov (United States)

Nam, Youngwoo; Ki, Dong-Keun; Soler-Delgado, David; Morpurgo, Alberto F.

2017-12-01

Ballistic transport occurs whenever electrons propagate without collisions deflecting their trajectory. It is normally observed in conductors with a negligible concentration of impurities, at low temperature, to avoid electron-phonon scattering. Here, we use suspended bilayer graphene devices to reveal a new regime, in which ballistic transport is not limited by scattering with phonons or impurities, but by electron-hole collisions. The phenomenon manifests itself in a negative four-terminal resistance that becomes visible when the density of holes (electrons) is suppressed by gate-shifting the Fermi level in the conduction (valence) band, above the thermal energy. For smaller densities, transport is diffusive, and the measured conductivity is reproduced quantitatively, with no fitting parameters, by including electron-hole scattering as the only process causing velocity relaxation. Experiments on a trilayer device show that the phenomenon is robust and that transport at charge neutrality is governed by the same physics. Our results provide a textbook illustration of a transport regime that had not been observed previously and clarify the nature of conduction through charge-neutral graphene under conditions in which carrier density inhomogeneity is immaterial. They also demonstrate that transport can be limited by a fully electronic mechanism, originating from the same microscopic processes that govern the physics of Dirac-like plasmas.

Electron capture in collisions between O6+ ions and H2O molecules

NARCIS (Netherlands)

Bodewits, D.; Hoekstra, R.

By means of photon emission spectroscopy, state selective electron capture cross section for low energy (0.1-7.5 keV/amu) collisions of O6+ on H2O molecules have been measured. Over the range of interaction energies the state selective cross sections change strongly, i.e., by factors up to 5, while

Resonant ion-pair formation in electron collisions with HD+ and OH+

International Nuclear Information System (INIS)

Larson, Aa.; Djuric, N.; Zong, W.; Greene, C. H.; Orel, A. E.; Al-Khalili, A.; Derkatch, A. M.; Le Padellec, A.; Neau, A.; Rosen, S.

2000-01-01

Resonant ion-pair formation from collisions of electrons with electronic and vibronic ground-state diatomic molecular ions has been studied in the present work for HD + and OH + . The cross section for HD + has a magnitude of the order of 3x10 -19 cm 2 and is characterized by an energy threshold and 14 resolved peaks in the energy range up to 16 eV. A theoretical study confirms that the structures derive primarily from quantum interference of the multiple dissociation pathways. Measurements for OH + reveal that the cross section for H + and O - formation is lower than 10 -21 cm 2 at energies of 6 and 12 eV. (c) 2000 The American Physical Society

Electron impact collision strengths and transition rates for extreme ultraviolet emission from Xe10+

International Nuclear Information System (INIS)

Shen Yunfeng; Gao Cheng; Zeng Jiaolong

2009-01-01

The energy levels, oscillator strengths, and electron impact collision strengths are calculated for the Xe 10+ ion using the configuration interaction scheme implemented by the Flexible Atomic Code. These data pertain to the 3917 levels belonging to the following configurations: 4s 2 4p 6 4d 8 , 4s 2 4p 6 4d 7 4f, 4s 2 4p 6 4d 7 5l (l = s, p, d, or f), 4s 2 4p 5 4d 9 , 4s 2 4p 5 4d 8 4f, 4s 2 4p 5 4d 8 5l, 4s 2 4p 6 4d 6 5s5p, 4s 2 4p 6 4d 6 5p5d. Configuration interactions among these configurations are included in the calculation. Collision strengths are obtained at 10 scattered electron energies (1-1000 eV) and are tabulated here at five representative energies of 10, 50, 100, 500, and 1000 eV. Effective collision strengths are obtained by assuming a Maxwellian electron velocity distribution at 10 temperatures ranging from 10 to 100 eV, and are tabulated at five representative temperatures of 10, 30, 50, 70 and 100 eV in this work. The whole data set should be useful for research involving extreme ultraviolet emission from Xe 10+

Theoretical interpretation of high-energy nuclear collisions

International Nuclear Information System (INIS)

Fai, G.

1992-06-01

Nuclear collisions are interpreted theoretically. The nuclear equation of state is studied in a wide energy range. Subnucleonic degrees of freedom are invoked at high energy densities and at short length-scales. Questions of dynamical collision simulations are investigated. Direct support is provided for experiment in the form of collaborative projects. The major objective of this nuclear theory program is a better understanding of the properties of strongly interacting matter on the nuclear energy scale, as manifested in high-energy heavy-ion collisions

Single-electron analysis and open charm cross section in proton-proton collisions at √(s)=7 TeV

Energy Technology Data Exchange (ETDEWEB)

Fasel, Markus

2012-11-15

The Large Hadron Collider (LHC) at CERN is the world's highest energy hadron collider, providing protonproton collisions currently at a centre-of-mass energy √(s)=8 TeV and Pb-Pb collisions at √(s{sub NN})=2.76 TeV. This opens a new energy regime, which allows the study of QCD in elementary pp-collisions and in the extreme environment of Pb-Pb collisions, as well as providing a discovery potential for rare and exotic particles. ALICE is the dedicated heavy-ion experiment at the LHC. The experiment is optimised to provide excellent tracking and particle identification capabilities, in particular at low-p{sub t}, where the bulk of the particles is produced in heavy-ion collisions as well as in proton-proton collisions. The production of heavy quarks is described in proton-proton collisions by next-to-leading order perturbative QCD (pQCD) calculations. Thus, the measurement of heavy-quark production in proton-proton collisions serves as a test of pQCD. Measurements performed at SPS, RHIC, and Tevatron experiments showed a good agreement with pQCD, where the data were usually at the upper limit of the prediction. In addition, measurements in proton-proton collisions serve as reference for heavy-ion collisions, in which heavy quarks are essential probes for parton energy loss in a deconfined medium. Heavy-quark production can be studied either with hadronic or in semi-leptonic decay channels. The analysis presented in this thesis is performed in the semi-electronic decay channel with the ALICE apparatus. A crucial device for the electron selection is the Transition Radiation Detector (TRD), which provides an important contribution to the electron-pion separation for momenta larger than 1 GeV/c. In November 2010, the first data were recorded with the experiment. The electron selection performance was studied for the first time on real data using data-driven methods. A pion-rejection factor of 23 at a momentum of 2 GeV/c was obtained using a likelihood method on

A parallel algorithm for Hamiltonian matrix construction in electron-molecule collision calculations: MPI-SCATCI

Science.gov (United States)

Al-Refaie, Ahmed F.; Tennyson, Jonathan

2017-12-01

Construction and diagonalization of the Hamiltonian matrix is the rate-limiting step in most low-energy electron - molecule collision calculations. Tennyson (1996) implemented a novel algorithm for Hamiltonian construction which took advantage of the structure of the wavefunction in such calculations. This algorithm is re-engineered to make use of modern computer architectures and the use of appropriate diagonalizers is considered. Test calculations demonstrate that significant speed-ups can be gained using multiple CPUs. This opens the way to calculations which consider higher collision energies, larger molecules and / or more target states. The methodology, which is implemented as part of the UK molecular R-matrix codes (UKRMol and UKRMol+) can also be used for studies of bound molecular Rydberg states, photoionization and positron-molecule collisions.

High energy nuclear collisions: Theory overview

Indian Academy of Sciences (India)

1012 K, were deconfined and existed as a quark gluon plasma (QGP). These ideas can be tested in collisions of nuclei at ultra-relativistic energies. At the relativistic heavy-ion collider (RHIC), nuclei as heavy as gold are accelerated to an energy of 100 GeV per nucleon. A total energy of 40 TeV is available in the collision of.

Investigation of Rare Particle Production in High Energy Nuclear Collisions

International Nuclear Information System (INIS)

Crawford, Henry J.; Engelage, Jon M.

1999-01-01

Our program is an investigation of the hadronization process through measurement of rare particle production in high energy nuclear interactions. Such collisions of heavy nuclei provide an environment similar in energy density to the conditions in the Big Bang. We are currently involved in two major experiments to study this environment, E896 at the AGS and STAR at RHIC. We have completed our physics running of E896, a search for the H dibaryon and measurement of hyperon production in AuAu collisions, and are in the process of analyzing the data. We have produced the electronics and software for the STAR trigger and will begin to use these tools to search for anti-nuclei and strange hadrons when RHIC turns on later this year

Effect of electron-electron collisions on the phase transition and kinetics of nonequilibrium superconductors

International Nuclear Information System (INIS)

Elesin, V.F.; Kashurnikov, V.A.; Kondrashov, V.E.; Shamraev, B.N.

1983-01-01

An explicit expression is obtained for the distribution function of excess quasiparticles, taking into account electron-electron collisions in nonequilibrium superconductors. It is shown that the character of the phase transition may change at a definite ratio of the electron-electron and electron-phonon interaction constants: the dependence of the order parameter on the power of the source becomes single-valued. In addition, diffusion instability and paramagnetism of the superconductors arise. The multiplication factor of the excess quasiparticles due to electron-electron collisions and to reabsorption of phonons is calculated

δ-electron spectroscopy and the atomic clock effect in heavy-ion collisions

International Nuclear Information System (INIS)

Mueller-Nehler, U.

1993-11-01

The properties of strongly bound electrons in superheavy quasimolecular systems with combined nuclear charge numbers Z = Z P + Z T ≥ 110 are investigated. The emission of δ-electrons may serve as an atomic clock for nuclear reactions which is associated with the large overlap of the electron probability density with the nuclear interior. Excitation and emission rates of inner-shell electrons in collisions of very heavy ions with beam energies at or above the nuclear Coulomb barrier depend explicitly on details of the nuclear dynamics. Theoretical and experimental results are reviewed. (orig.)

Bibliography of electron transfer in heavy particle collisions, 1950--1975

International Nuclear Information System (INIS)

Hawthorne, S.W.; Barnett, C.F.; Crandall, D.H.; Gilbody, H.B.; Kirkpatrick, M.I.; McDaniel, E.; Phaneuf, R.A.; Thomas, E.W.

1979-02-01

This annotated bibliography lists published work on electron transfer in heavy particle collisions for the period 1950 to 1975. Sources include scientific journals, abstract compilations, conference proceedings, books, and reports. The bibliography is arranged alphabetically by author. Each entry indicates whether the work was experimental or theoretical, what energy range was covered, and what reactants were investigated. Following the bibliographical listing are indexes of reactants and authors

Measurement of runaway electron energy distribution function during high-Z gas injection into runaway electron plateaus in DIII-Da)

Energy Technology Data Exchange (ETDEWEB)

Hollmann, E. M. [University of California—San Diego, 9500 Gilman Dr., La Jolla, California 92093, USA; Parks, P. B. [General Atomics, PO Box 85608, San Diego, California 92186, USA; Commaux, N. [Oak Ridge National Laboratory, PO Box 2008, Oak Ridge, Tennessee 37831, USA; Eidietis, N. W. [General Atomics, PO Box 85608, San Diego, California 92186, USA; Moyer, R. A. [University of California—San Diego, 9500 Gilman Dr., La Jolla, California 92093, USA; Shiraki, D. [Oak Ridge National Laboratory, PO Box 2008, Oak Ridge, Tennessee 37831, USA; Austin, M. E. [Institute for Fusion Studies, University of Texas—Austin, 2100 San Jacinto Blvd, Austin, Texas 78712, USA; Lasnier, C. J. [Lawrence Livermore National Laboratory, 7000 East Ave, Livermore, California 94550, USA; Paz-Soldan, C. [General Atomics, PO Box 85608, San Diego, California 92186, USA; Rudakov, D. L. [University of California—San Diego, 9500 Gilman Dr., La Jolla, California 92093, USA

2015-05-01

The evolution of the runaway electron (RE) energy distribution function fεfε during massive gas injection into centered post-disruption runaway electron plateaus has been reconstructed. Overall, fεfε is found to be much more skewed toward low energy than predicted by avalanche theory. The reconstructions also indicate that the RE pitch angle θ is not uniform, but tends to be large at low energies and small θ ~0.1–0.2 at high energies. Overall power loss from the RE plateau appears to be dominated by collisions with background free and bound electrons, leading to line radiation. However, the drag on the plasma current appears to be dominated by collisions with impurity ions in most cases. Synchrotron emission appears not to be significant for overall RE energy dissipation but may be important for limiting the peak RE energy.

Measurement of runaway electron energy distribution function during high-Z gas injection into runaway electron plateaus in DIII-D

International Nuclear Information System (INIS)

Hollmann, E. M.; Moyer, R. A.; Rudakov, D. L.; Parks, P. B.; Eidietis, N. W.; Paz-Soldan, C.; Commaux, N.; Shiraki, D.; Austin, M. E.; Lasnier, C. J.

2015-01-01

The evolution of the runaway electron (RE) energy distribution function f ε during massive gas injection into centered post-disruption runaway electron plateaus has been reconstructed. Overall, f ε is found to be much more skewed toward low energy than predicted by avalanche theory. The reconstructions also indicate that the RE pitch angle θ is not uniform, but tends to be large at low energies and small θ ∼ 0.1–0.2 at high energies. Overall power loss from the RE plateau appears to be dominated by collisions with background free and bound electrons, leading to line radiation. However, the drag on the plasma current appears to be dominated by collisions with impurity ions in most cases. Synchrotron emission appears not to be significant for overall RE energy dissipation but may be important for limiting the peak RE energy

Accelerator-based atomic and molecular collision physics

International Nuclear Information System (INIS)

Datz, S.

1993-01-01

Accelerators have been shown to have great utility in addressing a broad range of problems in experimental atomic physics. There are, of course, phenomena such as inner-shell MO promotion which can occur only at high collision energies. At much higher energies, large transient Coulomb fields can be generated which lead to copious production electron-positron pairs and to capture of electrons from the negative continuum. But in addition, many advantages can be gained by carrying out low-energy (center-of-mass) collisions at high laboratory energies, specifically in a single pass mode or in multi-pass modes in ion storage rings in which, e.g., collision in the milli-electron volt region can be achieved for electron-molecule reactions. Certain advantages also accrue using open-quotes reverse kinematicsclose quotes in which high velocity ions collide with almost open-quotes stationaryclose quotes electrons as in resonant transfer and excitation (RTE) and collisions of energetic ions in the dense open-quotes electron gasclose quotes found in crystal channels

Observation of exclusive electron-positron production in hadron-hadron collisions.

Science.gov (United States)

Abulencia, A; Adelman, J; Affolder, T; Akimoto, T; Albrow, M G; Ambrose, D; Amerio, S; Amidei, D; Anastassov, A; Anikeev, K; Annovi, A; Antos, J; Aoki, M; Apollinari, G; Arguin, J-F; Arisawa, T; Artikov, A; Ashmanskas, W; Attal, A; Azfar, F; Azzi-Bacchetta, P; Azzurri, P; Bacchetta, N; Badgett, W; Barbaro-Galtieri, A; Barnes, V E; Barnett, B A; Baroiant, S; Bartsch, V; Bauer, G; Bedeschi, F; Behari, S; Belforte, S; Bellettini, G; Bellinger, J; Belloni, A; Benjamin, D; Beretvas, A; Beringer, J; Berry, T; Bhatti, A; Binkley, M; Bisello, D; Blair, R E; Blocker, C; Blumenfeld, B; Bocci, A; Bodek, A; Boisvert, V; Bolla, G; Bolshov, A; Bortoletto, D; Boudreau, J; Boveia, A; Brau, B; Brigliadori, L; Bromberg, C; Brubaker, E; Budagov, J; Budd, H S; Budd, S; Budroni, S; Burkett, K; Busetto, G; Bussey, P; Byrum, K L; Cabrera, S; Campanelli, M; Campbell, M; Canelli, F; Canepa, A; Carillo, S; Carlsmith, D; Caron, B; Carosi, R; Casarsa, M; Castro, A; Catastini, P; Cauz, D; Cavalli-Sforza, M; Cerri, A; Cerrito, L; Chang, S H; Chen, Y C; Chertok, M; Chiarelli, G; Chlachidze, G; Chlebana, F; Cho, I; Cho, K; Chokheli, D; Chou, J P; Choudalakis, G; Chuang, S H; Chung, K; Chung, W H; Chung, Y S; Ciljak, M; Ciobanu, C I; Ciocci, M A; Clark, A; Clark, D; Coca, M; Compostella, G; Convery, M E; Conway, J; Cooper, B; Copic, K; Cordelli, M; Cortiana, G; Crescioli, F; Almenar, C Cuenca; Cuevas, J; Culbertson, R; Cully, J C; Cyr, D; Daronco, S; D'Auria, S; Davies, T; D'Onofrio, M; Dagenhart, D; de Barbaro, P; Cecco, S De; Deisher, A; Lentdecker, G De; Dell'orso, M; Paoli, F Delli; Demortier, L; Deng, J; Deninno, M; Pedis, D De; Derwent, P F; Giovanni, G P Di; Dionisi, C; Ruzza, B Di; Dittmann, J R; Dituro, P; Dörr, C; Donati, S; Donega, M; Dong, P; Donini, J; Dorigo, T; Dube, S; Efron, J; Erbacher, R; Errede, D; Errede, S; Eusebi, R; Fang, H C; Farrington, S; Fedorko, I; Fedorko, W T; Feild, R G; Feindt, M; Fernandez, J P; Field, R; Flanagan, G; Foland, A; Forrester, S; Foster, G W; Franklin, M; Freeman, J C; Furic, I; Gallinaro, M; Galyardt, J; Garcia, J E; Garberson, F; Garfinkel, A F; Gay, C; Gerberich, H; Gerdes, D; Giagu, S; Giannetti, P; Gibson, A; Gibson, K; Gimmell, J L; Ginsburg, C; Giokaris, N; Giordani, M; Giromini, P; Giunta, M; Giurgiu, G; Glagolev, V; Glenzinski, D; Gold, M; Goldschmidt, N; Goldstein, J; Gomez, G; Gomez-Ceballos, G; Goncharov, M; González, O; Gorelov, I; Goshaw, A T; Goulianos, K; Gresele, A; Griffiths, M; Grinstein, S; Grosso-Pilcher, C; Grundler, U; da Costa, J Guimaraes; Gunay-Unalan, Z; Haber, C; Hahn, K; Hahn, S R; Halkiadakis, E; Hamilton, A; Han, B-Y; Han, J Y; Handler, R; Happacher, F; Hara, K; Hare, M; Harper, S; Harr, R F; Harris, R M; Hartz, M; Hatakeyama, K; Hauser, J; Heijboer, A; Heinemann, B; Heinrich, J; Henderson, C; Herndon, M; Heuser, J; Hidas, D; Hill, C S; Hirschbuehl, D; Hocker, A; Holloway, A; Hou, S; Houlden, M; Hsu, S-C; Huffman, B T; Hughes, R E; Husemann, U; Huston, J; Incandela, J; Introzzi, G; Iori, M; Ishizawa, Y; Ivanov, A; Iyutin, B; James, E; Jang, D; Jayatilaka, B; Jeans, D; Jensen, H; Jeon, E J; Jindariani, S; Jones, M; Joo, K K; Jun, S Y; Jung, J E; Junk, T R; Kamon, T; Karchin, P E; Kato, Y; Kemp, Y; Kephart, R; Kerzel, U; Khotilovich, V; Kilminster, B; Kim, D H; Kim, H S; Kim, J E; Kim, M J; Kim, S B; Kim, S H; Kim, Y K; Kimura, N; Kirsch, L; Klimenko, S; Klute, M; Knuteson, B; Ko, B R; Kondo, K; Kong, D J; Konigsberg, J; Korytov, A; Kotwal, A V; Kovalev, A; Kraan, A C; Kraus, J; Kravchenko, I; Kreps, M; Kroll, J; Krumnack, N; Kruse, M; Krutelyov, V; Kubo, T; Kuhlmann, S E; Kuhr, T; Kusakabe, Y; Kwang, S; Laasanen, A T; Lai, S; Lami, S; Lammel, S; Lancaster, M; Lander, R L; Lannon, K; Lath, A; Latino, G; Lazzizzera, I; Lecompte, T; Lee, J; Lee, J; Lee, Y J; Lee, S W; Lefèvre, R; Leonardo, N; Leone, S; Levy, S; Lewis, J D; Lin, C; Lin, C S; Lindgren, M; Lipeles, E; Lister, A; Litvintsev, D O; Liu, T; Lockyer, N S; Loginov, A; Loreti, M; Loverre, P; Lu, R-S; Lucchesi, D; Lujan, P; Lukens, P; Lungu, G; Lyons, L; Lys, J; Lysak, R; Lytken, E; Mack, P; Macqueen, D; Madrak, R; Maeshima, K; Makhoul, K; Maki, T; Maksimovic, P; Malde, S; Manca, G; Margaroli, F; Marginean, R; Marino, C; Marino, C P; Martin, A; Martin, M; Martin, V; Martínez, M; Maruyama, T; Mastrandrea, P; Masubuchi, T; Matsunaga, H; Mattson, M E; Mazini, R; Mazzanti, P; McFarland, K S; McIntyre, P; McNulty, R; Mehta, A; Mehtala, P; Menzemer, S; Menzione, A; Merkel, P; Mesropian, C; Messina, A; Miao, T; Miladinovic, N; Miles, J; Miller, R; Mills, C; Milnik, M; Mitra, A; Mitselmakher, G; Miyamoto, A; Moed, S; Moggi, N; Mohr, B; Moore, R; Morello, M; Fernandez, P Movilla; Mülmenstädt, J; Mukherjee, A; Muller, Th; Mumford, R; Murat, P; Nachtman, J; Nagano, A; Naganoma, J; Nakano, I; Napier, A; Necula, V; Neu, C; Neubauer, M S; Nielsen, J; Nigmanov, T; Nodulman, L; Norniella, O; Nurse, E; Oh, S H; Oh, Y D; Oksuzian, I; Okusawa, T; Oldeman, R; Orava, R; Osterberg, K; Pagliarone, C; Palencia, E; Papadimitriou, V; Paramonov, A A; Parks, B; Pashapour, S; Patrick, J; Pauletta, G; Paulini, M; Paus, C; Pellett, D E; Penzo, A; Phillips, T J; Piacentino, G; Piedra, J; Pinera, L; Pinfold, J; Pitts, K; Plager, C; Pondrom, L; Portell, X; Poukhov, O; Pounder, N; Prakoshyn, F; Pronko, A; Proudfoot, J; Ptohos, F; Punzi, G; Pursley, J; Rademacker, J; Rahaman, A; Ranjan, N; Rappoccio, S; Reisert, B; Rekovic, V; Renton, P; Rescigno, M; Richter, S; Rimondi, F; Ristori, L; Robson, A; Rodrigo, T; Rogers, E; Rolli, S; Roser, R; Rossi, M; Rossin, R; Ruiz, A; Russ, J; Rusu, V; Saarikko, H; Sabik, S; Safonov, A; Sakumoto, W K; Salamanna, G; Saltó, O; Saltzberg, D; Sánchez, C; Santi, L; Sarkar, S; Sartori, L; Sato, K; Savard, P; Savoy-Navarro, A; Scheidle, T; Schlabach, P; Schmidt, E E; Schmidt, M P; Schmitt, M; Schwarz, T; Scodellaro, L; Scott, A L; Scribano, A; Scuri, F; Sedov, A; Seidel, S; Seiya, Y; Semenov, A; Sexton-Kennedy, L; Sfyrla, A; Shapiro, M D; Shears, T; Shepard, P F; Sherman, D; Shimojima, M; Shochet, M; Shon, Y; Shreyber, I; Sidoti, A; Sinervo, P; Sisakyan, A; Sjolin, J; Slaughter, A J; Slaunwhite, J; Sliwa, K; Smith, J R; Snider, F D; Snihur, R; Soderberg, M; Soha, A; Somalwar, S; Sorin, V; Spalding, J; Spinella, F; Spreitzer, T; Squillacioti, P; Stanitzki, M; Staveris-Polykalas, A; Denis, R St; Stelzer, B; Stelzer-Chilton, O; Stentz, D; Strologas, J; Stuart, D; Suh, J S; Sukhanov, A; Sun, H; Suzuki, T; Taffard, A; Takashima, R; Takeuchi, Y; Takikawa, K; Tanaka, M; Tanaka, R; Tecchio, M; Teng, P K; Terashi, K; Thom, J; Thompson, A S; Thomson, E; Tipton, P; Tiwari, V; Tkaczyk, S; Toback, D; Tokar, S; Tollefson, K; Tomura, T; Tonelli, D; Torre, S; Torretta, D; Tourneur, S; Trischuk, W; Tsuchiya, R; Tsuno, S; Turini, N; Ukegawa, F; Unverhau, T; Uozumi, S; Usynin, D; Vallecorsa, S; van Remortel, N; Varganov, A; Vataga, E; Vázquez, F; Velev, G; Veramendi, G; Veszpremi, V; Vidal, R; Vila, I; Vilar, R; Vine, T; Vollrath, I; Volobouev, I; Volpi, G; Würthwein, F; Wagner, P; Wagner, R G; Wagner, R L; Wagner, J; Wagner, W; Wallny, R; Wang, S M; Warburton, A; Waschke, S; Waters, D; Wester, W C; Whitehouse, B; Whiteson, D; Wicklund, A B; Wicklund, E; Williams, G; Williams, H H; Wilson, P; Winer, B L; Wittich, P; Wolbers, S; Wolfe, C; Wright, T; Wu, X; Wynne, S M; Yagil, A; Yamamoto, K; Yamaoka, J; Yamashita, T; Yang, C; Yang, U K; Yang, Y C; Yao, W M; Yeh, G P; Yoh, J; Yorita, K; Yoshida, T; Yu, G B; Yu, I; Yu, S S; Yun, J C; Zanello, L; Zanetti, A; Zaw, I; Zhang, X; Zhou, J; Zucchelli, S

2007-03-16

We present the first observation of exclusive e(+)e(-) production in hadron-hadron collisions, using pp[over] collision data at (square root) s = 1.96 TeV taken by the run II Collider Detector at Fermilab, and corresponding to an integrated luminosity of 532 pb(-1). We require the absence of any particle signatures in the detector except for an electron and a positron candidate, each with transverse energy E(T) > 5 GeV and pseudorapidity |eta| p + e(+)e(-) + p[over] through two-photon exchange. The measured cross section is 1.6(-0.3)(+0.5)(stat) +/- 0.3(syst) pb. This agrees with the theoretical prediction of 1.71+/-0.01 pb.

Classical analog for electronic degrees of freedom in nonadiabatic collision processes

International Nuclear Information System (INIS)

Meyer, H.; Miller, W.H.

1979-01-01

It is shown how a formally exact classical analog can be defined for a finite dimensional (in Hilbert space) quantum mechanical system. This approach is then used to obtain a classical model for the electronic degrees of freedom in a molecular collision system, and the combination of this with the usual classical description of the heavy particle (i.e., nuclear) motion provides a completely classical model for the electronic and heavy particle degrees of freedom. The resulting equations of motion are shown to be equivalent to describing the electronic degrees of freedom by the time-dependent Schroedinger equation, the time dependence arising from the classical motion of the nuclei, the trajectory of which is determined by the quantum mechanical average (i.e., Ehrenfest) force on the nuclei. Quantizing the system via classical S-matrix theory is shown to provide a dynamically consistent description of nonadiabatic collision processes; i.e., different electronic transitions have different heavy particle trajectories and, for example, the total energy of the electronic and heavy particle degrees of freedom is conserved. Application of this classical model for the electronic degrees of freedom (plus classical S-matrix theory) to the two-state model problem shows that the approach provides a good description of the electronic dynamics

Effective-energy budget in multiparticle production in nuclear collisions

Energy Technology Data Exchange (ETDEWEB)

Mishra, Aditya Nath; Sahoo, Raghunath [Indian Institute of Technology Indore, Discipline of Physics, School of Basic Sciences, Indore (India); Sarkisyan, Edward K.G. [CERN, Department of Physics, Geneva 23 (Switzerland); The University of Texas at Arlington, Department of Physics, Arlington, TX (United States); Sakharov, Alexander S. [CERN, Department of Physics, Geneva 23 (Switzerland); Kyungpook National University, Department of Physics, Daegu (Korea, Republic of)

2014-11-15

The dependencies of charged particle pseudorapidity density and transverse energy pseudorapidity density at midrapidity on the collision energy and on the number of nucleon participants, or centrality, measured in nucleus-nucleus collisions are studied in the energy range spanning a few GeV to a few TeV per nucleon. The approach in which the multiparticle production is driven by the dissipating effective energy of participants is introduced. This approach is based on the earlier proposed consideration, combining the constituent quark picture together with Landau relativistic hydrodynamics shown to interrelate the measurements from different types of collisions. Within this picture, the dependence on the number of participants in heavy-ion collisions are found to be well described in terms of the effective energy defined as a centrality-dependent fraction of the collision energy. For both variables under study, the effective-energy approach reveals a similarity in the energy dependence obtained for the most central collisions and centrality data in the entire available energy range. Predictions are made for the investigated dependencies for the forthcoming higher-energy measurements in heavy-ion collisions at the LHC. (orig.)

Effective-energy budget in multiparticle production in nuclear collisions

International Nuclear Information System (INIS)

Mishra, Aditya Nath; Sahoo, Raghunath; Sarkisyan, Edward K.G.; Sakharov, Alexander S.

2014-01-01

The dependencies of charged particle pseudorapidity density and transverse energy pseudorapidity density at midrapidity on the collision energy and on the number of nucleon participants, or centrality, measured in nucleus-nucleus collisions are studied in the energy range spanning a few GeV to a few TeV per nucleon. The approach in which the multiparticle production is driven by the dissipating effective energy of participants is introduced. This approach is based on the earlier proposed consideration, combining the constituent quark picture together with Landau relativistic hydrodynamics shown to interrelate the measurements from different types of collisions. Within this picture, the dependence on the number of participants in heavy-ion collisions are found to be well described in terms of the effective energy defined as a centrality-dependent fraction of the collision energy. For both variables under study, the effective-energy approach reveals a similarity in the energy dependence obtained for the most central collisions and centrality data in the entire available energy range. Predictions are made for the investigated dependencies for the forthcoming higher-energy measurements in heavy-ion collisions at the LHC. (orig.)

Electron collision cross sections of mercury

International Nuclear Information System (INIS)

Suzuki, Susumu; Kuzuma, Kiyotaka; Itoh, Haruo

2006-01-01

In this paper, we propose a new collision cross section set for mercury which revises the original set summarized by Hayashi in 1989. Hanne reported three excitation collision cross sections (6 3 P 0 , 6 3 P 1 , 6 3 P 2 ) determined from an electron beam experiment in 1988. As a matter for regret, no attentive consideration was given to combining these three excitation cross sections with the cross section set of Hayashi. Therefore we propose a new set where these three excitation cross sections are included. In this study, other two excitation cross sections (6 1 P 1 , 6 3 D 3 ) except for the three excitation collision cross sections (6 3 P 0 , 6 3 P 1 , 6 3 P 2 ) are taken from the original set of Hayashi. The momentum transfer cross section and the ionization collision cross section are also taken from Hayashi. A Monte Carlo Simulation (MCS) technique is applied for evaluating our new cross section set. The present results of the electron drift velocity and the ionization coefficient are compared to experimental values. Agreement is secured in relation to the electron drift velocity for 1.5 Td 2 ) is the reduced electric field, E (V/cm) is the electric field, N (1/cm 3 ) is the number density of mercury atoms at 0degC, 1 Torr, E/N is also equal to 2.828 x 10 -17 E/p 0 from the relation of the ideal gas equation, p 0 (Torr) is gas pressure at 0degC, 1 Torr=1.33322 x 10 -2 N/cm -2 and 10 -17 V/cm 2 is called 1 Td. Thus it is ensured that our new cross section set is reasonable enough to be used up to 100 eV when considering with the electron drift velocity and the ionization coefficient. (author)

Ab initio study of low-energy electron collisions with ethylene

International Nuclear Information System (INIS)

Trevisan, C.S.; Orel, A.E.; Rescigno, T.N.

2003-01-01

We present the results of an investigation of elastic electron scattering by ethylene C 2 H 4 with incident electron energies ranging from 0.5 to 20 eV, using the complex Kohn variational method. These fully ab initio calculations accurately reproduce experimental angular differential cross sections at energies below 3 eV. Low-energy electron scattering by ethylene is sensitive to the inclusion of electronic correlation and target-distortion effects. We therefore report results that describe the dynamic polarization of the target by the incident electron and involve calculations over a range of different geometries, including the effects of nuclear motion in the resonant 2 B 2g symmetry with an adiabatic nuclei treatment of the C-C stretch mode. The inclusion of dynamic polarization and the effect of nuclear motion are equally critical in obtaining accurate results. The calculated cross sections are compared with recent experimental measurements

Binary encounter electron production in ion-atom collisions

International Nuclear Information System (INIS)

Grabbe, S.; Bhalla, C.P.; Shingal, R.

1993-01-01

The binary encounter electrons are produced by hard collisions between the target electrons and the energetic projectiles. Richard et al. found the measured double differential cross section for BEe production at zero degree laboratory scattering angle, in collisions of F q+ with H 2 and He targets, to increase as the charge state of the projectile was decreased. The binary encounter electron production has recently been a subject of detailed investigations. We have calculated the differential elastic scattering cross sections of electrons from several ions incorporating the exchange contribution of the continuum and the bound orbitals in addition to the static potential. The double differential binary encounter electron production cross sections are presented using the impulse approximation

Cross-sections of charge and electronic states change of particles at ion-ion and ion-molecule collisions

International Nuclear Information System (INIS)

Panov, M.N.; Afrosimov, V.V.; Basalaev, A.A.; Guschina, N.A.; Nikulin, V.K.

2006-01-01

The interactions of protons and alpha-particles with hydrocarbons are investigated. A quantum-mechanical computation of the electronic structure of all hydrocarbons from methane to butane and its fragment ions was performed in the Hartree-Fock RHF/UHF approximation using a GAMESS program (General Atomic Molecular Electron Structure System). The correlation energy was taken into account within the framework of MP2 perturbation theory. The structural parameters of the hydrocarbon molecules and their charged and neutral fragments were calculated in two cases: in the geometry of the parent molecule or of the relaxation states. The difference of the full energy of the same fragments in and out of brackets gives us the vibration excitation energies of the fragments at the moment of creation. Additional Mulliken effective charges (in electron charge units) of atoms in the fragments have been calculated. The calculations show that removing one electron from the ethane molecule without electronic excitation produced a single charged molecular ion in vibration state with binding energy of hydrogen atoms, some decimal eV. As results we obtain C 2 H 6 + and C 2 H 5 + . Additional fragmentation of hydrocarbon needs electronic excitation of produced single charged ions. Cross sections for electron capture and excitation processes in collisions between the hydrogen-like He + , B 4+ and O 7+ ions have been evaluated. The purpose of the theory within this project during the period under review was to get for the first time new data on Single-Electron Capture (SEC) and Excitation Processes (EP) in collisions of He + (1s) ions with hydrogen-like impurity ions B 4+ (1s) and O 7+ (1s) in the energy range for He + ions from 0.2 MeV to 3.0 MeV. The calculations were carried out by using the method of close-coupling equations with basis sets of eleven and ten quasimolecular two-electron states for reactions (1, 2) and (3, 4), respectively (entrance channel, seven charge transfer channels

Models of high energy nuclear collisions

International Nuclear Information System (INIS)

Glendenning, N.K.

1978-06-01

The discussion covers nuclear collisions at relativistic energies including classes of high energy nucleus--nucleus collisions, and the kinetics of a central collision; and the asymptotic hadron spectrum including known and unknown hadrons, the relevance of the spectrum and the means of its study, thermodynamics of hadronic matter, examples of hadronic spectra, the temperature, composition of the initial fireball and its expansion, isoergic expansion with no pre-freezeout radiation, isentropic expansion of the fireball, the quasi-dynamical expansion, and finally antinuclei, hypernuclei, and the quark phase. 28 references

Electron loss from heavy heliumlike projectiles in ultrarelativistic collisions with many-electron atomic targets

International Nuclear Information System (INIS)

Mueller, C.; Gruen, N.; Voitkiv, A.B.

2002-01-01

We study single- and double-electron loss from heavy heliumlike projectiles in ultrarelativistic collisions with neutral many-electron target atoms. The simultaneous interaction of the target with two projectile electrons is found to be the dominant process in the double-electron loss provided the atomic number of the projectile, Z p , that of the target, Z t , and the collision velocity, v, satisfy the condition Z p Z t /v>0.4. It is shown that for a wide range of projectile and target atomic numbers the asymptotic double-to-single loss ratio strongly depends on the target atomic number but is nearly independent of the nuclear charge of the projectile. It is also demonstrated that many-photon exchange between the target and each of the projectile electrons considerably influences the double loss in collisions with very heavy targets

Single-electron capture for 2-8 keV incident energy and direct scattering at 6 keV in He[sup 2+]-He collisions

Energy Technology Data Exchange (ETDEWEB)

Bordenave-Montesquieu, D.; Dagnac, R. (Toulouse-3 Univ., 31 (France). Centre de Physique Atomique)

1992-06-14

We studied the single-electron capture as well as the direct processes occurring when a He[sup 2+] ion is scattered by a He target. Doubly differential cross sections were measured for single-electron capture with a collision energy ranging from 2 to 8 keV and a scattering angle varying from 10' to 3[sup o]30' (laboratory frame). Single-electron capture into excited states of He[sup +] was found to be the dominant process, confirming a previous experimental study. Elastic scattering and ionization differential cross sections were measured for E = 6 keV. (Author).

Influence of high energy electrons on ECRH in LHD

Directory of Open Access Journals (Sweden)

Ogasawara S.

2012-09-01

Full Text Available The central bulk electron temperature of more than 20 keV is achieved in LHD as a result of increasing the injection power and the lowering the electron density near 2 × 1018 m−3. Such collision-less regime is important from the aspect of the neoclassical transport and also the potential structure formation. The presences of appreciable amount of high energy electrons are indicated from hard X-ray PHA, and the discrepancy between the stored energy and kinetic energy estimated from Thomson scattering. ECE spectrum are also sensitive to the presence of high energy electrons and discussed by solving the radiation transfer equation. The ECRH power absorption to the bulk and the high energy electrons are dramatically affected by the acceleration and the confinement of high energy electrons. The heating mechanisms and the acceleration process of high energy electrons are discussed by comparing the experimental results and the ray tracing calculation under assumed various density and mean energy of high energy electrons.

Coulomb focusing and ''path'' interference of autoionizing electrons produced in 10 keV He+ + He collisions

International Nuclear Information System (INIS)

Swenson, J.K.; Burgdoerfer, J.; Meyer, F.W.; Havener, C.C.; Gregory, D.C.; Stolterfoht, N.

