WorldWideScience

Sample records for scattered electron ion

  1. Indirect processes in electron-ion scattering

    Energy Technology Data Exchange (ETDEWEB)

    Bottcher, C.; Griffin, D.C.; Pindzola, M.S.; Phaneuf, R.A.

    1983-10-01

    A summary is given of an informal workshop held at Oak Ridge National Laboratory on June 22-23, 1983, in which the current status of theoretical calculations of indirect processes in electron-ion scattering was reviewed. Processes of particular interest in astrophysical and fusion plasmas were emphasized. Topics discussed include atomic structure effects, electron-impact ionization, and dielectronic recombination.

  2. Quasi-free electron-ion scattering in ion-atom collisions

    Energy Technology Data Exchange (ETDEWEB)

    Richard, P.; Bhalla, C.; Hagmann, S.; Zavodszky, P. [Kansas State Univ., Manhattan, KS (United States). J.R. MacDonald Lab.

    1999-11-01

    The electron scattering model, ESM, for ion-atom collisions refers to the scattering of a quasi-free (loosely-bound) target electron in the field of a highly charged projectile ion. Many atomic processes have been successfully described by the ESM, which relates a differential scattering cross section for an ion-atom collision process to the cross section for the corresponding pure electron-ion collision process. The following processes have been studied in ion-atom collisions: resonant and non-resonant electron-ion elastic scattering, resonant and non-resonant inelastic electron-ion scattering, and dielectronic recombination. Recently, features have been observed in electron double differential cross sections from ion-atom collisions that have been attributed to ``super elastic`` electron-ion scattering, and intra-atomic double electron scattering in the case of molecular targets. Also, evidence for triply-excited states formed by resonance excitation has been observed. A survey of the results of these studies and the status of this field of research will be presented. (orig.) 31 refs.

  3. Stimulated Brillouin scatter and stimulated ion Bernstein scatter during electron gyroharmonic heating experiments

    Science.gov (United States)

    Fu, H.; Scales, W. A.; Bernhardt, P. A.; Samimi, A.; Mahmoudian, A.; Briczinski, S. J.; McCarrick, M. J.

    2013-09-01

    Results of secondary radiation, Stimulated Electromagnetic Emission (SEE), produced during ionospheric modification experiments using ground-based high-power radio waves are reported. These results obtained at the High Frequency Active Auroral Research Program (HAARP) facility specifically considered the generation of Magnetized Stimulated Brillouin Scatter (MSBS) and Stimulated Ion Bernstein Scatter (SIBS) lines in the SEE spectrum when the transmitter frequency is near harmonics of the electron gyrofrequency. The heater antenna beam angle effect was investigated on MSBS in detail and shows a new spectral line postulated to be generated near the upper hybrid resonance region due to ion acoustic wave interaction. Frequency sweeping experiments near the electron gyroharmonics show for the first time the transition from MSBS to SIBS lines as the heater pump frequency approaches the gyroharmonic. Significantly far from the gyroharmonic, MSBS lines dominate, while close to the gyroharmonic, SIBS lines strengthen while MSBS lines weaken. New possibilities for diagnostic information are discussed in light of these new observations.

  4. Differential electron-Cu{sup 5+} elastic scattering cross sections extracted from electron emission in ion-atom collisions

    Energy Technology Data Exchange (ETDEWEB)

    Liao, C.; Hagmann, S.; Bhalla, C.P.; Grabbe, S.R.; Cocke, C.L.; Richard, P. [J. R. Macdonald Laboratory, Kansas State University, Manhattan, Kansas 66506 (United States); Liao, C. [Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California 91109 (United States)

    1999-04-01

    We present a method of deriving energy and angle-dependent electron-ion elastic scattering cross sections from doubly differential cross sections for electron emission in ion-atom collisions. By analyzing the laboratory frame binary encounter electron production cross sections in energetic ion-atom collisions, we derive projectile frame differential cross sections for electrons elastically scattered from highly charged projectile ions in the range between 60{degree} and 180{degree}. The elastic scattering cross sections are observed to deviate strongly from the Rutherford cross sections for electron scattering from bare nuclei. They exhibit strong Ramsauer-Townsend electron diffraction in the angular distribution of elastically scattered electrons, providing evidence for the strong role of screening played in the collision. Experimental data are compared with partial-wave calculations using the Hartree-Fock model. {copyright} {ital 1999} {ital The American Physical Society}

  5. Electron elastic scattering resonances in the collision of fast hydrogenic ions with molecular hydrogen

    Energy Technology Data Exchange (ETDEWEB)

    Toth, G.; Zavodszky, P.; Bhalla, C.P.; Richard, P.; Grabbe, S.; Aliabadi, H. [Kansas State Univ., Manhattan, KS (United States). Dept. of Physics

    2001-07-01

    Absolute double differential cross sections for the electron production at zero degree laboratory observation angle were measured for high velocity hydrogenic carbon, nitrogen, oxygen and fluorine ions on molecular hydrogen. The energies of these ions were chosen so the elastic scattering resonance 2p{sup 2} {sup 1}D for each case can be clearly observed near the peak of the binary encounter electron distribution. Close coupling R-matrix calculations of elastic differential cross sections of electron impact of these ions were related to the measured ion-atom cross sections by using the elastic scattering model (ESM). Excellent agreement was found between theory and experimental data. (orig.)

  6. Superelastic Scattering Of Electrons From Highly Charged Ions With Inner Shell Vacancies

    Energy Technology Data Exchange (ETDEWEB)

    Zavodszky, P. A.; Aliabadi, H.; Bhalla, C. P.; Richard, P.; Toth, G.; Tanis, J. A.

    2001-07-16

    We report the measurement of electrons scattered superelastically from highly charged ions having an initial K -shell vacancy. In this process, the scattered electron gains {approx}725 eV of energy from the deexcitation of an excited He-like F{sup 7+}( 1s2sS{sup 3}) metastable ion to its ground state. Theoretical calculations based on an R -matrix approach agree well in position, shape, and magnitude with the experimental data.

  7. Plasma characterization using ultraviolet Thomson scattering from ion-acoustic and electron plasma waves (invited)

    Energy Technology Data Exchange (ETDEWEB)

    Follett, R. K., E-mail: rfollett@lle.rochester.edu; Delettrez, J. A.; Edgell, D. H.; Henchen, R. J.; Katz, J.; Myatt, J. F.; Froula, D. H. [Laboratory for Laser Energetics, University of Rochester, 250 East River Road, Rochester, New York 14623 (United States)

    2016-11-15

    Collective Thomson scattering is a technique for measuring the plasma conditions in laser-plasma experiments. Simultaneous measurements of ion-acoustic and electron plasma-wave spectra were obtained using a 263.25-nm Thomson-scattering probe beam. A fully reflective collection system was used to record light scattered from electron plasma waves at electron densities greater than 10{sup 21} cm{sup −3}, which produced scattering peaks near 200 nm. An accurate analysis of the experimental Thomson-scattering spectra required accounting for plasma gradients, instrument sensitivity, optical effects, and background radiation. Practical techniques for including these effects when fitting Thomson-scattering spectra are presented and applied to the measured spectra to show the improvements in plasma characterization.

  8. The Strength of Chaos: Accurate Simulation of Resonant Electron Scattering by Many-Electron Ions and Atoms in the Presence of Quantum Chaos

    Science.gov (United States)

    2017-01-20

    AFRL-AFOSR-JP-TR-2017-0012 The Strength of Chaos: accurate simulation of resonant electron scattering by many-electron ions and atoms in the presence...SUBTITLE The Strength of Chaos: accurate simulation of resonant electron scattering by many- electron ions and atoms in the presence of quantum chaos...Strength of Chaos: accurate simulation of resonant electron scattering by many-electron ions and atoms in the presence of quantum chaos” Date 13

  9. Double scattering production of two positron–electron pairs in ultraperipheral heavy-ion collisions

    Directory of Open Access Journals (Sweden)

    Mariola Kłusek-Gawenda

    2016-12-01

    Full Text Available We present first measurable predictions for electromagnetic (two-photon double scattering production of two positron–electron pairs in ultraperipheral heavy-ion collisions at LHC. Measurable cross sections are obtained with realistic cuts on electron/positron (pseudorapidities and transverse momenta for the ALICE and ATLAS or CMS experiments. The predictions for total and differential cross sections are presented. We show also two-dimensional distributions in rapidities of the opposite-sign (from the same or different subcollisions and of the same-sign (e+e+ or e−e− electrons and in rapidity distance between them. Expected number of events are presented and discussed. Our calculations strongly suggest that relevant measurements with the help of ATLAS, CMS and ALICE detectors are possible in a near future. We show and compare energy dependence of the cross sections for one-pair and two-pair production.

  10. The electron-ion scattering experiment ELISe at the International Facility for Antiproton and Ion Research (FAIR)-A conceptual design study

    NARCIS (Netherlands)

    Antonov, A. N.; Gaidarov, M. K.; Ivanov, M. V.; Kadrev, D. N.; Aiche, M.; Barreau, G.; Czajkowski, S.; Jurado, B.; Belier, G.; Chatillon, A.; Granier, T.; Taieb, J.; Dore, D.; Letourneau, A.; Ridikas, D.; Dupont, E.; Berthoumieux, E.; Panebianco, S.; Farget, F.; Schmitt, C.; Audouin, L.; Khan, E.; Tassan-Got, L.; Aumann, T.; Beller, P.; Boretzky, K.; Dolinskii, A.; Egelhof, P.; Emling, H.; Franzke, B.; Geissel, H.; Kelic-Heil, A.; Kester, O.; Kurz, N.; Litvinov, Y.; Muenzenberg, G.; Nolden, F.; Schmidt, K. -H.; Scheidenberger, Ch.; Simon, H.; Steck, M.; Weick, H.; Enders, J.; Pietralla, N.; Richter, A.; Schrieder, G.; Zilges, A.; Distler, M. O.; Merkel, H.; Mueller, U.; Junghans, A. R.; Lenske, H.; Fujiwara, M.; Suda, T.; Kato, S.; Adachi, T.; Hamieh, S.; Harakeh, M. N.; Kalantar-Nayestanaki, N.; Woertche, H.; Berg, G. P. A.; Koop, I. A.; Logatchov, P. V.; Otboev, A. V.; Parkhomchuk, V. V.; Shatilov, D. N.; Shatunov, P. Y.; Shatunov, Y. M.; Shiyankov, S. V.; Shvartz, D. I.; Skrinsky, A. N.; Chulkov, L. V.; Danilin, B. V.; Korsheninnikov, A. A.; Kuzmin, E. A.; Ogloblin, A. A.; Volkov, V. A.; Grishkin, Y.; Lisin, V. P.; Mushkarenkov, A. N.; Nedorezov, V.; Polonski, A. L.; Rudnev, N. V.; Turinge, A. A.; Artukh, A.; Avdeichikov, V.; Ershov, S. N.; Fomichev, A.; Golovkov, M.; Gorshkov, A. V.; Grigorenko, L.; Klygin, S.; Krupko, S.; Meshkov, I. N.; Rodin, A.; Sereda, Y.; Seleznev, I.; Sidorchuk, S.; Syresin, E.; Stepantsov, S.; Ter-Akopian, G.; Teterev, Y.; Vorontsov, A. N.; Kamerdzhiev, S. P.; Litvinova, E. V.; Karataglidis, S.; Alvarez Rodriguez, R.; Borge, M. J. G.; Ramirez, C. Fernandez; Garrido, E.; Sarriguren, P.; Vignote, J. R.; Fraile Prieto, L. M.; Lopez Herraiz, J.; Moya de Guerra, E.; Udias-Moinelo, J.; Amaro Soriano, J. E.; Rojo, A. M. Lallena; Caballero, J. A.; Johansson, H. T.; Jonson, B.; Nilsson, T.; Nyman, G.; Zhukov, M.; Golubev, P.; Rudolph, D.; Hencken, K.; Jourdan, J.; Krusche, B.; Rauscher, T.; Kiselev, D.; Trautmann, D.; Al-Khalili, J.; Catford, W.; Johnson, R.; Stevenson, P. D.; Barton, C.; Jenkins, D.; Lemmon, R.; Chartier, M.; Cullen, D.; Bertulani, C. A.; Heinz, A.

    2011-01-01

    The electron-ion scattering experiment ELISe is part of the installations envisaged at the new experimental storage ring at the International Facility for Antiproton and Ion Research (FAIR) in Darmstadt, Germany. It offers an unique opportunity to use electrons as probe in investigations of the

  11. The electron-ion scattering experiment ELISe at the International Facility for Antiproton and Ion Research (FAIR)-A conceptual design study

    Energy Technology Data Exchange (ETDEWEB)

    Antonov, A.N.; Gaidarov, M.K. [INRNE-BAS Sofia (Bulgaria); Ivanov, M.V. [Grupo de Physica Nuclear, Complutense University of Madrid (Spain); Kadrev, D.N. [INRNE-BAS Sofia (Bulgaria); Aiche, M.; Barreau, G.; Czajkowski, S.; Jurado, B. [Centre d' Etudes Nucleaires Bordeaux-Gradingnan (CENBG) (France); Belier, G.; Chatillon, A.; Granier, T.; Taieb, J. [CEA Bruyeres-le-Chatel (France); Dore, D.; Letourneau, A.; Ridikas, D.; Dupont, E.; Berthoumieux, E.; Panebianco, S. [CEA Saclay (France); Farget, F.; Schmitt, C. [GANIL Caen (France)

    2011-05-01

    The electron-ion scattering experiment ELISe is part of the installations envisaged at the new experimental storage ring at the International Facility for Antiproton and Ion Research (FAIR) in Darmstadt, Germany. It offers an unique opportunity to use electrons as probe in investigations of the structure of exotic nuclei. The conceptual design and the scientific challenges of ELISe are presented.

  12. Electron scattering for exotic nuclei

    Indian Academy of Sciences (India)

    2014-11-04

    Nov 4, 2014 ... determine the charge density distributions of short-lived exotic nuclei by elastic electron scattering. The first collision ... Electron scattering of highly unstable nuclei is not easy because it is difficult to produce ... both ends form a mirror potential to keep the ions longitudinally inside the SCRIT device, and the ...

  13. Main-ion temperature and plasma rotation measurements based on scattering of electron cyclotron heating waves in ASDEX Upgrade

    DEFF Research Database (Denmark)

    Pedersen, Morten Stejner; Rasmussen, Jesper; Nielsen, Stefan Kragh

    2017-01-01

    We demonstrate measurements of spectra of O-mode electron cyclotron resonance heating (ECRH) waves scattered collectively from microscopic plasma fluctuations in ASDEX Upgrade discharges with an ITER-like ECRH scenario. The measured spectra are shown to allow determination of the main ion...

  14. ITER Plasma at Electron Cyclotron Frequency Domain: Stimulated Raman Scattering off Gould-Trivelpiece Modes and Generation of Suprathermal Electrons and Energetic Ions

    Science.gov (United States)

    Stefan, V. Alexander

    2011-04-01

    Stimulated Raman scattering in the electron cyclotron frequency range of the X-Mode and O-Mode driver with the ITER plasma leads to the ``tail heating'' via the generation of suprathermal electrons and energetic ions. The scattering off Trivelpiece-Gould (T-G) modes is studied for the gyrotron frequency of 170GHz; X-Mode and O-Mode power of 24 MW CW; on-axis B-field of 10T. The synergy between the two-plasmon decay and Raman scattering is analyzed in reference to the bulk plasma heating. Supported in part by Nikola TESLA Labs, La Jolla, CA

  15. Differential electron-ion elastic scattering cross sections extracted from ion-atom collisions of 0.53 MeV/u Cu{sup 5+} on H{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Liao, C. [Kansas State Univ., Manhattan, KS (United States). J.R. MacDonald Lab.]|[Jet Propulsion Lab., Pasadena, CA (United States); Hagmann, S.; Bhalla, C.P.; Grabbe, S.R. [Kansas State Univ., Manhattan, KS (United States). J.R. MacDonald Lab.

    1997-12-31

    A method of extracting electron-ion elastic scattering cross sections from ion-atom collisions has been developed. By analyzing the binary encounter electron (BEe) production in energetic ion-atom collisions, which is due to loosely bound target electrons ionized through direct, hard collisions with the projectile ions, differential cross sections of electrons elastic scattered from highly charged ions are derived for a broad range of scattering angles. The cross sections are observed to deviate strongly from the Rutherford cross sections, and immediately yielded an electron diffraction in angular distribution of elastically scattered electrons. Experimental data are compared with a partial-wave treatment using the Hartree-Fock model. (orig.). 19 refs.

  16. Effect of Oblique Electromagnetic Ion Cyclotron Waves on Relativistic Electron Scattering: CRRES Based Calculation

    Science.gov (United States)

    Gamayunov, K. V.; Khazanov, G. V.

    2007-01-01

    We consider the effect of oblique EMIC waves on relativistic electron scattering in the outer radiation belt using simultaneous observations of plasma and wave parameters from CRRES. The main findings can be s ummarized as follows: 1. In 1comparison with field-aligned waves, int ermediate and highly oblique distributions decrease the range of pitc h-angles subject to diffusion, and reduce the local scattering rate b y an order of magnitude at pitch-angles where the principle absolute value of n = 1 resonances operate. Oblique waves allow the absolute va lue of n > 1 resonances to operate, extending the range of local pitc h-angle diffusion down to the loss cone, and increasing the diffusion at lower pitch angles by orders of magnitude; 2. The local diffusion coefficients derived from CRRES data are qualitatively similar to the local results obtained for prescribed plasma/wave parameters. Conseq uently, it is likely that the bounce-averaged diffusion coefficients, if estimated from concurrent data, will exhibit the dependencies similar to those we found for model calculations; 3. In comparison with f ield-aligned waves, intermediate and highly oblique waves decrease th e bounce-averaged scattering rate near the edge of the equatorial lo ss cone by orders of magnitude if the electron energy does not excee d a threshold (approximately equal to 2 - 5 MeV) depending on specified plasma and/or wave parameters; 4. For greater electron energies_ ob lique waves operating the absolute value of n > 1 resonances are more effective and provide the same bounce_averaged diffusion rate near the loss cone as fiel_aligned waves do.

  17. Pitch angle scattering of relativistic electrons near electromagnetic ion cyclotron resonances in diverging magnetic fields

    Science.gov (United States)

    Eliasson, B.; Papadopoulos, K.

    2017-10-01

    A theoretical study of the propagation of left-hand polarized shear Alfvén waves in spatially decreasing magnetic field geometries near the EMIC resonance, including the spectrum and amplitude of the mode converted EMIC waves and the pitch angle scattering of relativistic electrons transiting the resonant region, is presented. The objective of the paper is to motivate an experimental study of the subject using the UCLA LAPD chamber. The results are relevant in exploring the possibility that shear Alfvén waves strategically injected into the radiation belts using either ionospheric heating from ground based RF transmitters or injected by transmitters based on space platforms can enhance the precipitation rate of trapped relativistic electrons. Effects of multi-ionic composition are also investigated.

  18. Parametric dependence of ion temperature and electron density in the SUMMA hot-ion plasma using laser light scattering and emission spectroscopy

    Science.gov (United States)

    Snyder, A.; Patch, R. W.; Lauver, M. R.

    1980-01-01

    Hot-ion plasma experiments were conducted in the NASA Lewis SUMMA facility. A steady-state modified Penning discharge was formed by applying a radially inward dc electric field of several kilovolts near the magnetic mirror maxima. Results are reported for a hydrogen plasma covering a wide range in midplane magnetic flux densities from 0.5 to 3.37 T. Input power greater than 45 kW was obtained with water-cooled cathodes. Steady-state plasmas with ion kinetic temperatures from 18 to 830 eV were produced and measured spectroscopically. These ion temperatures were correlated with current, voltage, and magnetic flux density as the independent variables. Electron density measurements were made using an unusually sensitive Thomson scattering apparatus. The measured electron densities range from 2.1 x 10 to the 11th to 6.8 x 10 to the 12th per cu cm.

  19. Heavy-ion nucleus scattering

    CERN Document Server

    Rahman, M A; Haque, S

    2003-01-01

    Heavy ion-nucleus scattering is an excellent laboratory to probe high spin phenomena, exotic nuclei and for the analysis of various exit channels. The Strong Absorption Model or the generalized diffraction models, which are semi-classical in nature, have been employed in the description of various heavy ion-nucleus scattering phenomena with reasonable success. But one needs to treat the deflection function (scattering angles) quantum mechanically in the Wave Mechanical picture for the appropriate description of the heavy-ion nucleus scattering phenomena. We have brought the mathematics for the cross-section of the heavy-ion nucleus scattering to an analytic expression taking account of the deflection function (scattering angles) quantum mechanically. sup 9 Be, sup 1 sup 6 O, sup 2 sup 0 Ne and sup 3 sup 2 S heavy-ion beams elastic scattering from sup 2 sup 8 Si, sup 2 sup 4 Mg and sup 4 sup 0 Ca target nuclei at various projectile energies over the range 20-151 MeV have been analysed in terms of the 2-paramet...

  20. Correlated formation of the excited states of recoil and scattered ions in multiple electron capture collision of Ar8+ with CO2 and OCS

    Science.gov (United States)

    Tezuka, H.; Takahashi, K.; Matsumoto, J.; Karimi, R.; Sanderson, J. H.; Shiromaru, H.

    2018-02-01

    Multiple ionization events induced by low energy collisions between Ar8+ projectiles and linear triatomic molecular targets, CO2 and OCS, were studied in order to shed light on the correlation between the electronic states of the scattered ion and the ionic fragmentation processes. Position-sensitive time-of-flight measurements of all the recoil fragments, triggered by detection of a charge-selected scattered ion, allowed us to distinguish between ionic fragmentation processes in which different numbers of Auger electrons were emitted by the projectile, just after multiple electron capture. A strong correlation is found for triple capture collisions, between fragmentation with high kinetic energy and events when only single Auger electron emission takes place.

  1. Electron Scattering From Atoms, Molecules, Nuclei, and Bulk Matter

    CERN Document Server

    Whelan, Colm T

    2005-01-01

    Topics that are covered include electron scattering in the scanning TEM; basic theory of inelastic electron imaging; study of confined atoms by electron excitation; helium bubbles created in extreme pressure with application to nuclear safety; lithium ion implantation; electron and positron scattering from clusters; electron scattering from physi- and chemi-absorbed molecules on surfaces; coincidence studies; electron scattering from biological molecules; electron spectroscopy as a tool for environmental science; electron scattering in the presence of intense fields; electron scattering from astrophysical molecules; electon interatctions an detection of x-ray radiation.

  2. Electron scattering for exotic nuclei

    Indian Academy of Sciences (India)

    2014-11-04

    Nov 4, 2014 ... A brand-new electron scattering facility, the SCRIT Electron Scattering Facility, will soon start its operation at RIKEN RI Beam Factory, Japan. This is the world's first electron scattering facility dedicated to the structure studies of short-lived nuclei. The goal of this facility is to determine the charge density ...