1991-01-01

Autoionizing electrons emitted following low energy ion-atom collisions may scatter significantly from the receding spectator ion's attractive Coulomb field. In such cases the observed electron intensity is ''focused'' in the direction of the scattering ion as a result of the effective compression of the emission solid angle. In addition, interference may occur between trajectories, corresponding to electrons scattering around opposite sides of the ion, which lead to the same final laboratory electron energy and emission angle. This Coulomb ''path'' interference mechanism manifests itself in the uncharacteristically rapid angular dependence of the He target 2s 2 1 S autoionizing state measured near 0 degree following low energy He + + He collisions. A classical trajectory model for Coulomb focusing is presented and a semi-classical approximation is used to model the Coulomb ''path'' interference mechanism. In this description we account for the evolution of the phase of the autoionizing state until its decay and the path dependence of the amplitude of the emitted electron following decay of the autoionizing state. Calculated model lineshapes, which include contributions from adjacent overlapping resonances, reproduce quite well the angular dependence observed in the data near 0 degree. 14 refs., 7 figs

Measurement of semi-electronic beauty-hadron decays via their impact parameter in pp collisions in ALICE

International Nuclear Information System (INIS)

Heide, Markus Ansgar

2014-01-01

The measurement of beauty-hadron decays via the detection of electron tracks that are displaced from the primary vertex can be performed with ALICE, whose capabilities of electron identification and tracking fulfil all requirements for this task. While the large corresponding branching ratios guarantee sufficient yields of beauty-decay electrons at LHC energies, the wide electron impact parameter distribution due to the long lifetime and the decay kinematics of beauty hadrons allows for a separation of electrons from beauty-hadron decays from background electrons on a statistical basis. This thesis presents the analysis of electrons from beauty-hadron decays in protonproton collisions at centre-of-mass energies of 7 TeV and 2.76 TeV. Using the ALICE central-barrel detectors ITS, TPC, and TOF, p T -differential electron spectra are measured at mid-rapidity (vertical stroke y vertical stroke <0.8) for transverse momenta between 1 and 8 GeV/c. Information from the TPC and TOF signal is combined to select pure electron samples, whose signal-to-background ratio is subsequently enhanced via the requirement of a minimal impact parameter of the tracks towards the primary vertex in the x - y plane. Tracks from photon conversions occurring outside the innermost ITS layer, which have a wide impact parameter distribution, are rejected via the requirement of hits in both SPD layers of the ITS. The remaining hadron contamination in the selected electron track samples is determined on a statistical basis from the distributions of their energy deposition per unit of length in the TPC. A crucial challenge of this analysis is the subtraction of the electron background originating from charm decays, photon conversions, and light-meson decays from the measured inclusive electron spectrum. The corresponding electron yields are determined using spectra from PYTHIA simulations that are reweighted based on previous measurements of charmed hadrons, π 0 , and η. Minor contributions from

Electron collision data for polyatomic molecules in plasma processing and environmental processes

International Nuclear Information System (INIS)

Tanaka, H.; Kitajima, M.; Cho, H.

2002-01-01

The experimental studies for electron-polyatomic molecule collision are reviewed in connection with the plasma processing and environmental issues. Recent developments in electron scattering experiments on the differential cross section measurements for various processes such as elastic scattering, vibrational, and electronic excitations are summarized from high to low energy regions (1-100 eV). The need for cross-section data for a broad variety of molecular species is also discussed because there is an urgent need to develop an international program to provide the scientific and technological communities with authoritative cross sections for electron-molecule interactions

Ion induced fragmentation of biomolecular systems at low collision energies

International Nuclear Information System (INIS)

Bernigaud, V; Adoui, L; Chesnel, J Y; Rangama, J; Huber, B A; Manil, B; Alvarado, F; Bari, S; Hoekstra, R; Postma, J; Schlathoelter, T

2009-01-01

In this paper, we present results of different collision experiments between multiply charged ions at low collision energies (in the keV-region) and biomolecular systems. This kind of interaction allows to remove electrons form the biomolecule without transferring a large amount of vibrational excitation energy. Nevertheless, following the ionization of the target, fragmentation of biomolecular species may occur. It is the main objective of this work to study the physical processes involved in the dissociation of highly electronically excited systems. In order to elucidate the intrinsic properties of certain biomolecules (porphyrins and amino acids) we have performed experiments in the gas phase with isolated systems. The obtained results demonstrate the high stability of porphyrins after electron removal. Furthermore, a dependence of the fragmentation pattern produced by multiply charged ions on the isomeric structure of the alanine molecule has been shown. By considering the presence of other surrounding biomolecules (clusters of nucleobases), a strong influence of the environment of the biomolecule on the fragmentation channels and their modification, has been clearly proven. This result is explained, in the thymine and uracil case, by the formation of hydrogen bonds between O and H atoms, which is known to favor planar cluster geometries.

MEASURING NEBULAR TEMPERATURES: THE EFFECT OF NEW COLLISION STRENGTHS WITH EQUILIBRIUM AND {kappa}-DISTRIBUTED ELECTRON ENERGIES

Energy Technology Data Exchange (ETDEWEB)

Nicholls, David C.; Dopita, Michael A.; Sutherland, Ralph S.; Kewley, Lisa J. [Research School of Astronomy and Astrophysics, Australian National University, Cotter Rd., Weston ACT 2611 (Australia); Palay, Ethan, E-mail: david@mso.anu.edu.au [Department of Astronomy, Ohio State University, Columbus, OH 43210 (United States)

2013-08-15

In this paper we develop tools for observers to use when analyzing nebular spectra for temperatures and metallicities, with two goals: to present a new, simple method to calculate equilibrium electron temperatures for collisionally excited line flux ratios, using the latest atomic data; and to adapt current methods to include the effects of possible non-equilibrium ''{kappa}'' electron energy distributions. Adopting recent collision strength data for [O III], [S III], [O II], [S II], and [N II], we find that existing methods based on older atomic data seriously overestimate the electron temperatures, even when considering purely Maxwellian statistics. If {kappa} distributions exist in H II regions and planetary nebulae as they do in solar system plasmas, it is important to investigate the observational consequences. This paper continues our previous work on the {kappa} distribution. We present simple formulaic methods that allow observers to (1) measure equilibrium electron temperatures and atomic abundances using the latest atomic data, and (2) to apply simple corrections to existing equilibrium analysis techniques to allow for possible non-equilibrium effects. These tools should lead to better consistency in temperature and abundance measurements, and a clearer understanding of the physics of H II regions and planetary nebulae.

Low energy electron scattering from fuels

International Nuclear Information System (INIS)

Lopes, M. Cristina A.; Silva, Daniel G.M.; Coelho, Rafael F.; Duque, Humberto V.; Santos, Rodrigo R. dos; Ribeiro, Thiago M.

2011-01-01

Full text. Accurate and precise values of absolute total cross section (TCS) represent important information in many scientific and technological applications. In our case, for example, we are motivated to provide such information for electron-fuel collision processes which are specifically relevant to modeling spark ignition in alcohol-fuelled internal combustion engines. Many electron scattering TCS measurements are presently available for a diverse range of atomic and molecular targets. However, lack of data for important bio-molecular targets still remains. Disagreements between the available TCS data for the alcohols have prompted several studies of electron scattering collision of slow electrons with these molecules which are currently important in applications as bio- fuels. This relevance, which has attracted much attention, has been one of the subjects of a recent collaboration between experimental and theoretical groups in the USA and Brazil. Recently this collaboration reported first measurements and calculations of differential cross sections for elastic low-energy (rotationally unresolved) electron scattering by several primary alcohols. In this work we address methanol and ethanol TCSs at low energy range and report additional studies of resonant structure in ethanol using the detection of metastable states produced by electron impact excitation with high energy resolution. We have recently constructed a TCS apparatus in our laboratory at Universidade Federal de Juiz de Fora, Brazil, based on the well-known linear transmission technique. The experimental setup is based on the measurement of the attenuation of a collimated electron beam through a gas cell containing the atoms or molecules to be studied at a given pressure. It consists essentially of an electron gun, a gas cell and an electron energy analyzer composed of an array of decelerating electrostatic lenses, a cylindrical dispersive 127o analyzer and a Faraday cup. To our knowledge, there exist

Low energy electron scattering from fuels

Energy Technology Data Exchange (ETDEWEB)

Lopes, M. Cristina A.; Silva, Daniel G.M.; Coelho, Rafael F.; Duque, Humberto V.; Santos, Rodrigo R. dos; Ribeiro, Thiago M. [Universidade Federal de Juiz de Fora (UFJF), MG (Brazil). Dept. de Fisica; Yates, Brent; Hong, Ling; Khakoo, Murtadha A. [California State University at Fullerton, CA (US). Physics Department; Bettega, Marcio H.F. [Universidade Federal do Parana (UFPR), Curitiba, PR (Brazil). Dept. de Fisica; Costa, Romarly F. da [Universidade Federal do ABC (UFABC), Santo Andre, SP (Brazil). Centro de Ciencias Naturais e Humanas; Lima, Marco A.P. [Laboratorio Nacional de Ciencia e Tecnologia do Bioetanol (CTBE/CNPEM), Campinas, SP (Brazil)

2011-07-01

Full text. Accurate and precise values of absolute total cross section (TCS) represent important information in many scientific and technological applications. In our case, for example, we are motivated to provide such information for electron-fuel collision processes which are specifically relevant to modeling spark ignition in alcohol-fuelled internal combustion engines. Many electron scattering TCS measurements are presently available for a diverse range of atomic and molecular targets. However, lack of data for important bio-molecular targets still remains. Disagreements between the available TCS data for the alcohols have prompted several studies of electron scattering collision of slow electrons with these molecules which are currently important in applications as bio- fuels. This relevance, which has attracted much attention, has been one of the subjects of a recent collaboration between experimental and theoretical groups in the USA and Brazil. Recently this collaboration reported first measurements and calculations of differential cross sections for elastic low-energy (rotationally unresolved) electron scattering by several primary alcohols. In this work we address methanol and ethanol TCSs at low energy range and report additional studies of resonant structure in ethanol using the detection of metastable states produced by electron impact excitation with high energy resolution. We have recently constructed a TCS apparatus in our laboratory at Universidade Federal de Juiz de Fora, Brazil, based on the well-known linear transmission technique. The experimental setup is based on the measurement of the attenuation of a collimated electron beam through a gas cell containing the atoms or molecules to be studied at a given pressure. It consists essentially of an electron gun, a gas cell and an electron energy analyzer composed of an array of decelerating electrostatic lenses, a cylindrical dispersive 127o analyzer and a Faraday cup. To our knowledge, there exist

Shape of electron lines emitted by a fast particle in atomic collisions. Influence of the acceptance function

International Nuclear Information System (INIS)

Bordenave-Montesquieu, A.; Gleizes, A.; Benoit-Cattin, P.; Boudjema, M.

1980-01-01

In order to explain the large energy broadening of the lines observed in energy spectra of electrons emitted by fast particles, an accurate knowledge of the angular acceptance function of the electron energy analyser is necessary. A simple method is proposed which can give an accurate function for most atomic collisions: the various approximations are discussed. It is also shown that the analyser transmission depends on the acceptance angle. (author)

Angular distribution of scattered electron and medium energy electron spectroscopy for metals

International Nuclear Information System (INIS)

Oguri, Takeo; Ishioka, Hisamichi; Fukuda, Hisashi; Irako, Mitsuhiro

1986-01-01

The angular distribution (AD) of scattered electrons produced by medium energy incident electrons (E P = 50 ∼ 300 eV) from polycrystalline Ti, Fe, Ni, Cu and Au were obtained by the angle-resolved medium energy electron spectrometer. The AD of the energy loss peaks are similar figures to AD of the elastically reflected electron peaks. Therefore, the exchanged electrons produced by the knock-on collision between the incident electrons and those of metals without momentum transfer are observed as the energy loss spectra (ELS). This interpretation differs from the inconsequent interpretation by the dielectric theory or the interband transition. The information depth and penetration length are obtained from AD of the Auger electron peaks. The contribution of the surface to spectra is 3 % at the maximum for E P = 50 eV. The true secondary peaks representing the secondary electron emission spectroscopy (SES) are caused by the emissions of the energetic electrons (kT e ≥ 4 eV), and SES is the inversion of ELS. The established fundamental view is that the medium energy electron spectra represent the total bulk density of states. (author)

Interferometry of high energy nuclear collisions

International Nuclear Information System (INIS)

Padula, S.S.

1990-01-01

The interferometry is used for determining large space time dimensions of the Quark Gluon Plasma formed in high energy nuclear collisions or in high multiplicity fluctuations in p-barp collisions. (M.C.K.)

Electron capture in slow collisions of multicharged ions with hydrogen atoms using merged beams

International Nuclear Information System (INIS)

Havener, C.C.; Nesnidal, M.P.; Porter, M.R.; Phaneuf, R.A.

1991-01-01

Absolute total electron-capture cross-section mesurements are reported for collisions of O 3+ and O 4+ with atomic hydrogen in the energy range 1-1000 eV /amu using merged beams. The data are compared with available coupled-states theoretical calculations. (orig.)

Electron-electron interaction and transfer ionization in fast ion-atom collisions

International Nuclear Information System (INIS)

Voitkiv, A B

2008-01-01

Recently it was pointed out that electron capture occurring in fast ion-atom collisions can proceed via a mechanism which earlier was not considered. In the present paper we study this mechanism in more detail. Similarly as in radiative capture, where the electron transfer occurs due to the interaction with the radiation field and proceeds via emission of a photon, within this mechanism the electron capture is caused by the interaction with another atomic electron leading mainly to the emission of the latter. In contrast to the electron-electron Thomas capture, this electron-electron (E-E) mechanism is basically a first-order one having similarities to the kinematic and radiative capture channels. It also possesses important differences with the latter two. Leading to transfer ionization, this first-order capture mechanism results in the electron emission mainly in the direction opposite to the motion of the projectile ion. The same, although less pronounced, feature is also characteristic for the momenta of the target recoil ions produced via this mechanism. It is also shown that the action of the E-E mechanism is clearly seen in recent experimental data on the transfer ionization in fast proton-helium collisions.

Electron-hydrogen atom collisions in the presence of a laser field

International Nuclear Information System (INIS)

Brandi, H.S.; Koiller, B.; Barros, H.G.P.L. de

1978-01-01

The collision of an electron and a hydrogen atom in the presence of a laser field is studied within a previously proposed approximation (based on the space translation approximation) for the bound states of the hydrogen atom. Fhe Green's function formalism is applied to derive an expression for the scattering amplitude associated to multiphoton processes. The Born-Oppenheimer approximation is obtained and numerical calculations are performed for the ls→2s inelastic excitation. It is shown as expected that exchange effects are important only for scattering processes involving low energy electrons [pt

Recent measurements of low energy charge exchange cross sections for collisions of multicharged ions on neutral atoms and molecules

International Nuclear Information System (INIS)

Havener, Charles C.

2001-01-01

At ORNL Multicharged Ion Research Facility (MIRF), charge exchange (CX) cross sections have been measured for multicharged ions (MCI) on neutral atoms and molecules. The ORNL ion-atom merged-beam apparatus was used to measure single electron capture by MCI from H at eV/amu energies. A gas cell was used to measure single and double electron capture by MCI from a variety of molecular targets at keV collision energies. The merged-beams experiment has been successful in providing benchmark total electron capture measurements for several collision systems with a variety of multicharged ions on H or D

Initial electron energy spectra in water irradiated by photons with energies to 1 GeV

International Nuclear Information System (INIS)

Todo, A.S.; Hiromoto, G.; Turner, J.E.; Hamm, R.N.; Wright, H.A.

1984-02-01

This work was undertaken to provide basic physical data for use in the dosimetry of high-energy photons. Present and future sources of such photons are described, and the relevant literature is reviewed and summarized. Calculations were performed with a Monte Carlo computer code, PHOEL-3, which is also described. Tables of initial electron and positron energies are presented for monoenergetic photons undergoing single interactions in water. Photon energies to 1 GeV are treated. The code treats explicitly the production of electron-positron pairs, Compton scattering, photoelectric absorption, and the emission of Auger electrons following the occurrence of K-shell vacancies in oxygen. The tables give directly the information needed to specify the absolute single-collision kerma in water, which approximates tissue, at each photon energy. Results for continuous photon energy spectra can be obtained by using linear interpolation with the tables. (Continuous spectra can also be used directly in PHOEL-3.) The conditions under whch first-collision kerma approximate absorbed dose are discussed. A formula is given for estimating bremsstrahlung energy loss, one of the principal differences between kerma and absorbed dose in practical cases. 31 references, 4 figures, 18 tables

Dynamics of solid inner-shell electrons in collisions with bare and dressed swift ions

International Nuclear Information System (INIS)

Montanari, C.C.; Miraglia, J. E.; Arista, N.R.

2002-01-01

We analyze the dynamical interactions of swift heavy projectiles and solid inner-shell electrons. The dielectric formalism employed to deal with the free-electron gas is extended to account for the core electrons, by using the local plasma approximation. Results for stopping power, energy straggling, and inner-shell ionization in collisions of bare ions with metals are displayed, showing very good accord with the experimental data. Simultaneous excitations of projectile and target electrons are also analyzed. In the high-energy range we find a similar contribution of target core and valence electrons to the probability of projectile-electron loss. The problem of no excitation threshold within the local plasma approximation and the possibility of collective excitations of the shells are discussed

Electron capture and excitation in collisions of O+(4S,2D,2P) with H2 molecules

International Nuclear Information System (INIS)

Pichl, Lukas; Li Yan; Liebermann, Heinz-Peter; Buenker, Robert J.; Kimura, Mineo

2004-01-01

Using an electronic-state close-coupling method, we treated the electron capture and excitation processes of O + ions both in ground state O + ( 4 S) and metastable states O +* ( 2 D) and O +* ( 2 P) in collisions with the H 2 molecule. In the ground-state projectile energy region considered (from 50 eV/amu to 10 keV/amu), the experimental data vary by orders of magnitude: our results smoothly connect to the data by Flesch and Ng [J. Chem. Phys. 94, 2372 (1991)] and Xu et al. [J. Phys. B 23, 1235 (1990)] at low energy and agree with Phaneuf et al. [Phys. Rev. A 17, 534 (1978)] in the high-energy region. The present values differ from Sieglaff et al. [Phys. Rev. A 59, 3538 (1999)] and Nutt et al. [J. Phys. B 12, L157 (1979)], especially in the energy region below 1 keV/amu. We provide the first calculated state-resolved cross sections of electron capture and target-projectile electronic excitations for the O + ( 4 S, 2 D, 2 P)-H 2 collision system

Backward ejected electrons from collisions of 1 MeV/u Oq+ projectiles with argon gas

International Nuclear Information System (INIS)

Berryman, J.W.; Breinig, M.; Segner, F.; Desai, D.

1993-01-01

We will be presenting results from a series of experiments measuring the yields and energy distributions of electrons emitted at 1800 with respect to the 1 MeV/u O q+ [q=3-8] ion beam. We have systematically studied the yield per incident ion and the energy distribution of electrons as a function of the incident projectile charge state. The energy distributions show two prominent structures: a narrow peak due to target LMM Auger electrons and a broad hump due to projectile binary-encounter electrons. The shapes and yields of the Auger electron peaks are nearly independent of the incident charge state. The shapes and yields of the binary-encounter electron peaks are sensitive functions of the number of projectile electrons carried into the collision. A well defined binary-encounter electron peak appears only for charge states q=3, 4, and 5

The effects of low energy electron capture collisions (H0 + Csup(n+)) on the particle and energy balance of Tokamak plasmas

International Nuclear Information System (INIS)

Hogan, J.T.

1982-01-01

To illustrate the way in which atomic data provides enlightenment in the search for understandable (and thus extrapolable) confinement models, the scope of the paper is restricted to electron capture collisions involving H 0 and multiply-charged ions. Many such foreign (impurity) multiply-charged ion species are found in plasma discharges, as a result of gas recycling and damage to the surrounding surfaces by energetic plasma particles. Typical 'low-Z' ions are carbon and oxygen; the major constituents of the stainless steel wall (Fe, Ni, Cr) are intermediate impurities, while 'high-Z' impurities (Mo, W) enter from 'limiter' plates which constrict the hot plasma zone to reduce direct plasma-wall contact. In this discussion, however, attention is given only to applications of data involving H 0 + Csup(n+) → H + + Csup((n-1)+) reactions with energy 10 eV to 2 keV. This energy range is typical of the plasma edge in present devices. (Auth.)

Electron collision cross sections and electron swarm parameters for gas molecules

International Nuclear Information System (INIS)

Hayashi, Makoto

1986-01-01

Elastic and inelastic electron collision cross sections for molecules which interest in radiation research have been determined from available electron beam and electron swarm data by utilizing the Boltzmann equation and Monte Carlo simulation method. Electron drift velocity data which interest in radiation Pysics have been discussed and some calculated results of electron drift velocity data for CF 4 and CF 4 -inert gases mixtures will be presented. (author)

Energy and orientation dependence of electron-irradiation-induced defects in InP

International Nuclear Information System (INIS)

Sibille, A.; Suski, J.; LeRoux, G.

1984-01-01

The concentration of several electron-irradiation-induced deep defect levels in InP has been measured by deep-level transient spectroscopy (DLTS) as a function of electron energy. The dominant centers exhibit a threshold at about 100 keV, which clearly points to a primary production event by electron--phosphorus-atom collision. This unambiguous determination allowed a test of the recently proposed orientation dependence technique to find the nature of the sublattice involved in the collision process for III-V compounds. A good quantitative agreement is obtained with a hard-sphere model for secondary collisions if disorientation of the beam in the sample is taken into account. Other traps exhibit higher thresholds which correspond either to indium-atom displacements or to the involvement of secondary collisions in the production event

Single electron capture measurements in collisions of K{sup +} on N{sub 2}

Energy Technology Data Exchange (ETDEWEB)

Alarcón, F.B. [Laboratorio de Espectroscopia, Instituto de Ciencias Físicas, Universidad Nacional Autónoma de México, Apartado Postal 48-3, 62210 Cuernavaca, Morelos (Mexico); Fuentes, B.E., E-mail: beatriz.fuentes@ciencias.unam.mx [Facultad de Ciencias, Universidad Nacional Autónoma de México, Circuito Exterior, Cd. Universitaria, 04510 México D.F. (Mexico); Martínez, H. [Laboratorio de Espectroscopia, Instituto de Ciencias Físicas, Universidad Nacional Autónoma de México, Apartado Postal 48-3, 62210 Cuernavaca, Morelos (Mexico); Yousif, F.B. [Facultad de Ciencias, Universidad Autónoma del Estado de Morelos, Av. Universidad #1000, Col. Chamilpa, C.P. 62210, Cuernavaca, Morelos (Mexico)

2014-08-01

Absolute total charge transfer cross sections have been measured for K{sup +}–N{sub 2} collisions, at impact energies between 1.0 and 3.5 keV. The charge transfer cross sections show a monotonic increasing behaviour as a function of the incident energy. Agreement with other groups is observed as the present measurements extend to lower energies. A semi-empirical calculation shows a similar behaviour to the present data with respect to the electron capture cross sections as a function of energy.

Electron capture in ion atom and ion-ion collisions

International Nuclear Information System (INIS)

Barat, M.

1986-01-01

Electron capture (EC) by positive ions in collision with various targets has remained one of the most important subjects of research since the early 30's. From a theoretical point of view, EC is obviously a coupled 3-body problem: at least two cores and an active electron that jumps between them. Practical interest in EC arose in a variety of fields. Recently a renewed interest arose from the physics of thermonuclear fusion, where capture by highly charged ionic impurities were found to be an important process in tokamak devices. For that reasons, a number of reviews were devoted to this subject during the past years, including lectures given in various NATO advanced science institutes. The aim of this lecture is not at all to add a new review to this list, but (i) to summarize the very basis of the present theoretical approaches at low and moderate collision energy, (ii) to pinpoint some crucial difficulties in the theoretical treatment, (iii) to select specific examples which, to the taste of the author, reflect some present practical interest, or some significant advances. 48 references, 38 figures, 1 table

Discussion of electron capture theories for ion-atom collisions at high energies

Energy Technology Data Exchange (ETDEWEB)

Miraglia, J E [Instituto de Astronomia y Fisica del Espacio, Buenos Aires (Argentina); Piacentini, R D [Consejo Nacional de Investigaciones Cientificas y Tecnicas, Buenos Aires (Argentina); Rivarola, R D [Rosario Univ. Nacional (Argentina). Dept. de Fisica; Salin, A [Bordeaux-1 Univ., 33 - Talence (France)

1981-03-14

Different theories of charge exchange processes in ion-atom collisions at high energies for the H/sup +/-H system are considered. Large discrepancies are found in the differential cross sections obtained from the various models. The validity of Dettmann's peaking approximation is analysed by comparison with exact values for the first- and second-order Oppenheimer-Brinkman-Kramers (OBK 1 and OBK 2) theories. It is also shown that for energies up to a few MeV the OBK 2 differential cross sections are higher than the corresponding OBK 1 ones. Total cross sections in the OBK 2 approximation are given.

High energy nucleus-nucleus collisions

International Nuclear Information System (INIS)

Bhalla, K.B.

1980-01-01

An attempt is made to explain nucleus-nucleus collisions based on nuclear emulsion experiments. Peripheral and central collisions are described in detail. Assuming the fireball model, the concepts of geometry, kinematics and thermodynamics in this model are discussed. Projectile and target fragmentations are studied. The advantages of using nuclear emulsions as detectors, are mentioned. Proton-nucleus collisions and nucleus-nucleus collisions are compared. Interactions, of projectiles such as Ca, B and C on targets such as Pb, Ag, Br etc. at very high energies (approximately 300 to 1700 Gev) are listed. A comparison of the near multiplicities in these interactions is given. A generalized explanation is given on the processes involved in these interactions. (A.K.)

Energy sharing and sputtering in low-energy collision cascades

International Nuclear Information System (INIS)

Weller, R.A.; Weller, M.R.

1982-01-01

Using a non-linear transport equation to describe the energy-sharing process in an isotropic collision cascade, we have numerically calculated sputtered particle velocity spectra for several very low energy (=< 10 eV) primary recoil distributions. Our formulation of the sputtering process is essentially that used in the linear model and our equations yield the familiar linear model results in the appropriate limit. Discrepancies between our calculations and the linear model results in other cases may be understood by considering the effects of the linear model assumptions on the sputtering yield at very low energies. Our calculations are also compared with recent experimental results investigating ion-explosion sputtering. The results of this comparison support the conclusion that in insulators sputtering is initiated by very low energy recoil atoms when the energy of the incident beam is high enough that the stopping power is dominated by the electronic contribution. The calculations also suggest that energy spectra similar to those for evaporation may result from non-equilibrium processes but that the apparent temperatures of evaporation are not related in a simple way to any real temperature within the target. (author)

Collision dynamics of H+ + N2 at low energies based on time-dependent density-functional theory

Science.gov (United States)

Yu, W.; Zhang, Y.; Zhang, F. S.; Hutton, R.; Zou, Y.; Gao, C.-Z.; Wei, B.

2018-02-01

Using time-dependent density-functional theory at the level of local density approximation augmented by a self-interaction correction and coupled non-adiabatically to molecular dynamics, we study, from a theoretical perspective, scattering dynamics of the proton in collisions with the N2 molecule at 30 eV. Nine different collision configurations are employed to analyze the proton energy loss spectra, electron depletion, scattering angles and self-interaction effects. Our results agree qualitatively with the experimental data and previous theoretical calculations. The discrepancies are ascribed to the limitation of the theoretical models in use. We find that self-interaction effects can significantly influence the electron capture and the excited diatomic vibrational motion, which is in consistent with other calculations. In addition, it is found that the molecular structure can be readily retrieved from the proton energy loss spectra due to a significant momentum transfer in head-on collisions.

Collision energy-resolved study of the emission cross-section and the Penning ionization cross-section in the reaction of BrCN with He*(2 3S)

Science.gov (United States)

Kanda, Kazuhiro; Yamakita, Yoshihiro; Ohno, Koichi

2001-12-01

The dissociative excitation of BrCN producing CN(B 2Σ +) fragment by the collision of He *(2 3S) was investigated by the collision energy-resolved electron and emission spectroscopy using time-of-flight method with a high-intensity He * beam. The Penning electrons ejected from BrCN and the subsequent CN ( B2Σ +- X2Σ +) emission were measured as a function of collision energy in the range of 90-180 meV. The formation of CN ( B2Σ +) is concluded to proceed dominantly via the promotion of an electron from Π-character orbital, by comparison between the collision energy dependence of the partial Penning ionization cross-sections and the CN ( B2Σ +- X2Σ +) emission cross-section.

Electron energy distribution in a weakly ionized plasma

International Nuclear Information System (INIS)

Cesari, C.

1967-03-01

The aim of this work is to determine from both the theoretical and experimental points of view the type of distribution function for the electronic energies existing in a positive-column type cold laboratory plasma having an ionization rate of between 10 -6 and 10 -7 . The theoretical analysis, based on the imperfect Lorentz model and taking into account inelastic collisions is developed from the Boltzmann equation. The experimental method which we have employed for making an electrostatic analysis of the electronic energies makes use of a Langmuir probe used in conjunction with a transistorized electronic device. A comparison between the experimental and theoretical results yields information concerning the mechanisms governing electronic energy transfer on a microscopic scale. (author) [fr

Improved atomic data for electron-transport predictions by the codes TIGER and TIGERP. I. Inner-shell ionization by electron collision

International Nuclear Information System (INIS)

Peek, J.M.; Halbleib, J.A.

1983-01-01

The inner-shell ionization data for electron-target collisions now in use in the TIGER and TIGERP electron-transport codes are extracted and compared with other data for these processes. The TIGER cross sections for K-shell ionization by electron collisions are found to be seriously in error for large-Z targets and incident electron energies greater than 1 MeV. A series of TIGER and TIGERP runs were carried out with and without improved K-shell electron ionization cross section data replacing that now in use. The relative importance of electron-impact and photon ionization of the various subshells was also extracted from these runs. In general, photon ionization dominated in the examples studied so the sensitivity of many predicted properties to errors in the electron-impact subshell ionization data was not large. However, some differences were found and, as all possible applications were not covered in this study, it is recommended that these electron-impact data now in TIGER and TIGERP be replaced. Cross section data for the processes under study are reviewed and those that are most suitable for this application are identified. 19 references, 9 figures, 2 tables

Diffraction structures in delta electron spectra emitted in heavy-ion atom collisions

International Nuclear Information System (INIS)

Liao, C.; Bhalla, C.; Shingal, R.; Schmidt-Boecking, H.; Shinpaugh, J.; Wolf, W.; Wolf, H.

1992-01-01

We have measured doubly differential cross sections DDCS for projectiles between F and Au and find evidence for strong diffraction structure in the Binary Encounter region of the emitted electron spectra for Au(Z=79), I(Z=53) and Cu(Z=29) projectiles, however not for F projectiles in the collision energy range between 0.2 and 0.5 MeV/u. (orig.)

Single and double electron capture in collisions of highly ionized, decelerated Ge ions with Ne

International Nuclear Information System (INIS)

Stoehlker, T.; Kozhuharov, C.; Mokler, P.H.; Olson, R.E.; Stachura, Z.; Warczak, A.

1992-03-01

Experimental cross-sections for non-radiative single and double electron capture from Ne target into H-like Ge ions at low intermediate collision energies (4-12) MeV/u are presented. The results are compared with theoretical calculations and an empirical scaling rule. Information concerning the impact parameter dependence of electron capture is extracted using classical trajectory Monte Carlo calculations. (orig.)

Heavy ion collisions at intermediate energy

International Nuclear Information System (INIS)

Bertsch, G.; Amsden, A.A.

1978-01-01

Two types of measurement are proposed for the analysis of heavy ion collisions in the range of energy of 20--200 MeV/A. First, measurement of the longitudinal component of the kinetic energy of the collision products characterizes the impact parameter of the collision. The distribution in this quantity allows the dissipation in the theoretical models to be determined. A second kind of measurement is that of the coefficients of a spherical harmonic expansion of the angular distribution of the products. Besides giving independent information on the impact parameter and reaction dynamics, measurement of these coefficients offers the possibility of measuring the stiffness of the equation of state of nuclear matter. These ideas are explored in the context of a hydrodynamic model for the collision. In the purely hydrodynamic model there is a large measurable asymmetry in the angular distribution, but the dependence on the equation of state is small

Atomic excitation and molecular dissociation by low energy electron collisions

International Nuclear Information System (INIS)

Weyland, Marvin

2016-01-01

In this work, momentum imaging experiments have been conducted for the electron impact excitation of metastable states in noble gases and for dissociative electron attachment (DEA) in polyatomic molecules. For the electron impact excitation study a new experimental technique has been developed which is able to measure the scattering angle distribution of the electrons by detection of the momentum transfer to the atoms. Momentum transfer images have been recorded for helium and neon at fixed electron impact energy close to the excitation threshold and good agreement with current R-matrix theory calculations was found. A new momentum imaging apparatus for negative ions has been built for the purpose of studying DEA in biologically relevant molecules. During this work, DEA was investigated in the molecules ammonia, water, formic acid, furan, pyridine and in two chlorofluorocarbons. Furthermore, the change of DEA resonance energies when molecules form clusters compared to monomers was investigated in ammonia and formic acid. The experimental results of most studied molecules could be compared to recent theoretical calculations and they support further development in the theoretical description of DEA. The new apparatus built in this work also delivered a superior momentum resolution compared to existing setups. This allows the momentum imaging of heavier fragments and fragments with lower kinetic energy.

Atomic excitation and molecular dissociation by low energy electron collisions

Energy Technology Data Exchange (ETDEWEB)

Weyland, Marvin

2016-11-16

In this work, momentum imaging experiments have been conducted for the electron impact excitation of metastable states in noble gases and for dissociative electron attachment (DEA) in polyatomic molecules. For the electron impact excitation study a new experimental technique has been developed which is able to measure the scattering angle distribution of the electrons by detection of the momentum transfer to the atoms. Momentum transfer images have been recorded for helium and neon at fixed electron impact energy close to the excitation threshold and good agreement with current R-matrix theory calculations was found. A new momentum imaging apparatus for negative ions has been built for the purpose of studying DEA in biologically relevant molecules. During this work, DEA was investigated in the molecules ammonia, water, formic acid, furan, pyridine and in two chlorofluorocarbons. Furthermore, the change of DEA resonance energies when molecules form clusters compared to monomers was investigated in ammonia and formic acid. The experimental results of most studied molecules could be compared to recent theoretical calculations and they support further development in the theoretical description of DEA. The new apparatus built in this work also delivered a superior momentum resolution compared to existing setups. This allows the momentum imaging of heavier fragments and fragments with lower kinetic energy.

Measurement of semi-electronic beauty-hadron decays via their impact parameter in pp collisions in ALICE

Energy Technology Data Exchange (ETDEWEB)

Heide, Markus Ansgar

2014-03-19

The measurement of beauty-hadron decays via the detection of electron tracks that are displaced from the primary vertex can be performed with ALICE, whose capabilities of electron identification and tracking fulfil all requirements for this task. While the large corresponding branching ratios guarantee sufficient yields of beauty-decay electrons at LHC energies, the wide electron impact parameter distribution due to the long lifetime and the decay kinematics of beauty hadrons allows for a separation of electrons from beauty-hadron decays from background electrons on a statistical basis. This thesis presents the analysis of electrons from beauty-hadron decays in protonproton collisions at centre-of-mass energies of 7 TeV and 2.76 TeV. Using the ALICE central-barrel detectors ITS, TPC, and TOF, p{sub T}-differential electron spectra are measured at mid-rapidity (vertical stroke y vertical stroke <0.8) for transverse momenta between 1 and 8 GeV/c. Information from the TPC and TOF signal is combined to select pure electron samples, whose signal-to-background ratio is subsequently enhanced via the requirement of a minimal impact parameter of the tracks towards the primary vertex in the x - y plane. Tracks from photon conversions occurring outside the innermost ITS layer, which have a wide impact parameter distribution, are rejected via the requirement of hits in both SPD layers of the ITS. The remaining hadron contamination in the selected electron track samples is determined on a statistical basis from the distributions of their energy deposition per unit of length in the TPC. A crucial challenge of this analysis is the subtraction of the electron background originating from charm decays, photon conversions, and light-meson decays from the measured inclusive electron spectrum. The corresponding electron yields are determined using spectra from PYTHIA simulations that are reweighted based on previous measurements of charmed hadrons, π{sup 0}, and η. Minor

Low-energy collisions between electrons and BeD+

Science.gov (United States)

Niyonzima, S.; Pop, N.; Iacob, F.; Larson, Å; Orel, A. E.; Mezei, J. Zs; Chakrabarti, K.; Laporta, V.; Hassouni, K.; Benredjem, D.; Bultel, A.; Tennyson, J.; Reiter, D.; Schneider, I. F.

2018-02-01

Multichannel quantum defect theory is applied in the treatment of the dissociative recombination and vibrational excitation processes for the BeD+ ion in the 24 vibrational levels of its ground electronic state ({{X}}{}1{{{Σ }}}+,{v}{{i}}+=0\\ldots 23). Three electronic symmetries of BeD** states ({}2{{\\Pi }}, {}2{{{Σ }}}+, and {}2{{Δ }}) are considered in the calculation of cross sections and the corresponding rate coefficients. The incident electron energy range is 10-5-2.7 eV and the electron temperature range is 100-5000 K. The vibrational dependence of these collisional processes is highlighted. The resulting data are useful in magnetic confinement fusion edge plasma modeling and spectroscopy, in devices with beryllium based main chamber materials, such as ITER and JET, and operating with the deuterium-tritium fuel mix. An extensive rate coefficients database is presented in graphical form and also by analytic fit functions whose parameters are tabulated in the supplementary material.

Study of electron pair and photon production in lead-gold collisions

CERN Multimedia

Ravinovich, I; Fraenkel, Z; Gnaenski, A

2002-01-01

This is a continuation of the NA45 experiment dedicated to the measurement of electron-positron pairs and direct photons produced in Pb-Pb collisions at SPS energies. The main goal remains as outlined in NA45. The strong enhancement of low-mass pairs, over the expected yield from hadronic sources, observed in S-Au collisions by NA45, adds considerably to the physics potential and to the interest in the measurement of these variables. \\\\\\\\The figure shows the layout of the CERES spectrometer which has been upgraded to cope with the higher multiplicities and background of central Pb-Pb collisions. The basic spectrometer remains unchanged, namely two Ring Imaging Cherenkov detectors (RICH), one situated before the other after a short superconducting double solenoid. The main elements of the upgrade are additional detectors, two silicon radial-drift chambers (instead of one in the original set-up) and a pad chamber (a large MWPC with pad readout) located behind the spectrometer. They allow real tracking and help...

Heavy-ion peripheral collisions in the Fermi energy domain: fragmentation processes or dissipative collisions

International Nuclear Information System (INIS)

Borderie, B.; Rivet, M.F.; Tassan-Got, L.

1990-01-01

For several years a new field in nuclear physics has been opened by the opportunity to accelerate heavy ions through an energy domain including the Fermi energy of nucleons. This new domain has to be seen as a link between dissipative processes observed at low energies, dominated by mean field considerations, and high energy collisions for which nucleon-nucleon collisions play an important role. This paper reviews our present knowledge on peripheral collisions. A reminder of contiguous energy domains is done as well as their extension in the new field. Specific calculations are also presented. Finally a wide comparison between experiments and calculations is performed. A fast dissipative stage proves to be responsible for the dominant mechanisms involved, at least when the incident energy is lower than 50 MeV/nucleon

Collision strengths for the excitation of lithium- and boron-like ions by electron impact

International Nuclear Information System (INIS)

Goett, S.J.

1983-01-01

The theory of collision strengths of highly charged ions is presented in terms of the R-matrix formalism by utilizing time-dependent perturbation theory. This theory is then applied to the general case of an ion with three valence electrons. The theory is general enough to admit the possiblity of three equivalent electrons. The effects of configuration interaction and intermediate coupling are incorporated through the mixing coefficients calculated by diagonalizing the perturbation matrix. This matrix is formed by taking into account the electron-electron electrostatic interaction as well as all first order relativistic corrections. The dipole radiative line strengths are also calculated using these mix coefficients. The line strengths are needed for the Coulomb-Bethe approximation which estimates the contributions to the collision strengths from large values of the impact electron's orbital angular momentum. All the above quantities are calculated in both the LS and jj coupling schemes. This dual calculation provides useful information about the mixing of the states present, as well as serving as a valuable check on the development of the theory and the coding of the computer programs. An application is made to the calculation of transition energies, line strengths and collision strengths of transitions from all lower states with a configuration of 1s 2 2I to all upper states with a configuraiton of 1s2I/sub a/'2I/sub b/'

One-electron capture and target ionization in He+-neutral-atom collisions

International Nuclear Information System (INIS)

Shevelko, V.P.; Tolstikhina, I.Yu.; Kato, D.; Tawara, H.; Song, M-.Y.; Yoon, J-.S.