  3. Electron scattering violates parity

    CERN Multimedia

    2004-01-01

    Parity violation has been observed in collisions between electrons at the Stanford Linear Accelerator Center (SLAC) in the US. The resuls, which are in agreement with the Stanford Model of particle physics, also provide a new measurement of the weak charge of the electron (½ page)

  4. Electron scattering and reactions from exotic nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Karataglidis, S. [University of Johannesburg, Department of Physics, Auckland Park (South Africa); University of Melbourne, School of Physics, Victoria (Australia)

    2017-04-15

    The SCRIT and FAIR/ELISe experiments are the first to attempt to measure directly electron scattering form factors from nuclei far from stability. This will give direct information for the (one-body) charge densities of those systems, about which there is little information available. The SCRIT experiment will be taking data for medium-mass exotic nuclei, while the electron-ion collider at ELISe, when constructed, will be able to measure form factors for a wide range of exotic nuclei, as available from the radioactive ion beams produced by the FAIR experiment. Other facilities are now being proposed, which will also consider electron scattering from exotic nuclei at higher energies, to study short-range correlations in exclusive reactions. This review will consider all available information concerning the current status (largely theoretical) of electron scattering from exotic nuclei and, where possible, complement such information with equivalent information concerning the neutron densities of those exotic systems, as obtained from intermediate energy proton scattering. The issue of long- and short-range correlations will be discussed, and whether extending such studies to the exotic sector will elicit new information. (orig.)

  5. Glancing-angle scattering of fast ions at crystal surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Mannami, Michihiko; Narumi, Kazumasa; Katoh, Humiya; Kimura, Kenji [Kyoto Univ. (Japan). Faculty of Engineering

    1997-03-01

    Glancing angle scattering of fast ions from a single crystal surface is a novel technique to study ion-surface interaction. Results of recent studies of ion-surface interaction are reviewed for ions with velocities faster than the Fermi velocity of solid. For the ions with velocities less than the Fermi velocity of target valence electrons the ion-surface interaction shows a new aspect where only the valence electrons of target solid participate in the stopping processes. It will show that the position-dependent stopping power of a surface for these ions governed by the elastic collisions of valence electrons and the ions. A method is proposed from this position-dependent stopping power to derived the electron density distribution averaged over the plane parallel to the surface. (author)

  6. Resonant two-electron processes in ion-atom collisions

    Energy Technology Data Exchange (ETDEWEB)

    Zavodszky, P.A. E-mail: paz@phys.ksu.edu; Richard, P.; Bhalla, C.P

    1999-06-03

    A review of some of the recent results in an effort to obtain electron-ion differential scattering cross sections using fast ion-atom collisions is given. In the projectile frame, if we neglect the effects from the target nucleus, the ion-atom collision can be described as an electron-ion scattering process where the energy distribution of the impinging quasi-free electrons is determined by the Compton-profile of the target. In this electron scattering model (ESM), in addition to the direct electron scattering, doubly excited state formation of the projectile ion is also possible. This is a resonant process in which the doubly excited states can subsequently decay by ejecting Auger-electrons. We have studied elastic, inelastic and superelastic electron scattering as a function of incoming electron energy by observing the outgoing electron energy in the ion-atom collision emission spectra.

  7. Wave packet propagation study of the electron transfer in back-scattering of H sup - ions from alkali adsorbates on an Al surface

    CERN Document Server

    Sjakste, J; Gauyacq, J P

    2003-01-01

    The charge transfer between an H sup - ion and a free-electron metal surface with a single alkali adsorbate (Li and Cs) is studied with the wave packet propagation approach in the back-scattering geometry. Both the static problem for a fixed projectile-surface distance and the problem of charge transfer during a collision are considered. The three body (projectile-adsorbate-surface) aspect of the charge transfer process in this case results in an avoided crossing between the projectile and adsorbate-localized quasi-stationary states. We analyze and discuss the local effect of the adsorbate on the resonant charge transfer and the applicability of the rate equation approach.

  8. Application of P-wave Hybrid Theory to the Scattering of Electrons from He+ and Resonances in He and H ion

    Science.gov (United States)

    Bhatia, A. K.

    2012-01-01

    The P-wave hybrid theory of electron-hydrogen elastic scattering [Phys. Rev. A 85, 052708 (2012)] is applied to the P-wave scattering from He ion. In this method, both short-range and long-range correlations are included in the Schroedinger equation at the same time, by using a combination of a modified method of polarized orbitals and the optical potential formalism. The short-correlation functions are of Hylleraas type. It is found that the phase shifts are not significantly affected by the modification of the target function by a method similar to the method of polarized orbitals and they are close to the phase shifts calculated earlier by Bhatia [Phys. Rev. A 69, 032714 (2004)]. This indicates that the correlation function is general enough to include the target distortion (polarization) in the presence of the incident electron. The important fact is that in the present calculation, to obtain similar results only a 20-term correlation function is needed in the wave function compared to the 220- term wave function required in the above-mentioned calculation. Results for the phase shifts, obtained in the present hybrid formalism, are rigorous lower bounds to the exact phase shifts. The lowest P-wave resonances in He atom and hydrogen ion have been calculated and compared with the results obtained using the Feshbach projection operator formalism [Phys. Rev. A, 11, 2018 (1975)]. It is concluded that accurate resonance parameters can be obtained by the present method, which has the advantage of including corrections due to neighboring resonances, bound states and the continuum in which these resonance are embedded.

  9. Nuclear matter and electron scattering

    Energy Technology Data Exchange (ETDEWEB)

    Sick, I. [Dept. fuer Physik und Astronomie, Univ. Basel (Switzerland)

    1998-06-01

    We show that inclusive electron scattering at large momentum transfer allows a measurement of short-range properties of nuclear matter. This provides a very valuable constraint in selecting the calculations appropriate for predicting nuclear matter properties at the densities of astrophysical interest. (orig.)

  10. Simulation of low-energy ion scattering

    Science.gov (United States)

    Langelaar, M. H.; Breeman, M.; Mijiritskii, A. V.; Boerma, D. O.

    A new simulation program `MATCH' has been developed for a detailed analysis of low-energy ion scattering (LEIS) and recoiling data. Instead of performing the full calculation of the three-dimensional trajectories through the sample from the ion source towards the detector, incoming trajectories as well as reversed-time outgoing trajectories are calculated, separately. Finally, these trajectories are matched to obtain the yield. The program has been tested for spectra and azimuthal scans of scattering and recoiling events of various sample species in different scattering geometries.

  11. ITER Fast Ion Collective Thomson Scattering

    DEFF Research Database (Denmark)

    Bindslev, Henrik; Larsen, Axel Wright; Meo, Fernando

    2005-01-01

    The EFDA Contract 04-1213 with Risø National Laboratory concerning a detailed integrated design of a Fast Ion Collective Thomson Scattering (CTS) diagnostic for ITER was signed on 31 December 2004. In 2003 the Risø CTS group finished a feasibility study and a conceptual design of an ITER Fast Ion...... Collective Thomson Scattering System (Contract 01.654) [1, 2]. The purpose of the CTS diagnostic is to measure the distribution function of fast ions in the plasma. The feasibility study demonstrated that the only system that can fully meet the ITER measurement requirements for confined fusion alphas is a 60...

  12. Measuring main-ion temperatures in ASDEX upgrade using scattering of ECRH radiation

    DEFF Research Database (Denmark)

    Pedersen, Morten Stejner; Nielsen, Stefan Kragh; Jacobsen, Asger Schou

    2016-01-01

    We demonstrate that collective Thomson scattering of millimeter wave electron cyclotron resonance heating radiation can be used for measurements of the main-ion temperature in the ASDEX Upgrade tokamak.......We demonstrate that collective Thomson scattering of millimeter wave electron cyclotron resonance heating radiation can be used for measurements of the main-ion temperature in the ASDEX Upgrade tokamak....

  13. The Controlling Parameters for EMIC Wave Scattering of Relativistic Electrons

    Science.gov (United States)

    Zhang, X.; Li, W.; Ma, Q.; Thorne, R. M.; Angelopoulos, V.; Bortnik, J.

    2016-12-01

    Although there is growing support for relativistic electron losses due to precipitation from electromagnetic ion cyclotron (EMIC) wave scattering, this mechanism is yet to be quantified. Such a quantification has been difficult in the past, because equatorial electron measurements simultaneous with EMIC waves have been limited, due to the highly localized presence of EMIC waves in the magnetosphere. In this study, we examine parameters controlling characteristics of EMIC wave induced relativistic (0.3-6 MeV) electron scattering, directly based on simultaneous wave and particle measurements from Van Allen Probes. We first present a case study when relativistic electrons respond differently during two intervals of intense ( 1 nT) EMIC wave observations: one with no scattering signature and one with efficient electron losses at >1.8 MeV. Based on the observed EMIC wave spectra and background plasma conditions, we calculate the wave diffusion rates and model the evolution of electron pitch angle distributions. By comparing the modeled results with local observations of pitch angle distributions, we demonstrate that fpe/fce is critical in controlling the effectiveness of EMIC waves in scattering multi-MeV electrons. We then expand our analysis to explore the conditions (such as fpe/fce, wave frequency spectra, and ring current ion temperature and anisotropy levels) favorable for EMIC wave scattering multi-MeV electrons through multi-event analyses. Our study is important for accurately modeling relativistic electron loss processes in radiation belt electron forecasts.

  14. Positronium and Electron Scattering on Helium

    Science.gov (United States)

    DiRienzi, Joseph

    2011-01-01

    A recent work [1] establishes experimentally that Positronium scattering by atoms of various elements is surprisingly close in total cross-section to that of an isolated electron of the same velocity. In this work we will look at the scattering of Ps on Helium and compare it to a determination of the scattering of an e- with the same element. For both the Ps scattering and the e- scattering on He, we assume the symmetrization of the e- with the closed shell He electrons is the dominant interaction. A local effective potential employed in [2] and [3] is used to model the electron exchange and cross- sections are determined for a set of partial waves. For the Ps scattering we include as a secondary effect the Van der Waals interaction. For single e- scattering of He, we also employ a short range Coulomb potential and dispersion as contributing effects. Results of the cross-sections determined in each case are then compared

  15. Prospects for electron scattering on unstable, exotic nuclei

    Science.gov (United States)

    Suda, Toshimi; Simon, Haik

    2017-09-01

    Electron scattering off radioactive ions becomes feasible for the first time due to advances in storage ring and trapping techniques in conjunction with intense secondary beams from novel beam facilities. Using a point-like purely leptonic probe enables the investigation of charge distributions and electromagnetic excitations in β-unstable exotic nuclei with an enhanced overshoot in proton and neutron numbers and the use of QED, one of the most precisely studied theories, for describing the scattering process.

  16. Dynamics of the storm time ring current and relativistic electrons : particle scattering by ion cyclotron waves inside the anisotropic proton zone

    Energy Technology Data Exchange (ETDEWEB)

    Sandanger, Marit Irene J.

    2009-07-01

    processes with no new injections of ring current particles and the Dst recovers fast to quiet day values. Paper II investigated the precipitation of relativistic electrons throughout a geomagnetic storm, and how their loss relates to the precipitating ring current protons. The precipitation of relativistic electrons takes place within the anisotropic proton zone. Inside this region, proton spikes will be found in association with increased loss of relativistic electrons. The proton population of the anisotropic proton zone and in the proton spikes are unstable and can cause growth of Electromagnetic Ion Cyclotron (EMIC) wave, which can in turn scatter relativistic electrons into the atmospheric loss cone. The precipitation of relativistic electrons are found at all Magnetic Local Time (MLT) considered in the study.

  17. Theoretical studies of slow collisions. Elastic electron scattering from positive ions, charge transfer in one-electron ion-ion systems and mutual neutralization of H sup - /D sup - and H sub 2 sup +

    CERN Document Server

    Shepherd, J

    2001-01-01

    et al (1997 Phys.Rev. Lett. 79 1002). Total cross sections for this and iso-electronic systems were found to agree with simple approximations. Total cross sections for the mutual neutralization reaction H sub 2 sup + + D sup - -> H sub 2 (1s, nl) + D(1s) + DELTA epsilon were found using the Landau-Zener curve-crossing model. This method of calculation is heavily dependent on the reliability of estimates of the coupling matrix elements. Potential energy curves for the H sub 2 molecule were found using the MOLPRO package in order to have a consistent base from which to determine the energetics of the reaction. Agreement with early experiments of Aberth et al (1971 AFCRL Report No. 71-0481 Bedford, Mass.) is satisfactory, but is less good with more recent experiments of Peart et al (1997 J.Phys.B: At.Mol.Phys. 30 4955) where there is some doubt over the adequacy of the detector acceptance angle. Quantal and semi-classical methods have been used to investigate slow electron, ionic and molecular collisions. Three ...

  18. Measurement of $T_{20}$ in Elastic Electron-Deuteron Scattering

    CERN Document Server

    Bouwhuis, M; Botto, T; Van den Brand, J F J; Bulten, H J; Dolfini, S M; Ent, R; Ferro-Luzzi, M; Higinbotham, D W; De Jager, C W; Lang, J; De Lange, D J; Papadakis, N H; Passchier, I; Poolman, H R; Six, E; Steijger, J J M; Vodinas, N P; De Vries, H; Zhou, Z L

    1999-01-01

    We report on a measurement of the tensor-analyzing power T20 in elastic electron-deuteron scattering in the range of four-momentum transfer from 1.8 to 3.2 fm-1. Electrons of 704 MeV were scattered from a polarized deuterium internal target. The tensor polarization of the deuterium nuclei was determined with an ion-extraction system, allowing an absolute measurement of T20. The data are described well by a non-relativistic calculation that includes the effects of meson-exchange currents.

  19. Diffusive scattering of electrons by electron holes around injection fronts

    Science.gov (United States)

    Vasko, I. Y.; Agapitov, O. V.; Mozer, F. S.; Artemyev, A. V.; Krasnoselskikh, V. V.; Bonnell, J. W.

    2017-03-01

    Van Allen Probes have detected nonlinear electrostatic spikes around injection fronts in the outer radiation belt. These spikes include electron holes (EH), double layers, and more complicated solitary waves. We show that EHs can efficiently scatter electrons due to their substantial transverse electric fields. Although the electron scattering driven by EHs is diffusive, it cannot be evaluated via the standard quasi-linear theory. We derive analytical formulas describing local electron scattering by a single EH and verify them via test particle simulations. We show that the most efficiently scattered are gyroresonant electrons (crossing EH on a time scale comparable to the local electron gyroperiod). We compute bounce-averaged diffusion coefficients and demonstrate their dependence on the EH spatial distribution (latitudinal extent and spatial filling factor) and individual EH parameters (amplitude of electrostatic potential, velocity, and spatial scales). We show that EHs can drive pitch angle scattering of ≲5 keV electrons at rates 10-2-10-4 s-1 and, hence, can contribute to electron losses and conjugated diffuse aurora brightenings. The momentum and pitch angle scattering rates can be comparable, so that EHs can also provide efficient electron heating. The scattering rates driven by EHs at L shells L ˜ 5-8 are comparable to those due to chorus waves and may exceed those due to electron cyclotron harmonics.

  20. Electron scattering sum rules in polarized nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Lipparini, E.; Stringari, S.

    1989-07-01

    Sum rules for the inelastic scattering of polarized electrons frompolarized nuclei are derived and discussed. The role of the nucleon formfactors is investigated with special emphasis to the case of deuteron and/sup 3/He.

  1. Inelastic electron-vortex-beam scattering

    OpenAIRE

    Boxem, Van, Ruben; Partoens, Bart; Verbeeck, Jo

    2015-01-01

    Abstract: Recent theoretical and experimental developments in the field of electron-vortex-beam physics have raised questions about what exactly this novelty in the field of electron microscopy (and other fields, such as particle physics) really provides. An important part of the answer to these questions lies in scattering theory. The present investigation explores various aspects of inelastic quantum scattering theory for cylindrically symmetric beams with orbital angular momentum. The mode...

  2. [Inelastic electron scattering from surfaces]. [Progress report

    Energy Technology Data Exchange (ETDEWEB)

    1993-10-01

    This program uses ab-initio and multiple scattering to study surface dynamical processes; high-resolution electron-energy loss spectroscopy is used in particular. Off-specular excitation cross sections are much larger if electron energies are in the LEED range (50--300 eV). The analyses have been extended to surfaces of ordered alloys. Phonon eigenvectors and eigenfrequencies were used as inputs to electron-energy-loss multiple scattering cross section calculations. Work on low-energy electron and positron holography is mentioned.

  3. Measurements of scattering processes in negative ion-atom collisions

    Energy Technology Data Exchange (ETDEWEB)

    Kvale, T.J.

    1992-01-01

    This Technical Progress Report describes the progress made on the research objectives during the past twelve months. This research project is designed to provide measurements of various scattering processes which occur in H{sup {minus}} collisions with atomic (specifically, noble gas and atomic hydrogen) targets at intermediate energies. These processes include: elastic scattering,single- and double-electron detachment, and target excitation/ionization. For the elastic and target inelastic processes where H{sup {minus}} is scattered intact, the experimental technique of Ion Energy-Loss Spectroscopy (IELS) will be employed to identify the final target state(s). In most of the above processes, cross sections are unknown both experimentally and theoretically. The measurements in progress will provide either experimentally-determined cross sections or set upper limits to those cross sections. In either case, these measurements will be stringent tests of our understanding in energetic negative ion-atom collisions. This series of experiments required the construction of a new facility and the initial ion beam was accelerated through the apparatus in April 1991.

  4. Resonance electronic Raman scattering in rare earth crystals

    Energy Technology Data Exchange (ETDEWEB)

    Williams, G.M.

    1988-11-10

    The intensities of Raman scattering transitions between electronic energy levels of trivalent rare earth ions doped into transparent crystals were measured and compared to theory. A particle emphasis was placed on the examination of the effect of intermediate state resonances on the Raman scattering intensities. Two specific systems were studied: Ce/sup 3 +/(4f/sup 1/) in single crystals of LuPO/sub 4/ and Er/sup 3 +/(4f/sup 11/) in single crystals of ErPO/sub 4/. 134 refs., 92 figs., 33 tabs.

  5. Modern topics in electron scattering

    CERN Document Server

    Frois, Bernard

    1991-01-01

    This book summarizes the considerable progress recently achieved in the understanding of nucleon and nuclear structure by using high energy electrons as a probe. A collection of papers discusses in detail the new frontiers of this field. Experimental and theoretical articles cover topics such as the structure of the nucleon, nucleon distributions, many-body correlations, non-nucleonic degrees of freedom and few-body systems. This book is an up-to-date introduction to the research planned with continuous beam electron accelerators.

  6. Optical Mixing Controlled Stimulated Scattering instabilities: Suppression of SRS by the Controlled Introduction of Ion Acoustic and Electron Plasma Wave Turbulence

    CERN Document Server

    Afeyan, Bedros; Won, K; Montgomery, D S; Hammer, J; Kirkwood, R K; Schmitt, A J

    2012-01-01

    In a series of experiments on the Omega laser facility at LLE, we have demonstrated the suppression of SRS in prescribed spectral windows due to the presence of externally controlled levels of ion acoustic waves (IAW, by crossing two blue beams at the Mach -1 surface) and electron plasma waves (EPW, by crossing a blue and a green beam around a tenth critical density plasma) generated via optical mixing. We have further observed SRS backscattering of a green beam when crossed with a blue pump beam, in whose absence, that (green beam) backscattering signature was five times smaller. This is direct evidence for green beam amplification when crossed with the blue. Additional proof comes from transmitted green beam measurements. A combination of these techniques may allow the suppression of unacceptable levels of SRS near the light entrance hole of large-scale hohlraums on the NIF or LMJ.

  7. Electron elastic scattering off endo-fullerenes

    Science.gov (United States)

    Dolmatov, Valeriy

    2017-04-01

    The given presentation highlights the physically transparent, relatively simple, and yet reasonably complete approximation to the problem of low-energy electron elastic scattering off endohedral fullerenes A@CN along with corresponding findings unraveled on its basis. It is believed that, as of today, the highlighted results provide the most complete information about features of e + A @CN elastic scattering brought about by the fullerene-cage-related, correlation-related, and polarization-related impacts of the individual and coupled members of the A@C60 target on the scattering process. Each of the impacts is shown to bring spectacular features into e + A @C60 scattering. A remarkable inherent quality of the developed approximation is its ability to account for mutual coupling between electronic excited configurations of CN with those of the encapsulated atom A without reference to complicated details of the electronic structure of CN itself. Spectacular effects in the scattering process, primarily associated with polarization of A@C60 by an incident electron, are thoughtfully detailed both quantitatively and qualitatively in a physically transparent manner for ease of understanding and convenience of the audience. This study was performed in collaboration with Professors M. Ya. Amusia, L. V. Chernysheva, and UNA undergraduate students. The past support by the NSF Grant PHY-1305085 is acknowledged.

  8. Hydrated interfacial ions and electrons.

    Science.gov (United States)

    Abel, Bernd

    2013-01-01

    Charged particles such as hydrated ions and transient hydrated electrons, the simplest anionic reducing agents in water, and the special hydronium and hydroxide ions at water interfaces play an important role in many fields of science, such as atmospheric chemistry, radiation chemistry, and biology, as well as biochemistry. This article focuses on these species near hydrophobic interfaces of water, such as the air or vacuum interface of water or water protein/membrane interfaces. Ions at interfaces as well as solvated electrons have been reviewed frequently during the past decade. Although all species have been known for some time with seemingly familiar features, recently the picture in all cases became increasingly diffuse rather than clearer. The current account gives a critical state-of-the art overview of what is known and what remains to be understood and investigated about hydrated interfacial ions and electrons.

  9. Rotational nuclear models and electron scattering

    Energy Technology Data Exchange (ETDEWEB)

    Moya de Guerra, E.

    1986-05-01

    A review is made of the basic formalism involved in the application of nuclear rotational models to the problem of electron scattering from axially symmetric deformed nuclei. Emphasis is made on the use of electron scattering to extract information on the nature of the collective rotational model. In this respect, the interest of using polarized beam and target is discussed with the help of illustrative examples. Concerning the nuclear structure four rotational models are considered: Two microscopic models, namely the Projected Hartree-Fock (PHF) and cranking models; and two collective models, the rigid rotor and the irrotational flow models. The problem of current conservation within the different models is also discussed.

  10. Theory of Electron-Ion Collisions

    Energy Technology Data Exchange (ETDEWEB)

    Griffin, Donald C

    2009-10-02

    Collisions of electrons with atoms and ions play a crucial role in the modeling and diagnostics of fusion plasmas. In the edge and divertor regions of magnetically confined plasmas, data for the collisions of electrons with neutral atoms and low charge-state ions are of particular importance, while in the inner region, data on highly ionized species are needed. Since experimental measurements for these collisional processes remain very limited, data for such processes depend primarily on the results of theoretical calculations. Over the period of the present grant (January 2006 - August 2009), we have made additional improvements in our parallel scattering programs, generated data of direct fusion interest and made these data available on The Controlled Fusion Atomic Data Center Web site at Oak Ridge National Laboratory. In addition, we have employed these data to do collsional-radiative modeling studies in support of a variety of experiments with magnetically confined fusion plasmas.

  11. Electron-like scattering of positronium.

    Science.gov (United States)

    Brawley, S J; Armitage, S; Beale, J; Leslie, D E; Williams, A I; Laricchia, G

    2010-11-05

    Positronium (Ps), a hydrogen-like atom composed of an electron and its antimatter partner, the positron, is formed in considerable quantities whenever positrons interact with matter. It has unexpectedly been found to scatter from a wide variety of atoms and molecules in a way very similar to that of a bare electron moving at the same velocity, despite Ps being neutral and twice the mass.

  12. Low Energy Electron Scattering from Fuels

    Science.gov (United States)

    Lopes, M. Cristina A.

    2012-06-01

    We report an investigation of processes that occur during the ignition of the plasma and its consequences in post-discharge time for an internal combustion engine, in order to find the appropriate parameters to be used in cars that operate with lean mixtures air-fuel. The relevance of this theme has attracted much attention, and has been one of the subjects of collaboration between experimental and theoretical groups in the USA and Brazil. We have produced some basic information necessary to modeling spark ignition in alcohol- fuelled engines. Total cross sections of electron scattering by methanol and ethanol molecules were obtained, using the linear transmission method based on the Beer-Lambert law to first approximation. Measurements and calculations of differential cross sections for low-energy (rotationally unresolved) electron scattering were also obtained, for scattering angles of 5 --130 . The measurements were taken using the relative flow method with an aperture source, and calculations using two different implementations of the Schwinger multichannel method, one that takes all electrons into account and is adapted for parallel computers, and another that uses pseudopotentials and considers only the valence electrons. Additionally to these, computer simulation studies of electronic discharge in mixtures of ethanol were performed, using a Zero-Dimensional Plasma Kinetic solver. Previous reported models for combustion of ethanol and cross sections data for momentum transfer of electron collisions with ethanol were used. The time evolutions of the main species densities are reported and the ignition time delay discussed.

  13. Study of multiple scattering effects in heavy ion RBS

    Energy Technology Data Exchange (ETDEWEB)

    Fang, Z.; O`Connor, D.J. [Newcastle Univ., NSW (Australia). Dept. of Physics

    1996-12-31

    Multiple scattering effect is normally neglected in conventional Rutherford Backscattering (RBS) analysis. The backscattered particle yield normally agrees well with the theory based on the single scattering model. However, when heavy incident ions are used such as in heavy ion Rutherford backscattering (HIRBS), or the incident ion energy is reduced, multiple scattering effect starts to play a role in the analysis. In this paper, the experimental data of 6MeV C ions backscattered from a Au target are presented. In measured time of flight spectrum a small step in front of the Au high energy edge is observed. The high energy edge of the step is about 3.4 ns ahead of the Au signal which corresponds to an energy {approx} 300 keV higher than the 135 degree single scattering energy. This value coincides with the double scattering energy of C ion undergoes two consecutive 67.5 degree scattering. Efforts made to investigate the origin of the high energy step observed lead to an Monte Carlo simulation aimed to reproduce the experimental spectrum on computer. As a large angle scattering event is a rare event, two consecutive large angle scattering is extremely hard to reproduce in a random simulation process. Thus, the simulation has not found a particle scattering into 130-140 deg with an energy higher than the single scattering energy. Obviously faster algorithms and a better physical model are necessary for a successful simulation. 16 refs., 3 figs.

  14. Strong directional out-of-plane scattering in multiple ionizing highly charged ion-atom collisions

    Energy Technology Data Exchange (ETDEWEB)

    Gonzalez, A.; Hagmann, S.; Quinteros, T. [Kansas State Univ., Manhattan, KS (United States). J.R. MacDonald Lab.; Kraessig, B. [Freiburg Univ. (Germany). Fakultaet fuer Physik; Koch, R.; Schmidt-Boecking, H. [Frankfurt Univ. (Germany). Inst. fuer Kernphysik; Skutlartz, A. [East Carolina Univ., Greenville, NC (United States)

    1990-12-31

    The azimuthal ({phi}{sub r}) and polar angle ({theta}{sub r}) scattering of projectiles in coincidence with recoil ions has been studied for 0.53 MeV/u F{sup 8+} + Ne. For high degree of ionization of the target we find the resultant transverse momentum of all electrons emitted into the continuum to increase with the number of ejected electrons and to have a direction mostly not co-planar with the scattering plane.

  15. Scattering of ultrarelativistic electrons in ultrathin crystals

    Energy Technology Data Exchange (ETDEWEB)

    Shul' ga, N.F., E-mail: shulga@kipt.kharkov.ua [National Science Center “Kharkov Institute of Physics and Technology”, 1, Akademichna str., Kharkiv, 61108 (Ukraine); Karazin Kharkiv National University, 4, Svobody sq., Kharkiv, 61000 (Ukraine); Shulga, S.N. [National Science Center “Kharkov Institute of Physics and Technology”, 1, Akademichna str., Kharkiv, 61108 (Ukraine); Karazin Kharkiv National University, 4, Svobody sq., Kharkiv, 61000 (Ukraine)

    2017-06-10

    Quantum theory is proposed of high energy electrons scattering in ultrathin crystals. This theory is based upon a special representation of the scattering amplitude in the form of an integral over the surface surrounding the crystal, and on the spectral method of determination of the wave function. The comparison is performed of quantum and classical differential scattering cross-sections in the transitional range of crystal thicknesses, from those at which the channeling phenomenon is not developed up to those at which it is established. It is shown that in this thickness range the quantum scattering cross-section, unlike the classical one, contains sharp peaks corresponding to some specific scattering angles, that is connected with the diffraction of the incident plane wave onto the periodically distributed crystal atomic strings. It is shown that the value of the scattering cross-section in the peaks varies periodically with the change of the target thickness. We note that this must lead to a new interference effect in radiation that is connected with the rearrangement of incident wave packet in transitional area of crystal thicknesses.

  16. Scattering of ultrarelativistic electrons in ultrathin crystals

    Directory of Open Access Journals (Sweden)

    N.F. Shul'ga

    2017-06-01

    Full Text Available Quantum theory is proposed of high energy electrons scattering in ultrathin crystals. This theory is based upon a special representation of the scattering amplitude in the form of an integral over the surface surrounding the crystal, and on the spectral method of determination of the wave function. The comparison is performed of quantum and classical differential scattering cross-sections in the transitional range of crystal thicknesses, from those at which the channeling phenomenon is not developed up to those at which it is established. It is shown that in this thickness range the quantum scattering cross-section, unlike the classical one, contains sharp peaks corresponding to some specific scattering angles, that is connected with the diffraction of the incident plane wave onto the periodically distributed crystal atomic strings. It is shown that the value of the scattering cross-section in the peaks varies periodically with the change of the target thickness. We note that this must lead to a new interference effect in radiation that is connected with the rearrangement of incident wave packet in transitional area of crystal thicknesses.

  17. 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

  18. Neutron Scattering Investigations of Correlated Electron Systems and Neutron Instrumentation

    DEFF Research Database (Denmark)

    Holm, Sonja Lindahl

    is on correlated electron systems. Here the magnetism of six different compounds have been studied with neutron scattering, including three different hole-doped cuprate high-temperature superconductors (HTSC), an electron-doped iron pnictide HTSC, a mineral with small clusters of geometrically frustrated magnetism...... contains antiferromagnetically coupled Cu2+ S = 1=2 ions forming truncated 24-spin cube clusters of linked triangles. The clusters in boleite afford a situation intermediate between molecular and bulk magnetism, accessible to both experiment and numerical theory, in which a spin liquid can be studied...... phonon modes and a coupling via the single-ion magnetostriction allows to calculate the spectra and the measured cross-section. An external magnetic field along the c-axis reveals a linear splitting of one spin wave branch which allows an exclusion of several proposed magnetic ground states based...

  19. Thermal diffuse scattering in transmission electron microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Forbes, B.D.; D' Alfonso, A.J. [School of Physics, University of Melbourne, Parkville, Victoria 3010 (Australia); Findlay, S.D. [School of Physics, Monash University, Victoria 3800 (Australia); Van Dyck, D. [EMAT, University of Antwerp, Groenenborgerlaan 171, B-2020 Antwerp (Belgium); LeBeau, J.M. [North Carolina State University, Raleigh, NC 27695-7907 (United States); Stemmer, S. [Materials Department, University of California, Santa Barbara, CA 93106-5050 (United States); Allen, L.J., E-mail: lja@unimelb.edu.au [School of Physics, University of Melbourne, Parkville, Victoria 3010 (Australia)

    2011-12-15

    In conventional transmission electron microscopy, thermal scattering significantly affects the image contrast. It has been suggested that not accounting for this correctly is the main cause of the Stobbs factor, the ubiquitous, large contrast mismatch found between theory and experiment. In the case where a hard aperture is applied, we show that previous conclusions drawn from work using bright field scanning transmission electron microscopy and invoking the principle of reciprocity are reliable in the presence of thermal scattering. In the aperture-free case it has been suggested that even the most sophisticated mathematical models for thermal diffuse scattering lack in their numerical implementation, specifically that there may be issues in sampling, including that of the contrast transfer function of the objective lens. We show that these concerns can be satisfactorily overcome with modest computing resources; thermal scattering can be modelled accurately enough for the purpose of making quantitative comparison between simulation and experiment. Spatial incoherence of the source is also investigated. Neglect or inadequate handling of thermal scattering in simulation can have an appreciable effect on the predicted contrast and can be a significant contribution to the Stobbs factor problem. -- Highlights: Black-Right-Pointing-Pointer We determine the numerical requirements for accurate simulation of TDS in CTEM. Black-Right-Pointing-Pointer TDS can be simulated to high precision using the Born-Oppenheimer model. Black-Right-Pointing-Pointer Such calculations establish the contribution of TDS to the Stobbs factor problem. Black-Right-Pointing-Pointer Treating spatial incoherence using envelope functions increases image contrast. Black-Right-Pointing-Pointer Rigorous treatment of spatial incoherence significantly reduces image contrast.

  20. Proton radius from electron scattering data

    Energy Technology Data Exchange (ETDEWEB)

    Higinbotham, Douglas W. [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Kabir, Al Amin [Kent State Univ., Kent, OH (United States). Dept. of Physics; Lin, Vincent [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Western Branch High School, Chesapeake, VA (United States); Meekins, David [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Norum, Blaine [Univ. of Virginia, Charlottesville, VA (United States). Dept. of Physics; Sawatzky, Brad [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States)

    2016-05-31

    Background: The proton charge radius extracted from recent muonic hydrogen Lamb shift measurements is significantly smaller than that extracted from atomic hydrogen and electron scattering measurements. The discrepancy has become known as the proton radius puzzle. Purpose: In an attempt to understand the discrepancy, we review high-precision electron scattering results from Mainz, Jefferson Lab, Saskatoon and Stanford. Methods: We make use of stepwise regression techniques using the F-test as well as the Akaike information criterion to systematically determine the predictive variables to use for a given set and range of electron scattering data as well as to provide multivariate error estimates. Results: Starting with the precision, low four-momentum transfer (Q2) data from Mainz (1980) and Saskatoon (1974), we find that a stepwise regression of the Maclaurin series using the F-test as well as the Akaike information criterion justify using a linear extrapolation which yields a value for the proton radius that is consistent with the result obtained from muonic hydrogen measurements. Applying the same Maclaurin series and statistical criteria to the 2014 Rosenbluth results on GE from Mainz, we again find that the stepwise regression tends to favor a radius consistent with the muonic hydrogen radius but produces results that are extremely sensitive to the range of data included in the fit. Making use of the high-Q2 data on GE to select functions which extrapolate to high Q2, we find that a Pad´e (N = M = 1) statistical model works remarkably well, as does a dipole function with a 0.84 fm radius, GE(Q2) = (1 + Q2/0.66 GeV2)-2. Conclusions: Rigorous applications of stepwise regression techniques and multivariate error estimates result in the extraction of a proton charge radius that is consistent with the muonic hydrogen result of 0.84 fm; either from linear extrapolation

  1. Future of Electron Scattering and Diffraction

    Energy Technology Data Exchange (ETDEWEB)

    Hall, Ernest [GE Global Research, Niskayuna, New York (United States); Stemmer, Susanne [Univ. of California, Santa Barbara, CA (United States); Zheng, Haimei [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Zhu, Yimei [Brookhaven National Lab. (BNL), Upton, NY (United States); Maracas, George [Dept. of Energy (DOE), Washington DC (United States). Office of Science

    2014-02-25

    The ability to correlate the atomic- and nanoscale-structure of condensed matter with physical properties (e.g., mechanical, electrical, catalytic, and optical) and functionality forms the core of many disciplines. Directing and controlling materials at the quantum-, atomic-, and molecular-levels creates enormous challenges and opportunities across a wide spectrum of critical technologies, including those involving the generation and use of energy. The workshop identified next generation electron scattering and diffraction instruments that are uniquely positioned to address these grand challenges. The workshop participants identified four key areas where the next generation of such instrumentation would have major impact: A – Multidimensional Visualization of Real Materials B – Atomic-scale Molecular Processes C – Photonic Control of Emergence in Quantum Materials D – Evolving Interfaces, Nucleation, and Mass Transport Real materials are comprised of complex three-dimensional arrangements of atoms and defects that directly determine their potential for energy applications. Understanding real materials requires new capabilities for three-dimensional atomic scale tomography and spectroscopy of atomic and electronic structures with unprecedented sensitivity, and with simultaneous spatial and energy resolution. Many molecules are able to selectively and efficiently convert sunlight into other forms of energy, like heat and electric current, or store it in altered chemical bonds. Understanding and controlling such process at the atomic scale require unprecedented time resolution. One of the grand challenges in condensed matter physics is to understand, and ultimately control, emergent phenomena in novel quantum materials that necessitate developing a new generation of instruments that probe the interplay among spin, charge, orbital, and lattice degrees of freedom with intrinsic time- and length-scale resolutions. Molecules and soft matter require imaging and

  2. Electron scattering and transport in liquid argon

    Energy Technology Data Exchange (ETDEWEB)

    Boyle, G. J.; Cocks, D. G.; White, R. D. [College of Science, Technology and Engineering, James Cook University, Townsville 4810 (Australia); McEachran, R. P. [Research School of Physical Sciences and Engineering, Australian National University, Canberra ACT 0200 (Australia)

    2015-04-21

    The transport of excess electrons in liquid argon driven out of equilibrium by an applied electric field is revisited using a multi-term solution of Boltzmann’s equation together with ab initio liquid phase cross-sections calculated using the Dirac-Fock scattering equations. The calculation of liquid phase cross-sections extends previous treatments to consider multipole polarisabilities and a non-local treatment of exchange, while the accuracy of the electron-argon potential is validated through comparison of the calculated gas phase cross-sections with experiment. The results presented highlight the inadequacy of local treatments of exchange that are commonly used in liquid and cluster phase cross-section calculations. The multi-term Boltzmann equation framework accounting for coherent scattering enables the inclusion of the full anisotropy in the differential cross-section arising from the interaction and the structure factor, without an a priori assumption of quasi-isotropy in the velocity distribution function. The model, which contains no free parameters and accounts for both coherent scattering and liquid phase screening effects, was found to reproduce well the experimental drift velocities and characteristic energies.

  3. Multiple scattering in electron fluid and energy loss in multi-ionic targets

    Energy Technology Data Exchange (ETDEWEB)

    Deutsch, C., E-mail: claude.deutsch@u-psud.fr [LPGP, UParis-Sud, 91405-Orsay (France); Tahir, N.A. [GSI, 1Planck Str., 64291-Darmstadt (Germany); Barriga-Carrasco, M. [ETSII, UCastilla-la-Mancha, 13071 Ciudad-Real (Spain); Ceban, V. [LPGP, UParis-Sud, 91405-Orsay (France); Fromy, P. [CRI, UParis-Sud, 91405-Orsay (France); Gilles, D. [CEA/Saclay/DSM/IRFU/SAP, 91191-Gif-s-Yvette (France); Leger, D. [Laboratoire Monthouy, UValenciennes-Hainaut Cambresis (France); Maynard, G. [LPGP, UParis-Sud, 91405-Orsay (France); Tashev, B. [Department of Physics, KazNu, Tole Bi82, Almaty (Kazakhstan); Volpe, L. [Department of Physics, UMilano-Bicocca, Milano 20126 (Italy)

    2014-01-01

    Extensions of the standard stopping model (SSM) for ion projectiles interacting with dense targets of timely concern for ICF and WDM are reviewed. They include multiple scattering on partially degenerate electrons, low velocity ion slowing down in demixing H–He mixtures within Jovian planets core or multiionic target such as Kapton.

  4. Fast Ion Collective Thomson Scattering Diagnostic for ITER

    DEFF Research Database (Denmark)

    Korsholm, Søren Bang; Bindslev, Henrik; Furtula, Vedran

    2008-01-01

    of the free energy of the plasma. This may affect instabilities and transport in the plasma. A key candidate for diagnosing confined fast ions in ITER is the technique of collective Thomson scattering (CTS). A fast ion CTS system with a probing frequency of 60 GHz has been proposed for ITER. Based...

  5. Evaluation of Pore Networks in Caprocks at Geologic Storage Sites: A Combined Study using High Temperature and Pressure Reaction Experiments, Small Angle Neutron Scattering, and Focused Ion Beam-Scanning Electron Microscopy

    Science.gov (United States)

    Mouzakis, K. M.; Sitchler, A.; Wang, X.; McCray, J. E.; Kaszuba, J. P.; Rother, G.; Dewers, T. A.; Heath, J. E.

    2011-12-01

    Low permeability rock units, often shales or mudstones, that overlie geologic formations under consideration for CO2 sequestration will help contain injected CO2. CO2 that does flow through these rocks will dissolve into the porewaters, creating carbonic acid lowering the pH. This perturbation of the system may result in mineral dissolution or precipitation, which can change the pore structure and impact the flow properties of the caprocks. In order to investigate the impacts that reaction can have on caprock pore structure, we performed a combination of high pressure high temperature reaction experiments, small angle neutron scattering (SANS) experiments and high resolution focused ion beam-scanning electron microscope (FIB-SEM) imaging on samples from the Gothic shale and Marine Tuscaloosa Group. Small angle neutron scattering was performed on unreacted and reacted caprocks at the High Flux Isotope Reactor at Oak Ridge National Laboratory. New precipitates and pores are observed in high-resolution images of the reacted samples. The precipitates have been preliminarily identified as gypsum or anhydrite, and sulfide minerals. Results from small angle neutron scattering, a technique that provides information about pores and pore/mineral interfaces at scales ~ 5 to 300 nm, show an increased porosity and specific surface area after reaction with brine and CO2. However, there appear to be differences in how the pore networks change between the two samples that are related to sample mineralogy and original pore network structure. Changes to pores and formation of new pores may lead to different capillary sealing behavior and permeability. This combination of controlled laboratory experiments, neutron scattering and high-resolution imaging provides detailed information about the geochemical processes that occur at the pore scale as CO2 reacts with rocks underground. Such information is integral to the evaluation of large-scale CO2 sequestration as a feasible technology

  6. ECR ion source with electron gun

    Science.gov (United States)

    Xie, Z.Q.; Lyneis, C.M.

    1993-10-26

    An Advanced Electron Cyclotron Resonance ion source having an electron gun for introducing electrons into the plasma chamber of the ion source is described. The ion source has a injection enclosure and a plasma chamber tank. The plasma chamber is defined by a plurality of longitudinal magnets. The electron gun injects electrons axially into the plasma chamber such that ionization within the plasma chamber occurs in the presence of the additional electrons produced by the electron gun. The electron gun has a cathode for emitting electrons therefrom which is heated by current supplied from an AC power supply while bias potential is provided by a bias power supply. A concentric inner conductor and outer conductor carry heating current to a carbon chuck and carbon pusher which hold the cathode in place and also heat the cathode. In the Advanced Electron Cyclotron Resonance ion source, the electron gun replaces the conventional first stage used in prior electron cyclotron resonance ion generators. 5 figures.

  7. Scattering of electrons from neon atoms

    Science.gov (United States)

    Dasgupta, A.; Bhatia, A. K.

    1984-01-01

    Scattering of electrons from neon atoms is investigated by the polarized-orbital method. The perturbed orbitals calculated with use of the Sternheimer approximation lead to the polarizability 2.803 a(0)-cube in fairly good agreement with the experimental value 2.66 a(0)-cube. Phase shifts for various partial waves are calculated in the exchange, exchange-adiabatic, and polarized-orbital approximations. They are compared with the previous results. The calculated elastic differential, total, and momentum-transfer cross sections are compared with the experimental results. The polarized-orbital approximation yields results which show general improvement over the exchange-adiabatic approximation.

  8. Dynamics of flexible counter-ions in conducting polyaniline a quasielastic neutron-scattering study

    CERN Document Server

    Bee, M; Djurado, D; Marque, D; Combet, J; Rannou, P; Dufour, B

    2002-01-01

    Conducting polyaniline protonated with sulphonic flexible counter-ions was investigated by quasielastic incoherent neutron scattering. In addition to their role in electrical properties, the flexible counter-ions also increase the elasticity of the samples. As in the case of more rigid counter-ions, polymer chains appear as very stiff objects whose dynamics is completely outside the investigated time scale. Conversely, the counter-ion dynamics was proved to be of major importance in charge transport since a dynamical transition is observed precisely in the temperature range where the electronic properties change from a metallic to a semiconducting regime. (orig.)

  9. Collective Thomson scattering system for determination of ion properties in a high flux plasma beam

    NARCIS (Netherlands)

    van der Meiden, H. J.; Vernimmen, J. W. M.; Bystrov, K.; Jesko, K.; Kantor, M. Y.; De Temmerman, G.; Morgan, T. W.

    2016-01-01

    A collective Thomson scattering system has been developed for measuring ion temperature, plasma velocity and impurity concentration in the high density magnetized Magnum-PSI plasma beam, allowing for measurements at low temperature (<5 eV) and high electron density >4 × 1020 m−3, while

  10. Ion optics of RHIC electron beam ion source.

    Science.gov (United States)

    Pikin, A; Alessi, J; Beebe, E; Kponou, A; Okamura, M; Raparia, D; Ritter, J; Tan, Y; Kuznetsov, G

    2012-02-01

    RHIC electron beam ion source has been commissioned to operate as a versatile ion source on RHIC injection facility supplying ion species from He to Au for Booster. Except for light gaseous elements RHIC EBIS employs ion injection from several external primary ion sources. With electrostatic optics fast switching from one ion species to another can be done on a pulse to pulse mode. The design of an ion optical structure and the results of simulations for different ion species are presented. In the choice of optical elements special attention was paid to spherical aberrations for high-current space charge dominated ion beams. The combination of a gridded lens and a magnet lens in LEBT provides flexibility of optical control for a wide range of ion species to satisfy acceptance parameters of RFQ. The results of ion transmission measurements are presented.

  11. Density-dependent electron scattering in photoexcited GaAs

    DEFF Research Database (Denmark)

    Mics, Zoltán; D'’Angio, Andrea; Jensen, Søren A.

    2013-01-01

    —In a series of systematic optical pump - terahertz probe experiments we study the density-dependent electron scattering rate in photoexcited GaAs in a large range of carrier densities. The electron scattering time decreases by as much as a factor of 4, from 320 to 60 fs, as the electron density...

  12. Quark-Hadron Duality in Electron Scattering

    Energy Technology Data Exchange (ETDEWEB)

    Wally Melnitchouk; Rolf Ent; Cynthia Keppel

    2004-08-01

    The duality between partonic and hadronic descriptions of physical phenomena is one of the most remarkable features of strong interaction physics. A classic example of this is in electron-nucleon scattering, in which low-energy cross sections, when averaged over appropriate energy intervals, are found to exhibit the scaling behavior expected from perturbative QCD. We present a comprehensive review of data on structure functions in the resonance region, from which the global and local aspects of duality are quantified, including its flavor, spin and nuclear medium dependence. To interpret the experimental findings, we discuss various theoretical approaches which have been developed to understand the microscopic origins of quark-hadron duality in QCD. Examples from other reactions are used to place duality in a broader context, and future experimental and theoretical challenges are identified.