2009-12-01

One-electron capture and target-ionization cross sections in collisions of He + ions with neutral atoms: He + + A → He + A + and He + + A → He + + A + + e, A = H, He(1s 2 , 1s2s), Ne, Ar, Kr, Xe, are calculated and compared with available experimental data over the broad energy range E = 0.1 keV/u - 10 MeV/u of He + ions. The role of the metastable states of neutral helium atoms in such collisions, which are of importance in plasma physics applications, is briefly discussed. The recommended cross section data for these processes are presented in a closed analytical form (nine-order polynomials) which can be used for a plasma modeling and diagnostics. (author)

Charged Particle, Photon Multiplicity, and Transverse Energy Production in High-Energy Heavy-Ion Collisions

Directory of Open Access Journals (Sweden)

Raghunath Sahoo

2015-01-01

Full Text Available We review the charged particle and photon multiplicities and transverse energy production in heavy-ion collisions starting from few GeV to TeV energies. The experimental results of pseudorapidity distribution of charged particles and photons at different collision energies and centralities are discussed. We also discuss the hypothesis of limiting fragmentation and expansion dynamics using the Landau hydrodynamics and the underlying physics. Meanwhile, we present the estimation of initial energy density multiplied with formation time as a function of different collision energies and centralities. In the end, the transverse energy per charged particle in connection with the chemical freeze-out criteria is discussed. We invoke various models and phenomenological arguments to interpret and characterize the fireball created in heavy-ion collisions. This review overall provides a scope to understand the heavy-ion collision data and a possible formation of a deconfined phase of partons via the global observables like charged particles, photons, and the transverse energy measurement.

Improved age-diffusion model for low-energy electron transport in solids. II. Application to secondary emission from aluminum

International Nuclear Information System (INIS)

Dubus, A.; Devooght, J.; Dehaes, J.C.

1987-01-01

The ''improved age-diffusion'' model for secondary-electron transport is applied to aluminum. Electron cross sections for inelastic collisions with the free-electron gas using the Lindhard dielectric function and for elastic collisions with the randomly distributed ionic cores are used in the calculations. The most important characteristics of backward secondary-electron emission induced by low-energy electrons on polycrystalline Al targets are calculated and compared to experimental results and to Monte Carlo calculations. The model appears to predict the electronic yield, the energy spectra, and the spatial dependence of secondary emission with reasonable accuracy

Mean charged hadron multiplicities in high-energy collisions

Energy Technology Data Exchange (ETDEWEB)

Albini, E [Istituto di Matematica dell' Universita Cattolica di Brescia (Italy); Capiluppi, P; Giacomelli, G; Rossi, A M [Bologna Univ. (Italy). Istituto di Fisica

1976-03-01

A collection of mean charged hadron multiplicities per inelastic collision in various high-energy processes is presented. An extensive list of fits of as a function of energy is presented and discussed. As the energy increases the multiplicities for different collisions tend to a unique curve, independent of the type of colliding particles.

Measurement of cross-sections for step-bystep excitation of inert gas atoms from metastable states by electron collisions

International Nuclear Information System (INIS)

Mityureva, A.A.; Penkin, N.P.; Smirnov, V.V.

1989-01-01

Excitation of argon atoms by electron collisions from metastable (MS) to high-lying states of inert gases (the so-called step-by-step excitation) is investigated. Formation of MS atoms m and their further step-by-step excitation up to k level is carried out by an electron beam with energy from 1 up to 40 eV. Time distribution of forming metastable and step-by-step electron collisions is used. The method used permits to measure the functions of step-by-step excitation and the absolute values of cross sections. Absolute values of cross-sections and functions of step-by-step excitation of some lines and argon levels are obtained

Single-electron capture in He[sup 2+]-D[sub 2] collisions

Energy Technology Data Exchange (ETDEWEB)

Bordenave-Montesquieu, D.; Dagnac, R. (Toulouse-3 Univ., 31 (France))

1994-02-14

Doubly differential cross sections of single-electron capture were measured for He[sup 2+] impinging on a molecular deuterium target. The investigated collision energies are 4, 6 and 8 keV and the scattering angles range from 10' to 2[sup o]30' (laboratory frame). The exothermic capture leading to He[sup +] (1s) + D[sub 2][sup +*] was found to be the most important process at low energies and angles, whereas the endothermic channels leading to dissociative capture become the main processes at high scattering angles, i.e. at small impact parameters. (author).

High-energy hadron-hadron collisions

International Nuclear Information System (INIS)

Yang, C.N.

1983-01-01

While high energy collision experiments yield a wealth of complicated patterns, there are a few general and very striking features that stand out. Because of the universality of these features, and because of the dominating influence they have on high energy phenomena, it is the authors opinion that a physical picture of high energy collisions must address itself first of all to these features before going into specific details. In this short talk these general and striking features are stated and a physical picture developed in the last few years to specifically accommodate these features is described. The picture was originally discussed for elastic scattering. But it leads naturally, indeed inevitably as they shall discuss, to conclusions about inelastic processes, resulting in an idea called the hypothesis of limiting fragmentation

Low-Energy Charge Transfer in Multiply-Charged Ion-Atom Collisions Studied with the Combined SCVB-MOCC Approach

Directory of Open Access Journals (Sweden)

B. Zygelman

2002-03-01

Full Text Available A survey of theoretical studies of charge transfer involving collisions of multiply-charged ions with atomic neutrals (H and He is presented. The calculations utilized the quantum-mechanical molecular-orbital close-coupling (MOCC approach where the requisite potential curves and coupling matrix elements have been obtained with the spin-coupled valence bond (SCVB method. Comparison is made among various collision partners, for equicharged systems, where it is illustrated that even for total charge transfer cross sections, scaling-laws do not exist for low-energy collisions (i.e. < 1 keV/amu. While various empirical scaling-laws are well known in the intermediateand high-energy regimes, the multi-electron configurations of the projectile ions results in a rich and varied low-energy dependence, requiring an explicit calculation for each collision-partner pair. Future charge transfer problems to be addressed with the combined SCVB-MOCC approach are briefly discussed.

Theory of e+e/sup /minus// collisions at very high energy

International Nuclear Information System (INIS)

Peskin, M.E.

1988-04-01

In these lectures, the array of new phenomena are reviewed which might be discovered in electron-positron reactions conducted at energies well above the Z/degree/. Before beginning a discussion of what new phenomena we might find, or how we might uncover them, the question is addressed of why such a program of research is important. The question of what we should be looking for, and what discoveries will be the most illuminating, as we search for the next layer of fundamental physics is argued. With this background, we can then discuss in some considerable detail the contributions that the study of electron-positron collisions at high energy can make in this search

Density and energy distribution of epithermal secondary electrons in a plasma with fast charged particles

International Nuclear Information System (INIS)

Jayakumar, R.; Fleischmann, H.H.

1989-01-01

The production of intermediate energy secondary electrons in plasmas through collisions with fast charged particles is investigated. The density and the distribution of the secondary electrons are obtained by calculating the generation, slow down and diffusion rates, using basic Rutherford collision cross sections. It is shown that the total density of secondaries is much smaller than the fast particle density and that the energy distribution has roughly a 1/√E dependence. The higher generation secondary populations are also obtained. (orig.)

Utilization of ion source 'SUPERSHYPIE' in the study of low energy ion-atom and ion-molecule collisions

International Nuclear Information System (INIS)

Bazin, V.; Boduch, P.; Chesnel, J.Y.; Fremont, F.; Lecler, D.; Pacquet, J. Y.; Gaubert, G.; Leroy, R.

1999-01-01

Modifications in the ECR 4M ion source are described, which conducted to realization of the advanced source 'SUPERSHYPIE'. The Ar 8+ ion collision with Cs(6s,6p) were studied by photon spectroscopy at low energy, where the process is dominated by simple electron capture. Results obtained with 'SUPERSHYPIE' source are presented. The source was utilized also in ion-molecule collisions (CO, H 2 ) to study the spectra of recoil ions and Auger electron spectra in the Ar 17+ He collisions. The excellent performances of 'SUPERSHYPIE' in high charge production and concerning its accurate and fine control and stability are illustrated and underlined as compared with those of ECR 4M source

Zero-degree binary encounter electrons in fast collisions of highly charged F and O ions with H2 targets

International Nuclear Information System (INIS)

Lee, D.H.; Zouros, T.J.M.; Sanders, J.M.; Hidmi, H.; Richard, P.

1993-01-01

Doubly differential cross sections (DDCS) for binary encounter electrons (BEe) produced by 0.5-2 MeV/u highly-charged F and O ions in collisions with H 2 gas targets have been studied at 0 with respect to the ion beam direction. The measured DDCS of the broad binary encounter peak was well described by a simple impulse approximation (IA) treatment for bare ions, and was demonstrated to provide in situ detection efficiency of the electron spectrometer. The projectile energy dependence of the BEe production for nonbare (clothed) projectiles is found to follow a scaled IA prediction, in which a BEe enhancement is consistently exhibited for the collision energy range studied. (orig.)

Observation of second harmonics in laser-electron scattering using low energy electron beam

Energy Technology Data Exchange (ETDEWEB)

Iinuma, Masataka [ADSM, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima 739-8530 (Japan)]. E-mail: iinuma@hiroshima-u.ac.jp; Matsukado, Koji [Venture Business Laboratory, Hiroshima University, 1-313 Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8527 (Japan); Endo, Ichita [ADSM, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima 739-8530 (Japan); Hashida, Masaki [Institute for chemical Research, Kyoto University, Gokasho, Uji, Kyoto 611-0011 (Japan); Hayashi, Kenji [ADSM, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima 739-8530 (Japan); Kohara, Akitsugu [ADSM, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima 739-8530 (Japan); Matsumoto, Fumihiko [ADSM, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima 739-8530 (Japan); Nakanishi, Yoshitaka [ADSM, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima 739-8530 (Japan); Sakabe, Shuji [Institute for chemical Research, Kyoto University, Gokasho, Uji, Kyoto 611-0011 (Japan); Shimizu, Seiji [Institute for chemical Research, Kyoto University, Gokasho, Uji, Kyoto 611-0011 (Japan); Tauchi, Toshiaki [High Energy Accelerator Research Organization (KEK), 1-1 Oho, Tsukuba, Ibaraki 305-0801 (Japan); Yamamoto, Ken [ADSM, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima 739-8530 (Japan); Takahashi, Tohru [ADSM, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima 739-8530 (Japan)

2005-10-17

We observed photon generation in the second harmonic region in collisions of 10 keV free electrons and the intense laser beam with the peak intensity of 4.0x10{sup 15} W/cm{sup 2}. Observed photon yield was 3 orders of magnitude higher than expectation from the nonlinear Compton scattering. The observation indicates necessity of further investigation for the interaction between the intense laser field and the low energy electron beam.

Fragmentation of the C60 molecule in collision with light ions studied by a multi-correlation technique. Cross-sections, electron spectroscopy; Fragmentation de la molecule C60 par impact d'ions legers etudiee en multicorrelation. Sections efficaces, spectroscopie d'electrons

Energy Technology Data Exchange (ETDEWEB)

Rentenier, A

2004-04-01

A quantitative study of the C60 fullerenes fragmentation in collision with light ions (H{sub n}{sup +} with n=1,2,3, He{sup q+} with q=1,2) in the velocity range 0,1 - 2,3 u.a.) is presented. The multi-correlation technique, developed between fragment ions and electrons with well defined energy, has enlightened some of the dependences and properties of fragmentation mechanisms (cross sections, electron spectroscopy, size distributions, kinetic energy of fragment ions, Campi's scatter plot, activation energies). The deposited energy hence appeared as an important parameter. Cross sections have been measured, for the first time, for all the collisional processes. Ionisation and capture only depends on the collision velocity. On the other hand, scaling laws with the deposited energy have been observed for the cross sections of multifragmentation, which depends on the collision energy and the nature of the projectile. The deposited energy has also been found as an essential parameter to understand the evolution of the charged fragment size distributions. The electron spectroscopy, achieved at an emission angle of 35 degrees, showed spectra peaked at important energies (from 5 to 20 eV). The spectra shape depends on the collision velocity. A first theoretical analysis points out the link between the observed energy distribution and the presence of a centrifugal potential barrier. Finally, correlation experiments between produced ions and electron energy reveal that electron energy increases with internal energy. (author)

${\\rm D}^0$-electron correlations in p$-$Pb collisions at $\\sqrt{s_{\\mathrm{NN}}}$=5.02 TeV

CERN Document Server

AUTHOR|(CDS)2078571; Altınpınar, Sedat; Nystrand, Joakim

2017-04-21

In collisions of lead nuclei at the Large Hadron Collider (LHC) at CERN, a state of matter called Quark-Gluon Plasma (QGP) is formed, where quarks and gluons are no longer confined into hadrons. Heavy-flavour quarks, i.e., charm and beauty, are effective probes for studying the QGP, as their relatively large mass limits their production predominantly, if not exclusively, to hard scattering processes in the very first moments of the collisions, before the QGP formation. As the quarks propagate through the hot and dense medium created in the Pb$-$Pb collisions they interact with the medium and lose energy via elastic collisions and gluon radiation. The study of the modification of angular correlations between D mesons and electrons from heavy-flavour hadron decays in Pb$-$Pb collisions with respect to pp and p$-$Pb collisions can provide relevant information on the energy-loss mechanism. This applies in particular to the dependence of the correlation on the path length traversed by the charm quark in the medium...

Three-jet production in electron-positron collisions using the CoLoRFulNNLO method

CERN Document Server

Del Duca, Vittorio

2016-01-01

We introduce a subtraction method for jet cross sections at next-to-next-to-leading order (NNLO) accuracy in the strong coupling and use it to compute event shapes in three-jet production in electron-positron collisions. We validate our method on two event shapes, thrust and C-parameter, which are already known in the literature at NNLO accuracy and compute for the first time oblateness and the energy-energy correlation at the same accuracy.

Electron-vibrational transitions under molecular ions collisions with slow electrons

International Nuclear Information System (INIS)

Andreev, E.A.

1993-01-01

A concept of a multichannel quantum defect is considered and basic theoretic ratios of inelastic collisional processes with the participation of molecular positive ions and slow electrons playing an important role both in atmospheric and laboratory plasma, are presented. The problem of scattering channel number limitation with the provision of S-matrix unique character is considered. Different models of electron rotation-vibrational connection under collision of two-atom molecular ions with slow electrons are analysed. Taking N 2 + as an example, a high efficiency of transitions between different electron states of a molecular ion is shown. 73 refs., 9 figs., 1 tab

Electron removal from H and He atoms in collisions with C q+ , O q+ ions

Science.gov (United States)

Janev, R. K.; McDowell, M. R. C.

1984-06-01

Cross sections for electron capture and ionisation in collision of partially and completely stripped C q+ , N q+ and O q+ ions with hydrogen and helium atoms have been calculated at selected energies. The classical trajectory Monte Carlo method was used with a variable-charge pseudopotential to describe the interaction of the active electron with the projectile ion. A scalling relationship has been derived for the electron removal (capture and ionisation) cross section which allows a unifield representation of the data.

Advances in the MQDT approach of electron/molecular cation reactive collisions: High precision extensive calculations for applications

Directory of Open Access Journals (Sweden)

Motapon O.

2015-01-01

Full Text Available Recent advances in the stepwise multichannel quantum defect theory approach of electron/molecular cation reactive collisions have been applied to perform computations of cross sections and rate coefficients for dissociative recombination and electron-impact ro-vibrational transitions of H2+, BeH+ and their deuterated isotopomers. At very low energy, rovibronic interactions play a significant role in the dynamics, whereas at high energy, the dissociative excitation strongly competes with all other reactive processes.

Search for a double-collision mechanism as a possible interpretation for ionization by low-energy light-ion impact

International Nuclear Information System (INIS)

Avaldi, L.; Magno, C.; Milazzo, M.; Rota, A.

1981-01-01

In a previous work the authors proposed, in the frame of the binary-encounter approximation (BEA) of the inner-shell atomic ionization by ion bombardment, a correction to the ion energy in order to account for the Coulomb repulsion by the atomic nucleus. Such corrected cross-section values numerically coincide with those of the PWBA model, but, as a consequence of the correction, they obtain a much higher-energy ionization threshold than the binding energy, which has no experimental evidence. In the present work it is shown that ionization below such a threshold can be explained by a double-collision mechanism which involves intermediate electron states and can directly be derived from the impulsive nature of the binary-collision model. Calculations have been performed by supposing a statistical independence between these two collisions. Relativistic corrections have not been taken into account. A remarkable agreement is obtained between the curves corresponding to single- and double-collision classical processes, since they match at the bombarding threshold ion energy. (author)

Electron transfer processes in ion collisions with atomic hydrogen. Final report for period February 1, 1975--June 30, 1976

International Nuclear Information System (INIS)

Bayfield, J.E.

1976-07-01

Results of experiments completed with Yale equipment coupled to the Oak Ridge Test Bench and Tandem Accelerator facilities are presented. Electron transfer cross sections have been measured at keV collision energies for B, C, N and O ions colliding with H, H 2 , Ar and He gas targets. The ion charge states studied range from +2 through +5. Also reported are cross sections for Si and Fe ions on H, H 2 and Ar at energies between 1.5 and 14 MeV, with charge states varying between +5 and +13. Also measured were the cross sections for H + collisions with H, H 2 and Ar for energies between 0.8 and 2.5 MeV. At keV energies the cross sections for highly charged B, C, N and O ions are found to be 1 x 10 -14 cm 2 . The cross sections for 4 MeV Fe ions scale roughly with the square of the ion charge, and have values as high as 0.5 x 10 -14 cm 2 for Fe 10+ + H collisions. A strong energy dependence is found for Fe ion collisions between 4 and 14 MeV. Previous results for MeV H + + Ar collisions are nicely reproduced, while our first results for the fundamental MeV H + - H collision problem are cross sections higher than many theoretical predictions

Measurement of the production of high-pT electrons from heavy-flavour hadron decays in Pb–Pb collisions at sNN=2.76 TeV

Directory of Open Access Journals (Sweden)

J. Adam

2017-08-01

Full Text Available Electrons from heavy-flavour hadron decays (charm and beauty were measured with the ALICE detector in Pb–Pb collisions at a centre-of-mass of energy sNN=2.76 TeV. The transverse momentum (pT differential production yields at mid-rapidity were used to calculate the nuclear modification factor RAA in the interval 3collisions at the same energy (up to a factor of 4 in the 10% most central Pb–Pb collisions. There is a centrality trend of suppression, and a weaker suppression (down to a factor of 2 in semi-peripheral (50–80% collisions is observed. The suppression of electrons in this broad pT interval indicates that both charm and beauty quarks lose energy when they traverse the hot medium formed in Pb–Pb collisions at LHC.

Direct processes in ion-atom collisions at intermediate and high energies

International Nuclear Information System (INIS)

Rodriguez Chariarse, V.D.

1990-01-01

This thesis deals with direct processes induced by Zp charge ion impact on one or two electron atoms and ions at intermediate energies. At a first step, a one-dimensional collision model is used in order to prove the different theoretical methods available to study collisions at such energy range, such as: perturbative and related variational principles, and distorted wave methods. The best description of both, symmetric and asymmetric collision type, is achieved by the distorted wave methods, particularly the ones using the exact impulsive wave function. As a next step, the appropriate formulations of the wave functions employed in the one-dimensional model to describe the real 3-dimensional Coulomb interaction case are examined by using the Eikonal and impulse hypothesis. In this way, the VPS and Eikonal wave functions are reviewed, and furtherly, the Eikonal form of the extended impulse wave function is derived. The Eikonal impulse approximation (EIA) is introduced. This is a distorted wave method using the Eikonal and extended impulse wave functions. The choice of the EIA prior version, i.e., the one using extended impulse wave function in the final channel for excitation is widely discussed and justified. (Author) [es

Measurement of electrons from beauty hadron decays in pp collisions at $\\sqrt{s}$ = 7 TeV

CERN Document Server

Abelev, Betty; Adamova, Dagmar; Adare, Andrew Marshall; Aggarwal, Madan; Aglieri Rinella, Gianluca; Agocs, Andras Gabor; Agostinelli, Andrea; Aguilar Salazar, Saul; Ahammed, Zubayer; Ahmad, Nazeer; Ahmad, Arshad; Ahn, Sul-Ah; Ahn, Sang Un; Akindinov, Alexander; Aleksandrov, Dmitry; Alessandro, Bruno; Alfaro Molina, Jose Ruben; Alici, Andrea; Alkin, Anton; Almaraz Avina, Erick Jonathan; Alme, Johan; Alt, Torsten; Altini, Valerio; Altinpinar, Sedat; Altsybeev, Igor; Andrei, Cristian; Andronic, Anton; Anguelov, Venelin; Anielski, Jonas; Anson, Christopher Daniel; Anticic, Tome; Antinori, Federico; Antonioli, Pietro; Aphecetche, Laurent Bernard; Appelshauser, Harald; Arbor, Nicolas; Arcelli, Silvia; Arend, Andreas; Armesto, Nestor; Arnaldi, Roberta; Aronsson, Tomas Robert; Arsene, Ionut Cristian; Arslandok, Mesut; Asryan, Andzhey; Augustinus, Andre; Averbeck, Ralf Peter; Awes, Terry; Aysto, Juha Heikki; Azmi, Mohd Danish; Bach, Matthias Jakob; Badala, Angela; Baek, Yong Wook; Bailhache, Raphaelle Marie; Bala, Renu; Baldini Ferroli, Rinaldo; Baldisseri, Alberto; Baldit, Alain; Baltasar Dos Santos Pedrosa, Fernando; Ban, Jaroslav; Baral, Rama Chandra; Barbera, Roberto; Barile, Francesco; Barnafoldi, Gergely Gabor; Barnby, Lee Stuart; Barret, Valerie; Bartke, Jerzy Gustaw; Basile, Maurizio; Bastid, Nicole; Basu, Sumit; Bathen, Bastian; Batigne, Guillaume; Batyunya, Boris; Baumann, Christoph Heinrich; Bearden, Ian Gardner; Beck, Hans; Behera, Nirbhay Kumar; Belikov, Iouri; Bellini, Francesca; Bellwied, Rene; Belmont-Moreno, Ernesto; Bencedi, Gyula; Beole, Stefania; Berceanu, Ionela; Bercuci, Alexandru; Berdnikov, Yaroslav; Berenyi, Daniel; Bergognon, Anais Annick Erica; Berzano, Dario; Betev, Latchezar; Bhasin, Anju; Bhati, Ashok Kumar; Bhom, Jihyun; Bianchi, Livio; Bianchi, Nicola; Bianchin, Chiara; Bielcik, Jaroslav; Bielcikova, Jana; Bilandzic, Ante; Bjelogrlic, Sandro; Blanco, F; Blanco, Francesco; Blau, Dmitry; Blume, Christoph; Boccioli, Marco; Bock, Nicolas; Boettger, Stefan; Bogdanov, Alexey; Boggild, Hans; Bogolyubsky, Mikhail; Boldizsar, Laszlo; Bombara, Marek; Book, Julian; Borel, Herve; Borissov, Alexander; Bose, Suvendu Nath; Bossu, Francesco; Botje, Michiel; Botta, Elena; Boyer, Bruno Alexandre; Braidot, Ermes; Braun-Munzinger, Peter; Bregant, Marco; Breitner, Timo Gunther; Browning, Tyler Allen; Broz, Michal; Brun, Rene; Bruna, Elena; Bruno, Giuseppe Eugenio; Budnikov, Dmitry; Buesching, Henner; Bufalino, Stefania; Busch, Oliver; Buthelezi, Edith Zinhle; Caballero Orduna, Diego; Caffarri, Davide; Cai, Xu; Caines, Helen Louise; Calvo Villar, Ernesto; Camerini, Paolo; Canoa Roman, Veronica; Cara Romeo, Giovanni; Carena, Francesco; Carena, Wisla; Carlin Filho, Nelson; Carminati, Federico; Casanova Diaz, Amaya Ofelia; Castillo Castellanos, Javier Ernesto; Castillo Hernandez, Juan Francisco; Casula, Ester Anna Rita; Catanescu, Vasile; Cavicchioli, Costanza; Ceballos Sanchez, Cesar; Cepila, Jan; Cerello, Piergiorgio; Chang, Beomsu; Chapeland, Sylvain; Charvet, Jean-Luc Fernand; Chattopadhyay, Subhasis; Chattopadhyay, Sukalyan; Chawla, Isha; Cherney, Michael Gerard; Cheshkov, Cvetan; Cheynis, Brigitte; Chibante Barroso, Vasco Miguel; Chinellato, David; Chochula, Peter; Chojnacki, Marek; Choudhury, Subikash; Christakoglou, Panagiotis; Christensen, Christian Holm; Christiansen, Peter; Chujo, Tatsuya; Chung, Suh-Urk; Cicalo, Corrado; Cifarelli, Luisa; Cindolo, Federico; Cleymans, Jean Willy Andre; Coccetti, Fabrizio; Colamaria, Fabio; Colella, Domenico; Conesa Balbastre, Gustavo; Conesa del Valle, Zaida; Constantin, Paul; Contin, Giacomo; Contreras, Jesus Guillermo; Cormier, Thomas Michael; Corrales Morales, Yasser; Cortese, Pietro; Cortes Maldonado, Ismael; Cosentino, Mauro Rogerio; Costa, Filippo; Cotallo, Manuel Enrique; Crescio, Elisabetta; Crochet, Philippe; Cruz Alaniz, Emilia; Cuautle, Eleazar; Cunqueiro, Leticia; Dainese, Andrea; Dalsgaard, Hans Hjersing; Danu, Andrea; Das, Debasish; Das, Indranil; Das, Kushal; Dash, Ajay Kumar; Dash, Sadhana; De, Sudipan; de Barros, Gabriel; De Caro, Annalisa; de Cataldo, Giacinto; de Cuveland, Jan; De Falco, Alessandro; De Gruttola, Daniele; Delagrange, Hugues; Deloff, Andrzej; Demanov, Vyacheslav; De Marco, Nora; Denes, Ervin; De Pasquale, Salvatore; Deppman, Airton; D'Erasmo, Ginevra; de Rooij, Raoul Stefan; Diaz Corchero, Miguel Angel; Di Bari, Domenico; Dietel, Thomas; Di Giglio, Carmelo; Di Liberto, Sergio; Di Mauro, Antonio; Di Nezza, Pasquale; Divia, Roberto; Djuvsland, Oeystein; Dobrin, Alexandru Florin; Dobrowolski, Tadeusz Antoni; Dominguez, Isabel; Donigus, Benjamin; Dordic, Olja; Driga, Olga; Dubey, Anand Kumar; Dubla, Andrea; Ducroux, Laurent; Dupieux, Pascal; Dutta Majumdar, Mihir Ranjan; Dutta Majumdar, AK; Elia, Domenico; Emschermann, David Philip; Engel, Heiko; Erazmus, Barbara; Erdal, Hege Austrheim; Espagnon, Bruno; Estienne, Magali Danielle; Esumi, Shinichi; Evans, David; Eyyubova, Gyulnara; Fabris, Daniela; Faivre, Julien; Falchieri, Davide; Fantoni, Alessandra; Fasel, Markus; Fearick, Roger Worsley; Fedunov, Anatoly; Fehlker, Dominik; Feldkamp, Linus; Felea, Daniel; Fenton-Olsen, Bo; Feofilov, Grigory; Fernandez Tellez, Arturo; Ferretti, Alessandro; Ferretti, Roberta; Festanti, Andrea; Figiel, Jan; Figueredo, Marcel; Filchagin, Sergey; Finogeev, Dmitry; Fionda, Fiorella; Fiore, Enrichetta Maria; Floris, Michele; Foertsch, Siegfried Valentin; Foka, Panagiota; Fokin, Sergey; Fragiacomo, Enrico; Francescon, Andrea; Frankenfeld, Ulrich Michael; Fuchs, Ulrich; Furget, Christophe; Fusco Girard, Mario; Gaardhoje, Jens Joergen; Gagliardi, Martino; Gago, Alberto; Gallio, Mauro; Gangadharan, Dhevan Raja; Ganoti, Paraskevi; Garabatos, Jose; Garcia-Solis, Edmundo; Garishvili, Irakli; Gerhard, Jochen; Germain, Marie; Geuna, Claudio; Gheata, Andrei George; Gheata, Mihaela; Ghidini, Bruno; Ghosh, Premomoy; Gianotti, Paola; Girard, Martin Robert; Giubellino, Paolo; Gladysz-Dziadus, Ewa; Glassel, Peter; Gomez, Ramon; Gonzalez Ferreiro, Elena; Gonzalez-Trueba, Laura Helena; Gonzalez-Zamora, Pedro; Gorbunov, Sergey; Goswami, Ankita; Gotovac, Sven; Grabski, Varlen; Graczykowski, Lukasz Kamil; Grajcarek, Robert; Grelli, Alessandro; Grigoras, Costin; Grigoras, Alina Gabriela; Grigoriev, Vladislav; Grigoryan, Ara; Grigoryan, Smbat; Grinyov, Boris; Grion, Nevio; Gros, Philippe; Grosse-Oetringhaus, Jan Fiete; Grossiord, Jean-Yves; Grosso, Raffaele; Guber, Fedor; Guernane, Rachid; Guerra Gutierrez, Cesar; Guerzoni, Barbara; Guilbaud, Maxime Rene Joseph; Gulbrandsen, Kristjan Herlache; Gunji, Taku; Gupta, Anik; Gupta, Ramni; Gutbrod, Hans; Haaland, Oystein Senneset; Hadjidakis, Cynthia Marie; Haiduc, Maria; Hamagaki, Hideki; Hamar, Gergoe; Han, Byounghee; Hanratty, Luke David; Hansen, Alexander; Harmanova, Zuzana; Harris, John William; Hartig, Matthias; Hasegan, Dumitru; Hatzifotiadou, Despoina; Hayrapetyan, Arsen; Heckel, Stefan Thomas; Heide, Markus Ansgar; Helstrup, Haavard; Herghelegiu, Andrei Ionut; Herrera Corral, Gerardo Antonio; Herrmann, Norbert; Hess, Benjamin Andreas; Hetland, Kristin Fanebust; Hicks, Bernard; Hille, Per Thomas; Hippolyte, Boris; Horaguchi, Takuma; Hori, Yasuto; Hristov, Peter Zahariev; Hrivnacova, Ivana; Huang, Meidana; Humanic, Thomas; Hwang, Dae Sung; Ichou, Raphaelle; Ilkaev, Radiy; Ilkiv, Iryna; Inaba, Motoi; Incani, Elisa; Innocenti, Pier Giorgio; Innocenti, Gian Michele; Ippolitov, Mikhail; Irfan, Muhammad; Ivan, Cristian George; Ivanov, Vladimir; Ivanov, Andrey; Ivanov, Marian; Ivanytskyi, Oleksii; Jacobs, Peter; Jang, Haeng Jin; Janik, Malgorzata Anna; Janik, Rudolf; Jayarathna, Sandun; Jena, Satyajit; Jha, Deeptanshu Manu; Jimenez Bustamante, Raul Tonatiuh; Jirden, Lennart; Jones, Peter Graham; Jung, Hyung Taik; Jusko, Anton; Kaidalov, Alexei; Kakoyan, Vanik; Kalcher, Sebastian; Kalinak, Peter; Kalliokoski, Tuomo Esa Aukusti; Kalweit, Alexander Philipp; Kang, Ju Hwan; Kaplin, Vladimir; Karasu Uysal, Ayben; Karavichev, Oleg; Karavicheva, Tatiana; Karpechev, Evgeny; Kazantsev, Andrey; Kebschull, Udo Wolfgang; Keidel, Ralf; Khan, Mohisin Mohammed; Khan, Shuaib Ahmad; Khan, Palash; Khanzadeev, Alexei; Kharlov, Yury; Kileng, Bjarte; Kim, Minwoo; Kim, Do Won; Kim, Jonghyun; Kim, Jin Sook; Kim, Mimae; Kim, Se Yong; Kim, Dong Jo; Kim, Beomkyu; Kim, Taesoo; Kirsch, Stefan; Kisel, Ivan; Kiselev, Sergey; Kisiel, Adam Ryszard; Klay, Jennifer Lynn; Klein, Jochen; Klein-Bosing, Christian; Kliemant, Michael; Kluge, Alexander; Knichel, Michael Linus; Knospe, Anders Garritt; Koch, Kathrin; Kohler, Markus; Kollegger, Thorsten; Kolojvari, Anatoly; Kondratiev, Valery; Kondratyeva, Natalia; Konevskih, Artem; Korneev, Andrey; Kour, Ravjeet; Kowalski, Marek; Kox, Serge; Koyithatta Meethaleveedu, Greeshma; Kral, Jiri; Kralik, Ivan; Kramer, Frederick; Kraus, Ingrid Christine; Krawutschke, Tobias; Krelina, Michal; Kretz, Matthias; Krivda, Marian; Krizek, Filip; Krus, Miroslav; Kryshen, Evgeny; Krzewicki, Mikolaj; Kucheriaev, Yury; Kugathasan, Thanushan; Kuhn, Christian Claude; Kuijer, Paul; Kulakov, Igor; Kumar, Jitendra; Kurashvili, Podist; Kurepin, A; Kurepin, AB; Kuryakin, Alexey; Kushpil, Svetlana; Kushpil, Vasily; Kvaerno, Henning; Kweon, Min Jung; Kwon, Youngil; Ladron de Guevara, Pedro; Lakomov, Igor; Langoy, Rune; La Pointe, Sarah Louise; Lara, Camilo Ernesto; Lardeux, Antoine Xavier; La Rocca, Paola; Lea, Ramona; Le Bornec, Yves; Lechman, Mateusz; Lee, Ki Sang; Lee, Sung Chul; Lee, Graham Richard; Lefevre, Frederic; Lehnert, Joerg Walter; Lenhardt, Matthieu Laurent; Lenti, Vito; Leon, Hermes; Leoncino, Marco; Leon Monzon, Ildefonso; Leon Vargas, Hermes; Levai, Peter; Lien, Jorgen; Lietava, Roman; Lindal, Svein; Lindenstruth, Volker; Lippmann, Christian; Lisa, Michael Annan; Liu, Lijiao; Loggins, Vera; Loginov, Vitaly; Lohn, Stefan Bernhard; Lohner, Daniel; Loizides, Constantinos; Loo, Kai Krister; Lopez, Xavier Bernard; Lopez Torres, Ernesto; Lovhoiden, Gunnar; Lu, Xianguo; Luettig, Philipp; Lunardon, Marcello; Luo, Jiebin; Luparello, Grazia; Luquin, Lionel; Luzzi, Cinzia; Ma, Rongrong; Ma, Ke; Madagodahettige-Don, Dilan Minthaka; Maevskaya, Alla; Mager, Magnus; Mahapatra, Durga Prasad; Maire, Antonin; Malaev, Mikhail; Maldonado Cervantes, Ivonne Alicia; Malinina, Ludmila; Mal'Kevich, Dmitry; Malzacher, Peter; Mamonov, Alexander; Mangotra, Lalit Kumar; Manko, Vladislav; Manso, Franck; Manzari, Vito; Mao, Yaxian; Marchisone, Massimiliano; Mares, Jiri; Margagliotti, Giacomo Vito; Margotti, Anselmo; Marin, Ana Maria; Marin Tobon, Cesar Augusto; Markert, Christina; Martashvili, Irakli; Martinengo, Paolo; Martinez, Mario Ivan; Martinez Davalos, Arnulfo; Martinez Garcia, Gines; Martynov, Yevgen; Mas, Alexis Jean-Michel; Masciocchi, Silvia; Masera, Massimo; Masoni, Alberto; Massacrier, Laure Marie; Mastroserio, Annalisa; Matthews, Zoe Louise; Matyja, Adam Tomasz; Mayer, Christoph; Mazer, Joel; Mazzoni, Alessandra Maria; Meddi, Franco; Menchaca-Rocha, Arturo Alejandro; Mercado Perez, Jorge; Meres, Michal; Miake, Yasuo; Milano, Leonardo; Milosevic, Jovan; Mischke, Andre; Mishra, Aditya Nath; Miskowiec, Dariusz; Mitu, Ciprian Mihai; Mlynarz, Jocelyn; Mohanty, Bedangadas; Molnar, Levente; Montano Zetina, Luis Manuel; Monteno, Marco; Montes, Esther; Moon, Taebong; Morando, Maurizio; Moreira De Godoy, Denise Aparecida; Moretto, Sandra; Morsch, Andreas; Muccifora, Valeria; Mudnic, Eugen; Muhuri, Sanjib; Mukherjee, Maitreyee; Muller, Hans; Munhoz, Marcelo; Musa, Luciano; Musso, Alfredo; Nandi, Basanta Kumar; Nania, Rosario; Nappi, Eugenio; Nattrass, Christine; Naumov, Nikolay; Navin, Sparsh; Nayak, Tapan Kumar; Nazarenko, Sergey; Nazarov, Gleb; Nedosekin, Alexander; Nicassio, Maria; Niculescu, Mihai; Nielsen, Borge Svane; Niida, Takafumi; Nikolaev, Sergey; Nikolic, Vedran; Nikulin, Sergey; Nikulin, Vladimir; Nilsen, Bjorn Steven; Nilsson, Mads Stormo; Noferini, Francesco; Nomokonov, Petr; Nooren, Gerardus; Novitzky, Norbert; Nyanin, Alexandre; Nyatha, Anitha; Nygaard, Casper; Nystrand, Joakim Ingemar; Ochirov, Alexander; Oeschler, Helmut Oskar; Oh, Saehanseul; Oh, Sun Kun; Oleniacz, Janusz; Oppedisano, Chiara; Ortiz Velasquez, Antonio; Ortona, Giacomo; Oskarsson, Anders Nils Erik; Ostrowski, Piotr Krystian; Otwinowski, Jacek Tomasz; Oyama, Ken; Ozawa, Kyoichiro; Pachmayer, Yvonne Chiara; Pachr, Milos; Padilla, Fatima; Pagano, Paola; Paic, Guy; Painke, Florian; Pajares, Carlos; Pal, Susanta Kumar; Palaha, Arvinder Singh; Palmeri, Armando; Papikyan, Vardanush; Pappalardo, Giuseppe; Park, Woo Jin; Passfeld, Annika; Pastircak, Blahoslav; Patalakha, Dmitri Ivanovich; Paticchio, Vincenzo; Pavlinov, Alexei; Pawlak, Tomasz Jan; Peitzmann, Thomas; Pereira Da Costa, Hugo Denis Antonio; Pereira De Oliveira Filho, Elienos; Peresunko, Dmitri; Perez Lara, Carlos Eugenio; Perez Lezama, Edgar; Perini, Diego; Perrino, Davide; Peryt, Wiktor Stanislaw; Pesci, Alessandro; Peskov, Vladimir; Pestov, Yury; Petracek, Vojtech; Petran, Michal; Petris, Mariana; Petrov, Plamen Rumenov; Petrovici, Mihai; Petta, Catia; Piano, Stefano; Piccotti, Anna; Pikna, Miroslav; Pillot, Philippe; Pinazza, Ombretta; Pinsky, Lawrence; Pitz, Nora; Piyarathna, Danthasinghe; Planinic, Mirko; Ploskon, Mateusz Andrzej; Pluta, Jan Marian; Pocheptsov, Timur; Pochybova, Sona; Podesta Lerma, Pedro Luis Manuel; Poghosyan, Martin; Polak, Karel; Polichtchouk, Boris; Pop, Amalia; Porteboeuf-Houssais, Sarah; Pospisil, Vladimir; Potukuchi, Baba; Prasad, Sidharth Kumar; Preghenella, Roberto; Prino, Francesco; Pruneau, Claude Andre; Pshenichnov, Igor; Puchagin, Sergey; Puddu, Giovanna; Pulvirenti, Alberto; Punin, Valery; Putis, Marian; Putschke, Jorn Henning; Quercigh, Emanuele; Qvigstad, Henrik; Rachevski, Alexandre; Rademakers, Alphonse; Raiha, Tomi Samuli; Rak, Jan; Rakotozafindrabe, Andry Malala; Ramello, Luciano; Ramirez Reyes, Abdiel; Raniwala, Rashmi; Raniwala, Sudhir; Rasanen, Sami Sakari; Rascanu, Bogdan Theodor; Rathee, Deepika; Read, Kenneth Francis; Real, Jean-Sebastien; Redlich, Krzysztof; Reichelt, Patrick; Reicher, Martijn; Renfordt, Rainer Arno Ernst; Reolon, Anna Rita; Reshetin, Andrey; Rettig, Felix Vincenz; Revol, Jean-Pierre; Reygers, Klaus Johannes; Riccati, Lodovico; Ricci, Renato Angelo; Richert, Tuva; Richter, Matthias Rudolph; Riedler, Petra; Riegler, Werner; Riggi, Francesco; Rodrigues Fernandes Rabacal, Bartolomeu; Rodriguez Cahuantzi, Mario; Rodriguez Manso, Alis; Roed, Ketil; Rohr, David; Rohrich, Dieter; Romita, Rosa; Ronchetti, Federico; Rosnet, Philippe; Rossegger, Stefan; Rossi, Andrea; Roy, Christelle Sophie; Roy, Pradip Kumar; Rubio Montero, Antonio Juan; Rui, Rinaldo; Russo, Riccardo; Ryabinkin, Evgeny; Rybicki, Andrzej; Sadovsky, Sergey; Safarik, Karel; Sahoo, Raghunath; Sahu, Pradip Kumar; Saini, Jogender; Sakaguchi, Hiroaki; Sakai, Shingo; Sakata, Dosatsu; Salgado, Carlos Albert; Salzwedel, Jai; Sambyal, Sanjeev Singh; Samsonov, Vladimir; Sanchez Castro, Xitzel; Sandor, Ladislav; Sandoval, Andres; Sano, Satoshi; Sano, Masato; Santo, Rainer; Santoro, Romualdo; Sarkamo, Juho Jaako; Scapparone, Eugenio; Scarlassara, Fernando; Scharenberg, Rolf Paul; Schiaua, Claudiu Cornel; Schicker, Rainer Martin; Schmidt, Christian Joachim; Schmidt, Hans Rudolf; Schreiner, Steffen; Schuchmann, Simone; Schukraft, Jurgen; Schutz, Yves Roland; Schwarz, Kilian Eberhard; Schweda, Kai Oliver; Scioli, Gilda; Scomparin, Enrico; Scott, Rebecca; Segato, Gianfranco; Selyuzhenkov, Ilya; Senyukov, Serhiy; Seo, Jeewon; Serci, Sergio; Serradilla, Eulogio; Sevcenco, Adrian; Shabetai, Alexandre; Shabratova, Galina; Shahoyan, Ruben; Sharma, Satish; Sharma, Natasha; Sharma, Rohini; Shigaki, Kenta; Shimomura, Maya; Shtejer, Katherin; Sibiriak, Yury; Siciliano, Melinda; Sicking, Eva; Siddhanta, Sabyasachi; Siemiarczuk, Teodor; Silvermyr, David Olle Rickard; Silvestre, Catherine; Simatovic, Goran; Simonetti, Giuseppe; Singaraju, Rama Narayana; Singh, Ranbir; Singha, Subhash; Singhal, Vikas; Sinha, Bikash; Sinha, Tinku; Sitar, Branislav; Sitta, Mario; Skaali, Bernhard; Skjerdal, Kyrre; Smakal, Radek; Smirnov, Nikolai; Snellings, Raimond; Sogaard, Carsten; Soltz, Ron Ariel; Son, Hyungsuk; Song, Jihye; Song, Myunggeun; Soos, Csaba; Soramel, Francesca; Sputowska, Iwona; Spyropoulou-Stassinaki, Martha; Srivastava, Brijesh Kumar; Stachel, Johanna; Stan, Ionel; Stan, Ionel; Stefanek, Grzegorz; Steinpreis, Matthew; Stenlund, Evert Anders; Steyn, Gideon Francois; Stiller, Johannes Hendrik; Stocco, Diego; Stolpovskiy, Mikhail; Strabykin, Kirill; Strmen, Peter; Suaide, Alexandre Alarcon do Passo; Subieta Vasquez, Martin Alfonso; Sugitate, Toru; Suire, Christophe Pierre; Sukhorukov, Mikhail; Sultanov, Rishat; Sumbera, Michal; Susa, Tatjana; Symons, Timothy; Szanto de Toledo, Alejandro; Szarka, Imrich; Szczepankiewicz, Adam; Szostak, Artur Krzysztof; Szymanski, Maciej; Takahashi, Jun; Tapia Takaki, Daniel Jesus; Tauro, Arturo; Tejeda Munoz, Guillermo; Telesca, Adriana; Terrevoli, Cristina; Thader, Jochen Mathias; Thomas, Deepa; Tieulent, Raphael Noel; Timmins, Anthony; Tlusty, David; Toia, Alberica; Torii, Hisayuki; Toscano, Luca; Trubnikov, Victor; Truesdale, David Christopher; Trzaska, Wladyslaw Henryk; Tsuji, Tomoya; Tumkin, Alexandr; Turrisi, Rosario; Tveter, Trine Spedstad; Ulery, Jason Glyndwr; Ullaland, Kjetil; Ulrich, Jochen; Uras, Antonio; Urban, Jozef; Urciuoli, Guido Marie; Usai, Gianluca; Vajzer, Michal; Vala, Martin; Valencia Palomo, Lizardo; Vallero, Sara; Vande Vyvre, Pierre; van Leeuwen, Marco; Vannucci, Luigi; Vargas, Aurora Diozcora; Varma, Raghava; Vasileiou, Maria; Vasiliev, Andrey; Vechernin, Vladimir; Veldhoen, Misha; Venaruzzo, Massimo; Vercellin, Ermanno; Vergara, Sergio; Vernet, Renaud; Verweij, Marta; Vickovic, Linda; Viesti, Giuseppe; Vikhlyantsev, Oleg; Vilakazi, Zabulon; Villalobos Baillie, Orlando; Vinogradov, Yury; Vinogradov, Leonid; Vinogradov, Alexander; Virgili, Tiziano; Viyogi, Yogendra; Vodopianov, Alexander; Voloshin, Kirill; Voloshin, Sergey; Volpe, Giacomo; von Haller, Barthelemy; Vranic, Danilo; Øvrebekk, Gaute; Vrlakova, Janka; Vulpescu, Bogdan; Vyushin, Alexey; Wagner, Vladimir; Wagner, Boris; Wan, Renzhuo; Wang, Dong; Wang, Mengliang; Wang, Yaping; Wang, Yifei; Watanabe, Kengo; Weber, Michael; Wessels, Johannes; Westerhoff, Uwe; Wiechula, Jens; Wikne, Jon; Wilde, Martin Rudolf; Wilk, Alexander; Wilk, Grzegorz Andrzej; Williams, Crispin; Windelband, Bernd Stefan; Xaplanteris Karampatsos, Leonidas; Yaldo, Chris G; Yamaguchi, Yorito; Yang, Shiming; Yang, Hongyan; Yasnopolsky, Stanislav; Yi, JunGyu; Yin, Zhongbao; Yoo, In-Kwon; Yoon, Jongik; Yu, Weilin; Yuan, Xianbao; Yushmanov, Igor; Zaccolo, Valentina; Zach, Cenek; Zampolli, Chiara; Zaporozhets, Sergey; Zarochentsev, Andrey; Zavada, Petr; Zaviyalov, Nikolai; Zbroszczyk, Hanna Paulina; Zelnicek, Pierre; Zgura, Sorin Ion; Zhalov, Mikhail; Zhang, Xiaoming; Zhang, Haitao; Zhou, Fengchu; Zhou, You; Zhou, Daicui; Zhu, Jianhui; Zhu, Xiangrong; Zhu, Jianlin; Zichichi, Antonino; Zimmermann, Alice; Zinovjev, Gennady; Zoccarato, Yannick Denis; Zynovyev, Mykhaylo; Zyzak, Maksym