  13. Soft Cold EI - approaching molecular ion only with electron ionization.

    Science.gov (United States)

    Amirav, Aviv; Keshet, Uri; Danon, Albert

    2015-11-15

    Cold EI is defined as electron ionization of cold molecules in supersonic molecular beams (SMB). Gas chromatography/mass spectrometry (GC/MS) with Cold EI provides informative mass spectra, which combine the usual library-searchable EI fragment ions with enhanced molecular ions for improved library-based identification probabilities. However, in some cases, such as in the analysis of complex petrochemical matrices, a soft ionization method that provides only molecular ions is desirable. GC/MS with Cold EI was used with a fly-through ion source at selected electron energies, including at low electron energies, in an attempt to observe molecular ions alone. We explored low electron energy Cold EI and found that once the sample compound is cooled by the supersonic expansion it can be reheated via reflected scattered helium atoms near the skimmer. Furthermore, once a labile molecular ion is formed it can undergo undesirable collision-induced dissociation (CID) in the same way as in tandem mass spectrometry (MS/MS), and the magnitude of such CID can be significant for labile molecular ions such as those of hydrocarbons. In order to reduce these adverse effects we reduced the helium pressure at the ion source and MS vacuum chamber by increasing the nozzle-skimmer distance. Cold EI at low electron energies was explored with a squalane isomer (C30 H62 ) and with n-C24 H50 . It was found that an increased nozzle-skimmer distance resulted in a noticeable increase in the abundance ratio of molecular ions to low mass fragment ions. Consequently, Cold EI at low electron energies and a large nozzle-skimmer distance converts EI into Soft Cold EI while further approaching the ideal of a molecular ion only ionization method. Copyright © 2015 John Wiley & Sons, Ltd.

  14. Fast-ion dynamics in the TEXTOR tokamak measured by collective Thomson scattering

    DEFF Research Database (Denmark)

    Bindslev, Henrik; Nielsen, Stefan Kragh; Porte, L.

    2007-01-01

    The dynamics of fast ion populations in the TEXTOR tokamak are measured by collective Thomson scattering of millimetre wave radiation generated by a gyrotron operated at 110 GHz and 100-150 kW. Temporal evolution of the energetic ion velocity distribution at switch on of neutral beam injection (NBI......) and the slowdown after switch off of NBI are measured. The turn on phase of the NBI has, furthermore, been measured in plasmas with a range of electron densities and temperatures. All of these measurements are shown to be in good agreement with simple Fokker-Planck modelling. Bulk ion rotation velocity is also...

  15. Cross section calculations for electron scattering from platinum chemotherapeutic compounds. Electron scattering from carboplatin and oxaliplatin

    Science.gov (United States)

    Żywicka, B.; Możejko, P.

    2013-10-01

    Cross section for electron impact ionization of carboplatin, C6H12N2O4Pt, and oxaliplatin, C8H14N2O4Pt, have been calculated within binary-encounter-Bethe model for energies from the ionization threshold up to 5000 eV. Cross section for elastic electron scattering from carboplatin and oxaliplatin molecules have also been derived using independent atom method (IAM) and additivity rule for collision energies ranging from 50 eV to 3000 eV. Obtained cross sections have been compared with relevant cross sections for cisplatin molecules.

  16. Relativistic models for quasielastic electron and neutrino-nucleus scattering

    Directory of Open Access Journals (Sweden)

    Meucci Andrea

    2012-12-01

    Full Text Available Relativistic models developed within the framework of the impulse approximation for quasielastic (QE electron scattering and successfully tested in comparison with electron-scattering data have been extended to neutrino-nucleus scattering. Different descriptions of final-state interactions (FSI in the inclusive scattering are compared. In the relativistic Green’s function (RGF model FSI are described consistently with the exclusive scattering using a complex optical potential. In the relativistic mean field (RMF model FSI are described by the same RMF potential which gives the bound states. The results of the models are compared for electron and neutrino scattering and, for neutrino scattering, with the recently measured charged-current QE (CCQE MiniBooNE cross sections.

  17. Ion-induced electron emission microscopy

    Science.gov (United States)

    Doyle, Barney L.; Vizkelethy, Gyorgy; Weller, Robert A.

    2001-01-01

    An ion beam analysis system that creates multidimensional maps of the effects of high energy ions from an unfocussed source upon a sample by correlating the exact entry point of an ion into a sample by projection imaging of the secondary electrons emitted at that point with a signal from a detector that measures the interaction of that ion within the sample. The emitted secondary electrons are collected in a strong electric field perpendicular to the sample surface and (optionally) projected and refocused by the electron lenses found in a photon emission electron microscope, amplified by microchannel plates and then their exact position is sensed by a very sensitive X Y position detector. Position signals from this secondary electron detector are then correlated in time with nuclear, atomic or electrical effects, including the malfunction of digital circuits, detected within the sample that were caused by the individual ion that created these secondary electrons in the fit place.

  18. Electron re-scattering from aligned linear molecules using the R-matrix method

    Energy Technology Data Exchange (ETDEWEB)

    Harvey, A G; Tennyson, J [Department of Physics and Astronomy, University College London, London WC1E 6BT (United Kingdom)], E-mail: j.tennyson@ucl.ac.uk

    2009-05-14

    Electron re-scattering in a strong laser field provides an important probe of molecular structure and processes. The laser field drives the ionization of the molecule, followed by acceleration and subsequent recollision of the electron with the parent molecular ion, the scattered electrons carry information about the nuclear geometry and electronic states of the molecular ion. It is advantageous in strong field experiments to work with aligned molecules, which introduces extra physics compared to the standard gas-phase, electron-molecule scattering problem. The formalism for scattering from oriented linear molecules is presented and applied to H{sub 2} and CO{sub 2}. Differential cross sections are presented for (re-)scattering by these systems concentrating on the most common, linear alignment. In H{sub 2} these cross sections show significant angular structure which, particularly for a scattering angle of 90 deg., are predicted to vary significantly between re-collisions stimulated by an even or an odd number of photons. In CO{sub 2} these cross sections are zero indicating the necessity of using non-parallel alignment with this molecule.

  19. Electron Scattering by biomass molecular fragments

    Science.gov (United States)

    Lima, Marco

    2015-09-01

    The replacement of fossil fuels by biofuels from renewable sources may not be a definite answer for greenhouse gas emissions problems, but it is a good step towards a sustainable energy strategy. Few per cent of ethanol is being mixed to gasoline in many countries and in some of them, like Brazil, a very aggressive program has been developed, using, in large scale, flex fuel engines that can run with any mixture of gasoline and ethanol, including 100% ethanol. Important points are how to produce ethanol in a sustainable way and with which technology? Biomass is a good candidate to enhance the first generation (produced from Corn in USA and from sugarcane in Brazil) production towards the so-called second-generation ethanol, since it has cellulose and hemicellulose as source of sugars. In order to liberate these sugars for fermentation, it is important to learn how to separate the main components. Chemical routes (acid treatment) and biological routes (enzymatic hydrolysis) are combined and used for these purposes. Atmospheric plasmas can be useful for attacking the biomass in a controlled manner and low energy electrons may have an important role in the process. Recently, we have been studying the interaction of electrons with lignin subunits (phenol, guaiacol, p-coumaryl alcohol), cellulose components, β-D-glucose and cellobiose (β(1-4) linked glucose dimer) and hemicellulose components [2] (β-D-xylose). We also obtained results for the amylose subunits α-D-glucose and maltose (α(1-4) linked glucose dimer). Altogether, the resonance spectra of lignin, cellulose and hemicellulose components establish a physical-chemical basis for electron-induced biomass pretreatment that could be applied to biofuel production. In order to describe a more realistic system (where molecules are ``wet''), we have obtained the shape resonance spectra of phenol-water clusters, as obtained previously from elastic electron scattering calculations. Our results, obtained in a simple

  20. Electron Elastic-Scattering Cross-Section Database

    Science.gov (United States)

    SRD 64 NIST Electron Elastic-Scattering Cross-Section Database (PC database, no charge)   This database provides values of differential elastic-scattering cross sections, corresponding total elastic-scattering cross sections, phase shifts, and transport cross sections for elements with atomic numbers from 1 to 96 and for electron energies between 50 eV and 20,000 eV (in steps of 1 eV).

  1. Measurement of T20 in Elastic Electron-Deuteron Scattering

    NARCIS (Netherlands)

    Bouwhuis, M.; Alarcon, R.; Botto, T.; Brand, J. F. J. van den; Bulten, H. J.; Dolfini, S.; Ent, R.; Ferro-Luzzi, M.; Higinbotham, D.W.; de Jager, C.W.; Lang, J.; de Lange, J.; Papadakis, N.; Passchier, I.; Poolman, H. R.; Six, E.; Steijger, J.J.M.; Vodinas, N.; Vries, H. de; Zhou, Z. -L.

    1998-01-01

    We report on a measurement of the tensor-analyzing power T20 in elastic electron-deuteron scattering in the range of four-momentum transfer from 1.8 to 3.2 fm-1. Electrons of 704 MeV were scattered from a polarized deuterium internal target. The tensor polarization of the deuterium nuclei was

  2. Electron cloud studies for heavy-ion and proton machines

    CERN Document Server

    Petrov, F; Weiland, Th

    2013-01-01

    Electron cloud effects are a known problem in various accelerator facilities around the world. Electron clouds cause instabilities and emittance growth in positron and proton beams as well as in heavy ion beams. Most of the hadron machines experience the build-up of EC due to the multipacting. In LHC and in positron machines production of electrons due to the synchrotron radiation becomes as important as the build-up due to the secondary emission. The main source of seed electrons in heavy ion machines is the residual gas ionization. FAIR facility in Darmstadt will operate with heavy-ion and proton beams. However, the beam parameters are such that the multipacting will start to play a role only for the unconditioned wall with the secondary emission yieldmore than 1.8. In this paperwe study the electron cloud build-up and its effect on the beam stability for FAIR heavy-ion coasting beams. These beams will be used during slow extraction. Electron scattering on the beam ions and its effect on the final neutraliz...

  3. Handbook of theoretical atomic physics data for photon absorption, electron scattering, and vacancies decay

    CERN Document Server

    Amusia, Miron Ya; Yarzhemsky, Victor

    2012-01-01

    The aim of this book is to present highly accurate and extensive theoretical Atomic data and to give a survey of selected calculational methods for atomic physics, used to obtain these data. The book presents the results of calculations of cross sections and probabilities of a broad variety of atomic processes with participation of photons and electrons, namely on photoabsorption, electron scattering and accompanying effects. Included are data for photoabsorption and electron scattering cross-sections and probabilities of vacancy decay formed for a large number of atoms and ions. Attention is also given to photoionization and vacancy decay in endohedrals and to positron-atom scattering. The book is richly illustrated. The methods used are one-electron Hartree-Fock and the technique of Feynman diagrams that permits to include many-electron correlations. This is done in the frames of the Random Phase approximation with exchange and the many-body perturbation theory. Newly obtained and previously collected atomi...

  4. RAMAN LIGHT SCATTERING IN PSEUDOSPIN-ELECTRON MODEL AT STRONG PSEUDOSPIN-ELECTRON INTERACTION

    Directory of Open Access Journals (Sweden)

    T.S.Mysakovych

    2004-01-01

    Full Text Available Anharmonic phonon contributions to Raman scattering in locally anharmonic crystal systems in the framework of the pseudospin-electron model with tunneling splitting of levels are investigated. The case of strong pseudospin-electron coupling is considered. Pseudospin and electron contributions to scattering are taken into account. Frequency dependences of Raman scattering intensity for different values of model parameters and for different polarization of scattering and incident light are investigated.

  5. Study of electronic excitation and diffraction effects as well as growth, structure, and magnetic properties of ultrathin 3d metal films on Cu(001) by means of grazing-incidence ion scattering; Untersuchung elektronischer Anregungs- und Beugungseffekte sowie Wachstum, Struktur und magnetischer Eigenschaften ultraduenner 3d-Metallfilme auf Cu(001) mittels streifender Ionenstreuung

    Energy Technology Data Exchange (ETDEWEB)

    Bernhard, T.

    2006-11-23

    H{sup +} and He{sup +} ions with an energy of 25 keV are scattered under a grazing angle of incidence from a clean and flat Cu(001) surface. For specific azimuthal orientations of the crystal surface with respect to low index directions in the surface plane we observe the ion induced emission of electrons with a conventional LEED (low energy electron diffraction) setup. By operating the instrument in an energy dispersive mode we find intensity distributions of emitted electrons which can unequivocally be ascribed to diffraction effects at the target surface. From this ion induced LEED-reflexes (IILEED) we get important information about the electron excitation- and emission effects during the scattering process. In the second part of this work we investigate the correlation between thin-film growth (Co,Fe,Mn on Cu(001)) and electron emission in the regime of grazing ion scattering. The ''rough'' surface of uncompleted layers increase the probability of binary collisions of incident ions with individual atoms at the surface. The energy spectras and the number distribution of emitted electrons are substantially influenced by these ''violent'' collisions and allow us to monitor growth of thin films via simple measurements of target current or from energy spectra of emitted electrons. The method provides excellent signals and is also applicable in the regime of poor layer growth. By making use of ion beam triangulation (IBT), direct information on the atomic structure of thin films and substrate surfaces is obtained. We discuss in the third part of this work a new variant of this method based on the detection of the number of emitted electrons. The data are analyzed via computer simulations using classical mechanics which provides a quantitative analysis with respect to projectile trajectories. This new detection scheme allows the determination of the in-plane structure of reconstructed thin films and surfaces with high precision

  6. Recent progress in electron scattering from atoms and molecules

    Energy Technology Data Exchange (ETDEWEB)

    Brunger, M. J. [Centre for Antimatter-Matter Studies, CAPS, Flinders University, GPO Box 2100, Adelaide, SA 5001, Australia and Institute of Mathematical Sciences, University of Malaya, Kuala Lumpur (Malaysia); Buckman, S. J. [Institute of Mathematical Sciences, University of Malaya, Kuala Lumpur, Malaysia and Centre for Antimatter-Matter Studies, AMPL, Australian National University, Canberra, ACT 0200 (Australia); Sullivan, J. P.; Palihawadana, P. [Centre for Antimatter-Matter Studies, AMPL, Australian National University, Canberra, ACT 0200 (Australia); Jones, D. B. [School of Chemical and Physical Sciences, Flinders University, GPO Box 2100, Adelaide, SA 5001 (Australia); Chiari, L.; Pettifer, Z. [Centre for Antimatter-Matter Studies, CAPS, Flinders University, GPO Box 2100, Adelaide, SA 5001 (Australia); Silva, G. B. da [Centre for Antimatter-Matter Studies, CAPS, Flinders University, GPO Box 2100, Adelaide, SA 5001, Australia and Universidade Federal de Mato Grosso, Barra do Garças, Mato Grosso (Brazil); Lopes, M. C. A. [Centre for Antimatter-Matter Studies, CAPS, Flinders University, GPO Box 2100, Adelaide, SA 5001, Australia and Departamento de Fisica, Universidade Federal de Juiz de Fora, Juiz de Fora, MG (Brazil); Duque, H. V. [Departamento de Fisica, Universidade Federal de Juiz de Fora, Juiz de Fora, MG (Brazil); Masin, Z.; Gorfinkiel, J. D. [Department of Physical Sciences, The Open University, Walton Hall, Milton Keynes, MK7 6AA (United Kingdom); Garcia, G. [Instituto de Fisica Fundamental, CSIC, Madrid E-28006 (Spain); Hoshino, M.; Tanaka, H. [Department of Physics, Sophia University, Tokyo, 102-8554 (Japan); Limão-Vieira, P. [Laboratório de Colisões Atómicas e Moleculares, CEFITEC, Universidade Nova de Lisboa, 2829-516 Caparica (Portugal)

    2014-03-05

    We present and discuss recent results, both experimental and theoretical (where possible), for electron impact excitation of the 3s[3/2 ]{sub 1} and 3s′[1/2 ]{sub 1} electronic states in neon, elastic electron scattering from the structurally similar molecules benzene, pyrazine, and 1,4-dioxane and excitation of the electronic states of the important bio-molecule analogue α-tetrahydrofurfuryl alcohol. While comparison between theoretical and experimental results suggests that benchmarked cross sections for electron scattering from atoms is feasible in the near-term, significant further theoretical development for electron-molecule collisions, particularly in respect to discrete excitation processes, is still required.

  7. Fast ion collective Thomson scattering diagnostic for ITER: Design elements

    DEFF Research Database (Denmark)

    Tsakadze, Erekle; Bindslev, Henrik; Korsholm, Søren Bang

    2008-01-01

    The proposed fast ion collective Thomson scattering (CTS) diagnostic system for ITER provides the unique capability of measuring the temporally and spatially resolved velocity distribution of the confined fast ions and fusion alpha particles in a burning ITER plasma. The present paper describes...... perpendicular, and the other measures the component near parallel to the magnetic field. Each system has a high-power probe beam at an operating frequency of 60 GHz and a receiver unit. In order to prevent neutron damage to moveable parts, the geometry of the probes and receivers is fixed An array of receivers...

  8. The threshold anomaly for heavy-ion scattering

    Energy Technology Data Exchange (ETDEWEB)

    Satchler, G.R.

    1987-01-01

    The real parts of optical potentials deduced from heavy-ion scattering measurements become rapidly more attractive as the bombarding energy is reduced close to the top of the Coulomb barrier. This behavior is explained as a coupled-channels effect, and is related to the corresponding reduction in the absorptive potential through a dispersion relation which expresses the consequences of causality. Another manifestation of this ''anomaly'' is the striking enhancement observed for the near- and sub-barrier fusion of two heavy ions. The barrier penetration model of fusion is examined critically in this context. It is also stressed that similar anomalies could appear in the energy dependence of nonelastic scattering. 21 refs., 4 figs.

  9. Electron string ion sources for carbon ion cancer therapy accelerators

    Science.gov (United States)

    Boytsov, A. Yu.; Donets, D. E.; Donets, E. D.; Donets, E. E.; Katagiri, K.; Noda, K.; Ponkin, D. O.; Ramzdorf, A. Yu.; Salnikov, V. V.; Shutov, V. B.

    2015-08-01

    The type of the Electron String Ion Sources (ESIS) is considered to be the appropriate one to produce pulsed C4+ and C6+ ion beams for cancer therapy accelerators. In fact, the new test ESIS Krion-6T already now provides more than 1010 C4+ ions per pulse and about 5 × 109 C6+ ions per pulse. Such ion sources could be suitable to apply at synchrotrons. It has also been found that Krion-6T can provide more than 1011 C6+ ions per second at the 100 Hz repetition rate, and the repetition rate can be increased at the same or larger ion output per second. This makes ESIS applicable at cyclotrons as well. ESIS can be also a suitable type of ion source to produce the 11C radioactive ion beams. A specialized cryogenic cell was experimentally tested at the Krion-2M ESIS for pulse injection of gaseous species into the electron string. It has been shown in experiments with stable methane that the total conversion efficiency of methane molecules to C4+ ions reached 5%÷10%. For cancer therapy with simultaneous irradiation and precise dose control (positron emission tomography) by means of 11C, transporting to the tumor with the primary accelerated 11C4+ beam, this efficiency is preliminarily considered to be large enough to produce the 11C4+ beam from radioactive methane and to inject this beam into synchrotrons.

  10. Completing electron scattering studies with the inert gas column:e - Rn scattering and Ionization

    CERN Document Server

    Joshi, Foram M; Chaudhari, Asha S; Modi, Hitesh S; Pindaria, Manish J

    2016-01-01

    Interest in the inert or noble- gas atoms in general arises because they are ideal as test systems for various theoretical models of electron scattering and also since their interaction processes serve as reference for the determination of instrumental responses in electron scattering experiments. The ionization cross section data of ground state inert gas atoms He through Xe are considered to be benchmark data. Our aim in this paper is to provide theoretical results on electron scattering with Radon atoms, as it would complete the studies on the entire inert gas column. That is possible with this particular column only, in view of the preceding literature on He through Xe . Inert gas radon is radioactive, and would be a difficult target for electron scattering experiments. In the present calculations, the complications arising from radioactivity are not considered. We provide hitherto unavailable cross sections on atomic radon, and also provide opportunity of the comparison of electron impact cross sections ...

  11. RCCC calculations for electron scattering on quasi-two electron targets

    Science.gov (United States)

    Bostock, C.; Fursa, D. V.; Bray, I.

    2012-11-01

    We report on the recent extension of the RCCC method to accommodate electron scattering from quasi-two electron targets. We present results for electron scattering from mercury (Z = 80) which serves as a testing ground for relativistic theories due to its high atomic number. Furthermore electron-mercury scattering plays an important practical role in the physics of fluorescent and high intensity discharge lamps.

  12. Differential cross sections of electron silver scattering at varying ...

    African Journals Online (AJOL)

    The differential scattering cross sections of electron - silver atom are calculated using the Eikonal approximation at incident energies of 50 eV, 60 eV and 70 eV, with the Lenz-Jensen potential. Results obtained are in good agreement with the NIST SRD 64 at scattering angles of about 80 to 180 degrees; and are in very ...

  13. The Empowerment of Plasma Modeling by Fundamental Electron Scattering Data

    Science.gov (United States)

    Kushner, Mark J.

    2015-09-01

    Modeling of low temperature plasmas addresses at least 3 goals - investigation of fundamental processes, analysis and optimization of current technologies, and prediction of performance of as yet unbuilt systems for new applications. The former modeling may be performed on somewhat idealized systems in simple gases, while the latter will likely address geometrically and electromagnetically intricate systems with complex gas mixtures, and now gases in contact with liquids. The variety of fundamental electron and ion scattering data (FSD) required for these activities increases from the former to the latter, while the accuracy required of that data probably decreases. In each case, the fidelity, depth and impact of the modeling depends on the availability of FSD. Modeling is, in fact, empowered by the availability and robustness of FSD. In this talk, examples of the impact of and requirements for FSD in plasma modeling will be discussed from each of these three perspectives using results from multidimensional and global models. The fundamental studies will focus on modeling of inductively coupled plasmas sustained in Ar/Cl2 where the electron scattering from feed gases and their fragments ultimately determine gas temperatures. Examples of the optimization of current technologies will focus on modeling of remote plasma etching of Si and Si3N4 in Ar/NF3/N2/O2 mixtures. Modeling of systems as yet unbuilt will address the interaction of atmospheric pressure plasmas with liquids Work was supported by the US Dept. of Energy (DE-SC0001939), National Science Foundation (CHE-124752), and the Semiconductor Research Corp.

  14. Nucleon momentum distributions and elastic electron scattering form ...

    Indian Academy of Sciences (India)

    Electrons interact with nuclei basically through the electromagnetic force. If the energy of the electrons is high enough, they become a relatively clean probe to explore precisely the internal structure of the nuclei [7]. There are many reasons why inclusive electron scattering provides a powerful tool for studying the structure of ...

  15. Neutrino-electron scattering in a dense strongly magnetized plasma

    Directory of Open Access Journals (Sweden)

    Kuznetsov Alexander

    2017-01-01

    Full Text Available We investigate the process of neutrino-electron scattering in a dense plasma and magnetic field of arbitrary strength, where electrons can occupy the states corresponding to excited Landau levels. We calculate the total probability of this process, summarized over all initial states of the plasma electrons which is only physically meaningful. Possible astrophysical manifestations of the process are briefly discussed.

  16. Electron scattering from the octupole band in /sup 238/U

    Energy Technology Data Exchange (ETDEWEB)

    Hirsch, A.; Creswell, C.; Bertozzi, W.; Heisenberg, J.; Hynes, M.V.; Kowalski, S.; Miska, H.; Norum, B.; Rad, F.N.; Sargent, C.P.; Sasanuma, T.; Turchinetz, W.

    1978-03-06

    A simple model for nuclear surface vibrations in permanently deformed nuclei does well in reproducing electron scattering cross sections of rotational levels built on a K/sup ..pi../= 0/sup -/ intrinsic octupole vibration in /sup 238/U.

  17. Electron Dynamics by Inelastic X-Ray Scattering

    CERN Document Server

    Schülke, Winfried

    2007-01-01

    The book offers the first comprehensive review of experimental methods, theory, and successful applications of synchrotron radiation based inelastic X-ray scattering (IXS) spectroscopy, which enables the investigation of electron dynamics in condensed matter (correlated motion and excitation).

  18. Electron-cyclotron-resonance ion sources (review)

    Energy Technology Data Exchange (ETDEWEB)

    Golovanivskii, K.S.; Dougar-Jabon, V.D. [People`s Friendship Univ., Moscow (Russian Federation)

    1992-01-01

    The physical principles are described and a brief survey of the present state is given of ion sources based on electron-cyclotron heating of plasma in a mirror trap. The characteristics of ECR sources of positive and negative ions used chiefly in accelerator technology are presented. 20 refs., 10 figs., 3 tabs.

  19. Ion beam processing of advanced electronic materials

    Energy Technology Data Exchange (ETDEWEB)

    Cheung, N.W.; Marwick, A.D.; Roberto, J.B. (eds.) (California Univ., Berkeley, CA (USA); International Business Machines Corp., Yorktown Heights, NY (USA). Thomas J. Watson Research Center; Oak Ridge National Lab., TN (USA))

    1989-01-01

    This report contains research programs discussed at the materials research society symposia on ion beam processing of advanced electronic materials. Major topics include: shallow implantation and solid-phase epitaxy; damage effects; focused ion beams; MeV implantation; high-dose implantation; implantation in III-V materials and multilayers; and implantation in electronic materials. Individual projects are processed separately for the data bases. (CBS)

  20. Scattering of H- Stripped Electrons from SEM Grids and Wire Scanners at the CERN LINAC4

    CERN Document Server

    Cheymol, B; Duraffourg, M; Focker, GJ; Roncarolo, F; Raich, U; Hessler, C; Vuitton, C; Zocca, F

    2013-01-01

    At the CERN LINAC4, wire grids and scanners will be used to characterize the H− beam transverse profiles from 45 keV to 160 MeV. The wire signal will be determined by the balance between secondary emission and number of charges stopped in the wire, which will depend on the wire material and diameter, the wire polarization and the beam energy. The outermost electrons of H− ions impinging on a wire are stripped in the first nanometers of material. A portion of such electrons are scattered away from the wire and can reach the neighboring wires. In addition, scattered electrons hitting the surrounding beam pipe generate secondary electrons that can also perturb the measurement. Monte Carlo simulations, analytical calculations and a laboratory experiment allowed quantifying the amount of scattering and the scattered particles distributions. The experiment was based on 70 keV electrons, well reproducing the case of 128 MeV H− ions. For all the LINAC4 simulated cases the predicted effect on the beam size rec...

  1. Three-dimensional simulations of ion dynamics in an Electron Cyclotron Resonance Ion Source

    NARCIS (Netherlands)

    Beijers, J. P. M.; Mironov, V.

    We present a three-dimensional simulation of the ion dynamics in an electron cyclotron resonance ion source. Ion trajectories in the min-B field of the source are calculated taking ion-ion and electron-ion collisions into account. The electrons are not tracked but considered as a neutralizing

  2. Elastic scattering of electrons from Rb, Cs and Fr atoms

    Science.gov (United States)

    Gangwar, R. K.; Tripathi, A. N.; Sharma, L.; Srivastava, R.

    2010-04-01

    Differential, integrated elastic, momentum-transfer and total cross sections as well as differential S, T and U spin parameters for scattering of electrons from rubidium, caesium and francium atoms in the incident energy range up to 300 eV are calculated using a relativistic Dirac equation. The projectile electron-target atom interaction is represented by both real and complex parameter-free optical potentials for obtaining the solution of a Dirac equation for scattered electrons. The Dirac-Fock wavefunctions have been used to represent the Rb, Cs and Fr target atoms. The results of differential cross sections and spin asymmetry parameter S for e-Rb and e-Cs have been compared with the available experimental and theoretical results. Detailed results are reported for the elastic scattering of electrons from the ground states of a francium atom for the first time in the wide range of incident electron energies. The results of electron-Fr elastic scattering show the similar features to those obtained in the case of e-Rb and e-Cs elastic scattering.

  3. Spin effects probed by Rayleigh X-ray scattering off hydrogenic ions

    CERN Document Server

    Safari, Laleh; Amaro, Pedro; Fratini, Filippo

    2014-01-01

    We study the polarization characteristics of x-ray photons scattered by hydrogenic atoms, based on the Dirac equation and second-order perturbation theory. The relativistic states used in calculations are obtained using the finite basis set method and expressed in terms of B-splines and B-polynomials. We derive general analytical expressions for the polarization-dependent total cross sections, which are applicable to any atom and ion, and evaluate them separately for linear and circular polarization of photons. In particular, detailed calculations are performed for the integrated Stokes parameters of the scattered light for hydrogen as well as hydrogenlike neon and argon. Analyzing such integrated Stokes parameters, special attention is given to the electron-photon spin-spin interaction, which mostly stems from the magnetic-dipole contribution of the electron-photon interaction. Subsequently, we find an energy window for the selected targets in which such spin-spin interactions can be probed.

  4. Influence of scattering processes on electron quantum states in nanowires

    Directory of Open Access Journals (Sweden)

    Pozdnyakov Dmitry

    2007-01-01

    Full Text Available AbstractIn the framework of quantum perturbation theory the self-consistent method of calculation of electron scattering rates in nanowires with the one-dimensional electron gas in the quantum limit is worked out. The developed method allows both the collisional broadening and the quantum correlations between scattering events to be taken into account. It is an alternativeper seto the Fock approximation for the self-energy approach based on Green’s function formalism. However this approach is free of mathematical difficulties typical to the Fock approximation. Moreover, the developed method is simpler than the Fock approximation from the computational point of view. Using the approximation of stable one-particle quantum states it is proved that the electron scattering processes determine the dependence of electron energy versus its wave vector.

  5. Spectrum response and analysis of 77 GHz band collective Thomson scattering diagnostic for bulk and fast ions in LHD plasmas

    DEFF Research Database (Denmark)

    Nishiura, M.; Kubo, S.; Tanaka, K.

    2014-01-01

    A collective Thomson scattering (CTS) diagnostic was developed and used to measure the bulk and fast ions originating from 180 keV neutral beams in the Large Helical Device (LHD). Electromagnetic waves from a gyrotron at 77 GHz with 1 MW power output function as both the probe and electron cyclot...

  6. Rosetta Mission: Electron Scattering Cross Sections—Data Needs and Coverage in BEAMDB Database

    Directory of Open Access Journals (Sweden)

    Bratislav P. Marinković

    2017-11-01

    Full Text Available The emission of [O I] lines in the coma of Comet 67P/Churyumov-Gerasimenko during the Rosetta mission have been explained by electron impact dissociation of water rather than the process of photodissociation. This is the direct evidence for the role of electron induced processing has been seen on such a body. Analysis of other emission features is handicapped by a lack of detailed knowledge of electron impact cross sections which highlights the need for a broad range of electron scattering data from the molecular systems detected on the comet. In this paper, we present an overview of the needs for electron scattering data relevant for the understanding of observations in coma, the tenuous atmosphere and on the surface of 67P/Churyumov-Gerasimenko during the Rosetta mission. The relevant observations for elucidating the role of electrons come from optical spectra, particle analysis using the ion and electron sensors and mass spectrometry measurements. To model these processes electron impact data should be collated and reviewed in an electron scattering database and an example is given in the BEAMD, which is a part of a larger consortium of Virtual Atomic and Molecular Data Centre—VAMDC.

  7. Variational methods in electron-atom scattering theory

    CERN Document Server

    Nesbet, Robert K

    1980-01-01

    The investigation of scattering phenomena is a major theme of modern physics. A scattered particle provides a dynamical probe of the target system. The practical problem of interest here is the scattering of a low­ energy electron by an N-electron atom. It has been difficult in this area of study to achieve theoretical results that are even qualitatively correct, yet quantitative accuracy is often needed as an adjunct to experiment. The present book describes a quantitative theoretical method, or class of methods, that has been applied effectively to this problem. Quantum mechanical theory relevant to the scattering of an electron by an N-electron atom, which may gain or lose energy in the process, is summarized in Chapter 1. The variational theory itself is presented in Chapter 2, both as currently used and in forms that may facilitate future applications. The theory of multichannel resonance and threshold effects, which provide a rich structure to observed electron-atom scattering data, is presented in Cha...

  8. Interpreting the data on helium-ion scattering in metallic films

    Science.gov (United States)

    Bednyakov, A. A.

    2017-07-01

    Earlier measurements of angular distributions in the multiple scattering of a helium-ion beam with energy below 300 keV on Al yielded rather unexpected results: the ratio between the half-width of the measured angular distribution, (θ1/2)e, and that predicted with the Moliere-Bethe theory, (θ1/2)MB, proved to stay almost constant throughout the investigated energy range. At the same time, one could expect the (θ1/2)e/(θ1/2)MB value to be affected by the beam-content variation due to the charge-exchange scattering. Towards resolving this problem, we compute the interaction potentials between the He++, He+, and He0 ions and the scattering atoms and reveal the electron-screening effects on the scattering process. Thereby, we explain the energy dependence of (θ1/2)e/(θ1/2)MB observed in the old and new measurements carried out at higher beam energies.

  9. Magnetic dipole transitions and spin currents in inelastic electron scattering

    Energy Technology Data Exchange (ETDEWEB)

    Lipas, P.O.; Koskinen, M. (Jyvaeskylae Univ. (Finland). Dept. of Physics); Harter, H.; Nojarov, R.; Faessler, A. (Tuebingen Univ. (Germany, F.R.). Inst. fuer Theoretische Physik)

    1989-10-26

    We use the microscopic interacting-boson approximation (IBA-2) to calculate the nuclear M1 transition current density for excitation by inelastic electron scattering. Although the strong 1{sup +} excitations are commonly regarded as due to proton convection, we find, with {sup 164}Dy as a test case, that proton and neutron spins cause strong oscillations in the current and are responsible for high-q-scattering. (orig.).

  10. Parity nonconservation in polarized electron scattering at high energies

    Energy Technology Data Exchange (ETDEWEB)

    Prescott, C.Y.

    1979-10-01

    Recent observations of parity violation in inelastic scattering of electrons at high energy is discussed with reference to the process e(polarized) + D(unpolarized) ..-->.. e + X. The kinetics of this process, the idealized case of scattering from free quark targets, experimental techniques and results, and relations to atomic physics of parity violation in bismuth and thallium atoms with a model independent analysis. 17 references. (JFP)

  11. Geometrical calibration of the NBS electron scattering apparatus. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Penner, S.; Fivozinsky, S.P.; Lightbody, J.W. Jr.; Cardman, L.S.; Trower, W.P.

    1975-06-01

    A comprehensive calibration of the geometry of the NBS electron scattering apparatus is described. A complete set of measured parameters is tabulated in this report. Combining these parameters with observed values of certain variables as described herein permits the accurate determination of the solid angle, scattering angle, and target angle for each cross section measurement made with the apparatus. The uncertainty in cross section measurement due to the imprecision of the geometry calibrations is less than one part in 1,000. (GRA)

  12. Modelling Thomson scattering for systems with non-equilibrium electron distributions

    Directory of Open Access Journals (Sweden)

    Chapman D.A.

    2013-11-01

    Full Text Available We investigate the effect of non-equilibrium electron distributions in the analysis of Thomson scattering for a range of conditions of interest to inertial confinement fusion experiments. Firstly, a generalised one-component model based on quantum statistical theory is given in the random phase approximation (RPA. The Chihara expression for electron-ion plasmas is then adapted to include the new non-equilibrium electron physics. The theoretical scattering spectra for both diffuse and dense plasmas in which non-equilibrium electron distributions are expected to arise are considered. We find that such distributions strongly influence the spectra and are hence an important consideration for accurately determining the plasma conditions.

  13. Electron Scattering in Intrananotube Quantum Dots

    NARCIS (Netherlands)

    Buchs, G.; Bercioux, D.; Ruffieux, P.; Gröning, P.; Grabert, H.; Gröning, O.

    2009-01-01

    Intratube quantum dots showing particle-in-a-box-like states with level spacings up to 200 meV are realized in metallic single-walled carbon nanotubes by means of low dose medium energy Ar+ irradiation. Fourier-transform scanning tunneling spectroscopy compared to results of a Fabry-Perot electron

  14. Laser-modified electron scattering from a slowly ionising atom

    Science.gov (United States)

    Fiordilino, E.; Mittleman, M. H.

    1983-01-01

    When an electron scatters from an atom in the presence of a laser field which is resonant with an atomic transition, off-shell effects enter into the cross section. These only become significant at higher laser intensities where the atom may also be ionised by the laser. Cross-sections are obtained for electron-atom scattering in which these off-shell effects appear and in which the slow ionisation of the atom by the laser is included. Experiments are suggested in which simplifications can occur and which still retain these 'exotic' effects.

  15. Theory of neutron scattering by electrons in magnetic materials

    Science.gov (United States)

    Lovesey, S. W.

    2015-10-01

    A theory of neutron scattering by magnetic materials is reviewed with emphasis on the use of electronic multipoles that have universal appeal, because they are amenable to calculation and appear in theories of many other experimental techniques. The conventional theory of magnetic neutron scattering, which dates back to Schwinger (1937 Phys. Rev. 51 544) and Trammell (1953 Phys. Rev. 92 1387), yields an approximation for the scattering amplitude in terms of magnetic dipoles formed with the spin (S) and orbital angular momentum (L) of valence electrons. The so-called dipole-approximation has been widely adopted by researchers during the past few decades that has seen neutron scattering develop to its present status as the method of choice for investigations of magnetic structure and excitations. Looking beyond the dipole-approximation, however, reveals a wealth of additional information about electronic degrees of freedom conveniently encapsulated in magnetic multipoles. In this language, the dipole-approximation retains electronic axial dipoles, S and L. At the same level of approximation are polar dipoles—called anapoles or toroidal dipoles—allowed in the absence of a centre of inversion symmetry. Anapoles are examples of magneto-electric multipoles, time-odd and parity-odd irreducible tensors, that have come to the fore as signatures of electronic complexity in materials.

  16. A Recoil Detector for electron scattering experiments with internal targets

    CERN Document Server

    Sambeek, M J M V; Blok, H P; Borrius, W C; Botto, T; Dodge, G E; Heimberg, P; Jansweijer, P; Kormanyos, C M; Lange, D J; Lienen, J V; Mul, F A; Steenbakkers, M F M; Steijger, J J M; Sturm, F C; Verkooijen, J C; Welling, J J; Zwanenburg, J

    1999-01-01

    A Recoil Detector has been constructed for electron-scattering experiments with gas targets internal to the Amsterdam Pulse Stretcher and storage ring (AmPS) at NIKHEF. The detector was designed to detect low-energy (1-20 MeV/nucleon) and low-mass (A <= 4) recoiling nuclei emerging from electron-induced reactions. It consists of four sensitive elements: a low-pressure two-step avalanche chamber, two layers of silicon strip detectors of 100 and 475 mu m thickness, and a scintillator. The signals from the separate detector elements are processed by custom-made analog and digital electronics. The detector was operated successfully at the AmPS electron scattering facility with a gaseous helium target of 10 sup 1 sup 5 atoms cm sup - sup 2 internal to the storage ring and beam currents of up to 200 mA. (author)

  17. Monte Carlo modeling of ion beam induced secondary electrons

    Energy Technology Data Exchange (ETDEWEB)

    Huh, U., E-mail: uhuh@vols.utk.edu [Biochemistry & Cellular & Molecular Biology, University of Tennessee, Knoxville, TN 37996-0840 (United States); Cho, W. [Electrical and Computer Engineering, University of Tennessee, Knoxville, TN 37996-2100 (United States); Joy, D.C. [Biochemistry & Cellular & Molecular Biology, University of Tennessee, Knoxville, TN 37996-0840 (United States); Center for Nanophase Materials Science, Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States)

    2016-09-15

    Ion induced secondary electrons (iSE) can produce high-resolution images ranging from a few eV to 100 keV over a wide range of materials. The interpretation of such images requires knowledge of the secondary electron yields (iSE δ) for each of the elements and materials present and as a function of the incident beam energy. Experimental data for helium ions are currently limited to 40 elements and six compounds while other ions are not well represented. To overcome this limitation, we propose a simple procedure based on the comprehensive work of Berger et al. Here we show that between the energy range of 10–100 keV the Berger et al. data for elements and compounds can be accurately represented by a single universal curve. The agreement between the limited experimental data that is available and the predictive model is good, and has been found to provide reliable yield data for a wide range of elements and compounds. - Highlights: • The Universal ASTAR Yield Curve was derived from data recently published by NIST. • IONiSE incorporated with the Curve will predict iSE yield for elements and compounds. • This approach can also handle other ion beams by changing basic scattering profile.

  18. Ion fractions in the scattering of hydrogen on silicon surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Garcia, Evelina A. [Instituto de Desarrollo Tecnologico para la Industria Quimica (CONICET-UNL), Gueemes 3450, cc91, 3000 Santa Fe (Argentina); Gonzalez Pascual, C. [Departamento Fisica Teorica de la Materia Condensada, C-V, Universidad Autonoma de Madrid, Canto Blanco 28049 (Spain); Bolcatto, P.G. [Facultad de Ingenieria Quimica, Universidad Nacional del Litoral, Santa Fe (Argentina); Faculad de Humanidades y Ciencias, Universidad Nacional del Litoral, Santa Fe (Argentina); Passeggi, M.C.G. [Instituto de Desarrollo Tecnologico para la Industria Quimica (CONICET-UNL), Gueemes 3450, cc91, 3000 Santa Fe (Argentina); Facultad de Bioquimica y Ciencias Biolologicas, Universidad Nacional del Litoral, Santa Fe (Argentina); Goldberg, E.C. [Instituto de Desarrollo Tecnologico para la Industria Quimica (CONICET-UNL), Gueemes 3450, cc91, 3000 Santa Fe (Argentina); Facultad de Ingenieria Quimica, Universidad Nacional del Litoral, Santa Fe (Argentina)

    2005-08-01

    We present a theoretical calculation of the resonant charge-exchange process occurring in H{sup 0} scattering by Si(100)2 x 1 surfaces. In the atom-surface interacting system the core states of the surface atoms are included and the parameters of the Hamiltonian are calculated in an ab initio basis taking into account the extended features of the surface and the localized atom-atom interactions within a mean-field approximation. The density of states of the surface and sub-surface atoms are obtained from a molecular dynamic-density functional theory in the local density approximation. An elastic binary collision is assumed to fix the projectile trajectory, while the inelastic processes are determined by the interaction of the projectile atom with all the surface atoms 'seen' along its trajectory. The ion fractions are calculated by using the Green-Keldysh formalism to solve the time dependent process. The results, obtained as an average over different possibilities for the scattering center, reproduce the general trends of the experiment. (copyright 2005 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  19. Theory of nuclear excitation by electron capture for heavy ions

    Energy Technology Data Exchange (ETDEWEB)

    Gagyi-Palffy, A.

    2006-07-01

    The resonant process of nuclear excitation by electron capture (NEEC) in collisions involving highly-charged ions has been investigated theoretically. NEEC is a rare recombination process in which a free electron is captured into a bound shell of an ion with the simultaneous excitation of the nucleus. Total cross sections for NEEC followed by the radiative decay of the excited nucleus are presented for various collision systems. The possibility to observe the NEEC in scattering experiments with trapped or stored ions was discussed focusing on the cases with the largest calculated resonance strength. As the photons emitted in different channels of the electron recombination process are indistinguishable in the total cross section, the interference between NEEC followed by the radiative decay of the nucleus and radiative recombination was investigated. The angular distribution of the emitted photons in the recombination process provides means to discern the two processes. Angular differential cross sections for the emitted photons in the case of E2 nuclear transitions were presented for several heavy elements. (orig.)

  20. Electron and ion induced electron emission from metals and insulators

    CERN Document Server

    Steinbatz, M

    2001-01-01

    gradually exposed to oxygen as an experimental probe. The experimental data are fitted with an analytical model, that is able to describe the observed kinetics. The fit parameters give absolute values of sticking probabilities and of surface reaction rates. During oxidation of aluminum and magnesium also spontaneous emission of electrons (exoelectrons) is observed. This effect is quantitatively studied for different oxygen partial pressures. The experimental data also indicate a significant influence of the surface morphology on the exoemission process. An important consequence of atomic collisions in solids is ionization leading to electron ejection from the target atoms with subsequent migration through the solid. A certain fraction of these electrons finally reaches the surface and is ejected into vacuum. A standard measurement of this phenomenon is the observation of the particle (electron, ion) induced electron emission yield g, defined as the average number of ejected electrons per incoming projectile. ...

  1. Characteristic energy range of electron scattering due to plasmaspheric hiss

    Science.gov (United States)

    Ma, Q.; Li, W.; Thorne, R. M.; Bortnik, J.; Reeves, G. D.; Kletzing, C. A.; Kurth, W. S.; Hospodarsky, G. B.; Spence, H. E.; Baker, D. N.; Blake, J. B.; Fennell, J. F.; Claudepierre, S. G.; Angelopoulos, V.

    2016-12-01

    We investigate the characteristic energy range of electron flux decay due to the interaction with plasmaspheric hiss in the Earth's inner magnetosphere. The Van Allen Probes have measured the energetic electron flux decay profiles in the Earth's outer radiation belt during a quiet period following the geomagnetic storm that occurred on 7 November 2015. The observed energy of significant electron decay increases with decreasing L shell and is well correlated with the energy band corresponding to the first adiabatic invariant μ = 4-200 MeV/G. The electron diffusion coefficients due to hiss scattering are calculated at L = 2-6, and the modeled energy band of effective pitch angle scattering is also well correlated with the constant μ lines and is consistent with the observed energy range of electron decay. Using the previously developed statistical plasmaspheric hiss model during modestly disturbed periods, we perform a 2-D Fokker-Planck simulation of the electron phase space density evolution at L = 3.5 and demonstrate that plasmaspheric hiss causes the significant decay of 100 keV-1 MeV electrons with the largest decay rate occurring at around 340 keV, forming anisotropic pitch angle distributions at lower energies and more flattened distributions at higher energies. Our study provides reasonable estimates of the electron populations that can be most significantly affected by plasmaspheric hiss and the consequent electron decay profiles.

  2. The Jovian aurora: Electron or ion precipitation

    Science.gov (United States)

    Waite, J. H., Jr.; Clarke, J. T.; Cravens, T. E.

    1986-01-01

    High signal-to-noise spectra of the Jovian aurora at UV wavelengths obtained using the International Ultraviolet Explorer Observatory (including the brightest Jovian aurora observed to date) set strigent upper limits for sulfur and oxygen emissions, which would be associated with the precipitation of energetic heavy ions in the upper Jovian atmosphere if they were solely responsible for Jovian auroral processes. Model calculations of heavy ion precipitation and corresponding estimates of the associated sulfur and oxygen UV emissions previously carried out suggest emission values for 1304 A OI emission that are at least 30 times larger than the upper limit values set by the IUE observations reported. On the other hand the observed (feature of SII at 1256 A of 2 kR) is quite comparable to the theoretically predicted emission intensity. Taken together these observations and calculations suggest that electron as well as ion precipitation play a role in Jovian auroral processes. In light of earlier X-ray observations and in-situ plasma observations that suggest energetic heavy ion precipitation in the Jovian auroral zone, a scenario is suggested where heavy ion auroral energy deposition is concentrated at altitudes below the homopause. Electrons with energies of 10 to 30 keV are responsible for the bulk of the observable UV and EUV emissions since they deposit their energy above the methane absorbing layer defined by the homopause.