2013-04-10

The production cross section of electrons from semileptonic decays of beauty hadrons was measured at mid-rapidity (|y| < 0.8) in the transverse momentum range 1 < pt < 8 Gev/c with the ALICE experiment at the CERN LHC in pp collisions at a center of mass energy $\\sqrt{s}$ = 7 TeV using an integrated luminosity of 2.2 nb$^{-1}$. Electrons from beauty hadron decays were selected based on the displacement of the decay vertex from the collision vertex. A perturbative QCD calculation agrees with the measurement within uncertainties. The data were extrapolated to the full phase space to determine the total cross section for the production of beauty quark-antiquark pairs.

Resonant Ion Pair Formation in Electron Collisions with Ground State Molecular Ions

International Nuclear Information System (INIS)

Zong, W.; Dunn, G.H.; Djuric, N.; Greene, C.H.; Neau, A.; Zong, W.; Larsson, M.; Al-Khalili, A.; Neau, A.; Derkatch, A.M.; Vikor, L.; Shi, W.; Rosen, S.; Le Padellec, A.; Danared, H.; Ugglas, M. af

1999-01-01

Resonant ion pair formation from collisions of electrons with ground state diatomic molecular ions has been observed and absolute cross sections measured. The cross section for HD + is characterized by an abrupt threshold at 1.9thinspthinspeV and 14 resolved peaks in the range of energies 0≤E≤14 eV . The dominant mechanism responsible for the structures appears to be resonant capture and stabilization, modified by two-channel quantum interference. Data on HF + show structure correlated with photoionization of HF and with dissociative recombination of electrons with this ion. copyright 1999 The American Physical Society

Electron collisions in noble gases

International Nuclear Information System (INIS)

Barros, H.G. P.L. de.

1973-12-01

Calculations for excitation cross section for some states of He and Ne by electron impact have been carried out. A parametrization of total and differential cross section in the Born-Ochkur approximation has been proposed. Using this parametrization and appropriated wave functions for the states involved in the collisions processes, the possibility of inversion of population in the He-Ne laser has been studied

Fine-structure excitation of Fe II and Fe III due to collisions with electrons

Science.gov (United States)

Wan, Yier; Qi, Yueying; Favreau, Connor; Loch, Stuart; Stancil, P.; Ballance, Connor; McLaughlin, Brendan

2018-06-01

Atomic data of iron peak elements are of great importance in astronomical observations. Among all the ionization stages of iron, Fe II and Fe III are of particular importance because of the high cosmic abundance, relatively low ionization potential and complex open d-shell atomic structure. Fe II and Fe III emission are observed from nearly all classes of astronomical objects over a wide spectral range from the infrared to the ultraviolet. To meaningfully interpret these spectra, astronomers have to employ highly complex modeling codes with reliable collision data to simulate the astrophysical observations. The major aim of this work is to provide reliable atomic data for diagnostics. We present new collision strengths and effective collisions for electron impact excitation of Fe II and Fe III for the forbidden transitions among the fine-structure levels of the ground terms. A very fine energy mesh is used for the collision strengths and the effective collision strengths are calculated over a wide range of electron temperatures of astrophysical importance (10-2000 K). The configuration interaction state wave functions are generated with a scaled Thomas-Fermi-Dirac-Amaldi (TFDA) potential, while the R-matrix plus intermediate coupling frame transformation (ICFT), Breit-Pauli R-matrix and Dirac R-matrix packages are used to obtain collision strengths. Influences of the different methods and configuration expansions on the collisional data are discussed. Comparison is made with earlier theoretical work and differences are found to occur at the low temperatures considered here.This work was funded by NASA grant NNX15AE47G.

COINCIDENCES BETWEEN ELECTRONS AND TARGET IONS TO IDENTIFY CAPTURE CHANNELS IN COLLISIONS OF MULTIPLY CHARGED IONS ON GAS TARGETS

NARCIS (Netherlands)

POSTHUMUS, JH; MORGENSTERN, R

1992-01-01

We have investigated multielectron capture processes in collisions of Ar9+ on Ar by measuring the resulting Auger electrons in coincidence with charge-state-analyzed target ions. In this way it was possible to reconstruct partial electron energy spectra, each corresponding to a particular number of

Studies of electron collisions with polyatomic molecules using distributed-memory parallel computers

International Nuclear Information System (INIS)

Winstead, C.; Hipes, P.G.; Lima, M.A.P.; McKoy, V.

1991-01-01

Elastic electron scattering cross sections from 5--30 eV are reported for the molecules C 2 H 4 , C 2 H 6 , C 3 H 8 , Si 2 H 6 , and GeH 4 , obtained using an implementation of the Schwinger multichannel method for distributed-memory parallel computer architectures. These results, obtained within the static-exchange approximation, are in generally good agreement with the available experimental data. These calculations demonstrate the potential of highly parallel computation in the study of collisions between low-energy electrons and polyatomic gases. The computational methodology discussed is also directly applicable to the calculation of elastic cross sections at higher levels of approximation (target polarization) and of electronic excitation cross sections

Linear algebraic approach to electron-molecule collisions

International Nuclear Information System (INIS)

Schneider, B.I.; Collins, L.A.

1983-01-01

The various levels of sophistication of the linear algebraic method are discussed and its application to electron-molecule collisions of H 2 , N 2 LiH, LiF and HCl is described. 13 references, 2 tables

Theoretical interpretation of high-energy nuclear collisions

International Nuclear Information System (INIS)

Fai, G.

1991-07-01

Nuclear collision data are interpreted theoretically. The nuclear equation of state is investigated with particular emphasis on momentum-dependent mean field effects. Subnucleonic degrees of freedom are invoked at high energies and densities, and a short length-scales. A nontopological soliton model for baryons is studied in which effective meson fields are generated from extended quark-antiquark pairs. The major objective of this nuclear theory project is a better understanding of the properties of strongly interacting matter on the nuclear energy scale, as manifested in high-energy heavy-ion collisions

Di-electron spectroscopy in HADES and CBM. From p+p and n+p collisions at GSI to Au+Au collisions at FAIR

International Nuclear Information System (INIS)

Galatyuk, Tetyana

2009-01-01

In this work the di-electron production in p+p and d+p reactions at a kinetic beam energy of 1.25 GeV/u measured by the HADES spectrometer is discussed. At E kin =1.25 GeV/u, i.e. below the η meson production threshold in proton-proton reactions, the Δ Dalitz decay is expected to be the most abundant source above the π 0 Dalitz decay region. The observed large difference in di-electron production in p+p and d+p collisions suggests that di-electron production in the d+p system is dominated by the n+p interaction. In order to separate Δ Dalitz decays and np bremsstrahlung the di-electron yield observed in p+p and n+p reactions, both measured at the same beam energy, has been compared. The main interest here is the investigation of iso-spin effects in baryonic resonance excitations and the off-shell production of vector mesons. We indeed observe a large difference in di-electron production in p+p and n+p reactions. Results of these studies will be compared to recent calculations. We will also present our experimentally defined cocktail for heavy-ion data. A strong excess of lepton pairs observed by recent high energy heavy-ion dilepton experiments hint to a strong influence of baryons, however no data exist at highly compressed baryonic matter, achievable in heavy-ion collisions from 8.45 GeV/u beam energy. These conditions would allow to study the expected restoration of chiral symmetry by measuring in-medium modifications of hadronic properties, an experimental program which is foreseen by the future CBM experiment at FAIR. The experimental challenge is to suppress the large physical background on the one hand and to provide a clean identification of electrons on the other hand. In this work, strategies to reduce the combinatorial background in electron pair measurements with the CBM detector are discussed. The main goal is to study the feasibility of effectively reducing combinatorial background with the currently foreseen experimental setup, which does not

Di-electron spectroscopy in HADES and CBM. From p+p and n+p collisions at GSI to Au+Au collisions at FAIR

Energy Technology Data Exchange (ETDEWEB)

Galatyuk, Tetyana

2009-07-17

In this work the di-electron production in p+p and d+p reactions at a kinetic beam energy of 1.25 GeV/u measured by the HADES spectrometer is discussed. At E{sub kin}=1.25 GeV/u, i.e. below the {eta} meson production threshold in proton-proton reactions, the {delta} Dalitz decay is expected to be the most abundant source above the {pi}{sup 0} Dalitz decay region. The observed large difference in di-electron production in p+p and d+p collisions suggests that di-electron production in the d+p system is dominated by the n+p interaction. In order to separate {delta} Dalitz decays and np bremsstrahlung the di-electron yield observed in p+p and n+p reactions, both measured at the same beam energy, has been compared. The main interest here is the investigation of iso-spin effects in baryonic resonance excitations and the off-shell production of vector mesons. We indeed observe a large difference in di-electron production in p+p and n+p reactions. Results of these studies will be compared to recent calculations. We will also present our experimentally defined cocktail for heavy-ion data. A strong excess of lepton pairs observed by recent high energy heavy-ion dilepton experiments hint to a strong influence of baryons, however no data exist at highly compressed baryonic matter, achievable in heavy-ion collisions from 8.45 GeV/u beam energy. These conditions would allow to study the expected restoration of chiral symmetry by measuring in-medium modifications of hadronic properties, an experimental program which is foreseen by the future CBM experiment at FAIR. The experimental challenge is to suppress the large physical background on the one hand and to provide a clean identification of electrons on the other hand. In this work, strategies to reduce the combinatorial background in electron pair measurements with the CBM detector are discussed. The main goal is to study the feasibility of effectively reducing combinatorial background with the currently foreseen experimental

Solution of the non-stationary electron Boltzmann equation for a weakly ionized collision dominated plasma

International Nuclear Information System (INIS)

Winkler, R.; Wilhelm, J.

A detailed description is presented of calculating the nonstationary electron distribution function in a weakly ionized collision-dominated plasma from the Boltzmann kinetic equation respecting the effects of the time-dependent electric field, collision processes and the electron formation and loss. The finite difference approximation was used for numerical solution. Using the Crank-Nicolson method and parabolic interpolation between the grid points the Boltzmann equation was transformed to a system of linear equations which was then solved by iterations at a preset accuracy. Using the calculated distribution function values, the macroscopic plasma parameters were determined and the balance of electron density and energy checked in each time step. The mathematical procedure is illustrated using a neon plasma perturbed by a rectangular electric pulse. The time development shown of the distribution function at moments when the pulse was switched on and off demonstrates the great stability of the numerical solution. (J.U.)

Electron-hydrogen collisions with dressed target and Volkov projectile states in a laser field

International Nuclear Information System (INIS)

Smith, P.H.G.; Flannery, M.R.

1992-01-01

Cross sections for the 1S-2S and 1S-2P O transitions in laser-assisted e - -H(1S) collisions are calculated in both the multi-channel eikonal treatment and the Born wave approximation, as a function of impact energy and laser field intensity. The laser considered is a monotonic, plane-polarized CO 2 laser (photon energy = 0.117 eV) with the polarization direction parallel to the initial projectile velocity. The first part of this paper confines the laser perturbation to the bound electrons of the atom. The second part extends the laser perturbation to the projectile electron, and the familiar Volkov dressed states are used. (author)

Differential cross sections for single-electron capture in He{sup 2+}-D collisions

Energy Technology Data Exchange (ETDEWEB)

Bordenave-Montesquieu, D.; Dagnac, R. [Centre National de la Recherche Scientifique (CNRS), 31 - Toulouse (France)]|[Toulouse-3 Univ., 31 (France)

1995-06-14

A translational energy spectroscopy technique was used to study single-electron capture into the He{sup +} (n = 2) and He{sup +} (n 3) states in He{sup 2+}-D collisions. Differential cross sections were determined at 4, 6 and 8 keV in the angular range 5`-1{sup o}30` (laboratory frame). As expected, single-electron capture into the n = 2 state was found to be the dominant process; total cross sections for capture into the He{sup +} (n = 3) state were compared to other experimental and theoretical results. (author).

Momentum spectra for single and double electron ionization of He in relativistic collisions

International Nuclear Information System (INIS)

Wood, C.J.; Olson, R.E.

1997-08-01

The complete momentum spectra for single and double ionization of He by 1GeV/u (β=0.88) U 92+ have been investigated using a classical trajectory Monte Carlo method corrected for the relativistic projectile. The 1/r 12 electron-electron interaction has been included in the post-collision region for double ionization to incorporate the effects of both the nuclear-electron and electron-electron ionizing interactions, and to access the effects of electron correlation in the electron spectra. Experimental measurements were able to determine the longitudinal momentum spectra for single ionization; these observations are in accordance with the theoretical predictions for the three-body momentum balance between projectile, recoil ion, and ionized electron. In particular, the Lorentz contraction of the Coulomb interaction of the projectile manifests itself in the decrease of the post-collision interaction of the projectile with the electron and recoil ion, causing them to recoil back-to-back as in the case for a short electromagnetic pulse. This feature is clearly displayed in both the theoretical and experimental longitudinal momentum spectra, and by comparing to calculations that are performed at the same collision speed but do not include the relativistic potentials. Moreover, collision plane spectra of the three particles demonstrate that the momenta of the recoil ion and ionized electron are preferentially equal, and opposite, to each other. The electron spectra for double ionization show that the inclusion of the electron-electron interaction in the post-collision regime partitions the combined ionization momentum of the electrons so that the electrons are preferentially emitted in opposite azimuthal angles to one another. This is in contrast to calculations made assuming independent electrons. (orig.)

Measurements of Pair Production and Electron Capture from the Continuum in Heavy Particle Collisions

CERN Multimedia

2002-01-01

Large transient Coulomb fields, which are generated in collisions of high-Z systems at sufficiently high energies, lead to copious production of electron-positron pairs. It has been suggested that these lepton pairs might mask signals arising from plasma phase interaction. Pair-production cross sections have been calculated by several authors with results which differ significantly from each other. Some of the electrons produced may be captured into bound states of the ion, thereby, reducing its charge state by one unit. This process which has been termed ``Electron Capture from Pair Production``, represents the only electron capture pro which increases with energy, and as such, will dominate all others in the ultrarelativistic energy regime. Ions having undergone this process would be lost from storage-type accelerators. The absolute cross sections for capture have been calculated with results which differ by as much as an order of magnitude. If as large as some of the calculations predict, Relativistic Heav...

Electron collision frequency variations and electric fields in the lower ionosphere

International Nuclear Information System (INIS)

Gokov, A.M.; Martynenko, S.I.

1997-01-01

Distribution of relative variations of the electron effective collision frequency at the ionosphere lower boundary is determined on the basis of analysis of radio-signals partially reflected from the lower ionosphere. Technique to evaluate the strength of electrical fields at the ionosphere lower boundary using experimentally measured variations of the effective frequency of electron collisions is elaborated. 12 refs., 2 figs

Global flow of glasma in high energy nuclear collisions

Energy Technology Data Exchange (ETDEWEB)

Chen, Guangyao; Fries, Rainer J., E-mail: rjfries@comp.tamu.edu

2013-06-25

We discuss the energy flow of the classical gluon fields created in collisions of heavy nuclei at collider energies. We show how the Yang–Mills analog of Faraday's Law and Gauss' Law predicts the initial gluon flux tubes to expand or bend. The resulting transverse and longitudinal structure of the Poynting vector field has a rich phenomenology. Besides the well-known radial and elliptic flow in transverse direction, classical quantum chromodynamics predicts a rapidity-odd transverse flow that tilts the fireball for non-central collisions, and it implies a characteristic flow pattern for collisions of non-symmetric systems A+B. The rapidity-odd transverse flow translates into a directed particle flow v{sub 1} which has been observed at RHIC and LHC. The global flow fields in heavy ion collisions could be a powerful check for the validity of classical Yang–Mills dynamics in high energy collisions.

Dynamics in ion-molecule collisions at high velocities: One- and two-electron processes

International Nuclear Information System (INIS)

Wang, Yudong.

1992-01-01

This dissertation addresses the dynamic interactions in ion-molecule collisions. Theoretical methods are developed for single and multiple electron transitions in fast collisions with diatomic molecules by heavy-ion projectiles. Various theories and models are developed to treat the three basic inelastic processes (excitation, ionization and charge transfer) involving one and more electrons. The development, incorporating the understanding of ion-atom collision theories with some unique characteristics for molecular targets, provides new insights into phenomena that are absent from collisions with atomic targets. The influence from the multiple scattering centers on collision dynamics is assessed. For diatomic molecules, effects due to a fixed molecular orientation or alignment are calculated and compared with available experimental observations. Compared with excitation and ionization, electron capture, which probes deeper into the target, presents significant two-center interference and strong orientation dependence. Attention has been given in this dissertation to exploring mechanisms for two-and multiple electron transitions. Application of independent electron approximation to transfer excitation from molecular hydrogen is studied. Electron-electron interaction originated from projectile and target nuclear centers is studied in conjunction with the molecular nature of target. Limitations of the present theories and models as well as possible new areas for future theoretical and experimental applications are also discussed. This is the first attempt to describe multi-electron processes in molecular dynamics involving fast highly charged ions

Few electron transitions in atomic collisions. Final report, September 1, 1992--December 31, 1995

Energy Technology Data Exchange (ETDEWEB)

McGuire, J.

1997-04-01

During the past three years we have evaluated probabilities and cross sections for few and multiple electron transitions in atomic collisions. Our studies included interactions of atoms and molecules with incident protons, bare ions, electrons, positrons, anti-protons, ions carrying electrons and photons. We also: studied the inter-relation between collisions with charged particles and collisions involving various processes with photons. This work has complemented various studies of collisions of atoms with charged particles and with photons as well as more general efforts to understand the nature of multi-electron systems. Our aim has been to begin with relatively simple two electron systems and to focus on fast processes in which there is too little time for complicated processes to occur. We have used a variety of computational techniques, but we emphasize those appropriate for fast collisions in which we hope to obtain insight into the physical nature of the process itself. We generally considered systems in which experimental data was available.

Transverse-momentum and collision-energy dependence of high-pT hadron suppression in Au+Au collisions at ultrarelativistic energies.

Science.gov (United States)

Adams, J; Adler, C; Aggarwal, M M; Ahammed, Z; Amonett, J; Anderson, B D; Anderson, M; Arkhipkin, D; Averichev, G S; Badyal, S K; Balewski, J; Barannikova, O; Barnby, L S; Baudot, J; Bekele, S; Belaga, V V; Bellwied, R; Berger, J; Bezverkhny, B I; Bhardwaj, S; Bhaskar, P; Bhati, A K; Bichsel, H; Billmeier, A; Bland, L C; Blyth, C O; Bonner, B E; Botje, M; Boucham, A; Brandin, A; Bravar, A; Cadman, R V; Cai, X Z; Caines, H; Calderón de la Barca Sánchez, M; Carroll, J; Castillo, J; Castro, M; Cebra, D; Chaloupka, P; Chattopadhyay, S; Chen, H F; Chen, Y; Chernenko, S P; Cherney, M; Chikanian, A; Choi, B; Christie, W; Coffin, J P; Cormier, T M; Cramer, J G; Crawford, H J; Das, D; Das, S; Derevschikov, A A; Didenko, L; Dietel, T; Dong, X; Draper, J E; Drees, K A; Du, F; Dubey, A K; Dunin, V B; Dunlop, J C; Dutta Majumdar, M R; Eckardt, V; Efimov, L G; Emelianov, V; Engelage, J; Eppley, G; Erazmus, B; Fachini, P; Faine, V; Faivre, J; Fatemi, R; Filimonov, K; Filip, P; Finch, E; Fisyak, Y; Flierl, D; Foley, K J; Fu, J; Gagliardi, C A; Ganti, M S; Gagunashvili, N; Gans, J; Gaudichet, L; Germain, M; Geurts, F; Ghazikhanian, V; Ghosh, P; Gonzalez, J E; Grachov, O; Grigoriev, V; Gronstal, S; Grosnick, D; Guedon, M; Guertin, S M; Gupta, A; Gushin, E; Gutierrez, T D; Hallman, T J; Hardtke, D; Harris, J W; Heinz, M; Henry, T W; Heppelmann, S; Herston, T; Hippolyte, B; Hirsch, A; Hjort, E; Hoffmann, G W; Horsley, M; Huang, H Z; Huang, S L; Humanic, T J; Igo, G; Ishihara, A; Jacobs, P; Jacobs, W W; Janik, M; Johnson, I; Jones, P G; Judd, E G; Kabana, S; Kaneta, M; Kaplan, M; Keane, D; Kiryluk, J; Kisiel, A; Klay, J; Klein, S R; Klyachko, A; Kollegger, T; Konstantinov, A S; Kopytine, M; Kotchenda, L; Kovalenko, A D; Kramer, M; Kravtsov, P; Krueger, K; Kuhn, C; Kulikov, A I; Kumar, A; Kunde, G J; Kunz, C L; Kutuev, R Kh; Kuznetsov, A A; Lamont, M A C; Landgraf, J M; Lange, S; Lansdell, C P; Lasiuk, B; Laue, F; Lauret, J; Lebedev, A; Lednický, R; Leontiev, V M; LeVine, M J; Li, C; Li, Q; Lindenbaum, S J; Lisa, M A; Liu, F; Liu, L; Liu, Z; Liu, Q J; Ljubicic, T; Llope, W J; Long, H; Longacre, R S; Lopez-Noriega, M; Love, W A; Ludlam, T; Lynn, D; Ma, J; Ma, Y G; Magestro, D; Mahajan, S; Mangotra, L K; Mahapatra, D P; Majka, R; Manweiler, R; Margetis, S; Markert, C; Martin, L; Marx, J; Matis, H S; Matulenko, Yu A; McShane, T S; Meissner, F; Melnick, Yu; Meschanin, A; Messer, M; Miller, M L; Milosevich, Z; Minaev, N G; Mironov, C; Mishra, D; Mitchell, J; Mohanty, B; Molnar, L; Moore, C F; Mora-Corral, M J; Morozov, V; de Moura, M M; Munhoz, M G; Nandi, B K; Nayak, S K; Nayak, T K; Nelson, J M; Nevski, P; Nikitin, V A; Nogach, L V; Norman, B; Nurushev, S B; Odyniec, G; Ogawa, A; Okorokov, V; Oldenburg, M; Olson, D; Paic, G; Pandey, S U; Pal, S K; Panebratsev, Y; Panitkin, S Y; Pavlinov, A I; Pawlak, T; Perevoztchikov, V; Peryt, W; Petrov, V A; Phatak, S C; Picha, R; Planinic, M; Pluta, J; Porile, N; Porter, J; Poskanzer, A M; Potekhin, M; Potrebenikova, E; Potukuchi, B V K S; Prindle, D; Pruneau, C; Putschke, J; Rai, G; Rakness, G; Raniwala, R; Raniwala, S; Ravel, O; Ray, R L; Razin, S V; Reichhold, D; Reid, J G; Renault, G; Retiere, F; Ridiger, A; Ritter, H G; Roberts, J B; Rogachevski, O V; Romero, J L; Rose, A; Roy, C; Ruan, L J; Rykov, V; Sahoo, R; Sakrejda, I; Salur, S; Sandweiss, J; Savin, I; Schambach, J; Scharenberg, R P; Schmitz, N; Schroeder, L S; Schweda, K; Seger, J; Seliverstov, D; Seyboth, P; Shahaliev, E; Shao, M; Sharma, M; Shestermanov, K E; Shimanskii, S S; Singaraju, R N; Simon, F; Skoro, G; Smirnov, N; Snellings, R; Sood, G; Sorensen, P; Sowinski, J; Spinka, H M; Srivastava, B; Stanislaus, S; Stock, R; Stolpovsky, A; Strikhanov, M; Stringfellow, B; Struck, C; Suaide, A A P; Sugarbaker, E; Suire, C; Sumbera, M; Surrow, B; Symons, T J M; Szanto de Toledo, A; Szarwas, P; Tai, A; Takahashi, J; Tang, A H; Thein, D; Thomas, J H; Tikhomirov, V; Tokarev, M; Tonjes, M B; Trainor, T A; Trentalange, S; Tribble, R E; Trivedi, M D; Trofimov, V; Tsai, O; Ullrich, T; Underwood, D G; Van Buren, G; VanderMolen, A M; Vasiliev, A N; Vasiliev, M; Vigdor, S E; Viyogi, Y P; Voloshin, S A; Waggoner, W; Wang, F; Wang, G; Wang, X L; Wang, Z M; Ward, H; Watson, J W; Wells, R; Westfall, G D; Whitten, C; Wieman, H; Willson, R; Wissink, S W; Witt, R; Wood, J; Wu, J; Xu, N; Xu, Z; Xu, Z Z; Yakutin, A E; Yamamoto, E; Yang, J; Yepes, P; Yurevich, V I; Zanevski, Y V; Zborovský, I; Zhang, H; Zhang, H Y; Zhang, W M; Zhang, Z P; Zołnierczuk, P A; Zoulkarneev, R; Zoulkarneeva, J; Zubarev, A N

2003-10-24

We report high statistics measurements of inclusive charged hadron production in Au+Au and p+p collisions at sqrt[s(NN)]=200 GeV. A large, approximately constant hadron suppression is observed in central Au+Au collisions for 5collision energy dependence of the yields and the centrality and p(T) dependence of the suppression provide stringent constraints on theoretical models of suppression. Models incorporating initial-state gluon saturation or partonic energy loss in dense matter are largely consistent with observations. We observe no evidence of p(T)-dependent suppression, which may be expected from models incorporating jet attenuation in cold nuclear matter or scattering of fragmentation hadrons.

Quantum-kinetic modeling of electron release in low-energy surface collisions of atoms and molecules

Energy Technology Data Exchange (ETDEWEB)

Marbach, Johannes

2012-09-20

In this work we present a theoretical description of electron release in the collision of atomic and molecular projectiles with metallic and especially dielectric surfaces. The associated electron yield, the secondary electron emission coefficient, is an important input parameter for numerical simulations of dielectric barrier discharges and other bounded low-temperature gas discharges. The available reference data for emission coefficients is, however, very sparse and often uncertain, especially for molecular projectiles. With the present work we aim to contribute to the filling of these gaps by providing a flexible and easy-to-use model that allows for a convenient calculation of the emission coefficient and related quantities for a wide range of projectile-surface systems and the most dominant reaction channels.

Quantum-kinetic modeling of electron release in low-energy surface collisions of atoms and molecules

International Nuclear Information System (INIS)

Marbach, Johannes

2012-01-01

In this work we present a theoretical description of electron release in the collision of atomic and molecular projectiles with metallic and especially dielectric surfaces. The associated electron yield, the secondary electron emission coefficient, is an important input parameter for numerical simulations of dielectric barrier discharges and other bounded low-temperature gas discharges. The available reference data for emission coefficients is, however, very sparse and often uncertain, especially for molecular projectiles. With the present work we aim to contribute to the filling of these gaps by providing a flexible and easy-to-use model that allows for a convenient calculation of the emission coefficient and related quantities for a wide range of projectile-surface systems and the most dominant reaction channels.

On the global ship hull bending energy in ship collisions

DEFF Research Database (Denmark)

Pedersen, Preben Terndrup; Li, Yujie

2009-01-01

During ship collisions part of the kinetic energy of the involved vessels immediately prior to contact is absorbed as energy dissipated by crushing of the hull structures, by friction and by elastic energy. The purpose of this report is to present an estimate of the elastic energy that can...... be stored in elastic hull vibrations during a ship collision. When a ship side is strengthened in order to improve the crashworthiness it has been argued in the scientific literature that a non-trivial part of the energy released for structural deformation during the collision can be absorbed as elastic...... energy in global ship hull vibrations, such that with strong ship sides less energy has to be spent in crushing of the striking ship bow and/or the struck ship side. In normal ship–ship collision analyses both the striking and struck ship are usually considered as rigid bodies where structural crushing...

Reaction mechanism in high energy heavy-ion collisions

International Nuclear Information System (INIS)

Tanihata, Isao.

1982-04-01

The reaction mechanism in high energy heavy-ion collision is discussed. The discussion is mainly based on the experimental data. Empirical equations have been given for the total cross-sections of nucleus-nucleus reactions and the reaction cross-sections. These cross-sections are well described by the geometrical size of the colliding nuclei. The cross-sections are also understood by microscopic calculation. The charged particle multiplicity gives additional information about the geometrical aspect of heavy ion collision. The data suggested that the total energy, independent of projectile size, is most important for determining the multiplicity. The inclusive proton spectrum in a heavy ion collision showed two distinct regions. The one is the fragment region, and the other the participant region. The spectral shapes of inclusive pion spectra are reasonably well explained by the Coulomb interaction of pions with nuclear fragments. The high energy heavy ion reaction occurs in the overlap region of the projectile and target. This has been tested by measuring the number of participants for various reactions. The space and the time structure of the collision are also discussed in this paper as well as the dynamical aspects of the collision. (Kato, T.)

A new type of interference phenomenon in cold collisions of electrons with N2

DEFF Research Database (Denmark)

Sulc, Miroslav; Curik, Roman; Ziesel, Jean-Pierre

2011-01-01

A novel cold collision phenomenon is described which is caused by interference within the manifold of electron waves of unit angular momentum (p-waves). Experimental electron scattering data in N2, down to energies of 10 meV, reveal this phenomenon through the angular distribution of scattered...... electrons. Ab initio theory, analytical results and a simple physical model illustrate how interference arises through the presence of a quadrupole on the target N2. The effect is of a general nature and may be found in all systems in which, in the cold regime, charged particles interact with target species...

Electron-positron-paircreation in heavy ion collisions

International Nuclear Information System (INIS)

Kienle, P.

1987-09-01

Recent experiments to study e + -e - paircreation in heavy ion atom collisions at energies close to the Coulomb barrier are reviewed. For high combined charges of the collision system Z u = Z 1 +Z 2 one finds pairs produced by the strong time changing Coulomb field with cross sections rising proportional to Z u 16 . The characteristics of the e + production line Z u and scattering angle dependence as well as their spectral distribution is well understood theoretically. Superimposed on the e + continua, e + lines were discovered with energies independent on Z u but with cross sections which rise with Z u 22 . The line energies are grouped around 250 and 340 keV for all systems with 164 u + -e - pairs. This is indicated by e + -e - coincidence experiments which show evidence for energy and angle correlated e + -e - emission expected for a particle decay. (orig.)

Momentum spectra for single and double electron ionization of He in relativistic collisions

International Nuclear Information System (INIS)

Anon.