  3. Jovian aurora: electron or ion precipitation

    Energy Technology Data Exchange (ETDEWEB)

    Waite, J.H. Jr.; Clarke, J.T.; Cravens, T.E.

    1986-01-01

    High signal-to-noise spectra of the Jovian aurora at UV wavelengths obtained using the International Ultraviolet Explorer Observatory (including the brightest Jovian aurora observed to date) set strigent upper limits for sulfur and oxygen emissions, which would be associated with the precipitation of energetic heavy ions in the upper Jovian atmosphere if they were solely responsible for Jovian auroral processes. Model calculations of heavy ion precipitation and corresponding estimates of the associated sulfur and oxygen UV emissions previously carried out suggest emission values for 1304 A OI emission that are at least 30 times larger than the upper limit values set by the IUE observations reported. On the other hand the observed (feature of SII at 1256 A of 2 kR) is quite comparable to the theoretically predicted emission intensity. Taken together these observations and calculations suggest that electron as well as ion precipitation play a role in Jovian auroral processes. In light of earlier X-ray observations and in-situ plasma observations that suggest energetic heavy ion precipitation in the Jovian auroral zone, a scenario is suggested where heavy ion auroral energy deposition is concentrated at altitudes below the homopause. Electrons with energies of 10 to 30 keV are responsible for the bulk of the observable UV and EUV emissions since they deposit their energy above the methane absorbing layer defined by the homopause.

  4. Effects of target polarization in electron elastic scattering off endohedral A @C60

    Science.gov (United States)

    Dolmatov, V. K.; Amusia, M. Ya.; Chernysheva, L. V.

    2017-01-01

    We have developed an efficient approximation to describe the low-energy electron elastic scattering off an endohedral fullerene A @CN . It accounts for polarization of A @CN by incoming electrons without reference to complicated details of the electronic structure of CN itself. The developed approach has permitted us to unravel spectacular A @CN polarization effects in low-energy e-+A @CN elastic scattering, particularly the effects due to interelectron interaction between the electrons of both CN and A . We show that contribution of a single atom A remains unscreened by the multiatomic CN despite the fact that the projectile's wavelength is bigger than the size of the target. Inclusion of A and CN polarizability interference leads to violation of the previously predicted phase additivity rule. The partial scattering cross sections acquire prominent Ramsauer-type minima which, however, disappear in the total cross section. The study reveals notable trends in e-+A @CN elastic scattering versus the polarizability of an encapsulated atom. We also predict the existence of certain negative ions A @CN- . We chose Ne, Xe, and Ba as atoms A , and C60 as the endohedral CN, as the case study. The work focuses on a reasonable compromise between the qualitative and quantitative aspects of the problem in general rather than on carrying out detailed calculations for one particular system.

  5. An angle-sensitive detection system for scattered heavy ions

    CERN Document Server

    Ganz, R E; Bär, R; Bethge, Klaus; Bokemeyer, H; Folger, H; Samek, M; Salabura, P; Schwalm, D; Stiebing, K E

    1999-01-01

    A compact detection system for heavy ions scattered in collisions at the Coulomb barrier is presented. This system, consisting of four identical, low-pressure Parallel Plate Avalanche Counter (PPAC) modules with two sensitive layers each, was built to operate in an ultra-high-vacuum environment inside the EPoS II solenoid spectrometer at GSI Darmstadt. The detector covers polar angles between 20 deg. and 70 deg. with respect to the beam axis, and about 80% of 2 pi in azimuthal angle. Segmented cathodes and a delay-line read-out allow for a determination of both angles with a precision of delta THETA approx 0.7 deg. in polar and delta PHI approx 1.5 deg. in azimuthal angle, respectively. The system has been proven to be capable of handling instantaneous rates of up to 5x10 sup 5 detected ions per second per module. It neither exhibits the degradation of detection efficiency nor loss in resolution over a 500 h period of a 6 MeV/u sup 2 sup 3 sup 8 U+ sup 1 sup 8 sup 1 Ta measurement at average luminosities of 8...

  6. Neutron scattering effects on fusion ion temperature measurements.

    Energy Technology Data Exchange (ETDEWEB)

    Ziegler, Lee (Bechtel/Nevada, Las Vegas, NV); Starner, Jason R.; Cooper, Gary Wayne; Ruiz, Carlos L.; Franklin, James Kenneth (Ktech Corporation, Albuquerque, NM); Casey, Daniel T.

    2006-06-01

    To support the nuclear fusion program at Sandia National Laboratories (SNL), a consistent and verifiable method to determine fusion ion temperatures needs to be developed. Since the fusion temperature directly affects the width in the spread of neutron energies produced, a measurement of the neutron energy width can yield the fusion temperature. Traditionally, the spread in neutron energies is measured by using time-of-flight to convert a spread in neutron energies at the source to a spread in time at detector. One potential obstacle to using this technique at the Z facility at SNL is the need to shield the neutron detectors from the intense bremsstrahlung produced. The shielding consists of eight inches of lead and the concern is that neutrons will scatter in the lead, artificially broaden the neutron pulse width and lead to an erroneous measurement. To address this issue, experiments were performed at the University of Rochester's Laboratory for Laser Energetics, which demonstrated that a reliable ion temperature measurement can be achieved behind eight inches of lead shielding. To further expand upon this finding, Monte Carlo N-Particle eXtended (MCNPX) was used to simulate the experimental geometric conditions and perform the neutron transport. MCNPX was able to confidently estimate results observed at the University of Rochester.

  7. Ion Scattering in a Self-Consistent Cylindrical Plasma Sheath

    National Research Council Canada - National Science Library

    Figueroa, Shana S; Cooke, D. L; Gatsonis, Nikos A

    2005-01-01

    .... Results indicate that higher plasma shielding limits the range of impact parameters that experience significant scattering, and that attracted particles entering tangent to the sheath experience increased scattering...

  8. Electron-electron scattering in linear transport in two-dimensional systems

    DEFF Research Database (Denmark)

    Hu, Ben Yu-Kuang; Flensberg, Karsten

    1996-01-01

    We describe a method for numerically incorporating electron-electron scattering in quantum wells for small deviations of the distribution function from equilibrium, within the framework of the Boltzmann equation. For a given temperature T and density n, a symmetric matrix needs to be evaluated only...... once, and henceforth it can be used to describe electron-electron scattering in any Boltzmann equation linear-response calculation for that particular T and n. Using this method, we calculate the distribution function and mobility for electrons in a quantum well, including full finite...

  9. Fast-ion dynamics in the TEXTOR tokamak measured by collective Thomson scattering

    DEFF Research Database (Denmark)

    Bindslev, H.; Nielsen, S.K.; Porte, L.

    2006-01-01

    Here we present the first measurements by collective Thomson scattering of the evolution of fast-ion populations in a magnetically confined fusion plasma. 150 kW and 110 Ghz radiation from a gyrotron were scattered in the TEXTOR tokamak plasma with energetic ions generated by neutral beam injection...

  10. Electron paramagnetic resonance of transition ions

    CERN Document Server

    Abragam, A

    2012-01-01

    This book is a reissue of a classic Oxford text, and provides a comprehensive treatment of electron paramagnetic resonance of ions of the transition groups. The emphasis is on basic principles, with numerous references to publications containing further experimental results and more detailed developments of the theory. An introductory survey gives a general understanding, and a general survey presents such topics as the classical and quantum resonance equations, thespin-Hamiltonian, Endor, spin-spin and spin-lattice interactions, together with an outline of the known behaviour of ions of each

  11. The Effect of Nuclear Elastic Scattering on Temperature Equilibration Rate of Ions in Fusion Plasma

    Directory of Open Access Journals (Sweden)

    M. Mahdavi

    2014-01-01

    Full Text Available A plasma with two different particle types and at different temperatures has been considered, so that each type of ion with Maxwell-Boltzmann distribution function is in temperature equilibrium with itself. Using the extracted nuclear elastic scattering differential cross-section from experimental data, solving the Boltzmann equation, and also taking into account the mobility of the background particles, temperature equilibration rate between two different ions in a fusion plasma is calculated. The results show that, at higher temperature differences, effect of nuclear elastic scattering is more important in calculating the temperature equilibration rate. The obtained expressions have general form so that they are applicable to each type of particle for background (b and each type for projectile (p. In this paper, for example, an equimolar Deuterium-Hydrogen plasma with density n=5×1025 cm−3 is chosen in which the deuteron is the background particle with temperature (also electron temperature Tb=1 keV (usual conditions for a fusion plasma at the ignition instant and the proton is the projectile with temperature Tp>Tb. These calculations, particularly, are very important for ion fast ignition in inertial confinement fusion concept.

  12. Electron scattering by laser-excited barium atoms

    Science.gov (United States)

    Register, D. F.; Trajmar, S.; Jensen, S. W.; Poe, R. T.

    1978-01-01

    Inelastic and superelastic scattering of 30- and 100-eV electrons by laser-excited 6s 6p 1P and subsequent cascade-populated 6s 6p 3P, 6s 5d 1D, and 6s 5d 3D Ba atoms have been observed. Absolute differential cross sections for the singlet and relative scattering intensities for the triplet species have been determined in the 5 to 20 deg angular region. Under the present conditions excitations dominate over deexcitations.

  13. Polarized Parton Distributions at an Electron-Ion Collider

    CERN Document Server

    Ball, Richard D.; Guffanti, Alberto; Nocera, Emanuele R.; Ridolfi, Giovanni; Rojo, Juan

    2014-01-01

    We study the potential impact of inclusive deep-inelastic scattering data from a future electron-ion collider (EIC) on longitudinally polarized parton distribution (PDFs). We perform a PDF determination using the NNPDF methodology, based on sets of deep-inelastic EIC pseudodata, for different realistic choices of the electron and proton beam energies. We compare the results to our current polarized PDF set, NNPDFpol1.0, based on a fit to fixed-target inclusive DIS data. We show that the uncertainties on the first moments of the polarized quark singlet and gluon distributions are substantially reduced in comparison to NNPDFpol1.0, but also that more measurements may be needed to ultimately pin down the size of the gluon contribution to the nucleon spin.

  14. Analysis of incoherent scatter during ionospheric heating near the fifth electron gyrofrequency

    Science.gov (United States)

    Wu, Jun; Wu, Jian; Zhao, Haisheng; Xu, Zhengwen

    2017-04-01

    The observation of ultra-high frequency radar during an ionospheric heating experiment carried out at Tromsø site of European Incoherent Scatter Scientific Association, Norway, is analyzed. When pump is operating slightly above the fifth electron gyrofrequency, some strong enhancements in radar echo and electron density occur in a wide altitude range and are in sync with the shifting and spread of plasma line around the reflection altitude, which may be due to the focusing or collimating of radar wave by irregularities. While some strong enhancements in electron density and radar echo around the reflection altitude do not correspond to the true increase in electron density, but due to the enhanced ion acoustic wave by parametric decay instability and oscillation two stream instability. In addition, the different heating rates and cooling rates at the pump frequencies below, around and above fifth gyrofrequency respectively result in the dependence of the enhancements in electron temperature on the pump frequency.

  15. Measurements of Relativistic Effects in Collective Thomson Scattering at Electron Temperatures less than 1 keV

    Energy Technology Data Exchange (ETDEWEB)

    Ross, James Steven [Univ. of California, San Diego, CA (United States)

    2010-01-01

    Simultaneous scattering from electron-plasma waves and ion-acoustic waves is used to measure local laser-produced plasma parameters with high spatiotemporal resolution including electron temperature and density, average charge state, plasma flow velocity, and ion temperature. In addition, the first measurements of relativistic modifications in the collective Thomson scattering spectrum from thermal electron-plasma fluctuations are presented [1]. Due to the high phase velocity of electron-plasma fluctuations, relativistic effects are important even at low electron temperatures (Te < 1 keV). These effects have been observed experimentally and agree well with a relativistic treatment of the Thomson scattering form factor [2]. The results are important for the interpretation of scattering measurements from laser produced plasmas. Thomson scattering measurements are used to characterize the hydrodynamics of a gas jet plasma which is the foundation for a broad series of laser-plasma interaction studies [3, 4, 5, 6]. The temporal evolution of the electron temperature, density and ion temperature are measured. The measured electron density evolution shows excellent agreement with a simple adiabatic expansion model. The effects of high temperatures on coupling to hohlraum targets is discussed [7]. A peak electron temperature of 12 keV at a density of 4.7 × 1020cm-3 are measured 200 μm outside the laser entrance hole using a two-color Thomson scattering method we developed in gas jet plasmas [8]. These measurements are used to assess laser-plasma interactions that reduce laser hohlraum coupling and can significantly reduce the hohlraum radiation temperature.

  16. Raman scattering of photons by the channeling electrons

    Science.gov (United States)

    Badreeva, D. R.; Kalashnikov, N. P.

    2017-07-01

    The motion of channeling particles in the accompanying coordinate system can be considered as a two-dimensional atom in the case of axial channeling. The transversal motion of the channeling particles is characterized by discrete spectrum. The occupation probability of the transversal motion levels depends on the entrance angle of the charged particles relative to the crystallographic axis. In the scattering of a photon by the ;quasi-bound; electron moving in the axial channeling regime would appear the frequencies ω which are a combination of the incident photon frequency ω0 and the frequency ωNM (ωNM is the transition frequency in transverse quantized motion of the channeling electron: ω =ω0 ±ωMN , where ℏωMN = 2γ2 ΔE⊥NM for the relativistic electron, γ2 = E / (mc2) is the Lorentz factor of the channeling electron). In the article are discussed the criteria for choosing an adequate continuous potential of the crystallographic axis and the quantum characteristics of a transversal motion of the channeling electron. The peculiarities of the Raman scattering spectrum of photons by electrons in the axial channeling regime are analyzed and the differential cross section of this process is found.

  17. Inclusive quasielastic scattering of polarized electrons from polarized nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Amaro, J.E. [Massachusetts Inst. of Tech., Cambridge, MA (United States). Center for Theoretical Physics]|[Universidad de Granada (Spain). Dept. de Fisica Moderna]|[Massachusetts Inst. of Tech., Cambridge, MA (United States). Lab. for Nuclear Science]|[Massachusetts Inst. of Tech., Cambridge, MA (United States). Dept. of Physics; Caballero, J.A. [Consejo Superior de Investigaciones Cientificas (CSIC), Madrid (Spain). Inst. de Estructura de la Materia]|[Sevilla Univ. (Spain). Dept. de Fisica Atomica, Molecular y Nuclear; Donnelly, T.W. [Massachusetts Inst. of Tech., Cambridge, MA (United States). Center for Theoretical Physics]|[Massachusetts Inst. of Tech., Cambridge, MA (United States). Lab. for Nuclear Science]|[Massachusetts Inst. of Tech., Cambridge, MA (United States). Dept. of Physics; Moya de Guerra, E. [Consejo Superior de Investigaciones Cientificas (CSIC), Madrid (Spain). Inst. de Estructura de la Materia

    1996-12-23

    The inclusive quasielastic response functions that appear in the scattering of polarized electrons from polarized nuclei are computed and analyzed for several closed-shell-minus-one nuclei with special attention paid to {sup 39}K. Results are presented using two models for the ejected nucleon - when described by a distorted wave in the continuum shell model or by a plane wave in PWIA with on- and off-shell nucleons. Relativistic effects in kinematics and in the electromagnetic current have been incorporated throughout. Specifically, the recently obtained expansion of the electromagnetic current in powers only of the struck nucleon`s momentum is employed for the on-shell current and the effects of the first-order terms (spin-orbit and convection) are compared with the zeroth-order (charge and magnetization) contributions. The use of polarized inclusive quasielastic electron scattering as a tool for determining near-valence nucleon momentum distributions is discussed. (orig.).

  18. Quasielastic electron-deuteron scattering in the weak binding approximation

    Energy Technology Data Exchange (ETDEWEB)

    Ethier, Jacob J. [William and Mary College, JLAB; Doshi, Nidhi P. [Carnegie Mellon University; Malace, Simona P. [JLAB; Melnitchouk, Wally [JLAB

    2014-06-01

    We perform a global analysis of all available electron-deuteron quasielastic scattering data using Q^2-dependent smearing functions that describe inclusive inelastic e-d scattering within the weak binding approximation. We study the dependence of the cross sections on the deuteron wave function and the off-shell extrapolation of the elastic electron-nucleon cross section, which show particular sensitivity at x >> 1. The excellent overall agreement with data over a large range of Q^2 and x suggest a limited need for effects beyond the impulse approximation, with the exception of the very high-x or very low-Q^2 regions, where short-distance effects in the deuteron become more relevant.

  19. Total cross sections for positron and electron scattering from pyrimidine

    Energy Technology Data Exchange (ETDEWEB)

    Zecca, A; Chiari, L; Trainotti, E [Department of Physics, University of Trento, Povo, I-38123, Trento (Italy); GarcIa, G [Instituto de Matematicas y FIsica Fundamental, Consejo Superior de Investigaciones Cientificas, Serrano 121, 28006 Madrid (Spain); Blanco, F [Departamento de FIsica Atomica Molecular y Nuclear, Facultad de Ciencias FIsicas, Universidad Complutense, Avda. Complutense s/n, E-28040 Madrid (Spain); Brunger, M J, E-mail: michael.brunger@flinders.edu.a [ARC Centre for Antimatter-Matter Studies, School of Chemical and Physical Sciences, Flinders University, GPO Box 2100, Adelaide, South Australia 5001 (Australia)

    2010-11-14

    In this paper we report original measurements of total cross sections for positron scattering from the important biomolecule pyrimidine. The energy range of these measurements was 0.3-45 eV, while the energy resolution was {approx}260 meV. In addition, we report theoretical results, calculated within the independent atom-screened additivity rule (IAM-SCAR) formalism, for the corresponding electron impact total cross sections. In that case the energy range is 1-10 000 eV. Total cross sections are very important input data for codes that seek to simulate charged-particle tracks in matter, as they define the mean-free path between collisions. As the present data and computations are to the best of our knowledge the first total cross sections to be reported for either positron or electron scattering from pyrimidine, they fill an important void in our available knowledge in the literature.

  20. Electron Scattering on a Magnetic Skyrmion in the Nonadiabatic Approximation.

    Science.gov (United States)

    Denisov, K S; Rozhansky, I V; Averkiev, N S; Lähderanta, E

    2016-07-08

    We present a theory of electron scattering on a magnetic Skyrmion for the case when the exchange interaction is moderate so that the adiabatic approximation and the Berry phase approach are not applicable. The theory explains the appearance of a topological Hall current in the systems with magnetic Skyrmions, the special importance of which is its applicability to dilute magnetic semiconductors with a weak exchange interaction.

  1. Electron scattering in graphene with adsorbed NaCl nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Drabińska, Aneta, E-mail: Aneta.Drabinska@fuw.edu.pl; Kaźmierczak, Piotr; Bożek, Rafał; Karpierz, Ewelina; Wysmołek, Andrzej; Kamińska, Maria [Faculty of Physics, University of Warsaw, Pasteura 5, 02-093 Warsaw (Poland); Wołoś, Agnieszka [Faculty of Physics, University of Warsaw, Pasteura 5, 02-093 Warsaw (Poland); Institute of Physics, Polish Academy of Sciences, Al. Lotników 32/46, 02-668 Warsaw (Poland); Pasternak, Iwona; Strupiński, Włodek [Institute of Electronic Materials Technology, Wólczyńska 133, 01-919 Warsaw (Poland); Krajewska, Aleksandra [Institute of Electronic Materials Technology, Wólczyńska 133, 01-919 Warsaw (Poland); Institute of Optoelectronics, Military University of Technology, Kaliskiego 2, 00-908 Warsaw (Poland)

    2015-01-07

    In this work, the results of contactless magnetoconductance and Raman spectroscopy measurements performed for a graphene sample after its immersion in NaCl solution were presented. The properties of the immersed sample were compared with those of a non-immersed reference sample. Atomic force microscopy and electron spin resonance experiments confirmed the deposition of NaCl nanoparticles on the graphene surface. A weak localization signal observed using contactless magnetoconductance showed the reduction of the coherence length after NaCl treatment of graphene. Temperature dependence of the coherence length indicated a change from ballistic to diffusive regime in electron transport after NaCl treatment. The main inelastic scattering process was of the electron-electron type but the major reason for the reduction of the coherence length at low temperatures was additional, temperature independent, inelastic scattering. We associate it with spin flip scattering, caused by NaCl nanoparticles present on the graphene surface. Raman spectroscopy showed an increase in the D and D′ bands intensities for graphene after its immersion in NaCl solution. An analysis of the D, D′, and G bands intensities proved that this additional scattering is related to the decoration of vacancies and grain boundaries with NaCl nanoparticles, as well as generation of new on-site defects as a result of the decoration of the graphene surface with NaCl nanoparticles. The observed energy shifts of 2D and G bands indicated that NaCl deposition on the graphene surface did not change carrier concentration, but reduced compressive biaxial strain in the graphene layer.

  2. Neutrino electron scattering and left-right symmetry: future tests

    OpenAIRE

    Miranda, O. G.; Semikoz, Victor B.; Furtado Valle, José Wagner

    1998-01-01

    Low-energy high-resolution neutrino-electron scattering experiments may play an important role in testing the gauge structure of the electroweak interaction. We propose the use of radioactive neutrino sources (e.g. $^{51}$Cr) in underground experiments such as BOREXINO and HELLAZ as a probe of the weak neutral current structure. As an illustration, we display the sensitivity of these detectors in testing the possible existence of right-handed weak neutral currents.

  3. Spin correlation tensor for measurement of quantum entanglement in electron-electron scattering

    Science.gov (United States)

    Tsurikov, D. E.; Samarin, S. N.; Williams, J. F.; Artamonov, O. M.

    2017-04-01

    We consider the problem of correct measurement of a quantum entanglement in the two-body electron-electron scattering. An expression is derived for a spin correlation tensor of a pure two-electron state. A geometric measure of a quantum entanglement as the distance between two forms of this tensor in entangled and separable cases is presented. Due to such definition, one does not need to look for the closest separable state to the analyzed state. We prove that introduced measure satisfies properties of a valid entanglement measure: nonnegativity, discriminance, normalization, non-growth under local operations and classical communication. This measure is calculated for a problem of electron-electron scattering. We prove that it does not depend on the azimuthal rotation angle of the second electron spin relative to the first electron spin before scattering. We specify how to find a spin correlation tensor and the related measure of a quantum entanglement in an experiment with electron-electron scattering. Finally, the introduced measure is extended to the mixed states.

  4. The prospect for fuel ion ratio measurements in ITER by collective Thomson scattering

    DEFF Research Database (Denmark)

    Stejner Pedersen, Morten; Korsholm, Søren Bang; Nielsen, Stefan Kragh

    2012-01-01

    We show that collective Thomson scattering (CTS) holds the potential to become a new diagnostic principle for measurements of the fuel ion ratio, nT/nD, in ITER. Fuel ion ratio measurements will be important for plasma control and machine protection in ITER. Measurements of ion cyclotron structur...

  5. Dynamics of fast ions during sawtooth oscillations in the TEXTOR tokamak measured by collective Thomson scattering

    DEFF Research Database (Denmark)

    Nielsen, Stefan Kragh; Salewski, Mirko; Bindslev, Henrik

    2011-01-01

    Experimental investigations of sawteeth interaction with fast ions measured by collective Thomson scattering on TEXTOR are presented. Time-resolved measurements of localized 1D fast-ion distribution functions allow us to study fast-ion dynamics during several sawtooth cycles. Sawtooth oscillation...

  6. Collective Thomson scattering measurements of fast-ion transport due to sawtooth crashes in ASDEX Upgrade

    DEFF Research Database (Denmark)

    Rasmussen, Jesper; Nielsen, Stefan Kragh; Pedersen, Morten Stejner

    2016-01-01

    . Here we present the first collective Thomson scattering (CTS) measurements of sawtooth-induced redistribution of fast ions at ASDEX Upgrade. These also represent the first localized fast-ion measurements on the high-field side of this device. The results indicate fast-ion losses in the phase...

  7. 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

  8. New electron multiple scattering distributions for Monte Carlo transport simulation

    Energy Technology Data Exchange (ETDEWEB)

    Chibani, Omar (Haut Commissariat a la Recherche (C.R.S.), 2 Boulevard Franz Fanon, Alger B.P. 1017, Alger-Gare (Algeria)); Patau, Jean Paul (Laboratoire de Biophysique et Biomathematiques, Faculte des Sciences Pharmaceutiques, Universite Paul Sabatier, 35 Chemin des Maraichers, 31062 Toulouse cedex (France))

    1994-10-01

    New forms of electron (positron) multiple scattering distributions are proposed. The first is intended for use in the conditions of validity of the Moliere theory. The second distribution takes place when the electron path is so short that only few elastic collisions occur. These distributions are adjustable formulas. The introduction of some parameters allows impositions of the correct value of the first moment. Only positive and analytic functions were used in constructing the present expressions. This makes sampling procedures easier. Systematic tests are presented and some Monte Carlo simulations, as benchmarks, are carried out. ((orig.))

  9. The Jovian Aurora - Electron or ion precipitation?

    Science.gov (United States)

    Waite, J. H., Jr.; Clarke, J. T.; Cravens, T. E.; Hammond, C. M.

    1988-01-01

    High signal-to-noise spectra of the Jovian aurora obtained at 1200 to 1500 A by the IUE Observatory were examined for the existence of sulfur and oxygen emissions that would be expected if the UV emissions were produced by precipitating heavy ions. The results of these measurements and subsequent spectral modeling, using a model of heavy aurora constructed by Horanyi et al. (1988), showed mixed evidence of the oxygen and sulfur emissions. It was noted that only the UV emissions which are produced above the UV absorbing hydrocarbon layer were observed by the IUE and Voyager UV spectrometers. This fact, combined with the recent observations of the longitudinal distribution of the Jovian UV aurora, indicates that electrons as well as ions play a role in Jovian auroral processes. Based on the observations, it is suggested that heavy-ion auroral energy deposition is concentrated at altitudes below the homopause, while electrons with energies of 10 to 30 keV are responsible for the bulk of the observable UV and EUV emissions.

  10. Stimulated Brillouin scattering during electron gyro-harmonic heating at EISCAT

    Directory of Open Access Journals (Sweden)

    H. Y. Fu

    2015-08-01

    Full Text Available Observations of secondary radiation, stimulated electromagnetic emission (SEE, produced during ionospheric modification experiments using ground-based, high-power, high-frequency (HF radio waves are considered. The High Frequency Active Auroral Research Program (HAARP facility is capable of generating narrowband SEE in the form of stimulated Brillouin scatter (SBS and stimulated ion Bernstein scatter (SIBS in the SEE spectrum. Such narrowband SEE spectral lines have not been reported using the European Incoherent Scatter (EISCAT heater facility before. This work reports the first EISCAT results of narrowband SEE spectra and compares them to SEE previously observed at HAARP during electron gyro-harmonic heating. An analysis of experimental SEE data shows observations of emission lines within 100 Hz of the pump frequency, interpreted as SBS, during the 2012 July EISCAT campaign. Experimental results indicate that SBS strengthens as the pump frequency approaches the third electron gyro-harmonic. Also, for different heater antenna beam angles, the CUTLASS radar backscatter induced by HF radio pumping is suppressed near electron gyro-harmonics, whereas electron temperature enhancement weakens as measured by EISCAT/UHF radar. The main features of these new narrowband EISCAT observations are generally consistent with previous SBS measurements at HAARP.

  11. Heavy Ion Injection Into Synchrotrons, Based On Electron String Ion Sources

    CERN Document Server

    Donets, E E; Syresin, E M

    2004-01-01

    A possibility of heavy ions injection into synchrotrons is discussed on the base of two novel ion sources, which are under development JINR during last decade: 1) the electron string ion source (ESIS), which is a modified version of a conventional electron beam ion source (EBIS), working in a reflex mode of operation, and 2) the tubular electron string ion source (TESIS). The Electron String Ion Source "Krion-2" (VBLHE, JINR, Dubna) with an applied confining magnetic field of 3 T was used for injection into the superconducting JINR synchrotron - Nuclotron and during this runs the source provided a high pulse intensity of the highly charged ion beams: Ar16+

  12. The Jovian aurora: Electron or ion precipitation

    Energy Technology Data Exchange (ETDEWEB)

    Waite, J.H., Jr. (NASA Marshall Space Flight Center, Huntsville, AL (USA)); Clarke, J.T. (NASA Goddard Space Flight Center, Greenbelt, MD (USA)); Cravens, T.E. (Univ. of Michigan, Ann Arbor (USA)); Hammond, C.M. (Univ. of California, Los Angeles (USA))

    1988-07-01

    High signal-to-noise spectra of the Jovian aurora at UV wavelengths obtained using the International Ultraviolet Explorer Observatory (including the brightest Jovian aurora observed to date) are used to study the existence of sulfur and oxygen emissions which would be associated with the precipitation of energetic heavy ions in the upper Jovian atmosphere. Model calculations of heavy ion precipitation and corresponding estimates of the associated sulfur and oxygen UV emissions carried out in the preceding companion paper of Horanyi et al. suggest emission values for 1,304-{angstrom} O I emission that are at least 50 times larger than the upper limit values set by the IUE observations reported here. On the other hand a possible emission feature of S II at 1,256 {angstrom} is comparable to the theoretically predicted emission intensity. Earlier X ray observations and in situ plasma observations have indicated the existence of energetic heavy ion precipitation in the Jovian auroral zone. Based on the IUE observations reported here, the authors suggest a scenario where heavy ion auroral energy deposition is concentrated at altitudes below the homopause (i.e. > 300 keV/nucleon) and electrons with energies of 10 to 30 keV are responsible for the bulk of the observable UV and EUV emissions since they deposit their energy above the methane-absorbing layer defined by the homopause.

  13. Electron Bubbles in Superfluid $^3$He-A: Exploring the Quasiparticle-Ion Interaction

    OpenAIRE

    Shevtsov, Oleksii; Sauls, J. A.

    2016-01-01

    When an electron is forced into liquid $^3$He it forms an "electron bubble", a heavy ion with radius, $R\\simeq 1.5$ nm, and mass, $M\\simeq 100\\,m_3$, where $m_3$ is the mass of a $^3$He atom. These negative ions have proven to be powerful local probes of the physical properties of the host quantum fluid, especially the excitation spectra of the superfluid phases. We recently developed a theory for Bogoliubov quasiparticles scattering off electron bubbles embedded in a chiral superfluid that p...

  14. Parity Violation in Forward Angle Elastic Electron-Proton Scattering

    Energy Technology Data Exchange (ETDEWEB)

    Miller, IV, Grady Wilson [Princeton Univ., NJ (United States)

    2001-01-01

    We have measured the parity-violating electroweak asymmetry in the elastic scattering of polarized electrons from the proton at Jefferson Laboratory. The kinematic point (θlab = 12.3 deg. and (Q2) = 0.48 (GeV/c)2) is chosen to provide sensitivity to the strange electric form factor GsE. A 3.36 GeV beam of longitudinally polarized electrons was scattered from protons in a liquid hydrogen target. The scattered flux was detected by a pair of spectrometers which focussed the elastically-scattered electrons onto total-absorption detectors. The detector signals were integrated and digitized by a custom data acquisition system. A feedback system reduced systematic errors by controlling helicity-correlated beam intensity differences at the sub-ppm (part per million) level. The experimental result, A = 14.5 +/- 2.0 (stat) ± 1.1 (syst) ppm, is consistent with the electroweak Standard Model with no additional contributions from strange quarks. In particular, the measurement implies GSE + 0.39 GsM = 0.023 ± 0.040 ± 0.026 (ζGnE), where the last uncertainty is due to the estimated uncertainty in the neutron electric form factor GnE . This result represents the first experimental constraint of the strange electric form factor.

  15. Understanding charge transfer of Li+ and Na+ ions scattered from metal surfaces with high work function

    Science.gov (United States)

    Chen, Lin; Wu, Wen-Bin; Liu, Pin-Yang; Xiao, Yun-Qing; Li, Guo-Peng; Liu, Yi-Ran; Jiang, Hao-Yu; Guo, Yan-Ling; Chen, Xi-Meng

    2016-08-01

    For Li+ and Na+ ions scattered from high work function metal surfaces, efficient neutralization is observed, and it cannot be explained by the conventional free electron model. In order to explain these experimental data, we investigate the velocity-dependent neutral fraction with the modified Brako-Newns (BN) model. The calculated results are in agreement with the experimental data. We find that the parallel velocity effect plays an important role in neutralizing the Li+ and Na+ ions for large angle scattering. The nonmonotonic velocity behavior of neutral fraction is strongly related to the distance-dependent coupling strength between the atomic level and metal states. Project supported by the National Natural Science Foundation of China (Grant Nos. 11405078 and 11474140), the Fundamental Research Funds for the Central Universities, China (Grant Nos. lzujbky-2014-169 and lzujbky-2015-244), the Project sponsored by the Scientific Research Foundation for the Returned Overseas Chinese Scholars, the State Education Ministry, and the National Students’ Innovation and Entrepreneurship Training Program (Grant Nos. 201410730069 and 201510730078).

  16. Quantum interferences induced by multiple scattering paths of the electron prior to emission in large molecules

    Science.gov (United States)

    Agueny, H.; Makhoute, A.; Tökési, K.; Dubois, A.; Hansen, J. P.

    2017-09-01

    We theoretically investigate electron emission process from a dimer generated by swift highly charged ions. The process under consideration is dealt with a non-perturbative approach by solving the time-dependent Schrödinger equation on a two-dimensional spatial grid. Numerical calculations show rich structures related to the multiple scattering paths of the electron prior to emission. This manifests by the emergence of additional oscillations with high-frequency superimposed on the Young-type oscillatory structure in the observed electron-ejected spectrum. This is not the case when calculations are performed based on the superposition principle, in which the final wave function is just a coherent sum of component wave functions described the electron emission from two-independent atoms. Within this assumption, only a direct electron emission process is taken into account. We find that contributions arising from these multiple scattering paths modify the dynamic electron emission process, and therefore, show the incorrect applicability of the above-mentioned principle, in concordance with the recent findings based on a simple three-slit interference experiment, reported in Sawant et al. (2014).

  17. Distinguishing attosecond electron-electron scattering and screening in transition metals

    Science.gov (United States)

    Chen, Cong; Tao, Zhensheng; Carr, Adra; Matyba, Piotr; Szilvási, Tibor; Emmerich, Sebastian; Piecuch, Martin; Keller, Mark; Zusin, Dmitriy; Eich, Steffen; Rollinger, Markus; You, Wenjing; Mathias, Stefan; Thumm, Uwe; Mavrikakis, Manos; Aeschlimann, Martin; Oppeneer, Peter M.; Kapteyn, Henry; Murnane, Margaret

    2017-07-01

    Electron-electron interactions are the fastest processes in materials, occurring on femtosecond to attosecond timescales, depending on the electronic band structure of the material and the excitation energy. Such interactions can play a dominant role in light-induced processes such as nano-enhanced plasmonics and catalysis, light harvesting, or phase transitions. However, to date it has not been possible to experimentally distinguish fundamental electron interactions such as scattering and screening. Here, we use sequences of attosecond pulses to directly measure electron-electron interactions in different bands of different materials with both simple and complex Fermi surfaces. By extracting the time delays associated with photoemission we show that the lifetime of photoelectrons from the d band of Cu are longer by ˜100 as compared with those from the same band of Ni. We attribute this to the enhanced electron-electron scattering in the unfilled d band of Ni. Using theoretical modeling, we can extract the contributions of electron-electron scattering and screening in different bands of different materials with both simple and complex Fermi surfaces. Our results also show that screening influences high-energy photoelectrons (≈20 eV) significantly less than low-energy photoelectrons. As a result, high-energy photoelectrons can serve as a direct probe of spin-dependent electron-electron scattering by neglecting screening. This can then be applied to quantifying the contribution of electron interactions and screening to low-energy excitations near the Fermi level. The information derived here provides valuable and unique information for a host of quantum materials.

  18. Diagnosis of energetic ions and ion composition in fusion plasmas by collective Thomson scattering of mm-waves

    DEFF Research Database (Denmark)

    Bindslev, Henrik; Korsholm, Søren Bang; Leipold, Frank

    2012-01-01

    distributions in fusion plasmas1,2. A beam of mm-waves with a diameter of 5–10 cm and a power of 150–600 kW is sent through the plasma, and radiation scattered from this probe beam by the microscopic fluctuations in the plasma is detected. These microscopic fluctuations are in part induced by the ion motion......In fusion plasmas, the dominant heating source will be fusion generated energetic ions slowing down in the plasma. The same ions can also drive waves and instabilities in the plasma. Their distribution in velocity and in space has major impact on plasma dynamics, and plasma dynamics in turn affects...... the energetic ion distributions. The dynamics of energetic ions is thus important to measure in order to understand fusion plasmas, and important to monitor as part of input to plasma control. The collective Thomson scattering of millimeter waves has proven to be a valuable means of diagnosing energetic ion...

  19. Dissociative and non-dissociative electron capture by keV diatomic molecular ions from noble gases

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, Nora G; Sayler, A M; McKenna, J; Gaire, B; Zohrabi, M; Berry, Ben; Carnes, K D; Ben-Itzhak, I [J. R. Macdonald Laboratory, Physics Department, Kansas State University, Manhattan, KS 66506 (United States); Wolff, Wania, E-mail: ibi@phys.ksu.ed [Instituto de Fisica, Universidade Federal do Rio de Janeiro, Rio de Janeiro, 21945-970, RJ (Brazil)

    2009-11-01

    Dissociative and non-dissociative electron capture from atoms by slow molecular ions were investigated by measuring in coincidence the momenta of the recoil ion and the projectile or its fragment pair. From these momenta we evaluate the reaction Q-value as well as the scattering angles. For the dissociative capture we also determine the alignment dependence of the process.

  20. Parity-Violating Electron Scattering: New Results and Future Prospects

    Energy Technology Data Exchange (ETDEWEB)

    Krishna S. Kumar

    2006-11-01

    We discuss the status and prospects of an experimental program of parity-violating asymmetry measurements in the scattering of longitudinally polarized electrons off unpolarized fixed targets. One thrust is the measurements of nucleon neutral weak form factors at intermediate four-momentum transfer (0.1 < Q2 < 1) (GeV/c)2 which provide information about the role of virtual strange quarks on the charge and current distributions inside nucleons. A new topic is the elastic neutral weak amplitude from scattering off a heavy spinless nucleus, which is sensitive to the presence of a neutron skin. Finally, we discuss the neutral current elastic amplitude at very low Q2, which allows precision measurements of the weak mixing angle at low energy and is thus sensitive to new physics at the TeV scale. The physics implications of recent results, potential measurements from experiments under construction as well as new ideas at future facilities are discussed.

  1. Multiple scattering of slow muons in an electron gas

    Science.gov (United States)

    Archubi, Claudio Darío; Arista, Nestor R.

    2017-09-01

    A comparative study of the angular dispersion of slow muons in an electron gas is performed using three dielectric models which represent the case of metals (Lindhard model for a free electron gas) and the cases of semiconductors and insulators (Levine and Louie model and Brandt and Reinheimer model for systems with a band gap) and a non-linear model for both cases at very low velocities. The contribution of collective electronic excitations according to the dielectric model are found to be negligible. The results from the calculation using Lindhard expressions for the angular half width are coincident with the result of a multiple scattering model. In particular, the effects produced by the band gap of the material are analyzed in detail. Finally, as the recoil effect is negligible, there is an almost exact scaling, for a given velocity, between the proton and the muon results.

  2. Experimental system of ejected electron spectroscopy with ECR ion source

    Energy Technology Data Exchange (ETDEWEB)

    Kitazawa, Sin-iti [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    1995-09-01

    The experiment of analyzing energy spectrum of electrons ejected from multiple electron capture process on ion-atom collision is carried out using ECR (Electron Cyclotron Resonance) ion source. An old collision system using gas atoms as target and a new system using vapour atoms are developed. In this report, the developments and exploitations of the experimental systems for the ejected electron spectroscopy with ECR Ion source are presented. (author).

  3. Electron-atom potential scattering assisted by a bichromatic elliptically polarized laser field

    Science.gov (United States)

    Korajac, Arman; Habibović, Dino; Čerkić, Aner; Busuladžić, Mustafa; Milošević, Dejan B.

    2017-10-01

    Electron-atom potential scattering assisted by a bichromatic (two-component) elliptically polarized laser field is analyzed in the frame of the S-matrix theory. The second Born approximation is applied in the expansion of the S-matrix element. The first term in the expansion corresponds to the single scattering, while the second term in the expansion corresponds to the double scattering of electrons on atomic targets. The double scattering is possible in the presence of a laser field. The electron that has scattered on an atomic target may be driven back by the laser field and scatter again on the same atom. The double-scattered electrons may have considerably higher energies than those that scattered only once. We have investigated the dependence of the energy spectrum on various laser-field and incident electron parameters. The calculated electron energy spectra show the plateau-like structures with abrupt cutoffs. These cutoffs are explained by a classical analysis.

  4. Fast Ion Dynamics in ASDEX Upgrade and TEXTOR Measured by Collective Thomson Scattering

    DEFF Research Database (Denmark)

    Moseev, Dmitry

    Fast ions are an essential ingredient in burning nuclear fusion plasmas: they are responsible for heating the bulk plasma, carry a significant amount of plasma current and moreover interact with various magnetohydrodynamic (MHD) instabilities. The collective Thomson scattering (CTS) diagnostic...

  5. Plasma rotation and ion temperature measurements by collective Thomson scattering at ASDEX Upgrade

    DEFF Research Database (Denmark)

    Stejner Pedersen, Morten; Nielsen, Stefan Kragh; Jacobsen, Asger Schou

    2015-01-01

    We present the first deuterium ion temperature and rotation measurements by collective Thomson scattering at ASDEX Upgrade. The results are in general agreement with boron-based charge exchange recombination spectroscopy measurements and consistent with neoclassical simulations for the plasma...

  6. Electron energy recovery system for negative ion sources

    Science.gov (United States)

    Dagenhart, W.K.; Stirling, W.L.

    1979-10-25

    An electron energy recovery system for negative ion sources is provided. The system, employing crossed electric and magnetic fields, separates the electrons from the ions as they are extracted from the ion source plasma generator and before the ions are accelerated to their full energy. With the electric and magnetic fields oriented 90/sup 0/ to each other, the electrons remain at approximately the electrical potential at which they were generated. The electromagnetic forces cause the ions to be accelerated to the full accelerating supply voltage energy while being deflected through an angle of less than 90/sup 0/. The electrons precess out of the accelerating field region into an electron recovery region where they are collected at a small fraction of the full accelerating supply energy. It is possible, by this method, to collect > 90% of the electrons extracted along with the negative ions from a negative ion source beam at energy.

  7. Dielectronic recombination measurements at EBIT (Electron Beam Ion Trap)

    Energy Technology Data Exchange (ETDEWEB)

    Knapp, D.A.

    1990-10-04

    The Electron Beam Ion Trap at the Lawrence Livermore National Laboratory has proved an ideal device for the study of interactions between electrons and highly-charged ions. I describe measurements of one such interaction, dielectronic recombination, in several ion species. The results are in marginal agreement with theoretical predictions. 8 refs., 6 figs.

  8. Electron Scattering at Surfaces and Interfaces of Transition Metals

    Science.gov (United States)

    Zheng, Pengyuan

    The effect of surfaces on the electron transport at reduced scales is attracting continuous interest due to its broad impact on both the understanding of materials properties and their application for nanoelectronics. The size dependence of for conductor's electrical resistivity rho due to electron surface scattering is most commonly described within the framework of Fuchs and Sondheimer (FS) and their various extensions, which uses a phenomenological scattering parameter p to define the probability of electrons being elastically (i.e. specularly) scattered by the surface without causing an increase of rho at reduced size. However, a basic understanding of what surface chemistry and structure parameters determine the specularity p is still lacking. In addition, the assumption of a spherical Fermi surface in the FS model is too simple for transition metals to give accurate account of the actual surface scattering effect. The goal of this study is to develop an understanding of the physics governing electron surface/interface scattering in transition metals and to study the significance of their Fermi surface shape on surface scattering. The advancement of the scientific knowledge in electron surface and interface scattering of transition metals can provide insights into how to design high-conductivity nanowires that will facilitate the viable development of advanced integrated circuits, thermoelectric power generation and spintronics. Sequential in situ and ex situ transport measurements as a function of surface chemistry demonstrate that electron surface/interface scattering can be engineered by surface doping, causing a decrease in the rho. For instance, the rho of 9.3-nm-thick epitaxial and polycrystalline Cu is reduced by 11--13% when coated with 0.75 nm Ni. This is due to electron surface scattering which exhibits a specularity p = 0.7 for the Cu-vacuum interface that transitions to completely diffuse (p = 0) when exposed to air. In contrast, Ni-coated surfaces

  9. Fast ion millimeter wave collective Thomson scattering diagnostics on TEXTOR and ASDEX upgrades

    DEFF Research Database (Denmark)

    Michelsen, S.; Korsholm, Søren Bang; Bindslev, H.

    2004-01-01

    Collective Thomson scattering (CTS) diagnostic systems for measuring fast ions in TEXTOR and ASDEX Upgrade are described in this article. Both systems use millimeter waves generated by gyrotrons as probing radiation and the scattered radiation is detected with heterodyne receivers having 40...

  10. Dynamics of electron-capture-to-continuum (ECC) formation in slow ion-atom collisions

    Energy Technology Data Exchange (ETDEWEB)

    Afaneh, F [Physics Department, The Hashemite University, PO Box 150459, Zarqa 13115 (Jordan); Schmidt, L Ph H [Institut fuer Kernphysik, Max-von-Laue-Str. 1, 60438 Frankfurt (Germany); Schoeffler, M [Institut fuer Kernphysik, Max-von-Laue-Str. 1, 60438 Frankfurt (Germany); Stiebing, K E [Institut fuer Kernphysik, Max-von-Laue-Str. 1, 60438 Frankfurt (Germany); Al-Jundi, J [Physics Department, The Hashemite University, PO Box 150459, Zarqa 13115 (Jordan); Schmidt-Boecking, H [Institut fuer Kernphysik, Max-von-Laue-Str. 1, 60438 Frankfurt (Germany); Doerner, R [Institut fuer Kernphysik, Max-von-Laue-Str. 1, 60438 Frankfurt (Germany)

    2007-05-28

    The zero-degree ejected-electron spectrum for protons incident on He at 25 keV is examined experimentally using the COLTRIMS technique. The momentum distribution of the emitted electrons for the transfer ionization (TI) reaction channel is measured in coincidence with the momentum vectors of the recoil ion and the scattered projectile. The momentum distribution of the electrons emitted around zero degree in the forward direction for the TI reaction channel shows two prominent structures: the electron-capture-to-the-continuum (ECC) peak and the saddle-point peak. From the measured fully differential electron emission cross sections with respect to the scattering plane we can deduce that the main ECC formation mechanism is electron promotion via quasimolecular orbitals.