1997-01-01

The complete momentum spectra for single and double ionization of He by 1-GeV/u (β=0.88) U 92+ have been investigated using a classical trajectory Monte Carlo method corrected for the relativistic projectile. The 1/r 12 electron-electron interaction has been included in the post-collision region for double ionization to incorporate the effects of both the nuclear-electron and electron-electron ionizing interactions, and to access the effects of electron correlation in the electron spectra. Experimental measurements were able to determine the longitudinal momentum spectra for single ionization; these observations are in accordance with the theoretical predictions for the three-body momentum balance between projectile, recoil ion, and ionized electron. In particular, the Lorentz contraction of the Coulomb interaction of the projectile manifests itself in the decrease of the post-collision interaction of the projectile with the electron and recoil ion, causing them to recoil back-to-back as in the case for a short electromagnetic pulse. This feature is clearly displayed in both the theoretical and experimental longitudinal momentum spectra, and by comparing to calculations that are performed at the same collision speed but do not include the relativistic potentials. Moreover, collision plane spectra of the three particles demonstrate that the momenta of the recoil ion and ionized electron are preferentially equal, and opposite, to each other. The electron spectra for double ionization show that the inclusion of the electron-electron interaction in the post-collision regime partitions the combined ionization momentum of the electrons so that the electrons are preferentially emitted in opposite azimuthal angles to one another. This is in contrast to calculations made assuming independent electrons. copyright 1997 The American Physical Society

Electron collisions with F2CO molecules

Science.gov (United States)

Freitas, Thiago Corrêa; Barbosa, Alessandra Souza; Bettega, Márcio Henrique Franco

2017-07-01

In this paper we present elastic differential, integral, and momentum-transfer cross sections for electron collisions with carbonyl fluoride (F2CO ) molecules for the incident electron's energy from 0.5 eV to 20 eV. The Schwinger multichannel method with pseudopotentials was employed to obtain the cross sections in the static-exchange and static-exchange plus polarization approximations. The present results were compared with the available data in the literature, in particular, with the results of Kaur, Mason, and Antony [Phys. Rev. A 92, 052702 (2015), 10.1103/PhysRevA.92.052702] for the differential, total, and momentum-transfer cross sections. We have found a π* shape resonance centered at 2.6 eV in the B1 symmetry and other resonance, in the B2 symmetry, located at around 9.7 eV. A systematic study of the inclusion of polarization effects was performed in order to have a well balanced description of this negative-ion transient state. The effects of the long-range electric dipole potential were included by the Born closure scheme. Electronic structure calculations were also performed to help in the interpretation of the scattering results, and associate the transient states to the unoccupied orbitals.

Signatures of quantum radiation reaction in laser-electron-beam collisions

International Nuclear Information System (INIS)

Wang, H. Y.; Yan, X. Q.; Zepf, M.

2015-01-01

Electron dynamics in the collision of an electron beam with a high-intensity focused ultrashort laser pulse are investigated using three-dimensional QED particle-in-cell (PIC) simulations, and the results are compared with those calculated by classical Landau and Lifshitz PIC simulations. Significant differences are observed from the angular dependence of the electron energy distribution patterns for the two different approaches, because photon emission is no longer well approximated by a continuous process in the quantum radiation-dominated regime. The stochastic nature of photon emission results in strong signatures of quantum radiation-reaction effects under certain conditions. We show that the laser spot size and duration greatly influence these signatures due to the competition of QED effects and the ponderomotive force, which is well described in the classical approximation. The clearest signatures of quantum radiation reaction are found in the limit of large laser spots and few cycle pulse durations

On the relativistic large-angle electron collision operator for runaway avalanches in plasmas

Science.gov (United States)

Embréus, O.; Stahl, A.; Fülöp, T.

2018-02-01

Large-angle Coulomb collisions lead to an avalanching generation of runaway electrons in a plasma. We present the first fully conservative large-angle collision operator, derived from the relativistic Boltzmann operator. The relation to previous models for large-angle collisions is investigated, and their validity assessed. We present a form of the generalized collision operator which is suitable for implementation in a numerical kinetic equation solver, and demonstrate the effect on the runaway-electron growth rate. Finally we consider the reverse avalanche effect, where runaways are slowed down by large-angle collisions, and show that the choice of operator is important if the electric field is close to the avalanche threshold.

One- and two-electron processes in collisions of heavy ions with H2 and He

International Nuclear Information System (INIS)

Richard, P.; Hall, J.; Shinpaugh, J.L.; Sanders, J.M.; Tipping, T.N.; Zouros, T.J.M.; Lee, D.H.; Schmidt-Boecking, H.

1987-01-01

In this paper we present a description of the apparatus and results for experiments involving one- and two-electron processes in collisions of heavy ions with H 2 and He. The experiments were performed using one-electron and bare projectiles. In the first section we describe the measurement of pure ionization of one-electron projectiles by H 2 targets and compare with previous results for He targets. We also present the results for one-electron capture by the projectile from H 2 targets. The energy dependence of the cross sections is compared to theoretical predictions for atomic and molecular hydrogen targets. Both experiments were performed by measuring only the final charge state of the projectile. In the second section we describe the measurement of partial cross sections for the same collisions by measuring the target recoil charge state in coincidence with the projectile charge state. By this method we can measure pure single- and double-ionization of the target, pure single-electron transfer and transfer ionization, and pure double-electron transfer. This experiment is presently being performed for bare flourine on He; however, absolute cross sections are not available at the time of this conference. (orig.)

First-principles investigation of the dissociation and coupling of methane on small copper clusters: Interplay of collision dynamics and geometric and electronic effects

Energy Technology Data Exchange (ETDEWEB)

Varghese, Jithin J.; Mushrif, Samir H., E-mail: shmushrif@ntu.edu.sg [School of Chemical and Biomedical Engineering, Nanyang Technological University, 62 Nanyang Drive, 637459 (Singapore)

2015-05-14

Small metal clusters exhibit unique size and morphology dependent catalytic activity. The search for alternate minimum energy pathways and catalysts to transform methane to more useful chemicals and carbon nanomaterials led us to investigate collision induced dissociation of methane on small Cu clusters. We report here for the first time, the free energy barriers for the collision induced activation, dissociation, and coupling of methane on small Cu clusters (Cu{sub n} where n = 2–12) using ab initio molecular dynamics and metadynamics simulations. The collision induced activation of the stretching and bending vibrations of methane significantly reduces the free energy barrier for its dissociation. Increase in the cluster size reduces the barrier for dissociation of methane due to the corresponding increase in delocalisation of electron density within the cluster, as demonstrated using the electron localisation function topology analysis. This enables higher probability of favourable alignment of the C–H stretching vibration of methane towards regions of high electron density within the cluster and makes higher number of sites available for the chemisorption of CH{sub 3} and H upon dissociation. These characteristics contribute in lowering the barrier for dissociation of methane. Distortion and reorganisation of cluster geometry due to high temperature collision dynamics disturb electron delocalisation within them and increase the barrier for dissociation. Coupling reactions of CH{sub x} (x = 1–3) species and recombination of H with CH{sub x} have free energy barriers significantly lower than complete dehydrogenation of methane to carbon. Thus, competition favours the former reactions at high hydrogen saturation on the clusters.

First-principles investigation of the dissociation and coupling of methane on small copper clusters: Interplay of collision dynamics and geometric and electronic effects

International Nuclear Information System (INIS)

Varghese, Jithin J.; Mushrif, Samir H.

2015-01-01

Small metal clusters exhibit unique size and morphology dependent catalytic activity. The search for alternate minimum energy pathways and catalysts to transform methane to more useful chemicals and carbon nanomaterials led us to investigate collision induced dissociation of methane on small Cu clusters. We report here for the first time, the free energy barriers for the collision induced activation, dissociation, and coupling of methane on small Cu clusters (Cu n where n = 2–12) using ab initio molecular dynamics and metadynamics simulations. The collision induced activation of the stretching and bending vibrations of methane significantly reduces the free energy barrier for its dissociation. Increase in the cluster size reduces the barrier for dissociation of methane due to the corresponding increase in delocalisation of electron density within the cluster, as demonstrated using the electron localisation function topology analysis. This enables higher probability of favourable alignment of the C–H stretching vibration of methane towards regions of high electron density within the cluster and makes higher number of sites available for the chemisorption of CH 3 and H upon dissociation. These characteristics contribute in lowering the barrier for dissociation of methane. Distortion and reorganisation of cluster geometry due to high temperature collision dynamics disturb electron delocalisation within them and increase the barrier for dissociation. Coupling reactions of CH x (x = 1–3) species and recombination of H with CH x have free energy barriers significantly lower than complete dehydrogenation of methane to carbon. Thus, competition favours the former reactions at high hydrogen saturation on the clusters

Multi-Electron Production at High Transverse Momenta in ep Collisions at HERA

CERN Document Server

Aktas, A.; Anthonis, T.; Asmone, A.; Babaev, A.; Backovic, S.; Bahr, J.; Baranov, P.; Barrelet, E.; Bartel, W.; Baumgartner, S.; Becker, J.; Beckingham, M.; Behnke, O.; Behrendt, O.; Belousov, A.; Berger, C.; Berndt, T.; Bizot, J.C.; Bohme, J.; Boenig, M.O.; Boudry, V.; Bracinik, J.; Braunschweig, W.; Brisson, V.; Broker, H.B.; Brown, D.P.; Bruncko, D.; Busser, F.W.; Bunyatyan, A.; Buschhorn, G.; Bystritskaya, L.; Campbell, A.J.; Caron, S.; Cassol-Brunner, F.; Chekelian, V.; Clarke, D.; Collard, C.; Contreras, J.G.; Coppens, Y.R.; Coughlan, J.A.; Cousinou, M.C.; Cox, B.E.; Cozzika, G.; Cvach, J.; Dainton, J.B.; Dau, W.D.; Daum, K.; Delcourt, B.; Delerue, N.; Demirchyan, R.; De Roeck, A.; De Wolf, E.A.; Diaconu, C.; Dingfelder, J.; Dodonov, V.; Dowell, J.D.; Dubak, A.; Duprel, C.; Eckerlin, Guenter; Efremenko, V.; Egli, S.; Eichler, R.; Eisele, F.; Ellerbrock, M.; Elsen, E.; Erdmann, M.; Erdmann, W.; Faulkner, P.J.W.; Favart, L.; Fedotov, A.; Felst, R.; Ferencei, J.; Fleischer, M.; Fleischmann, P.; Fleming, Y.H.; Flucke, G.; Flugge, G.; Fomenko, A.; Foresti, I.; Formanek, J.; Franke, G.; Frising, G.; Gabathuler, E.; Gabathuler, K.; Garvey, J.; Gassner, J.; Gayler, Joerg; Gerhards, R.; Gerlich, C.; Ghazaryan, Samvel; Goerlich, L.; Gogitidze, N.; Gorbounov, S.; Grab, C.; Grabski, V.; Grassler, H.; Greenshaw, T.; Gregori, M.; Grindhammer, Guenter; Haidt, D.; Hajduk, L.; Haller, J.; Heinzelmann, G.; Henderson, R.C.W.; Henschel, H.; Henshaw, O.; Heremans, R.; Herrera, G.; Herynek, I.; Hildebrandt, M.; Hiller, K.H.; Hladky, J.; Hoting, P.; Hoffmann, D.; Horisberger, R.; Hovhannisyan, A.; Ibbotson, M.; Jacquet, M.; Janauschek, L.; Janssen, X.; Jemanov, V.; Jonsson, L.; Johnson, C.; Johnson, D.P.; Jung, H.; Kant, D.; Kapichine, M.; Karlsson, M.; Katzy, J.; Keil, F.; Keller, N.; Kennedy, J.; Kenyon, I.R.; Kiesling, Christian M.; Klein, M.; Kleinwort, C.; Kluge, T.; Knies, G.; Koblitz, B.; Kolya, S.D.; Korbel, V.; Kostka, P.; Koutouev, R.; Kropivnitskaya, A.; Kroseberg, J.; Kueckens, J.; Kuhr, T.; Landon, M.P.J.; Lange, W.; Lastovicka, T.; Laycock, P.; Lebedev, A.; Leissner, B.; Lemrani, R.; Lendermann, V.; Levonian, S.; List, B.; Lobodzinska, E.; Loktionova, N.; Lopez-Fernandez, R.; Lubimov, V.; Lueders, H.; Luders, S.; Luke, D.; Lytkin, L.; Makankine, A.; Malden, N.; Malinovski, E.; Mangano, S.; Marage, P.; Marks, J.; Marshall, R.; Martyn, H.U.; Martyniak, J.; Maxfield, S.J.; Meer, D.; Mehta, A.; Meier, K.; Meyer, A.B.; Meyer, H.; Meyer, J.; Michine, S.; Mikocki, S.; Milstead, D.; Moreau, F.; Morozov, A.; Morris, J.V.; Muller, K.; Murin, P.; Nagovizin, V.; Naroska, B.; Naumann, J.; Naumann, T.; Newman, Paul R.; Niebergall, F.; Niebuhr, C.; Nikitin, D.; Nowak, G.; Nozicka, M.; Olivier, B.; Olsson, J.E.; Ozerov, D.; Pascaud, C.; Patel, G.D.; Peez, M.; Perez, E.; Petrukhin, A.; Pitzl, D.; Poschl, R.; Povh, B.; Raicevic, N.; Rauschenberger, J.; Reimer, P.; Reisert, B.; Risler, C.; Rizvi, E.; Robmann, P.; Roosen, R.; Rostovtsev, A.; Rusakov, S.; Rybicki, K.; Sankey, D.P.C.; Sauvan, E.; Schatzel, S.; Scheins, J.; Schilling, F.P.; Schleper, P.; Schmidt, D.; Schmidt, S.; Schmitt, S.; Schneider, M.; Schoeffel, L.; Schoning, A.; Schroder, V.; Schultz-Coulon, H.C.; Schwanenberger, C.; Sedlak, K.; Sefkow, F.; Sheviakov, I.; Shtarkov, L.N.; Sirois, Y.; Sloan, T.; Smirnov, P.; Soloviev, Y.; South, D.; Spaskov, V.; Specka, Arnd E.; Spitzer, H.; Stamen, R.; Stella, B.; Stiewe, J.; Strauch, I.; Straumann, U.; Thompson, Graham; Thompson, P.D.; Tomasz, F.; Traynor, D.; Truoel, Peter; Tsipolitis, G.; Tsurin, I.; Turnau, J.; Turney, J.E.; Tzamariudaki, E.; Uraev, A.; Urban, Marcel; Usik, A.; Valkar, S.; Valkarova, A.; Vallee, C.; Van Mechelen, P.; Vargas Trevino, A.; Vassiliev, S.; Vazdik, Y.; Veelken, C.; Vest, A.; Vichnevski, A.; Volchinski, V.; Wacker, K.; Wagner, J.; Waugh, B.; Weber, G.; Weber, R.; Wegener, D.; Werner, C.; Werner, N.; Wessels, M.; Wessling, B.; Winde, M.; Winter, G.G.; Wissing, C.; Woehrling, E.E.; Wunsch, E.; Zacek, J.; Zalesak, J.; Zhang, Z.; Zhokin, A.; Zomer, F.; zur Nedden, M.

2003-01-01

Multi-electron production is studied at high electron transverse momentum in positron- and electron-proton collisions using the H1 detector at HERA. The data correspond to an integrated luminosity of 115 pb-1. Di-electron and tri-electron event yields are measured. Cross sections are derived in a restricted phase space region dominated by photon-photon collisions. In general good agreement is found with the Standard Model predictions. However, for electron pair invariant masses above 100 GeV, three di-electron events and three tri-electron events are observed, compared to Standard Model expectations of 0.30 pm 0.04 and 0.23 pm 0.04, respectively.

Monte Carlo calculation of collisions of directionally-incident electrons on highly excited hydrogen atoms

International Nuclear Information System (INIS)

Kawakami, Kazuki; Fujimoto, Takasi

2001-01-01

We treat classically the n-, l- and m r -changing transitions and ionization. Excitation cross sections against the final state energy continue smoothly to the 'ionization cross sections'. The steady state populations determined by elastic collisions among the degenerate states in the same n level show higher populations in the m 1 =0 states, suggesting positive polarizations of Lyman lines emitted from plasmas having directional electrons. For ionization, the two outgoing electrons have large relative angles, suggesting reduced three body recombination rates for these plasmas. (author)

Charge transfer and excitation in high-energy ion-atom collisions

International Nuclear Information System (INIS)

Schlachter, A.S.; Berkner, K.H.; McDonald, R.J.

1986-11-01

Coincidence measurements of charge transfer and simultaneous projectile electron excitation provide insight into correlated two-electron processes in energetic ion-atom collisions. Projectile excitation and electron capture can occur simultaneously in a collision of a highly charged ion with a target atom; this process is called resonant transfer and excitation (RTE). The intermediate excited state which is thus formed can subsequently decay by photon emission or by Auger-electron emission. Results are shown for RTE in both the K shell of Ca ions and the L shell of Nb ions, for simultaneous projectile electron loss and excitation, and for the effect of RTE on electron capture

Semiclassical theory of resonance inelastic electron-molecule collisions

International Nuclear Information System (INIS)

Kazanskij, A.K.

1986-01-01

Semiclassical approach to the theory of resonance electron-molecule collisions, unlocal with respect to interatomic distance was developed. Two problems were considered: modified adiabatic approach for sigle-pole approximation of R-matrix and Fano-Feshbach-Bardsley theory. It is shown that these problems are similar in semiclassical approximation. A simple equation system with coefficients expressed in quadratures was obtained. It enables to determine amplitudes of all processes (including dissociation adhesion, association ejection, free-free and free-bound transitions) in energetic representation with respect to nucleus vibrations in molecule with allowance for both descrete and continuous spectra of nucleus motion in molecule. Quantitative investigation of the system results to the notion of dynamic energy curve of intermediate state, generalizing the motion of such curve in boomerang theory

On the Global Ship Hull Bending Energy in Ship Collisions

DEFF Research Database (Denmark)

Pedersen, Preben Terndrup; Li, Y.

2004-01-01

During ship collisions part of the kinetic energy of the involved vessels prior to contact is absorbed as energy dissipated by crushing of the hull structures, by friction and by elastic energy. The purpose of this report is to present an estimate of the elastic energy that can be stored in elastic...... hull vibrations during a ship collision. When a ship side is strengthened in order to improve the crashworthiness it has been argued in the scientific literature that a non trivial part of the energy released for structural deformation during the collision can be absorbed as elastic energy in global...... ship hull vibrations, such that with strong ship sides less energy has to be spent in crushing of the striking ship bow and/or the struck ship side. In normal ship-ship collision analyses both the striking and struck ship are usually considered as rigid bodies where structural crushing is confined...

Effect of collective response on electron capture and excitation in collisions of highly charged ions with fullerenes.

Science.gov (United States)

Kadhane, U; Misra, D; Singh, Y P; Tribedi, Lokesh C

2003-03-07

Projectile deexcitation Lyman x-ray emission following electron capture and K excitation has been studied in collisions of bare and Li-like sulphur ions (of energy 110 MeV) with fullerenes (C(60)/C(70)) and different gaseous targets. The intensity ratios of different Lyman x-ray lines in collisions with fullerenes are found to be substantially lower than those for the gas targets, both for capture and excitation. This has been explained in terms of a model based on "solidlike" effect, namely, wakefield induced stark mixing of the excited states populated via electron capture or K excitation: a collective phenomenon of plasmon excitation in the fullerenes under the influence of heavy, highly charged ions.

A theoretical study on the mechanism of electronic to vibrational energy transfer in Hg/3P/ + CO

Science.gov (United States)

Kato, S.; Jaffe, R. L.; Komornicki, A.; Morokuma, K.

1983-01-01

The mechanism of electronic-to-vibrational (E-V) energy transfer in Hg(3P) + CO collisions has been studied theoretically. The configuration interaction (CI) method was employed to calculate potential energy surfaces of the collision system. A simplified theoretical model, based on the reaction coordinate concept and the calculated potential energy characteristics, was used to discuss the mechanism of the singlet-triplet transition and the energy disposal in the collision. The results obtained were that: (a) the quenching process processed via a collision complex mechanism; and that (b) the triplet-singlet transition occurs near the collinear geometry. A model classical trajectory calculation gives a product CO vibrational distribution in good agreement with the experimental result.

Electron-positron pair production in ultrarelativistic atomic collisions: 6.4 TeV S16+ with Au, Pd and Al

International Nuclear Information System (INIS)

Datz, S.; Vane, C.R.; Dittner, P.F.; Krause, H.F.; Schuch, R.; Gao, H.; Hutton, R.

1994-01-01

Angular and momentum distributions have been measured for electron-positron pairs created in peripheral collisions of 6.4 TeV bare sulfur ions with thin targets of Al, Pd, and Au. Singly- and doubly-differential cross sections are presented for 1--17 MeV/c electrons and positrons detected independently and in coincidence as pairs. Various physical parameters are deduced from the coincident electron and positron data, including probability distributions for the pair transverse momentum, the pair total energy, and the positron fraction of the pair energy

Atomic scattering in the diffraction limit: electron transfer in keV Li+-Na(3s, 3p) collisions

DEFF Research Database (Denmark)

Poel, Mike van der; Nielsen, C.V.; Rybaltover, M.

2002-01-01

We measure angle differential cross sections (DCS) in Li+ + Na --> Li + Na+ electron transfer collisions in the 2.7-24 keV energy range. We do this with a newly constructed apparatus which combines the experimental technique of cold target recoil ion momentum spectroscopy with a laser-cooled target...... of the de Broglie wavelength lambda(dB) = 150 fm at a velocity v = 0.20 au and the effective atomic diameter for electron capture 2R = 20 au. Parallel AO and MO semiclassical coupled-channel calculations of the Na(3s, 3p) --> Li(2s, 2p) state-to-state collision amplitudes have been performed, and quantum...

Coulomb focusing and path'' interference of autoionizing electrons produced in 10 keV He sup + + He collisions

Energy Technology Data Exchange (ETDEWEB)

Swenson, J.K. (Lawrence Livermore National Lab., CA (USA)); Burgdoerfer, J. (Tennessee Univ., Knoxville, TN (USA)); Meyer, F.W.; Havener, C.C.; Gregory, D.C.; Stolterfoht, N. (Oak Ridge National Lab., TN (USA))

1991-03-13

Autoionizing electrons emitted following low energy ion-atom collisions may scatter significantly from the receding spectator ion's attractive Coulomb field. In such cases the observed electron intensity is focused'' in the direction of the scattering ion as a result of the effective compression of the emission solid angle. In addition, interference may occur between trajectories, corresponding to electrons scattering around opposite sides of the ion, which lead to the same final laboratory electron energy and emission angle. This Coulomb path'' interference mechanism manifests itself in the uncharacteristically rapid angular dependence of the He target 2s{sup 2} {sup 1}S autoionizing state measured near 0{degree} following low energy He{sup +} + He collisions. A classical trajectory model for Coulomb focusing is presented and a semi-classical approximation is used to model the Coulomb path'' interference mechanism. In this description we account for the evolution of the phase of the autoionizing state until its decay and the path dependence of the amplitude of the emitted electron following decay of the autoionizing state. Calculated model lineshapes, which include contributions from adjacent overlapping resonances, reproduce quite well the angular dependence observed in the data near 0{degree}. 14 refs., 7 figs.

Second-order symmetric eikonal approximation for electron capture at high energies

Energy Technology Data Exchange (ETDEWEB)

Deco, G R; Rivarola, R D [Rosario Univ. Nacional (Argentina). Dept. de Fisica

1985-06-14

A symmetric eikonal approximation for electron capture in ion-atom collisions at high energies has been developed within the Dodd and Greider (1966, Phys. Rev. 146 675) formalism. Implicit intermediate states are included through the choice of distorted initial and final wavefunctions. Explicit intermediate state are considered by the introduction of a free-particle Green's function G/sup +//sub 0/. The model is applied for the resonant charge exchange in H/sup +/+H(1s) collisions. Also, the characteristic dip of the continuum distorted-wave model is analysed when higher orders are included at 'realistic' high energies.

How does the Quark-Gluon Plasma know the collision energy?

Science.gov (United States)

McInnes, Brett

2018-02-01

Heavy ion collisions at the LHC facility generate a Quark-Gluon Plasma (QGP) which, for central collisions, has a higher energy density and temperature than the plasma generated in central collisions at the RHIC. But sufficiently peripheral LHC collisions give rise to plasmas which have the same energy density and temperature as the "central" RHIC plasmas. One might assume that the two versions of the QGP would have very similar properties (for example, with regard to jet quenching), but recent investigations have suggested that they do not: the plasma "knows" that the overall collision energy is different in the two cases. We argue, using a gauge-gravity analysis, that the strong magnetic fields arising in one case (peripheral collisions), but not the other, may be relevant here. If the residual magnetic field in peripheral LHC plasmas is of the order of at least eB ≈ 5mπ2, then the model predicts modifications of the relevant quenching parameter which approach those recently reported.

Electronic energy loss of fast molecules in matter

International Nuclear Information System (INIS)

Steinbeck, J.

1975-06-01

In high velocity collisions of molecular ions the correlated motion influence of the ion cores on the electronic energy loss is investigated. The stopping power in first Born approximation for a random arrangement of target atoms can be formulated in terms of the inelastic electronic structure factor. In treating the target atoms in Hartree-Fock approximation each electron can be regarded as stopping the ion independent of all other electrons without restriction by the Pauli principle. A second equivalent formulation of the stopping power leads to the dielectric function of the target. The results are applied to the stopping of H 2 + -ions. For vanishing distance between the two protons the stopping power per particle is twice that for single proton collisions. For distances in the order of the Bohr radius the correlated stopping power may even be smaller than for uncorrelated protons. With increasing distances the correlation influence vanishes. The stopping of H 2 + -ions in C, Si and Ge is discussed using Clementi wave functions for the core electrons and a free electron approximation with Lindhard's dielectric function for the valence electrons. The comparison with the only experimental result available for H 2 + in C at 300 keV yields qualitative agreement. (orig.) [de

High energy hadron-hadron collisions. Annual progress report

International Nuclear Information System (INIS)

Chou, T.T.

1979-03-01

Work on high energy hadron-hadron collisions in the geometrical model, performed under the DOE Contract No. EY-76-S-09-0946, is summarized. Specific items studied include the behavior of elastic hadron scatterings at super high energies and the existence of many dips, the computation of meson radii in the geometrical model, and the hadronic matter current effects in inelastic two-body collisions

Molecular (Feshbach) treatment of charge exchange Li3++He collisions. I. Energies and couplings

International Nuclear Information System (INIS)

Martin, F.; Riera, A.; Yanez, M.

1986-01-01

We point out a fundamental difference between the molecular treatment of charge exchange X/sup n/++H(1s) and X/sup n/++He(1s 2 ) collisions, which is that the latter process involves molecular states that are formally autoionizing. Then standard ab initio methods do not, in general, yield the relevant wave functions that are needed in the collision treatment, irrespective of whether quasimolecular autoionization be significant or not during the collision. We implement a particularly simple and useful form of the Feshbach formalism to calculate the energies of those two electron systems, and a method to evaluate the corresponding dynamical couplings is presented for the first time. Our implementation of this formalism together with the new computational techniques involved are presented in detail

A linear algebraic approach to electron-molecule collisions

International Nuclear Information System (INIS)

Collins, L.A.; Schnieder, B.I.

1982-01-01

The linear algebraic approach to electron-molecule collisions is examined by firstly deriving the general set of coupled integrodifferential equations that describe electron collisional processes and then describing the linear algebraic approach for obtaining a solution to the coupled equations. Application of the linear algebraic method to static-exchange, separable exchange and effective optical potential, is examined. (U.K.)

Investigation of plasma stream collision produced by thin films irradiated by powerful pulsed electron beam

International Nuclear Information System (INIS)

Efremov, V P; Demidov, B A; Ivkin, M V; Mescheryakov, A N; Petrov, V A; Potapenko, A I

2006-01-01

Collision of fast plasma streams in vacuum is investigated. Plasma streams were produced by irradiation of thin foils with a powerful pulsed electron beam. Interaction of the plasma flows was studied by using frame and streak cameras. One-dimensional numerical simulation was carried out. Application of this method for porous ICF targets and high-energy physics is discussed

Influence of Electron Molecule Resonant Vibrational Collisions over the Symmetric Mode and Direct Excitation-Dissociation Cross Sections of CO2 on the Electron Energy Distribution Function and Dissociation Mechanisms in Cold Pure CO2 Plasmas.

Science.gov (United States)

Pietanza, L D; Colonna, G; Laporta, V; Celiberto, R; D'Ammando, G; Laricchiuta, A; Capitelli, M

2016-05-05

A new set of electron-vibrational (e-V) processes linking the first 10 vibrational levels of the symmetric mode of CO2 is derived by using a decoupled vibrational model and inserted in the Boltzmann equation for the electron energy distribution function (eedf). The new eedf and dissociation rates are in satisfactory agreement with the corresponding ones obtained by using the e-V cross sections reported in the database of Hake and Phelps (H-P). Large differences are, on the contrary, found when the experimental dissociation cross sections of Cosby and Helm are inserted in the Boltzman equation. Comparison of the corresponding rates with those obtained by using the low-energy threshold energy, reported in the H-P database, shows differences up to orders of magnitude, which decrease with the increasing of the reduced electric field. In all cases, we show the importance of superelastic vibrational collisions in affecting eedf and dissociation rates either in the direct electron impact mechanism or in the pure vibrational mechanism.

Mechanical Energy Changes in Perfectly Inelastic Collisions

Science.gov (United States)

Mungan, Carl E.

2013-01-01

Suppose a block of mass "m"[subscript 1] traveling at speed "v"[subscript 1] makes a one-dimensional perfectly inelastic collision with another block of mass "m"[subscript 2]. What else does one need to know to calculate the fraction of the mechanical energy that is dissipated in the collision? (Contains 1 figure.)

Electronic excitations in fast ion-solid collisions

International Nuclear Information System (INIS)

Burgdoerfer, J.

1990-01-01

We review recent developments in the study of electronic excitation of projectiles in fast ion-solid collisions. Our focus will be primarily on theory but experimental advances will also be discussed. Topics include the evidence for velocity-dependent thresholds for the existence of bound states, wake-field effects on excited states, the electronic excitation of channeled projectiles, transport phenomena, and the interaction of highly charged ions with surfaces. 44 refs., 14 figs

Exotic phenomena in collisions of heavy ions

International Nuclear Information System (INIS)

Soff, G.; Schramm, S.; Reus, T. de; Mehler, G.; Reinhardt, J.; Mueller, B.; Greiner, W.; Mueller, U.

1985-08-01

To exemplify current theoretical investigations we discuss three different topics. After a presentation of the underlying theoretical framework for ionization processes we will sketch the possibility to employ delta-electron emission as a clock to measure nuclear reaction times in intermediate energy collisions of very heavy ions. Besides the phenomenon of vacuum decay into a new twofold negatively charged stable vacuum ground state, electron excitation in heavy ion collisions may be employed for the determination of delay and deceleration times on the nuclear time scale, i.e. offering an atomic clock, operating in the range 10 -21 -10 -24 s. In deep-inelastic heavy ion collisions this provides a test for classical nuclear reaction models. In collisions at intermediate energies an independent measurement of the deceleration time is of interest for comparison, e.g., with the results of the pion bremsstrahlung model. After that we investigate the influence of one or more pockets in the ion scattering potential on the energy distribution of emitted positrons within a quantum mechanical framework. Finally we very briefly consider some phenomenological corrections to the Dirac equation and its consequences on electron binding energies in heavy and superheavy atoms. (orig./HSI)

High energy particle collisions near black holes

Directory of Open Access Journals (Sweden)

Zaslavskii O. B.

2016-01-01

Full Text Available If two geodesic particles collide near a rotating black hole, their energy in the centre of mass frame Ec.m. can become unbound under certain conditions (the so-called BSW effect. The special role is played here by so-called critical geodesics when one of particles has fine-tuned energy and angular momentum. The nature of geodesics reveals itself also in fate of the debris after collisions. One of particles moving to a remote observer is necessarily near-critical. We discuss, when such a collision can give rise not only unboud Ec.m. but also unbound Killing energy E (so-called super-Penrose process.

Electron capture by He2+ ions in collisions with H and H2 at impact energies below 10 keV

International Nuclear Information System (INIS)

Nutt, W.L.; McCullough, R.W.; Brady, K.; Shah, M.B.; Gilbody, H.B.

1978-01-01

Total cross sections for the process He 2+ + H(1s) → He + (Σn, 1) + H + involving capture into all final bound states of He + have been determined for 3 He 2+ ions in the range 1.5-9.0 keV using a furnace-target technique previously employed for similar measurements at higher impact energies. Measured cross sections are considerably smaller than those measured previously by Fite et al (Proc. R.Soc.; A268:527 (1962)) and are in better accord with recent theoretical estimates. A likely explanation for the discrepancy is given in terms of the corresponding cross sections for electron capture in He 2+ -H 2 collisions which have also been determined. (author)

Violent heavy ion collisions around the Fermi energy

International Nuclear Information System (INIS)

Borderie, B.

1985-01-01

Experimental results on central collisions will be presented and it will be shown that a fusion process still occurs; deexcitation of the hot fused systems formed will be discussed. Then, from the qualitative evolution of central collision products from different reactions studied in the E/A range 20-84 MeV, the vanishing of fusion processes will be inferred; it will be discussed in terms of critical energy deposit and maximum excitation energy per nucleon that nuclei can carry. Finally results concerning the large production of light fragments (3 < approximately Z < approximately 12) experimentally observed in the Fermi energy domain will be presented and discussed in terms of a multifragmentation of the whole nuclear system or of part of it for intermediate impact parameter collisions (109 refs, 49 fig)

Central collisions in intermediate energy heavy-ion reactions

International Nuclear Information System (INIS)

Wong, C.Y.

1979-01-01

The critical collisions in intermediate energy heavy-ion reactions are examined from both a microscopic and macroscopic viewpoint. In the microscopic description the proper tool is the extended TDHF approximation involving both the mean field and the particle collisions. To understand the underlying physics, the effect of the mean field and the effect of particle collisions are studied separately. It is found that th sudden increase in the density of the overlapping region can cause the volcano effect, leading to the complete disintegration of one of the nuclei. The self-consistent mean field also gives rise to the bunching instability when the two Fermi spheres of the colliding nucleons separate. The collision between nucleons, on the other hand, leads to irreversible dissipation, thermalization, and the possibility of a hydrodynamical description of the dynamics. Next is studied the dynamics of central collisions using the hydrodynamical description for many combinations of targets and projectiles at different energies. The formation of shock waves, sidesplash, and the complete disintegration of the whole nucleus are examined. Nuclear viscosity is found to affect the angular distribution of the reaction products and also the maximum compression ratio achieved during the collision. 28 references

Three-Jet Production in Electron-Positron Collisions at Next-to-Next-to-Leading Order Accuracy

Science.gov (United States)

Del Duca, Vittorio; Duhr, Claude; Kardos, Adam; Somogyi, Gábor; Trócsányi, Zoltán

2016-10-01

We introduce a completely local subtraction method for fully differential predictions at next-to-next-to-leading order (NNLO) accuracy for jet cross sections and use it to compute event shapes in three-jet production in electron-positron collisions. We validate our method on two event shapes, thrust and C parameter, which are already known in the literature at NNLO accuracy and compute for the first time oblateness and the energy-energy correlation at the same accuracy.

Calculation of the positronium formation differential cross section for collision of electron with anti-hydrogen atoms

International Nuclear Information System (INIS)

Ghanbari Adivi, E.; Kanjuri, F.; Bolorizadeh, M.

2006-01-01

The positronium formation differential cross sections in collision of the high-energy but non-relativistic electrons with anti-hydrogen atoms are calculated by using the three-body Faddeev-Watson-Lovelace formalism. In a second-order approximation, the inter-nuclear and nuclear-electronic partial amplitudes therein the Faddeev-Watson series are calculated, analytically, in the range of 0-180 degrees of the scattering angles. The presence of the T homas peak a t 45 d egree i s investigated. The results are discussed for 1 and 10 keV impact energies and for electron transition from anti-hydrogen ground state into the different states therein the K-, L- and M- shells of the positronium atoms.

L-MM Auger electron production in 0.3-1.6 MeV Kr-Kr collisions

International Nuclear Information System (INIS)

DeGroot, P.; Zarcone, M.J.; Kessel, Q.C.; Connecticut Univ., Storrs

1987-01-01

Relative total cross sections for Kr L-Auger electron emission are presented and compared with the corresponding X-ray data of Woerlee and Shanker and coworkers. These data sets all show the same incident ion energy dependence, indicating a constant fluorescence yield for the collision conditions under consideration. These data are also in agreement with a rotational coupling calculation by shanker and coworkers that was carried out within the framework of the one-electron molecular orbital model of Fano and Lichten. (orig.)

Data Acquisition System for Electron Energy Loss Coincident Spectrometers

International Nuclear Information System (INIS)

Zhang Chi; Yu Xiaoqi; Yang Tao

2005-01-01

A Data Acquisition System (DAQ) for electron energy loss coincident spectrometers (EELCS) has been developed. The system is composed of a Multiplex Time-Digital Converter (TDC) that measures the flying time of positive and negative ions and a one-dimension position-sensitive detector that records the energy loss of scattering electrons. The experimental data are buffered in a first-in-first-out (FIFO) memory module, then transferred from the FIFO memory to PC by the USB interface. The DAQ system can record the flying time of several ions in one collision, and allows of different data collection modes. The system has been demonstrated at the Electron Energy Loss Coincident Spectrometers at the Laboratory of Atomic and Molecular Physics, USTC. A detail description of the whole system is given and experimental results shown

Charge exchange in ion-atom collisions

International Nuclear Information System (INIS)

Bransden, B.H.

1990-01-01

Charge exchange reactions in which electrons are transferred from one ion (or atom) to another during a collision have been studied both as interesting examples of rearrangement collisions and because of important applications in plasma physics. This article reviews the modern theory developed for use at non-relativistic energies, but excluding the thermal and very low energy region. (author)

Collisions of polyatomic ions with surfaces: incident energy partitioning and chemical reactions

International Nuclear Information System (INIS)

Zabka, J.; Roithova, J.; Dolejsek, Z.; Herman, Z.

2002-01-01

Collision of polyatomic ions with surfaces were investigated in ion-surface scattering experiments to obtain more information on energy partitioning in ion-surface collision and on chemical reactions at surfaces. Mass spectra, translation energy and angular distributions of product ions were measured in dependence on the incident energy and the incident angle of polyatomic projectiles. From these data distributions of energy fractions resulting in internal excitation of the projectile, translation energy of the product ions, and energy absorbed by the surface were determined. The surface investigated were a standard stainless steel surface, covered by hydrocarbons, carbon surfaces at room and elevated temperatures, and several surfaces covered by a self-assembled monolayers (C 12 -hydrocarbon SAM, C 11 -perfluorohydrocarbon SAM, and C 11 hydrocarbon with terminal -COOH group SAM). The main processes observed at collision energies of 10 - 50 eV were: neutralization of the ions at surfaces, inelastic scattering and dissociations of the projectile ions, quasi elastic scattering of the projectile ions, and chemical reactions with the surface material (usually hydrogen-atom transfer reactions). The ion survival factor was estimated to be a few percent for even-electron ions (like protonated ethanol ion, C 2 H 5 O + , CD 5 + ) and about 10 - 10 2 times lower for radical ions (like ethanol and benzene molecular ions, CD 4 + ). In the polyatomic ion -surface energy transfer experiments, the ethanol molecular ion was used as a well-characterized projectile ion. The results with most of the surfaces studied showed in the collision energy range of 13 - 32 eV that most collisions were strongly inelastic with about 6 - 8 % of the incident projectile energy transformed into internal excitation of the projectile (independent of the incident angle) and led partially to its further dissociation in a unimolecular way after the interaction with the surface. The incident energy

Electron capture by multicharged ions from hydrogen atoms at eV energies

International Nuclear Information System (INIS)

Havener, C.C.; Nesnidal, M.P.; Porter, M.R.; Phaneuf, R.A.

1990-01-01

To quantitatively study electron capture during collisions of multiply charged ions with neutral atoms at near-thermal energies, keV-energy multicharged ion beams are merged with ground-state beams of H or D atoms of chosen velocity such that collisions in the relative energy range 1--1000 eV/amu result. Recent data for O 3+ , O 4+ + H(D) are presented and compared with theoretical predictions. Recently completed modifications to the apparatus are described that will provide a significant improvement in signal-to-background and angular collection. These improvements will allow measurements to be extended to lower energies, where effects due to the ion-induced dipole attraction may be evident

Toward prethreshold gate-based quantum simulation of chemical dynamics: using potential energy surfaces to simulate few-channel molecular collisions

Science.gov (United States)

Sornborger, Andrew T.; Stancil, Phillip; Geller, Michael R.

2018-05-01

One of the most promising applications of an error-corrected universal quantum computer is the efficient simulation of complex quantum systems such as large molecular systems. In this application, one is interested in both the electronic structure such as the ground state energy and dynamical properties such as the scattering cross section and chemical reaction rates. However, most theoretical work and experimental demonstrations have focused on the quantum computation of energies and energy surfaces. In this work, we attempt to make the prethreshold (not error-corrected) quantum simulation of dynamical properties practical as well. We show that the use of precomputed potential energy surfaces and couplings enables the gate-based simulation of few-channel but otherwise realistic molecular collisions. Our approach is based on the widely used Born-Oppenheimer approximation for the structure problem coupled with a semiclassical method for the dynamics. In the latter the electrons are treated quantum mechanically but the nuclei are classical, which restricts the collisions to high energy or temperature (typically above ≈ 10 eV). By using operator splitting techniques optimized for the resulting time-dependent Hamiltonian simulation problem, we give several physically realistic collision examples, with 3-8 channels and circuit depths < 1000.

Energy Dependence of Particle Multiplicities in Central Au+Au Collisions

Science.gov (United States)

Back, B. B.; Baker, M. D.; Barton, D. S.; Betts, R. R.; Bindel, R.; Budzanowski, A.; Busza, W.; Carroll, A.; Corbo, J.; Decowski, M. P.; Garcia, E.; George, N.; Gulbrandsen, K.; Gushue, S.; Halliwell, C.; Hamblen, J.; Henderson, C.; Hicks, D.; Hofman, D.; Hollis, R. S.; Hołyński, R.; Holzman, B.; Iordanova, A.; Johnson, E.; Kane, J.; Katzy, J.; Khan, N.; Kucewicz, W.; Kulinich, P.; Kuo, C. M.; Lin, W. T.; Manly, S.; McLeod, D.; Michałowski, J.; Mignerey, A.; Mülmenstädt, J.; Nouicer, R.; Olszewski, A.; Pak, R.; Park, I. C.; Pernegger, H.; Rafelski, M.; Rbeiz, M.; Reed, C.; Remsberg, L. P.; Reuter, M.; Roland, C.; Roland, G.; Rosenberg, L.; Sagerer, J.; Sarin, P.; Sawicki, P.; Skulski, W.; Steadman, S. G.; Steinberg, P.; Stephans, G. S.; Stodulski, M.; Sukhanov, A.; Tang, J.-L.; Teng, R.; Trzupek, A.; Vale, C.; van Nieuwenhuizen, G. J.; Verdier, R.; Wadsworth, B.; Wolfs, F. L.; Wosiek, B.; Woźniak, K.; Wuosmaa, A. H.; Wysłouch, B.

2002-01-01

We present the first measurement of the pseudorapidity density of primary charged particles in Au+Au collisions at (sNN) = 200 GeV. For the 6% most central collisions, we obtain dNch/dη\\|\\|η\\|<1 = 650+/-35(syst). Compared to collisions at (sNN) = 130 GeV, the highest energy studied previously, an increase by a factor of 1.14+/-0.05 at 90% confidence level, is found. The energy dependence of the pseudorapidity density is discussed in comparison with data from proton-induced collisions and theoretical predictions.

Diagnosis of Unmagnetized Plasma Electron Number Density and Electron-neutral Collision Frequency by Using Microwave

International Nuclear Information System (INIS)

Yuan Zhongcai; Shi Jiaming; Xu Bo

2005-01-01

The plasma diagnostic method using the transmission attenuation of microwaves at double frequencies (PDMUTAMDF) indicates that the frequency and the electron-neutral collision frequency of the plasma can be deduced by utilizing the transmission attenuation of microwaves at two neighboring frequencies in a non-magnetized plasma. Then the electron density can be obtained from the plasma frequency. The PDMUTAMDF is a simple method to diagnose the plasma indirectly. In this paper, the interaction of electromagnetic waves and the plasma is analyzed. Then, based on the attenuation and the phase shift of a microwave in the plasma, the principle of the PDMUTAMDF is presented. With the diagnostic method, the spatially mean electron density and electron collision frequency of the plasma can be obtained. This method is suitable for the elementary diagnosis of the atmospheric-pressure plasma

DFT studies on proton-ethylene collisions

International Nuclear Information System (INIS)

Wang Zhiping; Zhang Fengshou; Wang Jing

2012-01-01

In the framework of the time-dependent local-density approximation (TDLDA)which applied to valence electrons, coupled non-adiabatically to molecular dynamics of ions, the microscopic mechanisms of collisions between energetic protons and ethylene are studied. Not only the amount of energy lost of the projectile, but also the electron and vibration excitations of the target are identified. In addition, the influences of the collision orientation on the energy loss of the proton and excitation dynamics of ethylene are discussed. It is found that the ionization is enhanced and more electrons are captured by the proton when the proton with the impact energy less than 250 eV moves perpendicularly to the molecular plane. A strong relation between the proton energy lost and the impact orientation is obtained when the impact energy is larger than 250 eV. (authors)

Recent research directions in Fribourg: nuclear dynamics in resonances revealed by 2-dimensional EEL spectra, electron collisions with ionic liquids and electronic excitation of pyrimidine

International Nuclear Information System (INIS)

Allan, M.; Regeta, K.; Gorfinkiel, J.D.; Masin, Z.; Grimme, S.; Bannwarth, C.

2016-01-01

The article briefly reviews three subjects recently investigated in Fribourg: 1) electron collisions with surfaces of ionic liquids, 2) two-dimensional (2D) electron energy loss spectra and 3) resonances in absolute cross sections for electronic excitation of unsaturated compounds. Electron energy loss spectra of four ionic liquids revealed a number of excited states, including triplet states. A solution of a dye in an ionic liquid showed an energy-loss band of the solute, but not in all ionic liquids. 2D spectra reveal state-to-state information (given resonance to given final state) and are shown to be an interesting means to gain insight into dynamics of nuclear motion in resonances. Absolute cross sections for pyrimidine are reported as a function of scattering angle and as a function of electron energy. They reveal resonant structure which was reproduced very nicely by R-matrix calculations. The calculation provided an assignment of the resonances which reveals common patterns in compounds containing double bonds. (authors)

Fluctuations in high-energy particle collisions

International Nuclear Information System (INIS)

Gronqvist, Hanna

2016-01-01

We study fluctuations that are omnipresent in high-energy particle collisions. These fluctuations can be either of either classical or quantum origin and we will study both. Firstly, we consider the type of quantum fluctuations that arise in proton-proton collisions. These are computable perturbatively in quantum field theory and we will focus on a specific class of diagrams in this set-up. Secondly, we will consider the fluctuations that are present in collisions between nuclei that can be heavier than protons. These are the quantum laws of nature that describe the positions of nucleons within a nucleus, but also the hydrodynamic fluctuations of classical, thermal origin that affect the evolution of the medium produced in heavy-ion collisions. The fluctuations arising in proton-proton collisions can be computed analytically up to a certain order in perturbative quantum field theory. We will focus on one-loop diagrams of a fixed topology. Loop diagrams give rise to integrals that typically are hard to evaluate. We show how modern mathematical methods can be used to ease their computation. We will study the relations among unitarity cuts of a diagram, the discontinuity across the corresponding branch cut and the coproduct. We show how the original integral corresponding to a given diagram can be reconstructed from the information contained in the coproduct. We expect that these methods can be applied to solve more complicated topologies and help in the computation of new amplitudes in the future. Finally, we study the two types of fluctuations arising in heavy-ion collisions. These are related either to the initial state or the intermediate state of matter produced in such collisions. The initial state fluctuations are experimentally observed to give rise to non-Gaussianities in the final-state spectra. We show how these non-Gaussianities can be explained by the random position and interaction energy of 'sources' in the colliding nuclei. Furthermore, we

Finite escape fraction for ultrahigh energy collisions around Kerr

Indian Academy of Sciences (India)

We investigate the issue of observability of high-energy collisions around Kerr naked singularity and show that results are in contrast with the Kerr black hole case. We had shown that it would be possible to have ultrahigh energy collisions between the particles close to the location = M around the Kerr naked singularity if ...

Finite escape fraction for ultrahigh energy collisions around Kerr ...

Indian Academy of Sciences (India)

Abstract. We investigate the issue of observability of high-energy collisions around Kerr naked singularity and show that results are in contrast with the Kerr black hole case. We had shown that it would be possible to have ultrahigh energy collisions between the particles close to the location r = M around the Kerr naked ...

Jets in high energy nucleon-nucleon collisions

International Nuclear Information System (INIS)

Strugalski, Z.

1982-01-01

From the experimental studies of high-energy hardon-nucleon and nucleon-nucleon collisions, by means of nuclear targets applied as detectors, it follows that particles are produced via intermediate objects created first in a 2 → 2 type endoergic reaction. These objects, called generons, decay in flight into finally observed particles and resonances after their lifetime tausub(g) > or approximately 10 - 22 s. The jet structure of the outcome in nucleon-nucleon collisions is a simple and indispensable consequence of this particle production mechanism. The picture of the jet structure in the collision outcome observed in the CMS of the colliding nucleons depends on the energy of these nUcleons. New particle production scheme is proposed, which can be tested experimentally; corresponding simple relations between characteristics of colliding nucleons and of produced jets are proposed for a testing

Energy transfer in reactive and non-reactive H2 + OH collisions

International Nuclear Information System (INIS)

Rashed, O.; Brown, N.J.

1985-04-01

We have used the methods of quasi-classical dynamics to compute energy transfer properties of non-reactive and reactive H 2 + OH collisions. Energy transfer has been investigated as function of translational temperature, reagent rotational energy, and reagent vibrational energy. The energy transfer mechanism is complex with ten types of energy transfer possible, and evidence was found for all types. There is much more exchange between the translational degree of freedom and the H 2 vibrational degree of freedom than there is between translation and OH vibration. Translational energy is transferred to the rotational degrees of freedom of each molecule. There is a greater propensity for the transfer of translation to OH rotation than H 2 rotation. In reactive collisions, increases in reagent translational temperature predominantly appear as vibrational energy in the water molecule. Energy transfer in non-reactive and reactive collisions does not depend strongly on the initial angular momentum in either molecule. In non-reactive collisions, vibrational energy is transferred to translation, to the rotational degree of freedom of the same molecule, and to the rotational and vibrational degrees of freedom of the other molecule. In reactive collisions, the major effect of increasing the vibrational energy in reagent molecules is that, on the average, the vibrational energy of the reagents appears as product vibrational energy. 18 refs., 16 figs., 6 tabs

Applications of cross sections for electron-molecule collision processes

International Nuclear Information System (INIS)

Cartwright, D.C.

1985-01-01

The role of electron-molecule collision cross sections is discussed for the study of the ionospheric and auroral processes in planetary atmospheres and of discharge-pumped lasers. These two areas emphasize the importance of further theoretical and experimental studies concerning electron-impact processes. 13 refs., 3 figs., 2 tabs

Perspectives in high energy nuclear collisions

International Nuclear Information System (INIS)

Rafelski, J.

1983-08-01

This report gives an overview of some aspects of hadronic physics relevant for the conception of a research facility devoted to the study of high energy nuclear collisions. Several concepts to be studied in nuclear collisions are selected, with emphasis placed on the properties and nature of the quark-gluon plasma, the formation of the plasma state in the central region and its anticipated lifetime, and the observability, through strangeness content of this new form of nuclear matter. (orig.)

Rapidity and multiplicity correlations in high energy hadronic collisions

International Nuclear Information System (INIS)

Heiselberg, H.

1993-01-01

Rapidity and multiplicity correlations of particle production in high energy hadronic collisions are studied. A simple model including short range correlations in rapidity due to clustering and long range correlations due to energy conservation is able to describe the two-body correlation functions well hadron-nucleon collisions around lab energies of 250 GeV. In this model fractional moments are calculated and compared to data. The strong rise of the factorial moments in rapidity intervals by size δy∝1 can be explained by long and short range correlation alone whereas the factorial moments approach a constant value at very small δy due to lack of correlations also in agreement with experiment. There is therefore no need for introducing intermittency in the particle production in hadronic collisions at these energies. (orig.)

COLLISION STRENGTHS AND EFFECTIVE COLLISION STRENGTHS FOR TRANSITIONS WITHIN THE GROUND-STATE CONFIGURATION OF S III

Energy Technology Data Exchange (ETDEWEB)

Hudson, C. E.; Ramsbottom, C. A.; Scott, M. P., E-mail: c.hudson@qub.ac.uk, E-mail: c.ramsbottom@qub.ac.uk, E-mail: p.scott@qub.ac.uk [Department of Applied Maths and Theoretical Physics, The Queen' s University of Belfast, Belfast BT7 1NN (United Kingdom)

2012-05-01

We have carried out a 29-state R-matrix calculation in order to calculate collision strengths and effective collision strengths for the electron impact excitation of S III. The recently developed parallel RMATRX II suite of codes have been used, which perform the calculation in intermediate coupling. Collision strengths have been generated over an electron energy range of 0-12 Ryd, and effective collision strength data have been calculated from these at electron temperatures in the range 1000-100,000 K. Results are here presented for the fine-structure transitions between the ground-state configurations of 3s {sup 2}3p {sup 23} P{sub 0,1,2}, {sup 1}D{sub 2}, and {sup 1} S{sub 0}, and the values given resolve a discrepancy between two previous R-matrix calculations.

High energy nuclear collisions: theory review

International Nuclear Information System (INIS)

Fries, Rainer J.

2009-01-01

Full text: High Energy Nuclear Collisions are studied at the Relativistic Heavy Ion Collider (RHIC) and, starting next year, also at the Large Hadron Collider (LHC) to study the formation and properties of quark gluon plasma (QGP). This effort is driven by the prediction that above a certain critical temperature quarks and gluons are deconfined. For the past ten years of running RHIC has performed marvelously. Data from RHIC has answered many initial questions, but it has also provided new, more challenging problems to understand the nature of quark gluon plasma and the dynamics of heavy ion collisions. In this talk I review some of the basic concepts of high energy nuclear collisions and quark gluon plasma formation. We also discuss some of the novel and open questions that we are faced with. We discuss recent predictions on properties of hot quantum chromodynamics, emerging signatures for the color glass condensate, the fascinating idea of local P and CP violation in QCD, as well as ongoing research on hard probes and electromagnetic signatures

Electron capture in collisions of ? with H and ? with C

Science.gov (United States)

Stancil, P. C.; Gu, J.-P.; Havener, C. C.; Krstic, P. S.; Schultz, D. R.; Kimura, M.; Zygelman, B.; Hirsch, G.; Buenker, R. J.; Bannister, M. E.

1998-08-01

A comprehensive theoretical and experimental study of electron capture in collisions of 0953-4075/31/16/017/img15 with H and 0953-4075/31/16/017/img16 with C extending over the energy range 0953-4075/31/16/017/img17 to 0953-4075/31/16/017/img18 is presented. A variety of theoretical approaches were used including those based on quantal molecular-orbital close-coupling (MOCC), multielectron hidden crossings (MEHC), quantal decay and classical trajectory Monte Carlo techniques. Radiative charge transfer cross sections were computed using the optical potential/distorted wave (OPDW) and fully quantal (FQ) approaches. The MOCC, OPDW and FQ calculations incorporated ab initio potentials, nonadiabatic coupling matrix elements and transition moments computed at the configuration-interaction level. Ab initio potential surfaces in the plane of complex internuclear distance were obtained for the MEHC calculations. Merged-beam measurements were performed between 0953-4075/31/16/017/img19 and 0953-4075/31/16/017/img20 for the 0953-4075/31/16/017/img21 collision system. Diagnostics of the 0953-4075/31/16/017/img15 beam with a crossed electron beam could find no presence of a 0953-4075/31/16/017/img15 metastable component. The current results, in conjunction with previous measurements, are used to deduce a set of recommended cross sections.

Multiplicity distributions in high energy collisions

International Nuclear Information System (INIS)

Giovannini, A.; Lupia, S.; Ugoccioni, R.

1992-01-01

We discuss the important phases in the evolution of our understanding of multiplicity distributions in high energy collisions with particular emphasis to intermittent behavior and shoulder structure problem. (orig.)

Multiplicity distributions in high energy collisions

Energy Technology Data Exchange (ETDEWEB)

Giovannini, A.; Lupia, S.; Ugoccioni, R. (Dipt. di Fisica Teorica, Univ. Turin (Italy) INFN, Turin (Italy))

1992-03-01

We discuss the important phases in the evolution of our understanding of multiplicity distributions in high energy collisions with particular emphasis to intermittent behavior and shoulder structure problem. (orig.).

Search for a heavy gauge boson W' in the final state with an electron and large missing transverse energy in pp collisions at $\\sqrt{s}$ = 7 TeV

CERN Document Server

Khachatryan, Vardan; Tumasyan, Armen; Adam, Wolfgang; Bergauer, Thomas; Dragicevic, Marko; Erö, Janos; Fabjan, Christian; Friedl, Markus; Fruehwirth, Rudolf; Ghete, Vasile Mihai; Hammer, Josef; Haensel, Stephan; Hartl, Christian; Hoch, Michael; Hörmann, Natascha; Hrubec, Josef; Jeitler, Manfred; Kasieczka, Gregor; Kiesenhofer, Wolfgang; Krammer, Manfred; Liko, Dietrich; Mikulec, Ivan; Pernicka, Manfred; Rohringer, Herbert; Schöfbeck, Robert; Strauss, Josef; Taurok, Anton; Teischinger, Florian; Waltenberger, Wolfgang; Walzel, Gerhard; Widl, Edmund; Wulz, Claudia-Elisabeth; Mossolov, Vladimir; Shumeiko, Nikolai; Suarez Gonzalez, Juan; Benucci, Leonardo; Cerny, Karel; De Wolf, Eddi A.; Janssen, Xavier; Maes, Thomas; Mucibello, Luca; Ochesanu, Silvia; Roland, Benoit; Rougny, Romain; Selvaggi, Michele; Van Haevermaet, Hans; Van Mechelen, Pierre; Van Remortel, Nick; Adler, Volker; Beauceron, Stephanie; Blekman, Freya; Blyweert, Stijn; D'Hondt, Jorgen; Devroede, Olivier; Gonzalez Suarez, Rebeca; Kalogeropoulos, Alexis; Maes, Joris; Maes, Michael; Tavernier, Stefaan; Van Doninck, Walter; Van Mulders, Petra; Van Onsem, Gerrit Patrick; Villella, Ilaria; Charaf, Otman; Clerbaux, Barbara; De Lentdecker, Gilles; Dero, Vincent; Gay, Arnaud; Hammad, Gregory Habib; Hreus, Tomas; Marage, Pierre Edouard; Thomas, Laurent; Vander Velde, Catherine; Vanlaer, Pascal; Wickens, John; Costantini, Silvia; Grunewald, Martin; Klein, Benjamin; Marinov, Andrey; Mccartin, Joseph; Ryckbosch, Dirk; Thyssen, Filip; Tytgat, Michael; Vanelderen, Lukas; Verwilligen, Piet; Walsh, Sinead; Zaganidis, Nicolas; Basegmez, Suzan; Bruno, Giacomo; Caudron, Julien; Ceard, Ludivine; De Favereau De Jeneret, Jerome; Delaere, Christophe; Demin, Pavel; Favart, Denis; Giammanco, Andrea; Grégoire, Ghislain; Hollar, Jonathan; Lemaitre, Vincent; Liao, Junhui; Militaru, Otilia; Ovyn, Severine; Pagano, Davide; Pin, Arnaud; Piotrzkowski, Krzysztof; Schul, Nicolas; Beliy, Nikita; Caebergs, Thierry; Daubie, Evelyne; Alves, Gilvan; De Jesus Damiao, Dilson; Pol, Maria Elena; Henrique Gomes E Souza, Moacyr; Carvalho, Wagner; Melo Da Costa, Eliza; De Oliveira Martins, Carley; Fonseca De Souza, Sandro; Mundim, Luiz; Nogima, Helio; Oguri, Vitor; Prado Da Silva, Wanda Lucia; Santoro, Alberto; Silva Do Amaral, Sheila Mara; Sznajder, Andre; De Almeida Dias, Flavia; Ferreira Dias, Marco Andre; Tomei, Thiago; De Moraes Gregores, Eduardo; Da Cunha Marinho, Franciole; Novaes, Sergio F.; Padula, Sandra; Darmenov, Nikolay; Dimitrov, Lubomir; Genchev, Vladimir; Iaydjiev, Plamen; Piperov, Stefan; Rodozov, Mircho; Stoykova, Stefka; Sultanov, Georgi; Tcholakov, Vanio; Trayanov, Rumen; Vankov, Ivan; Dyulendarova, Milena; Hadjiiska, Roumyana; Kozhuharov, Venelin; Litov, Leander; Marinova, Evelina; Mateev, Matey; Pavlov, Borislav; Petkov, Peicho; Bian, Jian-Guo; Chen, Guo-Ming; Chen, He-Sheng; Jiang, Chun-Hua; Liang, Dong; Liang, Song; Wang, Jian; Wang, Jian; Wang, Xianyou; Wang, Zheng; Xu, Ming; Yang, Min; Zang, Jingjing; Zhang, Zhen; Ban, Yong; Guo, Shuang; Guo, Yifei; Li, Wenbo; Mao, Yajun; Qian, Si-Jin; Teng, Haiyun; Zhang, Linlin; Zhu, Bo; Zou, Wei; Cabrera, Andrés; Gomez Moreno, Bernardo; Ocampo Rios, Alberto Andres; Osorio Oliveros, Andres Felipe; Sanabria, Juan Carlos; Godinovic, Nikola; Lelas, Damir; Lelas, Karlo; Plestina, Roko; Polic, Dunja; Puljak, Ivica; Antunovic, Zeljko; Dzelalija, Mile; Brigljevic, Vuko; Duric, Senka; Kadija, Kreso; Morovic, Srecko; Attikis, Alexandros; Galanti, Mario; Mousa, Jehad; Nicolaou, Charalambos; Ptochos, Fotios; Razis, Panos A.; Rykaczewski, Hans; Assran, Yasser; Mahmoud, Mohammed; Hektor, Andi; Kadastik, Mario; Kannike, Kristjan; Müntel, Mait; Raidal, Martti; Rebane, Liis; Azzolini, Virginia; Eerola, Paula; Czellar, Sandor; Härkönen, Jaakko; Heikkinen, Mika Aatos; Karimäki, Veikko; Kinnunen, Ritva; Klem, Jukka; Kortelainen, Matti J.; Lampén, Tapio; Lassila-Perini, Kati; Lehti, Sami; Lindén, Tomas; Luukka, Panja-Riina; Mäenpää, Teppo; Tuominen, Eija; Tuominiemi, Jorma; Tuovinen, Esa; Ungaro, Donatella; Wendland, Lauri; Banzuzi, Kukka; Korpela, Arja; Tuuva, Tuure; Sillou, Daniel; Besancon, Marc; Choudhury, Somnath; Dejardin, Marc; Denegri, Daniel; Fabbro, Bernard; Faure, Jean-Louis; Ferri, Federico; Ganjour, Serguei; Gentit, François-Xavier; Givernaud, Alain; Gras, Philippe; Hamel de Monchenault, Gautier; Jarry, Patrick; Locci, Elizabeth; Malcles, Julie; Marionneau, Matthieu; Millischer, Laurent; Rander, John; Rosowsky, André; Shreyber, Irina; Titov, Maksym; Verrecchia, Patrice; Baffioni, Stephanie; Beaudette, Florian; Bianchini, Lorenzo; Bluj, Michal; Broutin, Clementine; Busson, Philippe; Charlot, Claude; Dahms, Torsten; Dobrzynski, Ludwik; Granier de Cassagnac, Raphael; Haguenauer, Maurice; Miné, Philippe; Mironov, Camelia; Ochando, Christophe; Paganini, Pascal; Sabes, David; Salerno, Roberto; Sirois, Yves; Thiebaux, Christophe; Wyslouch, Bolek; Zabi, Alexandre; Agram, Jean-Laurent; Andrea, Jeremy; Besson, Auguste; Bloch, Daniel; Bodin, David; Brom, Jean-Marie; Cardaci, Marco; Chabert, Eric Christian; Collard, Caroline; Conte, Eric; Drouhin, Frédéric; Ferro, Cristina; Fontaine, Jean-Charles; Gelé, Denis; Goerlach, Ulrich; Greder, Sebastien; Juillot, Pierre; Karim, Mehdi; Le Bihan, Anne-Catherine; Mikami, Yoshinari; Van Hove, Pierre; Fassi, Farida; Mercier, Damien; Baty, Clement; Beaupere, Nicolas; Bedjidian, Marc; Bondu, Olivier; Boudoul, Gaelle; Boumediene, Djamel; Brun, Hugues; Chanon, Nicolas; Chierici, Roberto; Contardo, Didier; Depasse, Pierre; El Mamouni, Houmani; Falkiewicz, Anna; Fay, Jean; Gascon, Susan; Ille, Bernard; Kurca, Tibor; Le Grand, Thomas; Lethuillier, Morgan; Mirabito, Laurent; Perries, Stephane; Sordini, Viola; Tosi, Silvano; Tschudi, Yohann; Verdier, Patrice; Xiao, Hong; Roinishvili, Vladimir; Anagnostou, Georgios; Edelhoff, Matthias; Feld, Lutz; Heracleous, Natalie; Hindrichs, Otto; Jussen, Ruediger; Klein, Katja; Merz, Jennifer; Mohr, Niklas; Ostapchuk, Andrey; Perieanu, Adrian; Raupach, Frank; Sammet, Jan; Schael, Stefan; Sprenger, Daniel; Weber, Hendrik; Weber, Martin; Wittmer, Bruno; Ata, Metin; Bender, Walter; Erdmann, Martin; Frangenheim, Jens; Hebbeker, Thomas; Hinzmann, Andreas; Hoepfner, Kerstin; Hof, Carsten; Klimkovich, Tatsiana; Klingebiel, Dennis; Kreuzer, Peter; Lanske, Dankfried; Magass, Carsten; Masetti, Gianni; Merschmeyer, Markus; Meyer, Arnd; Papacz, Paul; Pieta, Holger; Reithler, Hans; Schmitz, Stefan Antonius; Sonnenschein, Lars; Steggemann, Jan; Teyssier, Daniel; Bontenackels, Michael; Davids, Martina; Duda, Markus; Flügge, Günter; Geenen, Heiko; Giffels, Manuel; Haj Ahmad, Wael; Heydhausen, Dirk; Kress, Thomas; Kuessel, Yvonne; Linn, Alexander; Nowack, Andreas; Perchalla, Lars; Pooth, Oliver; Rennefeld, Jörg; Sauerland, Philip; Stahl, Achim; Thomas, Maarten; Tornier, Daiske; Zoeller, Marc Henning; Aldaya Martin, Maria; Behrenhoff, Wolf; Behrens, Ulf; Bergholz, Matthias; Borras, Kerstin; Cakir, Altan; Campbell, Alan; Castro, Elena; Dammann, Dirk; Eckerlin, Guenter; Eckstein, Doris; Flossdorf, Alexander; Flucke, Gero; Geiser, Achim; Glushkov, Ivan; Hauk, Johannes; Jung, Hannes; Kasemann, Matthias; Katkov, Igor; Katsas, Panagiotis; Kleinwort, Claus; Kluge, Hannelies; Knutsson, Albert; Krücker, Dirk; Kuznetsova, Ekaterina; Lange, Wolfgang; Lohmann, Wolfgang; Mankel, Rainer; Marienfeld, Markus; Melzer-Pellmann, Isabell-Alissandra; Meyer, Andreas Bernhard; Mnich, Joachim; Mussgiller, Andreas; Olzem, Jan; Parenti, Andrea; Raspereza, Alexei; Raval, Amita; Schmidt, Ringo; Schoerner-Sadenius, Thomas; Sen, Niladri; Stein, Matthias; Tomaszewska, Justyna; Volyanskyy, Dmytro; Walsh, Roberval; Wissing, Christoph; Autermann, Christian; Bobrovskyi, Sergei; Draeger, Jula; Enderle, Holger; Gebbert, Ulla; Kaschube, Kolja; Kaussen, Gordon; Klanner, Robert; Lange, Jörn; Mura, Benedikt; Naumann-Emme, Sebastian; Nowak, Friederike; Pietsch, Niklas; Sander, Christian; Schettler, Hannes; Schleper, Peter; Schröder, Matthias; Schum, Torben; Schwandt, Joern; Srivastava, Ajay Kumar; Stadie, Hartmut; Steinbrück, Georg; Thomsen, Jan; Wolf, Roger; Barth, Christian; Bauer, Julia; Buege, Volker; Chwalek, Thorsten; De Boer, Wim; Dierlamm, Alexander; Dirkes, Guido; Feindt, Michael; Gruschke, Jasmin; Hackstein, Christoph; Hartmann, Frank; Heindl, Stefan Michael; Heinrich, Michael; Held, Hauke; Hoffmann, Karl-Heinz; Honc, Simon; Kuhr, Thomas; Martschei, Daniel; Mueller, Steffen; Müller, Thomas; Niegel, Martin; Oberst, Oliver; Oehler, Andreas; Ott, Jochen; Peiffer, Thomas; Piparo, Danilo; Quast, Gunter; Rabbertz, Klaus; Ratnikov, Fedor; Renz, Manuel; Saout, Christophe; Scheurer, Armin; Schieferdecker, Philipp; Schilling, Frank-Peter; Schott, Gregory; Simonis, Hans-Jürgen; Stober, Fred-Markus Helmut; Troendle, Daniel; Wagner-Kuhr, Jeannine; Zeise, Manuel; Zhukov, Valery; Ziebarth, Eva Barbara; Daskalakis, Georgios; Geralis, Theodoros; Kesisoglou, Stilianos; Kyriakis, Aristotelis; Loukas, Demetrios; Manolakos, Ioannis; Markou, Athanasios; Markou, Christos; Mavrommatis, Charalampos; Ntomari, Eleni; Petrakou, Eleni; Gouskos, Loukas; Mertzimekis, Theodoros; Panagiotou, Apostolos; Evangelou, Ioannis; Foudas, Costas; Kokkas, Panagiotis; Manthos, Nikolaos; Papadopoulos, Ioannis; Patras, Vaios; Triantis, Frixos A.; Aranyi, Attila; Bencze, Gyorgy; Boldizsar, Laszlo; Debreczeni, Gergely; Hajdu, Csaba; Horvath, Dezso; Kapusi, Anita; Krajczar, Krisztian; Laszlo, Andras; Sikler, Ferenc; Vesztergombi, Gyorgy; Beni, Noemi; Molnar, Jozsef; Palinkas, Jozsef; Szillasi, Zoltan; Veszpremi, Viktor; Raics, Peter; Trocsanyi, Zoltan Laszlo; Ujvari, Balazs; Bansal, Sunil; Beri, Suman Bala; Bhatnagar, Vipin; Dhingra, Nitish; Gupta, Ruchi; Jindal, Monika; Kaur, Manjit; Kohli, Jatinder Mohan; Mehta, Manuk Zubin; Nishu, Nishu; Saini, Lovedeep Kaur; Sharma, Archana; Sharma, Richa; Singh, Anil; Singh, Jas Bir; Singh, Supreet Pal; Ahuja, Sudha; Bhattacharya, Satyaki; Choudhary, Brajesh C.; Gupta, Pooja; Jain, Sandhya; Jain, Shilpi; Kumar, Ashok; Shivpuri, Ram Krishen; Choudhury, Rajani Kant; Dutta, Dipanwita; Kailas, Swaminathan; Kataria, Sushil Kumar; Mohanty, Ajit Kumar; Pant, Lalit Mohan; Shukla, Prashant; Aziz, Tariq; Guchait, Monoranjan; Gurtu, Atul; Maity, Manas; Majumder, Devdatta; Majumder, Gobinda; Mazumdar, Kajari; Mohanty, Gagan Bihari; Saha, Anirban; Sudhakar, Katta; Wickramage, Nadeesha; Banerjee, Sudeshna; Dugad, Shashikant; Mondal, Naba Kumar; Arfaei, Hessamaddin; Bakhshiansohi, Hamed; Etesami, Seyed Mohsen; Fahim, Ali; Hashemi, Majid; Jafari, Abideh; Khakzad, Mohsen; Mohammadi, Abdollah; Mohammadi Najafabadi, Mojtaba; Paktinat Mehdiabadi, Saeid; Safarzadeh, Batool; Zeinali, Maryam; Abbrescia, Marcello; Barbone, Lucia; Calabria, Cesare; Colaleo, Anna; Creanza, Donato; De Filippis, Nicola; De Palma, Mauro; Dimitrov, Anton; Fiore, Luigi; Iaselli, Giuseppe; Lusito, Letizia; Maggi, Giorgio; Maggi, Marcello; Manna, Norman; Marangelli, Bartolomeo; My, Salvatore; Nuzzo, Salvatore; Pacifico, Nicola; Pierro, Giuseppe Antonio; Pompili, Alexis; Pugliese, Gabriella; Romano, Francesco; Roselli, Giuseppe; Selvaggi, Giovanna; Silvestris, Lucia; Trentadue, Raffaello; Tupputi, Salvatore; Zito, Giuseppe; Abbiendi, Giovanni; Benvenuti, Alberto; Bonacorsi, Daniele; Braibant-Giacomelli, Sylvie; Brigliadori, Luca; Capiluppi, Paolo; Castro, Andrea; Cavallo, Francesca Romana; Cuffiani, Marco; Dallavalle, Gaetano-Marco; Fabbri, Fabrizio; Fanfani, Alessandra; Fasanella, Daniele; Giacomelli, Paolo; Giunta, Marina; Grandi, Claudio; Marcellini, Stefano; Meneghelli, Marco; Montanari, Alessandro; Navarria, Francesco; Odorici, Fabrizio; Perrotta, Andrea; Primavera, Federica; Rossi, Antonio; Rovelli, Tiziano; Siroli, Gianni; Albergo, Sebastiano; Cappello, Gigi; Chiorboli, Massimiliano; Costa, Salvatore; Tricomi, Alessia; Tuve, Cristina; Barbagli, Giuseppe; Ciulli, Vitaliano; Civinini, Carlo; D'Alessandro, Raffaello; Focardi, Ettore; Frosali, Simone; Gallo, Elisabetta; Genta, Chiara; Lenzi, Piergiulio; Meschini, Marco; Paoletti, Simone; Sguazzoni, Giacomo; Tropiano, Antonio; Benussi, Luigi; Bianco, Stefano; Colafranceschi, Stefano; Fabbri, Franco; Piccolo, Davide; Fabbricatore, Pasquale; Musenich, Riccardo; Benaglia, Andrea; De Guio, Federico; Di Matteo, Leonardo; Ghezzi, Alessio; Malberti, Martina; Malvezzi, Sandra; Martelli, Arabella; Massironi, Andrea; Menasce, Dario; Moroni, Luigi; Paganoni, Marco; Pedrini, Daniele; Ragazzi, Stefano; Redaelli, Nicola; Sala, Silvano; Tabarelli de Fatis, Tommaso; Tancini, Valentina; Buontempo, Salvatore; Carrillo Montoya, Camilo Andres; Cimmino, Anna; De Cosa, Annapaola; De Gruttola, Michele; Fabozzi, Francesco; Iorio, Alberto Orso Maria; Lista, Luca; Merola, Mario; Noli, Pasquale; Paolucci, Pierluigi; Azzi, Patrizia; Bacchetta, Nicola; Bellan, Paolo; Bisello, Dario; Branca, Antonio; Carlin, Roberto; Checchia, Paolo; De Mattia, Marco; Dorigo, Tommaso; Dosselli, Umberto; Gasparini, Fabrizio; Gasparini, Ugo; Giubilato, Piero; Gresele, Ambra; Lacaprara, Stefano; Lazzizzera, Ignazio; Margoni, Martino; Maron, Gaetano; Meneguzzo, Anna Teresa; Nespolo, Massimo; Passaseo, Marina; Perrozzi, Luca; Pozzobon, Nicola; Ronchese, Paolo; Simonetto, Franco; Torassa, Ezio; Tosi, Mia; Vanini, Sara; Zotto, Pierluigi; Zumerle, Gianni; Baesso, Paolo; Berzano, Umberto; Riccardi, Cristina; Torre, Paola; Vitulo, Paolo; Viviani, Claudio; Biasini, Maurizio; Bilei, Gian Mario; Caponeri, Benedetta; Fanò, Livio; Lariccia, Paolo; Lucaroni, Andrea; Mantovani, Giancarlo; Menichelli, Mauro; Nappi, Aniello; Santocchia, Attilio; Servoli, Leonello; Taroni, Silvia; Valdata, Marisa; Volpe, Roberta; Azzurri, Paolo; Bagliesi, Giuseppe; Bernardini, Jacopo; Boccali, Tommaso; Broccolo, Giuseppe; Castaldi, Rino; D'Agnolo, Raffaele Tito; Dell'Orso, Roberto; Fiori, Francesco; Foà, Lorenzo; Giassi, Alessandro; Kraan, Aafke; Ligabue, Franco; Lomtadze, Teimuraz; Martini, Luca; Messineo, Alberto; Palla, Fabrizio; Palmonari, Francesco; Sarkar, Subir; Segneri, Gabriele; Serban, Alin Titus; Spagnolo, Paolo; Tenchini, Roberto; Tonelli, Guido; Venturi, Andrea; Verdini, Piero Giorgio; Barone, Luciano; Cavallari, Francesca; Del Re, Daniele; Di Marco, Emanuele; Diemoz, Marcella; Franci, Daniele; Grassi, Marco; Longo, Egidio; Organtini, Giovanni; Palma, Alessandro; Pandolfi, Francesco; Paramatti, Riccardo; Rahatlou, Shahram; Amapane, Nicola; Arcidiacono, Roberta; Argiro, Stefano; Arneodo, Michele; Biino, Cristina; Botta, Cristina; Cartiglia, Nicolo; Castello, Roberto; Costa, Marco; Demaria, Natale; Graziano, Alberto; Mariotti, Chiara; Marone, Matteo; Maselli, Silvia; Migliore, Ernesto; Mila, Giorgia; Monaco, Vincenzo; Musich, Marco; Obertino, Maria Margherita; Pastrone, Nadia; Pelliccioni, Mario; Romero, Alessandra; Ruspa, Marta; Sacchi, Roberto; Sola, Valentina; Solano, Ada; Staiano, Amedeo; Trocino, Daniele; Vilela Pereira, Antonio; Ambroglini, Filippo; Belforte, Stefano; Cossutti, Fabio; Della Ricca, Giuseppe; Gobbo, Benigno; Montanino, Damiana; Penzo, Aldo; Heo, Seong Gu; Chang, Sunghyun; Chung, Jin Hyuk; Kim, Dong Hee; Kim, Gui Nyun; Kim, Ji Eun; Kong, Dae Jung; Park, Hyangkyu; Son, Dohhee; Son, Dong-Chul; Kim, Jaeho; Kim, Jae Yool; Song, Sanghyeon; Choi, Suyong; Hong, Byung-Sik; Jo, Mihee; Kim, Hyunchul; Kim, Ji Hyun; Kim, Tae Jeong; Lee, Kyong Sei; Moon, Dong Ho; Park, Sung Keun; Rhee, Han-Bum; Seo, Eunsung; Shin, Seungsu; Sim, Kwang Souk; Choi, Minkyoo; Kang, Seokon; Kim, Hyunyong; Park, Chawon; Park, Inkyu; Park, Sangnam; Ryu, Geonmo; Choi, Young-Il; Choi, Young Kyu; Goh, Junghwan; Lee, Jongseok; Lee, Sungeun; Seo, Hyunkwan; Yu, Intae; Bilinskas, Mykolas Jurgis; Grigelionis, Ignas; Janulis, Mindaugas; Martisiute, Dalia; Petrov, Pavel; Sabonis, Tomas; Castilla Valdez, Heriberto; De La Cruz Burelo, Eduard; Lopez-Fernandez, Ricardo; Sánchez Hernández, Alberto; Villasenor-Cendejas, Luis Manuel; Carrillo Moreno, Salvador; Vazquez Valencia, Fabiola; Salazar Ibarguen, Humberto Antonio; Casimiro Linares, Edgar; Morelos Pineda, Antonio; Reyes-Santos, Marco A.; Allfrey, Philip; Krofcheck, David; Butler, Philip H.; Doesburg, Robert; Silverwood, Hamish; Ahmad, Muhammad; Ahmed, Ijaz; Asghar, Muhammad Irfan; Hoorani, Hafeez R.; Khan, Wajid Ali; Khurshid, Taimoor; Qazi, Shamona; Cwiok, Mikolaj; Dominik, Wojciech; Doroba, Krzysztof; Kalinowski, Artur; Konecki, Marcin; Krolikowski, Jan; Frueboes, Tomasz; Gokieli, Ryszard; Górski, Maciej; Kazana, Malgorzata; Nawrocki, Krzysztof; Romanowska-Rybinska, Katarzyna; Szleper, Michal; Wrochna, Grzegorz; Zalewski, Piotr; Almeida, Nuno; David Tinoco Mendes, Andre; Faccioli, Pietro; Ferreira Parracho, Pedro Guilherme; Gallinaro, Michele; Sá Martins, Pedro; Musella, Pasquale; Nayak, Aruna; Ribeiro, Pedro Quinaz; Seixas, Joao; Silva, Pedro; Varela, Joao; Wöhri, Hermine Katharina; Belotelov, Ivan; Bunin, Pavel; Finger, Miroslav; Finger Jr., Michael; Golutvin, Igor; Kamenev, Alexey; Karjavin, Vladimir; Kozlov, Guennady; Lanev, Alexander; Moisenz, Petr; Palichik, Vladimir; Perelygin, Victor; Shmatov, Sergey; Smirnov, Vitaly; Volodko, Anton; Zarubin, Anatoli; Bondar, Nikolai; Golovtsov, Victor; Ivanov, Yury; Kim, Victor; Levchenko, Petr; Murzin, Victor; Oreshkin, Vadim; Smirnov, Igor; Sulimov, Valentin; Uvarov, Lev; Vavilov, Sergey; Vorobyev, Alexey; Andreev, Yuri; Gninenko, Sergei; Golubev, Nikolai; Kirsanov, Mikhail; Krasnikov, Nikolai; Matveev, Viktor; Pashenkov, Anatoli; Toropin, Alexander; Troitsky, Sergey; Epshteyn, Vladimir; Gavrilov, Vladimir; Kaftanov, Vitali; Kossov, Mikhail; Krokhotin, Andrey; Lychkovskaya, Natalia; Safronov, Grigory; Semenov, Sergey; Stolin, Viatcheslav; Vlasov, Evgueni; Zhokin, Alexander; Boos, Edouard; Dubinin, Mikhail; Dudko, Lev; Ershov, Alexander; Gribushin, Andrey; Kodolova, Olga; Lokhtin, Igor; Obraztsov, Stepan; Petrushanko, Sergey; Sarycheva, Ludmila; Savrin, Viktor; Snigirev, Alexander; Andreev, Vladimir; Azarkin, Maksim; Dremin, Igor; Kirakosyan, Martin; Rusakov, Sergey V.; Vinogradov, Alexey; Azhgirey, Igor; Bitioukov, Sergei; Grishin, Viatcheslav; Kachanov, Vassili; Konstantinov, Dmitri; Korablev, Andrey; Krychkine, Victor; Petrov, Vladimir; Ryutin, Roman; Slabospitsky, Sergey; Sobol, Andrei; Tourtchanovitch, Leonid; Troshin, Sergey; Tyurin, Nikolay; Uzunian, Andrey; Volkov, Alexey; Adzic, Petar; Djordjevic, Milos; Krpic, Dragomir; Milosevic, Jovan; Aguilar-Benitez, Manuel; Alcaraz Maestre, Juan; Arce, Pedro; Battilana, Carlo; Calvo, Enrique; Cepeda, Maria; Cerrada, Marcos; Colino, Nicanor; De La Cruz, Begona; Diez Pardos, Carmen; Domínguez Vázquez, Daniel; Fernandez Bedoya, Cristina; Fernández Ramos, Juan Pablo; Ferrando, Antonio; Flix, Jose; Fouz, Maria Cruz; Garcia-Abia, Pablo; Gonzalez Lopez, Oscar; Goy Lopez, Silvia; Hernandez, Jose M.; Josa, Maria Isabel; Merino, Gonzalo; Puerta Pelayo, Jesus; Redondo, Ignacio; Romero, Luciano; Santaolalla, Javier; Willmott, Carlos; Albajar, Carmen; Codispoti, Giuseppe; de Trocóniz, Jorge F; Cuevas, Javier; Fernandez Menendez, Javier; Folgueras, Santiago; Gonzalez Caballero, Isidro; Lloret Iglesias, Lara; Vizan Garcia, Jesus Manuel; Brochero Cifuentes, Javier Andres; Cabrillo, Iban Jose; Calderon, Alicia; Chamizo Llatas, Maria; Chuang, Shan-Huei; Duarte Campderros, Jordi; Felcini, Marta; Fernandez, Marcos; Gomez, Gervasio; Gonzalez Sanchez, Javier; Jorda, Clara; Lobelle Pardo, Patricia; Lopez Virto, Amparo; Marco, Jesus; Marco, Rafael; Martinez Rivero, Celso; Matorras, Francisco; Munoz Sanchez, Francisca Javiela; Piedra Gomez, Jonatan; Rodrigo, Teresa; Ruiz Jimeno, Alberto; Scodellaro, Luca; Sobron Sanudo, Mar; Vila, Ivan; Vilar Cortabitarte, Rocio; Abbaneo, Duccio; Auffray, Etiennette; Auzinger, Georg; Baillon, Paul; Ball, Austin; Barney, David; Bell, Alan James; Benedetti, Daniele; Bernet, Colin; Bialas, Wojciech; Bloch, Philippe; Bocci, Andrea; Bolognesi, Sara; Breuker, Horst; Brona, Grzegorz; Bunkowski, Karol; Camporesi, Tiziano; Cano, Eric; Cerminara, Gianluca; Christiansen, Tim; Coarasa Perez, Jose Antonio; Curé, Benoît; D'Enterria, David; De Roeck, Albert; Duarte Ramos, Fernando; Elliott-Peisert, Anna; Frisch, Benjamin; Funk, Wolfgang; Gaddi, Andrea; Gennai, Simone; Georgiou, Georgios; Gerwig, Hubert; Gigi, Dominique; Gill, Karl; Giordano, Domenico; Glege, Frank; Gomez-Reino Garrido, Robert; Gouzevitch, Maxime; Govoni, Pietro; Gowdy, Stephen; Guiducci, Luigi; Hansen, Magnus; Harvey, John; Hegeman, Jeroen; Hegner, Benedikt; Henderson, Conor; Hesketh, Gavin; Hoffmann, Hans Falk; Honma, Alan; Innocente, Vincenzo; Janot, Patrick; Karavakis, Edward; Lecoq, Paul; Leonidopoulos, Christos; Lourenco, Carlos; Macpherson, Alick; Maki, Tuula; Malgeri, Luca; Mannelli, Marcello; Masetti, Lorenzo; Meijers, Frans; Mersi, Stefano; Meschi, Emilio; Moser, Roland; Mozer, Matthias Ulrich; Mulders, Martijn; Nesvold, Erik; Nguyen, Matthew; Orimoto, Toyoko; Orsini, Luciano; Perez, Emmanuelle; Petrilli, Achille; Pfeiffer, Andreas; Pierini, Maurizio; Pimiä, Martti; Polese, Giovanni; Racz, Attila; Rodrigues Antunes, Joao; Rolandi, Gigi; Rommerskirchen, Tanja; Rovelli, Chiara; Rovere, Marco; Sakulin, Hannes; Schäfer, Christoph; Schwick, Christoph; Segoni, Ilaria; Sharma, Archana; Siegrist, Patrice; Simon, Michal; Sphicas, Paraskevas; Spiga, Daniele; Spiropulu, Maria; Stöckli, Fabian; Stoye, Markus; Tropea, Paola; Tsirou, Andromachi; Tsyganov, Andrey; Veres, Gabor Istvan; Vichoudis, Paschalis; Voutilainen, Mikko; Zeuner, Wolfram Dietrich; Bertl, Willi; Deiters, Konrad; Erdmann, Wolfram; Gabathuler, Kurt; Horisberger, Roland; Ingram, Quentin; Kaestli, Hans-Christian; König, Stefan; Kotlinski, Danek; Langenegger, Urs; Meier, Frank; Renker, Dieter; Rohe, Tilman; Sibille, Jennifer; Starodumov, Andrei; Bortignon, Pierluigi; Caminada, Lea; Chen, Zhiling; Cittolin, Sergio; Dissertori, Günther; Dittmar, Michael; Eugster, Jürg; Freudenreich, Klaus; Grab, Christoph; Hervé, Alain; Hintz, Wieland; Lecomte, Pierre; Lustermann, Werner; Marchica, Carmelo; Martinez Ruiz del Arbol, Pablo; Meridiani, Paolo; Milenovic, Predrag; Moortgat, Filip; Nef, Pascal; Nessi-Tedaldi, Francesca; Pape, Luc; Pauss, Felicitas; Punz, Thomas; Rizzi, Andrea; Ronga, Frederic Jean; Rossini, Marco; Sala, Leonardo; Sanchez, Ann - Karin; Sawley, Marie-Christine; Stieger, Benjamin; Tauscher, Ludwig; Thea, Alessandro; Theofilatos, Konstantinos; Treille, Daniel; Urscheler, Christina; Wallny, Rainer; Weber, Matthias; Wehrli, Lukas; Weng, Joanna; Aguiló, Ernest; Amsler, Claude; Chiochia, Vincenzo; De Visscher, Simon; Favaro, Carlotta; Ivova Rikova, Mirena; Millan Mejias, Barbara; Regenfus, Christian; Robmann, Peter; Schmidt, Alexander; Snoek, Hella; Chang, Yuan-Hann; Chen, Kuan-Hsin; Chen, Wan-Ting; Dutta, Suchandra; Go, Apollo; Kuo, Chia-Ming; Li, Syue-Wei; Lin, Willis; Liu, Ming-Hsiung; Liu, Zong-Kai; Lu, Yun-Ju; Wu, Jing-Han; Yu, Shin-Shan; Bartalini, Paolo; Chang, Paoti; Chang, You-Hao; Chang, Yu-Wei; Chao, Yuan; Chen, Kai-Feng; Hou, George Wei-Shu; Hsiung, Yee; Kao, Kai-Yi; Lei, Yeong-Jyi; Lu, Rong-Shyang; Shiu, Jing-Ge; Tzeng, Yeng-Ming; Wang, Minzu; Adiguzel, Aytul; Bakirci, Mustafa Numan; Cerci, Salim; Dozen, Candan; Dumanoglu, Isa; Eskut, Eda; Girgis, Semiray; Gokbulut, Gul; Guler, Yalcin; Gurpinar, Emine; Hos, Ilknur; Kangal, Evrim Ersin; Karaman, Turker; Kayis Topaksu, Aysel; Nart, Alisah; Onengut, Gulsen; Ozdemir, Kadri; Ozturk, Sertac; Polatoz, Ayse; Sogut, Kenan; Tali, Bayram; Topakli, Huseyin; Uzun, Dilber; Vergili, Latife Nukhet; Vergili, Mehmet; Zorbilmez, Caglar; Akin, Ilina Vasileva; Aliev, Takhmasib; Bilmis, Selcuk; Deniz, Muhammed; Gamsizkan, Halil; Guler, Ali Murat; Ocalan, Kadir; Ozpineci, Altug; Serin, Meltem; Sever, Ramazan; Surat, Ugur Emrah; Yildirim, Eda; Zeyrek, Mehmet; Deliomeroglu, Mehmet; Demir, Durmus; Gülmez, Erhan; Halu, Arda; Isildak, Bora; Kaya, Mithat; Kaya, Ozlem; Ozkorucuklu, Suat; Sonmez, Nasuf; Levchuk, Leonid; Bell, Peter; Bostock, Francis; Brooke, James John; Cheng, Teh Lee; Clement, Emyr; Cussans, David; Frazier, Robert; Goldstein, Joel; Grimes, Mark; Hansen, Maria; Hartley, Dominic; Heath, Greg P.; Heath, Helen F.; Huckvale, Benedickt; Jackson, James; Kreczko, Lukasz; Metson, Simon; Newbold, Dave M.; Nirunpong, Kachanon; Poll, Anthony; Senkin, Sergey; Smith, Vincent J.; Ward, Simon; Basso, Lorenzo; Bell, Ken W.; Belyaev, Alexander; Brew, Christopher; Brown, Robert M.; Camanzi, Barbara; Cockerill, David J.A.; Coughlan, John A.; Harder, Kristian; Harper, Sam; Kennedy, Bruce W.; Olaiya, Emmanuel; Petyt, David; Radburn-Smith, Benjamin Charles; Shepherd-Themistocleous, Claire; Tomalin, Ian R.; Womersley, William John; Worm, Steven; Bainbridge, Robert; Ball, Gordon; Ballin, Jamie; Beuselinck, Raymond; Buchmuller, Oliver; Colling, David; Cripps, Nicholas; Cutajar, Michael; Davies, Gavin; Della Negra, Michel; Fulcher, Jonathan; Futyan, David; Guneratne Bryer, Arlo; Hall, Geoffrey; Hatherell, Zoe; Hays, Jonathan; Iles, Gregory; Karapostoli, Georgia; Lyons, Louis; Magnan, Anne-Marie; Marrouche, Jad; Nandi, Robin; Nash, Jordan; Nikitenko, Alexander; Papageorgiou, Anastasios; Pesaresi, Mark; Petridis, Konstantinos; Pioppi, Michele; Raymond, David Mark; Rompotis, Nikolaos; Rose, Andrew; Ryan, Matthew John; Seez, Christopher; Sharp, Peter; Sparrow, Alex; Tapper, Alexander; Tourneur, Stephane; Vazquez Acosta, Monica; Virdee, Tejinder; Wakefield, Stuart; Wardrope, David; Whyntie, Tom; Barrett, Matthew; Chadwick, Matthew; Cole, Joanne; Hobson, Peter R.; Khan, Akram; Kyberd, Paul; Leslie, Dawn; Martin, William; Reid, Ivan; Teodorescu, Liliana; Hatakeyama, Kenichi; Bose, Tulika; Carrera Jarrin, Edgar; Clough, Andrew; Fantasia, Cory; Heister, Arno; St. John, Jason; Lawson, Philip; Lazic, Dragoslav; Rohlf, James; Sperka, David; Sulak, Lawrence; Avetisyan, Aram; Bhattacharya, Saptaparna; Chou, John Paul; Cutts, David; Ferapontov, Alexey; Heintz, Ulrich; Jabeen, Shabnam; Kukartsev, Gennadiy; Landsberg, Greg; Narain, Meenakshi; Nguyen, Duong; Segala, Michael; Speer, Thomas; Tsang, Ka Vang; Borgia, Maria Assunta; Breedon, Richard; Calderon De La Barca Sanchez, Manuel; Cebra, Daniel; Chauhan, Sushil; Chertok, Maxwell; Conway, John; Cox, Peter Timothy; Dolen, James; Erbacher, Robin; Friis, Evan; Ko, Winston; Kopecky, Alexandra; Lander, Richard; Liu, Haidong; Maruyama, Sho; Miceli, Tia; Nikolic, Milan; Pellett, Dave; Robles, Jorge; Salur, Sevil; Schwarz, Thomas; Searle, Matthew; Smith, John; Squires, Michael; Tripathi, Mani; Vasquez Sierra, Ricardo; Veelken, Christian; Andreev, Valeri; Arisaka, Katsushi; Cline, David; Cousins, Robert; Deisher, Amanda; Duris, Joseph; Erhan, Samim; Farrell, Chris; Hauser, Jay; Ignatenko, Mikhail; Jarvis, Chad; Plager, Charles; Rakness, Gregory; Schlein, Peter; Tucker, Jordan; Valuev, Vyacheslav; Babb, John; Clare, Robert; Ellison, John Anthony; Gary, J William; Giordano, Ferdinando; Hanson, Gail; Jeng, Geng-Yuan; Kao, Shih-Chuan; Liu, Feng; Liu, Hongliang; Luthra, Arun; Nguyen, Harold; Pasztor, Gabriella; Satpathy, Asish; Shen, Benjamin C.; Stringer, Robert; Sturdy, Jared; Sumowidagdo, Suharyo; Wilken, Rachel; Wimpenny, Stephen; Andrews, Warren; Branson, James G.; Cerati, Giuseppe Benedetto; Dusinberre, Elizabeth; Evans, David; Golf, Frank; Holzner, André; Kelley, Ryan; Lebourgeois, Matthew; Letts, James; Mangano, Boris; Muelmenstaedt, Johannes; Padhi, Sanjay; Palmer, Christopher; Petrucciani, Giovanni; Pi, Haifeng; Pieri, Marco; Ranieri, Riccardo; Sani, Matteo; Sharma, Vivek; Simon, Sean; Tu, Yanjun; Vartak, Adish; Würthwein, Frank; Yagil, Avraham; Barge, Derek; Bellan, Riccardo; Campagnari, Claudio; D'Alfonso, Mariarosaria; Danielson, Thomas; Flowers, Kristen; Geffert, Paul; Incandela, Joe; Justus, Christopher; Kalavase, Puneeth; Koay, Sue Ann; Kovalskyi, Dmytro; Krutelyov, Vyacheslav; Lowette, Steven; Mccoll, Nickolas; Pavlunin, Viktor; Rebassoo, Finn; Ribnik, Jacob; Richman, Jeffrey; Rossin, Roberto; Stuart, David; To, Wing; Vlimant, Jean-Roch; Bornheim, Adolf; Bunn, Julian; Chen, Yi; Gataullin, Marat; Kcira, Dorian; Litvine, Vladimir; Ma, Yousi; Mott, Alexander; Newman, Harvey B.; Rogan, Christopher; Timciuc, Vladlen; Traczyk, Piotr; Veverka, Jan; Wilkinson, Richard; Yang, Yong; Zhu, Ren-Yuan; Akgun, Bora; Carroll, Ryan; Ferguson, Thomas; Iiyama, Yutaro; Jang, Dong Wook; Jun, Soon Yung; Liu, Yueh-Feng; Paulini, Manfred; Russ, James; Terentyev, Nikolay; Vogel, Helmut; Vorobiev, Igor; Cumalat, John Perry; Dinardo, Mauro Emanuele; Drell, Brian Robert; Edelmaier, Christopher; Ford, William T.; Heyburn, Bernadette; Luiggi Lopez, Eduardo; Nauenberg, Uriel; Smith, James; Stenson, Kevin; Ulmer, Keith; Wagner, Stephen Robert; Zang, Shi-Lei; Agostino, Lorenzo; Alexander, James; Chatterjee, Avishek; Das, Souvik; Eggert, Nicholas; Fields, Laura Johanna; Gibbons, Lawrence Kent; Heltsley, Brian; Hopkins, Walter; Khukhunaishvili, Aleko; Kreis, Benjamin; Kuznetsov, Valentin; Nicolas Kaufman, Gala; Patterson, Juliet Ritchie; Puigh, Darren; Riley, Daniel; Ryd, Anders; Shi, Xin; Sun, Werner; Teo, Wee Don; Thom, Julia; Thompson, Joshua; Vaughan, Jennifer; Weng, Yao; Winstrom, Lucas; Wittich, Peter; Biselli, Angela; Cirino, Guy; Winn, Dave; Abdullin, Salavat; Albrow, Michael; Anderson, Jacob; Apollinari, Giorgio; Atac, Muzaffer; Bakken, Jon Alan; Banerjee, Sunanda; Bauerdick, Lothar A.T.; Beretvas, Andrew; Berryhill, Jeffrey; Bhat, Pushpalatha C.; Bloch, Ingo; Borcherding, Frederick; Burkett, Kevin; Butler, Joel Nathan; Chetluru, Vasundhara; Cheung, Harry; Chlebana, Frank; Cihangir, Selcuk; Demarteau, Marcel; Eartly, David P.; Elvira, Victor Daniel; Esen, Selda; Fisk, Ian; Freeman, Jim; Gao, Yanyan; Gottschalk, Erik; Green, Dan; Gunthoti, Kranti; Gutsche, Oliver; Hahn, Alan; Hanlon, Jim; Harris, Robert M.; Hirschauer, James; Hooberman, Benjamin; James, Eric; Jensen, Hans; Johnson, Marvin; Joshi, Umesh; Khatiwada, Rakshya; Kilminster, Benjamin; Klima, Boaz; Kousouris, Konstantinos; Kunori, Shuichi; Kwan, Simon; Limon, Peter; Lipton, Ron; Lykken, Joseph; Maeshima, Kaori; Marraffino, John Michael; Mason, David; McBride, Patricia; McCauley, Thomas; Miao, Ting; Mishra, Kalanand; Mrenna, Stephen; Musienko, Yuri; Newman-Holmes, Catherine; O'Dell, Vivian; Popescu, Sorina; Pordes, Ruth; Prokofyev, Oleg; Saoulidou, Niki; Sexton-Kennedy, Elizabeth; Sharma, Seema; Soha, Aron; Spalding, William J.; Spiegel, Leonard; Tan, Ping; Taylor, Lucas; Tkaczyk, Slawek; Uplegger, Lorenzo; Vaandering, Eric Wayne; Vidal, Richard; Whitmore, Juliana; Wu, Weimin; Yang, Fan; Yumiceva, Francisco; Yun, Jae Chul; Acosta, Darin; Avery, Paul; Bourilkov, Dimitri; Chen, Mingshui; Di Giovanni, Gian Piero; Dobur, Didar; Drozdetskiy, Alexey; Field, Richard D.; Fisher, Matthew; Fu, Yu; Furic, Ivan-Kresimir; Gartner, Joseph; Goldberg, Sean; Kim, Bockjoo; Klimenko, Sergey; Konigsberg, Jacobo; Korytov, Andrey; Kropivnitskaya, Anna; Kypreos, Theodore; Matchev, Konstantin; Mitselmakher, Guenakh; Muniz, Lana; Pakhotin, Yuriy; Prescott, Craig; Remington, Ronald; Schmitt, Michael Houston; Scurlock, Bobby; Sellers, Paul; Skhirtladze, Nikoloz; Wang, Dayong; Yelton, John; Zakaria, Mohammed; Ceron, Cristobal; Gaultney, Vanessa; Kramer, Laird; Lebolo, Luis Miguel; Linn, Stephan; Markowitz, Pete; Martinez, German; Rodriguez, Jorge Luis; Adams, Todd; Askew, Andrew; Bandurin, Dmitry; Bochenek, Joseph; Chen, Jie; Diamond, Brendan; Gleyzer, Sergei V; Haas, Jeff; Hagopian, Sharon; Hagopian, Vasken; Jenkins, Merrill; Johnson, Kurtis F.; Prosper, Harrison; Quertenmont, Loic; Sekmen, Sezen; Veeraraghavan, Venkatesh; Baarmand, Marc M.; Dorney, Brian; Guragain, Samir; Hohlmann, Marcus; Kalakhety, Himali; Ralich, Robert; Vodopiyanov, Igor; Adams, Mark Raymond; Anghel, Ioana Maria; Apanasevich, Leonard; Bai, Yuting; Bazterra, Victor Eduardo; Betts, Russell Richard; Callner, Jeremy; Cavanaugh, Richard; Dragoiu, Cosmin; Garcia-Solis, Edmundo Javier; Gerber, Cecilia Elena; Hofman, David Jonathan; Khalatyan, Samvel; Lacroix, Florent; Malek, Magdalena; O'Brien, Christine; Silvestre, Catherine; Smoron, Agata; Strom, Derek; Varelas, Nikos; Akgun, Ugur; Albayrak, Elif Asli; Bilki, Burak; Cankocak, Kerem; Clarida, Warren; Duru, Firdevs; Lae, Chung Khim; McCliment, Edward; Merlo, Jean-Pierre; Mermerkaya, Hamit; Mestvirishvili, Alexi; Moeller, Anthony; Nachtman, Jane; Newsom, Charles Ray; Norbeck, Edwin; Olson, Jonathan; Onel, Yasar; Ozok, Ferhat; Sen, Sercan; Wetzel, James; Yetkin, Taylan; Yi, Kai; Barnett, Bruce Arnold; Blumenfeld, Barry; Bonato, Alessio; Eskew, Christopher; Fehling, David; Giurgiu, Gavril; Gritsan, Andrei; Guo, Zijin; Hu, Guofan; Maksimovic, Petar; Rappoccio, Salvatore; Swartz, Morris; Tran, Nhan Viet; Whitbeck, Andrew; Baringer, Philip; Bean, Alice; Benelli, Gabriele; Grachov, Oleg; Murray, Michael; Noonan, Daniel; Radicci, Valeria; Sanders, Stephen; Wood, Jeffrey Scott; Zhukova, Victoria; Bolton, Tim; Chakaberia, Irakli; Ivanov, Andrew; Makouski, Mikhail; Maravin, Yurii; Shrestha, Shruti; Svintradze, Irakli; Wan, Zongru; Gronberg, Jeffrey; Lange, David; Wright, Douglas; Baden, Drew; Boutemeur, Madjid; Eno, Sarah Catherine; Ferencek, Dinko; Gomez, Jaime; Hadley, Nicholas John; Kellogg, Richard G.; Kirn, Malina; Lu, Ying; Mignerey, Alice; Rossato, Kenneth; Rumerio, Paolo; Santanastasio, Francesco; Skuja, Andris; Temple, Jeffrey; Tonjes, Marguerite; Tonwar, Suresh C.; Twedt, Elizabeth; Alver, Burak; Bauer, Gerry; Bendavid, Joshua; Busza, Wit; Butz, Erik; Cali, Ivan Amos; Chan, Matthew; Dutta, Valentina; Everaerts, Pieter; Gomez Ceballos, Guillelmo; Goncharov, Maxim; Hahn, Kristan Allan; Harris, Philip; Kim, Yongsun; Klute, Markus; Lee, Yen-Jie; Li, Wei; Loizides, Constantinos; Luckey, Paul David; Ma, Teng; Nahn, Steve; Paus, Christoph; Ralph, Duncan; Roland, Christof; Roland, Gunther; Rudolph, Matthew; Stephans, George; Sumorok, Konstanty; Sung, Kevin; Wenger, Edward Allen; Xie, Si; Yang, Mingming; Yilmaz, Yetkin; Yoon, Sungho; Zanetti, Marco; Cole, Perrie; Cooper, Seth; Cushman, Priscilla; Dahmes, Bryan; De Benedetti, Abraham; Dudero, Phillip Russell; Franzoni, Giovanni; Haupt, Jason; Klapoetke, Kevin; Kubota, Yuichi; Mans, Jeremy; Rekovic, Vladimir; Rusack, Roger; Sasseville, Michael; Singovsky, Alexander; Cremaldi, Lucien Marcus; Godang, Romulus; Kroeger, Rob; Perera, Lalith; Rahmat, Rahmat; Sanders, David A; Summers, Don; Bloom, Kenneth; Bose, Suvadeep; Butt, Jamila; Claes, Daniel R.; Dominguez, Aaron; Eads, Michael; Keller, Jason; Kelly, Tony; Kravchenko, Ilya; Lazo-Flores, Jose; Lundstedt, Carl; Malbouisson, Helena; Malik, Sudhir; Snow, Gregory R.; Baur, Ulrich; Godshalk, Andrew; Iashvili, Ia; Jain, Supriya; Kharchilava, Avto; Kumar, Ashish; Shipkowski, Simon Peter; Smith, Kenneth; Alverson, George; Barberis, Emanuela; Baumgartel, Darin; Boeriu, Oana; Chasco, Matthew; Kaadze, Ketino; Reucroft, Steve; Swain, John; Wood, Darien; Zhang, Jinzhong; Anastassov, Anton; Kubik, Andrew; Odell, Nathaniel; Ofierzynski, Radoslaw Adrian; Pollack, Brian; Pozdnyakov, Andrey; Schmitt, Michael Henry; Stoynev, Stoyan; Velasco, Mayda; Won, Steven; Antonelli, Louis; Berry, Douglas; Hildreth, Michael; Jessop, Colin; Karmgard, Daniel John; Kolb, Jeff; Kolberg, Ted; Lannon, Kevin; Luo, Wuming; Lynch, Sean; Marinelli, Nancy; Morse, David Michael; Pearson, Tessa; Ruchti, Randy; Slaunwhite, Jason; Valls, Nil; Warchol, Jadwiga; Wayne, Mitchell; Ziegler, Jill; Bylsma, Ben; Durkin, Lloyd Stanley; Gu, Jianhui; Hill, Christopher; Killewald, Phillip; Kotov, Khristian; Ling, Ta-Yung; Rodenburg, Marissa; Williams, Grayson; Adam, Nadia; Berry, Edmund; Elmer, Peter; Gerbaudo, Davide; Halyo, Valerie; Hebda, Philip; Hunt, Adam; Jones, John; Laird, Edward; Lopes Pegna, David; Marlow, Daniel; Medvedeva, Tatiana; Mooney, Michael; Olsen, James; Piroué, Pierre; Quan, Xiaohang; Saka, Halil; Stickland, David; Tully, Christopher; Werner, Jeremy Scott; Zuranski, Andrzej; Acosta, Jhon Gabriel; Huang, Xing Tao; Lopez, Angel; Mendez, Hector; Oliveros, Sandra; Ramirez Vargas, Juan Eduardo; Zatserklyaniy, Andriy; Alagoz, Enver; Barnes, Virgil E.; Bolla, Gino; Borrello, Laura; Bortoletto, Daniela; Everett, Adam; Garfinkel, Arthur F.; Gecse, Zoltan; Gutay, Laszlo; Hu, Zhen; Jones, Matthew; Koybasi, Ozhan; Laasanen, Alvin T.; Leonardo, Nuno; Liu, Chang; Maroussov, Vassili; Merkel, Petra; Miller, David Harry; Neumeister, Norbert; Shipsey, Ian; Silvers, David; Svyatkovskiy, Alexey; Yoo, Hwi Dong; Zablocki, Jakub; Zheng, Yu; Jindal, Pratima; Parashar, Neeti; Boulahouache, Chaouki; Cuplov, Vesna; Ecklund, Karl Matthew; Geurts, Frank J.M.; Liu, Jinghua H.; Padley, Brian Paul; Redjimi, Radia; Roberts, Jay; Zabel, James; Betchart, Burton; Bodek, Arie; Chung, Yeon Sei; Covarelli, Roberto; de Barbaro, Pawel; Demina, Regina; Eshaq, Yossof; Flacher, Henning; Garcia-Bellido, Aran; Goldenzweig, Pablo; Gotra, Yury; Han, Jiyeon; Harel, Amnon; Miner, Daniel Carl; Orbaker, Douglas; Petrillo, Gianluca; Vishnevskiy, Dmitry; Zielinski, Marek; Bhatti, Anwar; Ciesielski, Robert; Demortier, Luc; Goulianos, Konstantin; Lungu, Gheorghe; Mesropian, Christina; Yan, Ming; Atramentov, Oleksiy; Barker, Anthony; Duggan, Daniel; Gershtein, Yuri; Gray, Richard; Halkiadakis, Eva; Hidas, Dean; Hits, Dmitry; Lath, Amitabh; Panwalkar, Shruti; Patel, Rishi; Richards, Alan; Rose, Keith; Schnetzer, Steve; Somalwar, Sunil; Stone, Robert; Thomas, Scott; Cerizza, Giordano; Hollingsworth, Matthew; Spanier, Stefan; Yang, Zong-Chang; York, Andrew; Asaadi, Jonathan; Eusebi, Ricardo; Gilmore, Jason; Gurrola, Alfredo; Kamon, Teruki; Khotilovich, Vadim; Montalvo, Roy; Nguyen, Chi Nhan; Osipenkov, Ilya; Pivarski, James; Safonov, Alexei; Sengupta, Sinjini; Tatarinov, Aysen; Toback, David; Weinberger, Michael; Akchurin, Nural; Bardak, Cemile; Damgov, Jordan; Jeong, Chiyoung; Kovitanggoon, Kittikul; Lee, Sung Won; Mane, Poonam; Roh, Youn; Sill, Alan; Volobouev, Igor; Wigmans, Richard; Yazgan, Efe; Appelt, Eric; Brownson, Eric; Engh, Daniel; Florez, Carlos; Gabella, William; Johns, Willard; Kurt, Pelin; Maguire, Charles; Melo, Andrew; Sheldon, Paul; Velkovska, Julia; Arenton, Michael Wayne; Balazs, Michael; Boutle, Sarah; Buehler, Marc; Conetti, Sergio; Cox, Bradley; Francis, Brian; Hirosky, Robert; Ledovskoy, Alexander; Lin, Chuanzhe; Neu, Christopher; Yohay, Rachel; Gollapinni, Sowjanya; Harr, Robert; Karchin, Paul Edmund; Lamichhane, Pramod; Mattson, Mark; Milstène, Caroline; Sakharov, Alexandre; Anderson, Michael; Bachtis, Michail; Bellinger, James Nugent; Carlsmith, Duncan; Dasu, Sridhara; Efron, Jonathan; Gray, Lindsey; Grogg, Kira Suzanne; Grothe, Monika; Hall-Wilton, Richard; Herndon, Matthew; Klabbers, Pamela; Klukas, Jeffrey; Lanaro, Armando; Lazaridis, Christos; Leonard, Jessica; Lomidze, David; Loveless, Richard; Mohapatra, Ajit; Reeder, Don; Ross, Ian; Savin, Alexander; Smith, Wesley H.; Swanson, Joshua; Weinberg, Marc

2011-01-01

A search for a heavy gauge boson W' has been conducted by the CMS experiment at the LHC in the decay channel with an electron and large transverse energy imbalance, using proton-proton collision data corresponding to an integrated luminosity of 36 inverse picobarns. No excess above standard model expectations is seen in the transverse mass distribution of the electron-(missing E_T) system. Assuming standard-model-like couplings and decay branching fractions, a W' boson with a mass less than 1.36 TeV/$c^2$ is excluded at 95% confidence level.

EELOSS: the program for calculation of electron energy loss data

International Nuclear Information System (INIS)

Tanaka, Shun-ichi

1980-10-01

A computer code EELOSS has been developed to obtain the electron energy loss data required for shielding and dosimetry of beta- and gamma-rays in nuclear plants. With this code, the following data are obtainable for any energy from 0.01 to 15 MeV in any medium (metal, insulator, gas, compound, or mixture) composed of any choice of 69 elements with atomic number 1 -- 94: a) Collision stopping power, b) Restricted collision stopping power, c) Radiative stopping power, and d) Bremsstrahlung production cross section. The availability of bremsstrahlung production cross section data obtained by the EELOSS code is demonstrated by the comparison of calculated gamma-ray spectrum with measured one in Pb layer, where electron-photon cascade is included implicitly. As a result, it is concluded that the uncertainty in the bremsstrahlung production cross sections is negligible in the practical shielding calculations of gamma rays of energy less than 15 MeV, since the bremsstrahlung production cross sections increase with the gamma-ray energy and the uncertainty for them decreases with increasing the gamma-ray energy. Furthermore, the accuracy of output data of the EELOSS code is evaluated in comparison with experimental data, and satisfactory agreements are observed concerning the stopping power. (J.P.N.)

Study of Electron-Pair Spectroscopy in Pb-Pb Collisions at LHC

CERN Document Server

CERN. Geneva

1993-01-01

Among observables that have been proposed as signals of quark gluon plasma the lepton pairs from decays of vector bosons r, w, j, J/Y, U,... play important role. Effects such as the J/Y suppression, chiral symmetry restoration, strangeness enhancement and fast "clock" for the fireball lifetime are associated with possibilities of the lepton-pair spectroscopy in PbPb collisions at the LHC energies. In PbPb collisions the high particle density in central rapidity region is expected and therefore one has first of all to verify the feasibility of experiments aimed to measurement of cross sections, width and positions of vector resonances. For this purpose the programme LHCWPT has been developed which simulates production and two-and three-body decays of the ¹¡, h°, h, r, w, f, J/Y, U and Drell-Yan pairs in central rapidity region and also a detection of electrons and positrons in HEAVY ION DEDICATED EXPERIMENT.

Analytic formula of stopping power for high energy electrons in liquid media

International Nuclear Information System (INIS)

Scarlat, F.; Niculescu, V.I.R.

1994-01-01

This article is part of a series on the calculation of high energy electron dose using multiple scattering theory. In the current article we present an analytic formula obtained for the collision stopping power (S/ρ) c and the radiative stopping power (S/ρ) r for electrons with energy within 1 MeV - 35 MeV range. For that purpose we used data given for electrons in water in NBS-IR-2550A. The analytical formulae are approximating the data calculated by Berger and Seltzer within 1-2% limit. (Author)

Numerical analysis of energy density and particle density in high energy heavy-ion collisions

International Nuclear Information System (INIS)

Fu Yuanyong; Lu Zhongdao

2004-01-01

Energy density and particle density in high energy heavy-ion collisions are calculated with infinite series expansion method and Gauss-Laguerre formulas in numerical integration separately, and the results of these two methods are compared, the higher terms and linear terms in series expansion are also compared. The results show that Gauss-Laguerre formulas is a good method in calculations of high energy heavy-ion collisions. (author)

Molecular (Feshbach) treatment of charge exchange Li/sup 3 +/+He collisions. I. Energies and couplings

Energy Technology Data Exchange (ETDEWEB)

Martin, F.; Riera, A.; Yanez, M.

1986-05-15

We point out a fundamental difference between the molecular treatment of charge exchange X/sup n/++H(1s) and X/sup n/++He(1s/sup 2/) collisions, which is that the latter process involves molecular states that are formally autoionizing. Then standard ab initio methods do not, in general, yield the relevant wave functions that are needed in the collision treatment, irrespective of whether quasimolecular autoionization be significant or not during the collision. We implement a particularly simple and useful form of the Feshbach formalism to calculate the energies of those two electron systems, and a method to evaluate the corresponding dynamical couplings is presented for the first time. Our implementation of this formalism together with the new computational techniques involved are presented in detail.

Bremsstrahlung spectra from thick-target electron beams with noncollisional energy losses

International Nuclear Information System (INIS)

Brown, J.C.; MacKinnon, A.L.

1985-01-01

We consider what can be learned from the bremsstrahlung radiation of fast electrons in a thick target, generalized to include electron energy losses additional to collisions. We show that the observed photon spectrum can, in principle, be inverted to yield an integral functional of the electron spectrum and the effective energy loss rate. In the light of this result, there seems no reason to suppose, in the absence of a priori information to the contrary, that the photon spectrum is symptomatic more of the fast electron distribution than of the energy loss processes. In cases where the electron injection spectrum is known on independent observational or theoretical grounds, it is possible to infer an effective, ''phenomenological'' energy loss function. In the more general case, however, fullest possible modeling of the physical situation and comparison of the resulting spectrum with observations is all that can be attempted

Low energy collision experiments using the beam guide technique. Charge transfer cross sections of Ar/sup 3+/ and Kr/sup 3+/ in their own gases

Energy Technology Data Exchange (ETDEWEB)

Okuno, Kazuhiko; Kaneko, Yozaburo

1986-12-01

The trajectories of charged particles moving in an octopole ion beam guide (OPIG) are computer-simulated for various initial conditions of motion. Boundary conditions between the stable and unstable regions of beam trajectory in OPIG are obtained. These calculated results are very useful for operation of OPIG under the best condition. In low energy collision experiments using the beam guide technique, cross sections of one-, two- and three-electron capture processes in collision systems of Ar/sup 3+/-Ar and Kr/sup 3+/-Kr are measured in energy region from 0.375 to 768 eV in center-of-mass system. In both collision systems, one-electron capture reaction is predominant in higher energy side, however, the dominant reaction changes from one-electron capture reaction to the symmetric resonant three-electron capture reaction in the low energy region below about 10 eV. As was predicted, it was first confirmed that each cross section obtained for symmetric resonant triple-charge-transfer reaction of Ar/sup 3+/ and Kr/sup 3+/ at the low energy end of Ecm = 0.375 eV is larger than both cross sections of symmetric resonant double-charge-transfer for the doubly charged ion and symmetric resonant single-charge-transfer for the singly charged ion.

Influence of Doppler and 'Stark' effects on the shape of the autoionization peaks in electron energy spectra produced in ion-atom collisions

International Nuclear Information System (INIS)

Gleizes, A.; Benoit-Cattin, P.; Bordenave-Montesquieu, A.; Merchez, H.

1976-01-01

A detailed study is given of the influence of the Doppler shift and broadening on the spectra of electrons ejected by autoionization in collisions between heavy particles. General formulae have been obtained which permit the validity of results already published by other authors to be discussed. These results have been applied to the spectra of electrons ejected in He + -He collisions at 15 keV. The variation of the width of the autoionization peaks against ejection angle is well explained by Doppler broadening. On the contrary, the shape of these peaks cannot be due to the Doppler effect but rather to the Stark effect which is also studied in various experimental cases; it has been verified that the latter effect disappears in collisions between neutral particles for which symmetric peaks at 15 keV are obtained. (author)

Electron: Cluster interactions

International Nuclear Information System (INIS)

Scheidemann, A.A.; Knight, W.D.

1994-02-01

Beam depletion spectroscopy has been used to measure absolute total inelastic electron-sodium cluster collision cross sections in the energy range from E ∼ 0.1 to E ∼ 6 eV. The investigation focused on the closed shell clusters Na 8 , Na 20 , Na 40 . The measured cross sections show an increase for the lowest collision energies where electron attachment is the primary scattering channel. The electron attachment cross section can be understood in terms of Langevin scattering, connecting this measurement with the polarizability of the cluster. For energies above the dissociation energy the measured electron-cluster cross section is energy independent, thus defining an electron-cluster interaction range. This interaction range increases with the cluster size

Atlas electromagnetic calorimeter and electron reconstruction commissioning with the first LHC collision data: study of the W' -> eν heavy gauge boson discovery potential

International Nuclear Information System (INIS)

Kuna, M.

2010-09-01

ATLAS is a general purpose particle detector based at the Large Hadron Collider which has been delivering collisions since the beginning of 2010, with an energy in the center of mass of √(s) = 7 TeV. The electron and the discovery potential it carries is the subject of my thesis. The electromagnetic calorimeter is a crucial sub-detector for the measurement of electrons kinematic properties. In order to verify its functioning, I contributed to the first in situ data analysis, cosmic muons in 2008 and LHC beam data in 2009. These analyses showed the electromagnetic calorimeter was operational and efficient over its whole coverage. The knowledge of the electrons energy losses before they reach the calorimeter is mandatory to achieve precise measurements. For that purpose, I contributed to a method evaluating the amount of material upstream using Monte-Carlo simulations of high transverse momentum electrons. The information from the electrons allows the mapping of the material from the inner tracker to the calorimeter entrance. In 2009 and 2010, the LHC collisions at √(s) = 900 GeV and √(s) = 7 TeV collisions provided ATLAS with its first electron candidates and enabled the verification of their reconstruction performance. In this prospect, I compared the electron identification variables of data and simulation. Finally, I prepared the search for a charged heavy gauge boson W' decaying in an electron and a neutrino, using a calorimetry only definition of missing transverse energy in order to improve the method's robustness in the perspective of an early data analysis. (author)

Computer simulation studies of high energy collision cascades

International Nuclear Information System (INIS)

Robinson, M.T.

1991-07-01

A modified binary collision approximation allowing the proper order of the collisions in time was used to study cascades in Cu and Au at primary kinetic energies up to 100 keV. Nonlinearities were approximated by letting already-stopped cascade atoms become targets in later collisions, using an improved method of locating potential targets to extend the calculations to energies much higher than heretofore. Beside the effect of the approximate nonlinearity, the effect of thermal disorder in the targets was examined. Target redisplacements reduce the damage in Cu by 3% at most, but in Au they reduce it by amounts up to 20% at 100 keV. Thermal disorder is also important: by disrupting crystal effects, the damage is reduced significantly. 11 refs., 4 figs

Electron emission from transfer ionization reaction in 30 keV amu‑1 He 2+ on Ar collision

Science.gov (United States)

Amaya-Tapia, A.; Antillón, A.; Estrada, C. D.

2018-06-01

A model is presented that describes the transfer ionization process in H{e}2++Ar collision at a projectile energy of 30 keV amu‑1. It is based on a semiclassical independent-particle close-coupling method that yields a reasonable agreement between calculated and experimental values of the total single-ionization and single-capture cross sections. It is found that the transfer ionization reaction is predominantly carried out through simultaneous capture and ionization, rather than by sequential processes. The transfer-ionization differential cross section in energy that is obtained satisfactorily reproduces the global behavior of the experimental data. Additionally, the probabilities of capture and ionization as function of the impact parameter for H{e}2++A{r}+ and H{e}++A{r}+ collisions are calculated, as far as we know, for the first time. The results suggest that the model captures essential elements that describe the two-electron transfer ionization process and could be applied to systems and processes of two electrons.

Jet production in the CoLoRFulNNLO method: event shapes in electron-positron collisions

CERN Document Server

Del Duca, Vittorio

2016-01-01

We present the CoLoRFulNNLO method to compute higher order radiative corrections to jet cross sections in perturbative QCD. We apply our method to the computation of event shape observables in electron-positron collisions at NNLO accuracy and validate our code by comparing our predictions to previous results in the literature. We also calculate for the first time jet cone energy fraction at NNLO.

Strong forward-backward asymmetries in electron emission from overlapping resonance states in fast C3+ on He collisions

International Nuclear Information System (INIS)

Yamazaki, Y.; Miller, P.D.; Krause, H.F.; Pepmiller, P.L.; Datz, S.; Sellin, I.A.

1986-01-01

Autoionizing electrons from the configuration 1s 2 2pnl produced by transfer and excitation were measured for 2.5 to 5.0 MeV C 3+ + He-gas collision employing the method of zero-degree Auger spectroscopy. The elctron analyzer was operated with an energy resolution of 300 MeV (FWHM), which corresponds to the projectile rest frame energy resolution (approx.40 MeV)

A plausible picture of high-energy proton-nucleus collisions

International Nuclear Information System (INIS)

Kim, C.O.

1976-01-01

Results experimentally obtained from jets of E(p)=10-10 3 GeV in nuclear emulsion show that the target nucleus in proton-nucleus collisions seems to present ''limiting fragmentation''. In the same energy range, proton-nucleus collisions resemble closely proton-proton collisions and asymmetric shape of rapidities is only caused by the break-up products of heavy targets [fr

Elsevier Measurement of the production of high-$p_{\\rm T}$ electrons from heavy-flavour hadron decays in Pb-Pb collisions at $\\mathbf{\\sqrt{\\it s_{\\rm{NN}}}}$ = 2.76 TeV

CERN Document Server

Adam, Jaroslav; Aggarwal, Madan Mohan; Aglieri Rinella, Gianluca; Agnello, Michelangelo; Agrawal, Neelima; Ahammed, Zubayer; Ahmad, Shakeel; Ahn, Sang Un; Aiola, Salvatore; Akindinov, Alexander; Alam, Sk Noor; Silva De Albuquerque, Danilo; Aleksandrov, Dmitry; Alessandro, Bruno; Alexandre, Didier; Alfaro Molina, Jose Ruben; Alici, Andrea; Alkin, Anton; Alme, Johan; Alt, Torsten; Altinpinar, Sedat; Altsybeev, Igor; Alves Garcia Prado, Caio; An, Mangmang; Andrei, Cristian; Andrews, Harry Arthur; Andronic, Anton; Anguelov, Venelin; Anson, Christopher Daniel; Anticic, Tome; Antinori, Federico; Antonioli, Pietro; Anwar, Rafay; Aphecetche, Laurent Bernard; Appelshaeuser, Harald; Arcelli, Silvia; Arnaldi, Roberta; Arnold, Oliver Werner; Arsene, Ionut Cristian; Arslandok, Mesut; Audurier, Benjamin; Augustinus, Andre; Averbeck, Ralf Peter; Azmi, Mohd Danish; Badala, Angela; Baek, Yong Wook; Bagnasco, Stefano; Bailhache, Raphaelle Marie; Bala, Renu; Balasubramanian, Supraja; Baldisseri, Alberto; Baral, Rama Chandra; Barbano, Anastasia Maria; Barbera, Roberto; Barile, Francesco; Barnafoldi, Gergely Gabor; Barnby, Lee Stuart; Ramillien Barret, Valerie; Bartalini, Paolo; Barth, Klaus; Bartke, Jerzy Gustaw; Bartsch, Esther; Basile, Maurizio; Bastid, Nicole; Basu, Sumit; Bathen, Bastian; Batigne, Guillaume; Batista Camejo, Arianna; Batyunya, Boris; Batzing, Paul Christoph; Bearden, Ian Gardner; Beck, Hans; Bedda, Cristina; Behera, Nirbhay Kumar; Belikov, Iouri; Bellini, Francesca; Bello Martinez, Hector; Bellwied, Rene; Espinoza Beltran, Lucina Gabriela; Belyaev, Vladimir; Bencedi, Gyula; Beole, Stefania; Bercuci, Alexandru; Berdnikov, Yaroslav; Berenyi, Daniel; Bertens, Redmer Alexander; Berzano, Dario; Betev, Latchezar; Bhasin, Anju; Bhat, Inayat Rasool; Bhati, Ashok Kumar; Bhattacharjee, Buddhadeb; Bhom, Jihyun; Bianchi, Livio; Bianchi, Nicola; Bianchin, Chiara; Bielcik, Jaroslav; Bielcikova, Jana; Bilandzic, Ante; Biro, Gabor; Biswas, Rathijit; Biswas, Saikat; Bjelogrlic, Sandro; Blair, Justin Thomas; Blau, Dmitry; Blume, Christoph; Bock, Friederike; Bogdanov, Alexey; Boldizsar, Laszlo; Bombara, Marek; Bonora, Matthias; Book, Julian Heinz; Borel, Herve; Borissov, Alexander; Borri, Marcello; Botta, Elena; Bourjau, Christian; Braun-munzinger, Peter; Bregant, Marco; Broker, Theo Alexander; Browning, Tyler Allen; Broz, Michal; Brucken, Erik Jens; Bruna, Elena; Bruno, Giuseppe Eugenio; Budnikov, Dmitry; Buesching, Henner; Bufalino, Stefania; Buhler, Paul; Iga Buitron, Sergio Arturo; Buncic, Predrag; Busch, Oliver; Buthelezi, Edith Zinhle; Bashir Butt, Jamila; Buxton, Jesse Thomas; Cabala, Jan; Caffarri, Davide; Caines, Helen Louise; Caliva, Alberto; Calvo Villar, Ernesto; Camerini, Paolo; Carena, Francesco; Carena, Wisla; Carnesecchi, Francesca; Castillo Castellanos, Javier Ernesto; Castro, Andrew John; Casula, Ester Anna Rita; Ceballos Sanchez, Cesar; Cepila, Jan; Cerello, Piergiorgio; Cerkala, Jakub; Chang, Beomsu; Chapeland, Sylvain; Chartier, Marielle; Charvet, Jean-luc Fernand; Chattopadhyay, Subhasis; Chattopadhyay, Sukalyan; Chauvin, Alex; Chelnokov, Volodymyr; Cherney, Michael Gerard; Cheshkov, Cvetan Valeriev; Cheynis, Brigitte; Chibante Barroso, Vasco Miguel; Dobrigkeit Chinellato, David; Cho, Soyeon; Chochula, Peter; Choi, Kyungeon; Chojnacki, Marek; Choudhury, Subikash; Christakoglou, Panagiotis; Christensen, Christian Holm; Christiansen, Peter; Chujo, Tatsuya; Chung, Suh-urk; Cicalo, Corrado; Cifarelli, Luisa; Cindolo, Federico; Cleymans, Jean Willy Andre; Colamaria, Fabio Filippo; Colella, Domenico; Collu, Alberto; Colocci, Manuel; Conesa Balbastre, Gustavo; Conesa Del Valle, Zaida; Connors, Megan Elizabeth; Contreras Nuno, Jesus Guillermo; Cormier, Thomas Michael; Corrales Morales, Yasser; Cortes Maldonado, Ismael; Cortese, Pietro; Cosentino, Mauro Rogerio; Costa, Filippo; Crkovska, Jana; Crochet, Philippe; Cruz Albino, Rigoberto; Cuautle Flores, Eleazar; Cunqueiro Mendez, Leticia; Dahms, Torsten; Dainese, Andrea; Danisch, Meike Charlotte; Danu, Andrea; Das, Debasish; Das, Indranil; Das, Supriya; Dash, Ajay Kumar; Dash, Sadhana; De, Sudipan; De Caro, Annalisa; De Cataldo, Giacinto; De Conti, Camila; De Cuveland, Jan; De Falco, Alessandro; De Gruttola, Daniele; De Marco, Nora; De Pasquale, Salvatore; Derradi De Souza, Rafael; Deisting, Alexander; Deloff, Andrzej; Deplano, Caterina; Dhankher, Preeti; Di Bari, Domenico; Di Mauro, Antonio; Di Nezza, Pasquale; Di Ruzza, Benedetto; Diaz Corchero, Miguel Angel; Dietel, Thomas; Dillenseger, Pascal; Divia, Roberto; Djuvsland, Oeystein; Dobrin, Alexandru Florin; Domenicis Gimenez, Diogenes; Donigus, Benjamin; Dordic, Olja; Drozhzhova, Tatiana; Dubey, Anand Kumar; Dubla, Andrea; Ducroux, Laurent; Duggal, Ashpreet Kaur; Dupieux, Pascal; Ehlers Iii, Raymond James; Elia, Domenico; Endress, Eric; Engel, Heiko; Epple, Eliane; Erazmus, Barbara Ewa; Erhardt, Filip; Espagnon, Bruno; Esumi, Shinichi; Eulisse, Giulio; Eum, Jongsik; Evans, David; Evdokimov, Sergey; Eyyubova, Gyulnara; Fabbietti, Laura; Fabris, Daniela; Faivre, Julien; Fantoni, Alessandra; Fasel, Markus; Feldkamp, Linus; Feliciello, Alessandro; Feofilov, Grigorii; Ferencei, Jozef; Fernandez Tellez, Arturo; Gonzalez Ferreiro, Elena; Ferretti, Alessandro; Festanti, Andrea; Feuillard, Victor Jose Gaston; Figiel, Jan; Araujo Silva Figueredo, Marcel; Filchagin, Sergey; Finogeev, Dmitry; Fionda, Fiorella; Fiore, Enrichetta Maria; Floris, Michele; Foertsch, Siegfried Valentin; Foka, Panagiota; Fokin, Sergey; Fragiacomo, Enrico; Francescon, Andrea; Francisco, Audrey; Frankenfeld, Ulrich Michael; Fronze, Gabriele Gaetano; Fuchs, Ulrich; Furget, Christophe; Furs, Artur; Fusco Girard, Mario; Gaardhoeje, Jens Joergen; Gagliardi, Martino; Gago Medina, Alberto Martin; Gajdosova, Katarina; Gallio, Mauro; Duarte Galvan, Carlos; Gangadharan, Dhevan Raja; Ganoti, Paraskevi; Gao, Chaosong; Garabatos Cuadrado, Jose; Garcia-solis, Edmundo Javier; Garg, Kunal; Garg, Prakhar; Gargiulo, Corrado; Gasik, Piotr Jan; Gauger, Erin Frances; De Leone Gay, Maria Beatriz; Germain, Marie; Ghosh, Premomoy; Ghosh, Sanjay Kumar; Gianotti, Paola; Giubellino, Paolo; Giubilato, Piero; Gladysz-dziadus, Ewa; Glassel, Peter; Gomez Coral, Diego Mauricio; Gomez Ramirez, Andres; Sanchez Gonzalez, Andres; Gonzalez, Victor; Gonzalez Zamora, Pedro; Gorbunov, Sergey; Gorlich, Lidia Maria; Gotovac, Sven; Grabski, Varlen; Graczykowski, Lukasz Kamil; Graham, Katie Leanne; Greiner, Leo Clifford; Grelli, Alessandro; Grigoras, Costin; Grigoryev, Vladislav; Grigoryan, Ara; Grigoryan, Smbat; Grion, Nevio; Gronefeld, Julius Maximilian; Grosse-oetringhaus, Jan Fiete; Grosso, Raffaele; Gruber, Lukas; Guber, Fedor; Guernane, Rachid; Guerzoni, Barbara; Gulbrandsen, Kristjan Herlache; Gunji, Taku; Gupta, Anik; Gupta, Ramni; Bautista Guzman, Irais; Haake, Rudiger; Hadjidakis, Cynthia Marie; Hamagaki, Hideki; Hamar, Gergoe; Hamon, Julien Charles; Harris, John William; Harton, Austin Vincent; Hatzifotiadou, Despina; Hayashi, Shinichi; Heckel, Stefan Thomas; Hellbar, Ernst; Helstrup, Haavard; Herghelegiu, Andrei Ionut; Herrera Corral, Gerardo Antonio; Herrmann, Florian; Hess, Benjamin Andreas; Hetland, Kristin Fanebust; Hillemanns, Hartmut; Hippolyte, Boris; Hladky, Jan; Horak, David; Hosokawa, Ritsuya; Hristov, Peter Zahariev; Hughes, Charles; Humanic, Thomas; Hussain, Nur; Hussain, Tahir; Hutter, Dirk; Hwang, Dae Sung; Ilkaev, Radiy; Inaba, Motoi; Ippolitov, Mikhail; Irfan, Muhammad; Isakov, Vladimir; Islam, Md Samsul; Ivanov, Marian; Ivanov, Vladimir; Izucheev, Vladimir; Jacak, Barbara; Jacazio, Nicolo; Jacobs, Peter Martin; Jadhav, Manoj Bhanudas; Jadlovska, Slavka; Jadlovsky, Jan; Jahnke, Cristiane; Jakubowska, Monika Joanna; Janik, Malgorzata Anna; Pahula Hewage, Sandun; Jena, Chitrasen; Jena, Satyajit; Jimenez Bustamante, Raul Tonatiuh; Jones, Peter Graham; Jusko, Anton; Kalinak, Peter; Kalweit, Alexander Philipp; Kang, Ju Hwan; Kaplin, Vladimir; Kar, Somnath; Karasu Uysal, Ayben; Karavichev, Oleg; Karavicheva, Tatiana; Karayan, Lilit; Karpechev, Evgeny; Kebschull, Udo Wolfgang; Keidel, Ralf; Keijdener, Darius Laurens; Keil, Markus; Khan, Mohammed Mohisin; Khan, Palash; Khan, Shuaib Ahmad; Khanzadeev, Alexei; Kharlov, Yury; Khatun, Anisa; Khuntia, Arvind; Kileng, Bjarte; Kim, Do Won; Kim, Dong Jo; Kim, Daehyeok; Kim, Hyeonjoong; Kim, Jinsook; Kim, Jiyoung; Kim, Minjung; Kim, Minwoo; Kim, Se Yong; Kim, Taesoo; Kirsch, Stefan; Kisel, Ivan; Kiselev, Sergey; Kisiel, Adam Ryszard; Kiss, Gabor; Klay, Jennifer Lynn; Klein, Carsten; Klein, Jochen; Klein-boesing, Christian; Klewin, Sebastian; Kluge, Alexander; Knichel, Michael Linus; Knospe, Anders Garritt; Kobdaj, Chinorat; Kofarago, Monika; Kollegger, Thorsten; Kolozhvari, Anatoly; Kondratev, Valerii; Kondratyeva, Natalia; Kondratyuk, Evgeny; Konevskikh, Artem; Kopcik, Michal; Kour, Mandeep; Kouzinopoulos, Charalampos; Kovalenko, Oleksandr; Kovalenko, Vladimir; Kowalski, Marek; Koyithatta Meethaleveedu, Greeshma; Kralik, Ivan; Kravcakova, Adela; Krivda, Marian; Krizek, Filip; Kryshen, Evgeny; Krzewicki, Mikolaj; Kubera, Andrew Michael; Kucera, Vit; Kuhn, Christian Claude; Kuijer, Paulus Gerardus; Kumar, Ajay; Kumar, Jitendra; Kumar, Lokesh; Kumar, Shyam; Kundu, Sourav; Kurashvili, Podist; Kurepin, Alexander; Kurepin, Alexey; Kuryakin, Alexey; Kushpil, Svetlana; Kweon, Min Jung; Kwon, Youngil; La Pointe, Sarah Louise; La Rocca, Paola; Lagana Fernandes, Caio; Lakomov, Igor; Langoy, Rune; Lapidus, Kirill; Lara Martinez, Camilo Ernesto; Lardeux, Antoine Xavier; Lattuca, Alessandra; Laudi, Elisa; Lazaridis, Lazaros; Lea, Ramona; Leardini, Lucia; Lee, Seongjoo; Lehas, Fatiha; Lehner, Sebastian; Lehrbach, Johannes; Lemmon, Roy Crawford; Lenti, Vito; Leogrande, Emilia; Leon Monzon, Ildefonso; Levai, Peter; Li, Shuang; Li, Xiaomei; Lien, Jorgen Andre; Lietava, Roman; Lindal, Svein; Lindenstruth, Volker; Lippmann, Christian; Lisa, Michael Annan; Ljunggren, Hans Martin; Llope, William; Lodato, Davide Francesco; Lonne, Per-ivar; Loginov, Vitaly; Loizides, Constantinos; Lopez, Xavier Bernard; Lopez Torres, Ernesto; Lowe, Andrew John; Luettig, Philipp Johannes; Lunardon, Marcello; Luparello, Grazia; Lupi, Matteo; Lutz, Tyler Harrison; Maevskaya, Alla; Mager, Magnus; Mahajan, Sanjay; Mahmood, Sohail Musa; Maire, Antonin; Majka, Richard Daniel; Malaev, Mikhail; Maldonado Cervantes, Ivonne Alicia; Malinina, Liudmila; Mal'kevich, Dmitry; Malzacher, Peter; Mamonov, Alexander; Manko, Vladislav; Manso, Franck; Manzari, Vito; Mao, Yaxian; Marchisone, Massimiliano; Mares, Jiri; Margagliotti, Giacomo Vito; Margotti, Anselmo; Margutti, Jacopo; Marin, Ana Maria; Markert, Christina; Marquard, Marco; Martin, Nicole Alice; Martinengo, Paolo; Martinez Hernandez, Mario Ivan; Martinez-garcia, Gines; Martinez Pedreira, Miguel; Mas, Alexis Jean-michel; Masciocchi, Silvia; Masera, Massimo; Masoni, Alberto; Mastroserio, Annalisa; Matyja, Adam Tomasz; Mayer, Christoph; Mazer, Joel Anthony; Mazzilli, Marianna; Mazzoni, Alessandra Maria; Meddi, Franco; Melikyan, Yuri; Menchaca-rocha, Arturo Alejandro; Meninno, Elisa; Mercado-perez, Jorge; Meres, Michal; Mhlanga, Sibaliso; Miake, Yasuo; Mieskolainen, Matti Mikael; Mikhaylov, Konstantin; Milano, Leonardo; Milosevic, Jovan; Mischke, Andre; Mishra, Aditya Nath; Mishra, Tribeni; Miskowiec, Dariusz Czeslaw; Mitra, Jubin; Mitu, Ciprian Mihai; Mohammadi, Naghmeh; Mohanty, Bedangadas; Molnar, Levente; Montes Prado, Esther; Moreira De Godoy, Denise Aparecida; Perez Moreno, Luis Alberto; Moretto, Sandra; Morreale, Astrid; Morsch, Andreas; Muccifora, Valeria; Mudnic, Eugen; Muhlheim, Daniel Michael; Muhuri, Sanjib; Mukherjee, Maitreyee; Mulligan, James Declan; Gameiro Munhoz, Marcelo; Munning, Konstantin; Munzer, Robert Helmut; Murakami, Hikari; Murray, Sean; Musa, Luciano; Musinsky, Jan; Myers, Corey James; Naik, Bharati; Nair, Rahul; Nandi, Basanta Kumar; Nania, Rosario; Nappi, Eugenio; Naru, Muhammad Umair; Ferreira Natal Da Luz, Pedro Hugo; Nattrass, Christine; Rosado Navarro, Sebastian; Nayak, Kishora; Nayak, Ranjit; Nayak, Tapan Kumar; Nazarenko, Sergey; Nedosekin, Alexander; Negrao De Oliveira, Renato Aparecido; Nellen, Lukas; Ng, Fabian; Nicassio, Maria; Niculescu, Mihai; Niedziela, Jeremi; Nielsen, Borge Svane; Nikolaev, Sergey; Nikulin, Sergey; Nikulin, Vladimir; Noferini, Francesco; Nomokonov, Petr; Nooren, Gerardus; Cabanillas Noris, Juan Carlos; Norman, Jaime; Nyanin, Alexander; Nystrand, Joakim Ingemar; Oeschler, Helmut Oskar; Oh, Saehanseul; Ohlson, Alice Elisabeth; Okubo, Tsubasa; Olah, Laszlo; Oleniacz, Janusz; Oliveira Da Silva, Antonio Carlos; Oliver, Michael Henry; Onderwaater, Jacobus; Oppedisano, Chiara; Orava, Risto; Oravec, Matej; Ortiz Velasquez, Antonio; Oskarsson, Anders Nils Erik; Otwinowski, Jacek Tomasz; Oyama, Ken; Ozdemir, Mahmut; Pachmayer, Yvonne Chiara; Pacik, Vojtech; Pagano, Davide; Pagano, Paola; Paic, Guy; Pal, Susanta Kumar; Palni, Prabhakar; Pan, Jinjin; Pandey, Ashutosh Kumar; Papikyan, Vardanush; Pappalardo, Giuseppe; Pareek, Pooja; Park, Jonghan; Park, Woojin; Parmar, Sonia; Passfeld, Annika; Paticchio, Vincenzo; Patra, Rajendra Nath; Paul, Biswarup; Pei, Hua; Peitzmann, Thomas; Peng, Xinye; Pereira Da Costa, Hugo Denis Antonio; Peresunko, Dmitry Yurevich; Perez Lezama, Edgar; Peskov, Vladimir; Pestov, Yury; Petracek, Vojtech; Petrov, Viacheslav; Petrovici, Mihai; Petta, Catia; Piano, Stefano; Pikna, Miroslav; Pillot, Philippe; Ozelin De Lima Pimentel, Lais; Pinazza, Ombretta; Pinsky, Lawrence; Piyarathna, Danthasinghe; Ploskon, Mateusz Andrzej; Planinic, Mirko; Pluta, Jan Marian; Pochybova, Sona; Podesta Lerma, Pedro Luis Manuel; Poghosyan, Martin; Polishchuk, Boris; Poljak, Nikola; Poonsawat, Wanchaloem; Pop, Amalia; Poppenborg, Hendrik; Porteboeuf, Sarah Julie; Porter, R Jefferson; Pospisil, Jan; Pozdniakov, Valeriy; Prasad, Sidharth Kumar; Preghenella, Roberto; Prino, Francesco; Pruneau, Claude Andre; Pshenichnov, Igor; Puccio, Maximiliano; Puddu, Giovanna; Pujahari, Prabhat Ranjan; Punin, Valery; Putschke, Jorn Henning; Qvigstad, Henrik; Rachevski, Alexandre; Raha, Sibaji; Rajput, Sonia; Rak, Jan; Rakotozafindrabe, Andry Malala; Ramello, Luciano; Rami, Fouad; Rana, Dhan Bahadur; Raniwala, Rashmi; Raniwala, Sudhir; Rasanen, Sami Sakari; Rascanu, Bogdan Theodor; Rathee, Deepika; Ratza, Viktor; Ravasenga, Ivan; Read, Kenneth Francis; Redlich, Krzysztof; Rehman, Attiq Ur; Reichelt, Patrick Simon; Reidt, Felix; Ren, Xiaowen; Renfordt, Rainer Arno Ernst; Reolon, Anna Rita; Reshetin, Andrey; Reygers, Klaus Johannes; Riabov, Viktor; Ricci, Renato Angelo; Richert, Tuva Ora Herenui; Richter, Matthias Rudolph; Riedler, Petra; Riegler, Werner; Riggi, Francesco; Ristea, Catalin-lucian; Rodriguez Cahuantzi, Mario; Roeed, Ketil; Rogochaya, Elena; Rohr, David Michael; Roehrich, Dieter; Ronchetti, Federico; Ronflette, Lucile; Rosnet, Philippe; Rossi, Andrea; Roukoutakis, Filimon; Roy, Ankhi; Roy, Christelle Sophie; Roy, Pradip Kumar; Rubio Montero, Antonio Juan; Rui, Rinaldo; Russo, Riccardo; Ryabinkin, Evgeny; Ryabov, Yury; Rybicki, Andrzej; Saarinen, Sampo; Sadhu, Samrangy; Sadovskiy, Sergey; Safarik, Karel; Sahlmuller, Baldo; Sahoo, Baidyanath; Sahoo, Pragati; Sahoo, Raghunath; Sahoo, Sarita; Sahu, Pradip Kumar; Saini, Jogender; Sakai, Shingo; Saleh, Mohammad Ahmad; Salzwedel, Jai Samuel Nielsen; Sambyal, Sanjeev Singh; Samsonov, Vladimir; Sandoval, Andres; Sano, Masato; Sarkar, Debojit; Sarkar, Nachiketa; Sarma, Pranjal; Sas, Mike Henry Petrus; Scapparone, Eugenio; Scarlassara, Fernando; Scharenberg, Rolf Paul; Schiaua, Claudiu Cornel; Schicker, Rainer Martin; Schmidt, Christian Joachim; Schmidt, Hans Rudolf; Schmidt, Martin; Schukraft, Jurgen; Schutz, Yves Roland; Schwarz, Kilian Eberhard; Schweda, Kai Oliver; Scioli, Gilda; Scomparin, Enrico; Scott, Rebecca Michelle; Sefcik, Michal; Seger, Janet Elizabeth; Sekiguchi, Yuko; Sekihata, Daiki; Selyuzhenkov, Ilya; Senosi, Kgotlaesele; Senyukov, Serhiy; Serradilla Rodriguez, Eulogio; Sett, Priyanka; Sevcenco, Adrian; Shabanov, Arseniy; Shabetai, Alexandre; Shadura, Oksana; Shahoyan, Ruben; Shangaraev, Artem; Sharma, Ankita; Sharma, Anjali; Sharma, Mona; Sharma, Monika; Sharma, Natasha; Sheikh, Ashik Ikbal; Shigaki, Kenta; Shou, Qiye; Shtejer Diaz, Katherin; Sibiryak, Yury; Siddhanta, Sabyasachi; Sielewicz, Krzysztof Marek; Siemiarczuk, Teodor; Silvermyr, David Olle Rickard; Silvestre, Catherine Micaela; Simatovic, Goran; Simonetti, Giuseppe; Singaraju, Rama Narayana; Singh, Ranbir; Singhal, Vikas; Sarkar - Sinha, Tinku; Sitar, Branislav; Sitta, Mario; Skaali, Bernhard; Slupecki, Maciej; Smirnov, Nikolai; Snellings, Raimond; Snellman, Tomas Wilhelm; Song, Jihye; Song, Myunggeun; Song, Zixuan; Soramel, Francesca; Sorensen, Soren Pontoppidan; Sozzi, Federica; Spiriti, Eleuterio; Sputowska, Iwona Anna; Srivastava, Brijesh Kumar; Stachel, Johanna; Stan, Ionel; Stankus, Paul; Stenlund, Evert Anders; Steyn, Gideon Francois; Stiller, Johannes Hendrik; Stocco, Diego; Strmen, Peter; Alarcon Do Passo Suaide, Alexandre; Sugitate, Toru; Suire, Christophe Pierre; Suleymanov, Mais Kazim Oglu; Suljic, Miljenko; Sultanov, Rishat; Sumbera, Michal; Sumowidagdo, Suharyo; Suzuki, Ken; Swain, Sagarika; Szabo, Alexander; Szarka, Imrich; Szczepankiewicz, Adam; Szymanski, Maciej Pawel; Tabassam, Uzma; Takahashi, Jun; Tambave, Ganesh Jagannath; Tanaka, Naoto; Tarhini, Mohamad; Tariq, Mohammad; Tarzila, Madalina-gabriela; Tauro, Arturo; Tejeda Munoz, Guillermo; Telesca, Adriana; Terasaki, Kohei; Terrevoli, Cristina; Teyssier, Boris; Thakur, Dhananjaya; Thomas, Deepa; Tieulent, Raphael Noel; Tikhonov, Anatoly; Timmins, Anthony Robert; Toia, Alberica; Tripathy, Sushanta; Trogolo, Stefano; Trombetta, Giuseppe; Trubnikov, Victor; Trzaska, Wladyslaw Henryk; Tsuji, Tomoya; Tumkin, Alexandr; Turrisi, Rosario; Tveter, Trine Spedstad; Ullaland, Kjetil; Umaka, Ejiro Naomi; Uras, Antonio; Usai, Gianluca; Utrobicic, Antonija; Vala, Martin; Van Der Maarel, Jasper; Van Hoorne, Jacobus Willem; Van Leeuwen, Marco; Vanat, Tomas; Vande Vyvre, Pierre; Varga, Dezso; Diozcora Vargas Trevino, Aurora; Vargyas, Marton; Varma, Raghava; Vasileiou, Maria; Vasiliev, Andrey; Vauthier, Astrid; Vazquez Doce, Oton; Vechernin, Vladimir; Veen, Annelies Marianne; Velure, Arild; Vercellin, Ermanno; Vergara Limon, Sergio; Vernet, Renaud; Vertesi, Robert; Vickovic, Linda; Vigolo, Sonia; Viinikainen, Jussi Samuli; Vilakazi, Zabulon; Villalobos Baillie, Orlando; Villatoro Tello, Abraham; Vinogradov, Alexander; Vinogradov, Leonid; Virgili, Tiziano; Vislavicius, Vytautas; Vodopyanov, Alexander; Volkl, Martin Andreas; Voloshin, Kirill; Voloshin, Sergey; Volpe, Giacomo; Von Haller, Barthelemy; Vorobyev, Ivan; Voscek, Dominik; Vranic, Danilo; Vrlakova, Janka; Wagner, Boris; Wagner, Jan; Wang, Hongkai; Wang, Mengliang; Watanabe, Daisuke; Watanabe, Yosuke; Weber, Michael; Weber, Steffen Georg; Weiser, Dennis Franz; Wessels, Johannes Peter; Westerhoff, Uwe; Whitehead, Andile Mothegi; Wiechula, Jens; Wikne, Jon; Wilk, Grzegorz Andrzej; Wilkinson, Jeremy John; Willems, Guido Alexander; Williams, Crispin; Windelband, Bernd Stefan; Winn, Michael Andreas; Witt, William Edward; Yalcin, Serpil; Yang, Ping; Yano, Satoshi; Yin, Zhongbao; Yokoyama, Hiroki; Yoo, In-kwon; Yoon, Jin Hee; Yurchenko, Volodymyr; Zaccolo, Valentina; Zaman, Ali; Zampolli, Chiara; Correia Zanoli, Henrique Jose; Zaporozhets, Sergey; Zardoshti, Nima; Zarochentsev, Andrey; Zavada, Petr; Zavyalov, Nikolay; Zbroszczyk, Hanna Paulina; Zhalov, Mikhail; Zhang, Haitao; Zhang, Xiaoming; Zhang, Yonghong; Chunhui, Zhang; Zhang, Zuman; Zhao, Chengxin; Zhigareva, Natalia; Zhou, Daicui; Zhou, You; Zhou, Zhuo; Zhu, Hongsheng; Zhu, Jianhui; Zichichi, Antonino; Zimmermann, Alice; Zimmermann, Markus Bernhard; Zinovjev, Gennady; Zmeskal, Johann

2017-05-29

Electrons from heavy-flavour hadron decays (charm and beauty) were measured with the ALICE detector in Pb–Pb collisions at a centre-of-mass of energy $\\sqrt{s_{\\rm NN}}=2.76$ TeV. The transverse momentum ($p_{\\rm T}$) differential production yields at mid-rapidity were used to calculate the nuclear modification factor $R_{\\rm AA}$ in the interval $3collisions at the same energy (up to a factor of 4) in the 10% most central Pb–Pb collisions. There is a centrality trend of suppression, and a weaker suppression (down to a factor of 2) in semi-peripheral (50–80%) collisions is observed. The suppression of electrons in this broad $p_{\\rm T}$ interval indicates that both charm and beauty quarks lose energy when they traverse the hot medium formed in Pb-Pb collisions at LHC.

Relativistic Collisions of Structured Atomic Particles

CERN Document Server

Voitkiv, Alexander

2008-01-01

The book reviews the progress achieved over the last decade in the study of collisions between an ion and an atom in which both the atomic particles carry electrons and can undergo transitions between their internal states -- including continua. It presents the detailed considerations of different theoretical approaches, that can be used to describe collisions of structured atomic particles for the very broad interval of impact energies ranging from 0.5--1 MeV/u till extreme relativistic energies where the collision velocity very closely approaches the speed of light.

Atomic-orbital expansion model for describing ion-atom collisions at intermediate and low energies

International Nuclear Information System (INIS)

Lin, C.D.; Fritsch, W.

1983-01-01

In the description of inelastic processes in ion-atom collisions at moderate energies, the semiclassical close-coupling method is well established as the standard method. Ever since the pioneering work on H + + H in the early 60's, the standard procedure is to expand the electronic wavefunction in terms of molecular orbitals (MO) or atomic orbitals (AO) for describing collisions at, respectively, low or intermediate velocities. It has been recognized since early days that traveling orbitals are needed in the expansions in order to represent the asymptotic states in the collisions correctly. While the adoption of such traveling orbitals presents no conceptual difficulties for expansions using atomic orbitals, the situation for molecular orbitals is less clear. In recent years, various forms of traveling MO's have been proposed, but conflicting results for several well-studied systems have been reported

High-Energy Electron-Ion and Photon-Ion Collisions: Status and Challenges