  11. Terrestrial effects on dark matter-electron scattering experiments

    DEFF Research Database (Denmark)

    Emken, Timon; Kouvaris, Chris; Shoemaker, Ian M.

    2017-01-01

    techniques involving detection of dark matter-electron scattering offer new sensitivity to sub-GeV dark matter. Typically however it is implicitly assumed that the dark matter is not altered as it traverses the Earth to arrive at the detector. In this paper we study in detail the effects of terrestrial...... stopping on dark photon models of dark matter, and find that they significantly reduce the sensitivity of XENON10 and DAMIC. In particular we find that XENON10 only excludes masses in the range (5-3000) MeV while DAMIC only probes (20-50) MeV. Their corresponding cross section sensitivity is reduced...

  12. Ion Acoustic Waves in the Presence of Electron Plasma Waves

    DEFF Research Database (Denmark)

    Michelsen, Poul; Pécseli, Hans; Juul Rasmussen, Jens

    1977-01-01

    Long-wavelength ion acoustic waves in the presence of propagating short-wavelength electron plasma waves are examined. The influence of the high frequency oscillations is to decrease the phase velocity and the damping distance of the ion wave.......Long-wavelength ion acoustic waves in the presence of propagating short-wavelength electron plasma waves are examined. The influence of the high frequency oscillations is to decrease the phase velocity and the damping distance of the ion wave....

  13. Monte Carlo calculation of large and small-angle electron scattering in air

    Science.gov (United States)

    Cohen, B. I.; Higginson, D. P.; Eng, C. D.; Farmer, W. A.; Friedman, A.; Grote, D. P.; Larson, D. J.

    2017-11-01

    A Monte Carlo method for angle scattering of electrons in air that accommodates the small-angle multiple scattering and larger-angle single scattering limits is introduced. The algorithm is designed for use in a particle-in-cell simulation of electron transport and electromagnetic wave effects in air. The method is illustrated in example calculations.

  14. Electronic Raman scattering and the renormalization of the electron spectrum in LuB{sub 12}

    Energy Technology Data Exchange (ETDEWEB)

    Ponosov, Yu. S., E-mail: ponosov@imp.uran.ru; Streltsov, S. V., E-mail: streltsov@gmail.com [Russian Academy of Sciences, Institute of Metal Physics, Ural Branch (Russian Federation); Levchenko, A. V.; Filippov, V. B. [National Academy of Sciences of Ukraine, Frantsevich Institute of Materials Science Problems (Ukraine)

    2016-09-15

    The electronic Raman scattering in LuB{sub 12} single crystals of various isotope compositions is studied in the temperature range 10–650 K. The shape and the energy position of spectral maxima depend on the direction and magnitude of a probe wavevector, the temperature, and the excitation symmetry and remain unchanged when the isotope composition changes. Experimental spectra are compared with the spectra simulated on the basis of a calculated electronic structure. The experimental results are successfully described when the electron spectrum renormalization effects caused by electron–phonon coupling are taken into account. This confirms that the origin of the observed spectra in LuB{sub 12} is due to Raman scattering by electrons. A comparison of the calculated and experimental data makes it possible to determine the coupling constant (λ{sub ep} = 0.32) that gives the correct superconducting transition temperature.

  15. Nuclear isospin mixing and elastic parity-violating electron scattering

    Energy Technology Data Exchange (ETDEWEB)

    Moreno, O. [Instituto de Estructura de la Materia, CSIC, Serrano 123, E-28006 Madrid (Spain); Sarriguren, P. [Instituto de Estructura de la Materia, CSIC, Serrano 123, E-28006 Madrid (Spain)], E-mail: sarriguren@iem.cfmac.csic.es; Moya de Guerra, E.; Udias, J.M. [Departamento de Fisica Atomica, Molecular y Nuclear, Universidad Complutense de Madrid, E-28040 Madrid (Spain); Donnelly, T.W. [Center for Theoretical Physics, Laboratory for Nuclear Science and Department of Physics, Massachusetts Institute of Technology, Cambridge, MA 02139 (United States); Sick, I. [Departement fuer Physik, Universitaet Basel, CH-4056 Basel (Switzerland)

    2009-09-15

    The influence of nuclear isospin mixing on parity-violating elastic electron scattering is studied for the even-even, N=Z nuclei {sup 12}C, {sup 24}Mg, {sup 28}Si, and {sup 32}S. Their ground-state wave functions have been obtained using a self-consistent axially-symmetric mean-field approximation with density-dependent effective two-body Skyrme interactions. Some differences from previous shell-model calculations appear for the isovector Coulomb form factors which play a role in determining the parity-violating asymmetry. To gain an understanding of how these differences arise, the results have been expanded in a spherical harmonic oscillator basis. Results are obtained not only within the plane-wave Born approximation, but also using the distorted-wave Born approximation for comparison with potential future experimental studies of parity-violating electron scattering. To this end, for each nucleus the focus is placed on kinematic ranges where the signal (isospin-mixing effects on the parity-violating asymmetry) and the experimental figure-of-merit are maximized. Strangeness contributions to the asymmetry are also briefly discussed, since they and the isospin mixing contributions may play comparable roles for the nuclei being studied at the low momentum transfers of interest in the present work.

  16. Review of two-photon exchange in electron scattering

    Energy Technology Data Exchange (ETDEWEB)

    J. Arrington, P. G. Blunden, W. Melnitchouk

    2011-10-01

    We review the role of two-photon exchange (TPE) in electron-hadron scattering, focusing in particular on hadronic frameworks suitable for describing the low and moderate Q^2 region relevant to most experimental studies. We discuss the effects of TPE on the extraction of nucleon form factors and their role in the resolution of the proton electric to magnetic form factor ratio puzzle. The implications of TPE on various other observables, including neutron form factors, electroproduction of resonances and pions, and nuclear form factors, are summarized. Measurements seeking to directly identify TPE effects, such as through the angular dependence of polarization measurements, nonlinear epsilon contributions to the cross sections, and via e+p to e-p cross section ratios, are also outlined. In the weak sector, we describe the role of TPE and gamma-Z interference in parity-violating electron scattering, and assess their impact on the extraction of the strange form factors of the nucleon and the weak charge of the proton.

  17. Electron scattering from neon via effective range theory

    Energy Technology Data Exchange (ETDEWEB)

    Fedus, Kamil, E-mail: kamil@fizyka.umk.pl [Institute of Physics, Faculty of Physics, Astronomy and Informatics, Nicolaus Copernicus University, Torun (Poland)

    2014-07-01

    Elastic cross-sections for electron scattering on neon from 0 energy up to 16 eV are analyzed by an analytical approach to the modified effective range theory (MERT). It is shown that energy and angular variations of elastic differential, integral and momentum transfer cross sections can be accurately parameterized by six MERT coefficients up to the energy threshold for the first Feshbach resonance. MERT parameters are determined empirically by numerical comparison with large collection of available experimental data of elastic total (integral) cross-sections. The present analysis is validated against numerous electron beams and swarm experiments. The comparison of derived MERT parameters with those found for other noble gases, helium, argon and krypton, is done. The derived scattering length (for the s-partial wave) in neon, 0.227a0, agrees well with recent theories; it is small but, differently from Ar and Kr, still positive. Analogue parameters for the p-wave and the d-wave are negative and positive respectively for all the four gases compared. (author)

  18. Low-energy-electron scattering by CH3CN

    Science.gov (United States)

    Maioli, Leticia S.; Bettega, Márcio H. F.

    2017-12-01

    We report integral and differential cross sections for the elastic scattering of low-energy electrons by methyl cyanide (CH3CN), also known as acetonitrile. The cross sections were computed using the Schwinger multichannel method implemented with pseudopotentials. The fixed-nuclei scattering calculations were performed in the static-exchange and static-exchange plus polarization approximations for energies up to 15 eV. In our calculations with polarization effects, we found a π * shape resonance at around 2.22 eV and a broad structure associated to a σ * shape resonance at around 7 eV. The low-lying resonance was assigned to the electron capture by the two-fold degenerate π * orbital of the E symmetry of C 3 v group; the second was assigned to a σ * shape resonance in the A 1 symmetry. We compared our cross sections with theoretical results and experimental data available in the literature, and in general we found good agreement for the positions of the two resonances.

  19. Measurements of Intrinsic Ion Bernstein Waves in a Tokamak by Collective Thomson Scattering

    DEFF Research Database (Denmark)

    Korsholm, Søren Bang; Stejner Pedersen, Morten; Bindslev, Henrik

    2011-01-01

    In this Letter we report measurements of collective Thomson scattering (CTS) spectra with clear signatures of ion Bernstein waves and ion cyclotron motion in tokamak plasmas. The measured spectra are in accordance with theoretical predictions and show clear sensitivity to variation in the density...

  20. Antenna design for fast ion collective Thomson scattering diagnostic for the international thermonuclear experimental reactor

    DEFF Research Database (Denmark)

    Leipold, Frank; Furtula, Vedran; Salewski, Mirko

    2009-01-01

    Fast ion physics will play an important role for the international thermonuclear experimental reactor (ITER), where confined alpha particles will affect and be affected by plasma dynamics and thereby have impacts on the overall confinement. A fast ion collective Thomson scattering (CTS) diagnostic...

  1. Temporal evolution of confined fast-ion velocity distributions measured by collective Thomson scattering in TEXTOR

    DEFF Research Database (Denmark)

    Nielsen, Stefan Kragh; Bindslev, Henrik; Porte, L.

    2008-01-01

    Fast ions created in the fusion processes will provide up to 70% of the heating in ITER. To optimize heating and current drive in magnetically confined plasmas insight into fast-ion dynamics is important. First measurements of such dynamics by collective Thomson scattering (CTS) were recently...

  2. A United Effort for Crystal Growth, Neutron Scattering, and X-ray Scattering Studies of Novel Correlated Electron Materials

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Young S. [Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States)

    2015-02-12

    The research accomplishments during the award involved experimental studies of correlated electron systems and quantum magnetism. The techniques of crystal growth, neutron scattering, x-ray scattering, and thermodynamic & transport measurements were employed, and graduate students and postdoctoral research associates were trained in these techniques.

  3. Ion age transport: developing devices beyond electronics

    Science.gov (United States)

    Demming, Anna

    2014-03-01

    There is more to current devices than conventional electronics. Increasingly research into the controlled movement of ions and molecules is enabling a range of new technologies. For example, as Weihua Guan, Sylvia Xin Li and Mark Reed at Yale University explain, 'It offers a unique opportunity to integrate wet ionics with dry electronics seamlessly'. In this issue they provide an overview of voltage-gated ion and molecule transport in engineered nanochannels. They cover the theory governing these systems and fabrication techniques, as well as applications, including biological and chemical analysis, and energy conversion [1]. Studying the movement of particles in nanochannels is not new. The transport of materials in rock pores led Klinkenberg to describe an analogy between diffusion and electrical conductivity in porous rocks back in 1951 [2]. And already in 1940, Harold Abramson and Manuel Gorin noted that 'When an electric current is applied across the living human skin, the skin may be considered to act like a system of pores through which transfer of substances like ragweed pollen extract may be achieved both by electrophoretic and by diffusion phenomena' [3]. Transport in living systems through pore structures on a much smaller scale has attracted a great deal of research in recent years as well. The selective transport of ions and small organic molecules across the cell membrane facilitates a number of functions including communication between cells, nerve conduction and signal transmission. Understanding these processes may benefit a wide range of potential applications such as selective separation, biochemical sensing, and controlled release and drug delivery processes. In Germany researchers have successfully demonstrated controlled ionic transport through nanopores functionalized with amine-terminated polymer brushes [4]. The polymer nanobrushes swell and shrink in response to changes in temperature, thus opening and closing the nanopore passage to ionic

  4. Interaction of 3d transition metal atoms with charged ion projectiles from Electron Nuclear Dynamics computation

    Science.gov (United States)

    Hagelberg, Frank

    2003-03-01

    Computational results on atomic scattering between charged projectiles and transition metal target atoms are presented. This work aims at obtaining detailed information about charge, spin and energy transfer processes that occur between the interacting particles. An in-depth understanding of these phenomena is expected to provide a theoretical basis for the interpretation of various types of ion beam experiments, ranging from gas phase chromatography to spectroscopic observations of fast ions in ferromagnetic media. This contribution focuses on the scattering of light projectiles ranging from He to O, that are prepared in various initial charge states, by 3d transition metal atoms. The presented computations are performed in the framework of Electron Nuclear Dynamics (END)^1 theory which incorporates the coupling between electronic and nuclear degrees of freedom without reliance on the computationally cumbersome and frequently intractable determination of potential energy surfaces. In the present application of END theory to ion - transition metal atom scattering, a supermolecule approach is utilized in conjunction with a spin-unrestricted single determinantal wave function describing the electronic system. Integral scattering, charge and spin exchange cross sections are discussed as functions of the elementary parameters of the problem, such as projectile and target atomic numbers as well as projectile charge and initial kinetic energy. ^1 E.Deumens, A.Diz, R.Longo, Y.Oehrn, Rev.Mod.Phys. 66, 917 (1994)

  5. Principles of fuel ion ratio measurements in fusion plasmas by collective Thomson scattering

    DEFF Research Database (Denmark)

    Stejner Pedersen, Morten; Nielsen, Stefan Kragh; Bindslev, Henrik

    2011-01-01

    For certain scattering geometries collective Thomson scattering (CTS) measurements are sensitive to the composition of magnetically confined fusion plasmas. CTS therefore holds the potential to become a new diagnostic for measurements of the fuel ion ratio—i.e. the tritium to deuterium density...... ratio. Measurements of the fuel ion ratio will be important for plasma control and machine protection in future experiments with burning fusion plasmas. Here we examine the theoretical basis for fuel ion ratio measurements by CTS. We show that the sensitivity to plasma composition is enhanced...

  6. Effects of elastic and inelastic scattering in giving electrons tortuous paths in matter.

    Science.gov (United States)

    Turner, J E; Hamm, R N

    1995-09-01

    Heavy charged particles travel in essentially straight lines in matter, while electrons travel in tortuous paths. Frequent multiple elastic Coulomb scattering by atomic nuclei is often cited as the reason for this electron behavior. Heavy charged particles also undergo multiple Coulomb scattering. However, because they are massive, significant deflections occur only in rare, close encounters with nuclei. In contrast to heavy particles, the inelastic interaction of an electron with an atomic electron represents a collision with a particle of equal mass. In principle, therefore, repeated inelastic scattering of an electron can also produce large-angle deflections and thus contribute to the tortuous nature of an electron's track. To investigate the relative importance of elastic and inelastic scattering on determining the appearance of electron tracks, detailed Monte Carlo transport computations have been carried out for monoenergetic pencil beams of electrons normally incident on a water slab with initial energies from 1 keV to 1 MeV. The calculations have been performed with deflections due to (1) inelastic scattering only, (2) elastic scattering only, and (3) both types of scattering. Results are presented to show the spreading of the pencil beams with depth in the slab, the transmission through slabs of different thicknesses, and back-scattering from the slab. The results show that elastic nuclear scattering is indeed the principal physical process that causes electron paths to be tortuous; however, the smaller effect of inelastic electronic scattering is far from negligible.

  7. Fast ion dynamics in ASDEX upgrade and TEXTOR measured by collective Thomson scattering

    Energy Technology Data Exchange (ETDEWEB)

    Moseev, D.

    2011-11-15

    Fast ions are an essential ingredient in burning nuclear fusion plasmas: they are responsible for heating the bulk plasma, carry a significant amount of plasma current and moreover interact with various magnetohydrodynamic (MHD) instabilities. The collective Thomson scattering (CTS) diagnostic is sensitive to the projection of fast ion velocity distribution function. This thesis is mainly devoted to investigations of fast ion physics in tokamak plasmas by means of CTS. (Author)

  8. Electron Scattering From a High-Momentum Neutron in Deuterium

    Energy Technology Data Exchange (ETDEWEB)

    Klimenko, Alexei [Old Dominion Univ., Norfolk, VA (United States)

    2004-05-01

    The deuterium nucleus is a system of two nucleons (proton and neutron) bound together. The configuration of the system is described by a quantum-mechanical wave function and the state of the nucleons at a given time is not know a priori. However, by detecting a backward going proton of moderate momentum in coincidence with a reaction taking place on the neutron in deuterium, the initial state of that neutron can be inferred if we assume that the proton was a spectator to the reaction. This method, known as spectator tagging, was used to study the electron scattering from high-momentum neutrons in deuterium. The data were taken with a 5.765 GeV polarized electron beam on a deuterium target in Jefferson Laboratory's Hall B, using the CLAS detector. The accumulated data cover a wide kinematic range, reaching values of the invariant mass of the unobserved final state W* up to 3 GeV. A data sample of approximately 5 - 105 events, with protons detected at large scattering angles (as high as 136 degrees) in coincidence with the forward electrons, was selected. The product of the neutron structure function with the initial nucleon momentum distribution F2n. S was extracted for different values of W*, backward proton momenta ps and momentum transfer Q2. The data were compared to a calculation based on the spectator approximation and using the free nucleon form factors and structure functions. A strong enhancement in the data, not reproduced by the model, was observed at cos(thetapq) > -0.3 (where theta{sub pq} is the proton scattering angle relative to the direction of the momentum transfer) and can be associated with the contribution of final state interactions (FSI) that were not incorporated into the model. The bound nucleon structure function F2n was studied in the region cos(thetapq) < -0.3 as a function of W* and scaling variable x*. At high spectator proton momenta the struck neutron is

  9. Electron-molecule scattering in a strong laser field: Two-center interference effects

    Science.gov (United States)

    Dakić, J.; Habibović, D.; Čerkić, A.; Busuladžić, M.; Milošević, D. B.

    2017-10-01

    Laser-assisted scattering of electrons on diatomic molecules is considered using the S -matrix theory within the second Born approximation. The first term of the expansion in powers of the scattering potential corresponds to the direct or single laser-assisted scattering of electrons on molecular targets, while the second term of this expansion corresponds to the laser-assisted rescattering or double scattering. The rescattered electrons may have considerably higher energies in the final state than those that scattered only once. For multicenter polyatomic molecules scattering and rescattering may happen at any center and in any order. All these cases contribute to the scattering amplitude and the interference of different contributions leads to an increase or a decrease of the differential cross section in particular electron energy regions. For diatomic molecules there are two such contributions for single scattering and four contributions for double scattering. Analyzing the spectra of the scattered electrons, we find two interesting effects. For certain molecular orientations, the plateaus in the electron energy spectrum, characteristic of laser-assisted electron-atom scattering, are replaced by a sequence of gradually declining maxima, caused by the two-center interference effects. The second effect is the appearance of symmetric U -shaped structures in the angle-resolved energy spectra, which are described very well by the analytical formulas we provide.

  10. Electron impact phenomena and the properties of gaseous ions

    CERN Document Server

    Field, F H; Massey, H S W; Brueckner, Keith A

    1970-01-01

    Electron Impact Phenomena and the Properties of Gaseous Ions, Revised Edition deals with data pertaining to electron impact and to molecular gaseous ionic phenomena. This book discusses electron impact phenomena in gases at low pressure that involve low-energy electrons, which result in ion formation. The text also describes the use of mass spectrometers in electron impact studies and the degree of accuracy obtained when measuring electron impact energies. This book also reviews relatively low speed electrons and the transitions that result in the ionization of the atomic system. This text the

  11. Monte Carlo techniques for scattering foil design and dosimetry in total skin electron irradiations.

    Science.gov (United States)

    Ye, Sung-Joon; Pareek, Prem N; Spencer, Sharon; Duan, Jun; Brezovich, Ivan A

    2005-06-01

    Total skin electron irradiation (TSEI) with single fields requires large electron beams having good dose uniformity, dmax at the skin surface, and low bremsstrahlung contamination. To satisfy these requirements, energy degraders and scattering foils have to be specially designed for the given accelerator and treatment room. We used Monte Carlo (MC) techniques based on EGS4 user codes (BEAM, DOSXYZ, and DOSRZ) as a guide in the beam modifier design of our TSEI system. The dosimetric characteristics at the treatment distance of 382 cm source-to-surface distance (SSD) were verified experimentally using a linear array of 47 ion chambers, a parallel plate chamber, and radiochromic film. By matching MC simulations to standard beam measurements at 100 cm SSD, the parameters of the electron beam incident on the vacuum window were determined. Best match was achieved assuming that electrons were monoenergetic at 6.72 MeV, parallel, and distributed in a circular pattern having a Gaussian radial distribution with full width at half maximum = 0.13 cm. These parameters were then used to simulate our TSEI unit with various scattering foils. Two of the foils were fabricated and experimentally evaluated by measuring off-axis dose uniformity and depth doses. A scattering foil, consisting of a 12 x 12 cm2 aluminum plate of 0.6 cm thickness and placed at isocenter perpendicular to the beam direction, was considered optimal. It produced a beam that was flat within +/-3% up to 60 cm off-axis distance, dropped by not more than 8% at a distance of 90 cm, and had an x-ray contamination of irradiations.

  12. Reactive scattering of electronically excited alkali atoms with molecules

    Energy Technology Data Exchange (ETDEWEB)

    Mestdagh, J.M.; Balko, B.A.; Covinsky, M.H.; Weiss, P.S.; Vernon, M.F.; Schmidt, H.; Lee, Y.T.

    1987-06-01

    Representative families of excited alkali atom reactions have been studied using a crossed beam apparatus. For those alkali-molecule systems in which reactions are also known for ground state alkali and involve an early electron transfer step, no large differences are observed in the reactivity as Na is excited. More interesting are the reactions with hydrogen halides (HCl): it was found that adding electronic energy into Na changes the reaction mechanism. Early electron transfer is responsible of Na(5S, 4D) reactions, but not of Na(3P) reactions. Moreover, the NaCl product scattering is dominated by the HCl/sup -/ repulsion in Na(5S, 4D) reactions, and by the NaCl-H repulsion in the case of Na(3P). The reaction of Na with O/sub 2/ is of particular interest since it was found to be state specific. Only Na(4D) reacts, and the reaction requires restrictive constraints on the impact parameter and the reactants' relative orientation. The reaction with NO/sub 2/ is even more complex since Na(4D) leads to the formation of NaO by two different pathways. It must be mentioned however, that the identification of NaO as product in these reactions has yet to be confirmed.

  13. [Inelastic electron scattering from surfaces]. [Annual] progress report

    Energy Technology Data Exchange (ETDEWEB)

    1993-10-01

    This program is aimed at the quantitative study of surface dynamical processes (vibrational, magnetic excitations) in crystalline slabs, ultrathin-layered materials, and chemisorbed systems on substrates, and of the geometric structure connected to these dynamical excitations. High-resolution electron-energy loss spectroscopy (HREELS) is a powerful probe. Off-specular excitation cross sections are much larger if electron energies are in the LEED range (50-300 eV). The analyses has been used to study surfaces of ordered alloys (NiAl). Ab-initio surface lattice dynamical results were combined with phonon-loss cross sections to achieve a more accurate microscopic description. First-principles phonon eigenvectors and eigenfrequencies were used as inputs to electron-energy-loss multiple scattering cross-section calculations. The combined microscopic approach was used to analyze EELS data of Cu(0001) and Ag(001) at two points. Positron diffraction is discussed as a structural and imaging tool. The relation between geometric structure of a film and its local magnetic properties will be studied in the future, along with other things.

  14. Electron capture by highly charged ions from surfaces and gases

    Energy Technology Data Exchange (ETDEWEB)

    Allen, F.

    2008-01-11

    In this study highly charged ions produced in Electron Beam Ion Traps are used to investigate electron capture from surfaces and gases. The experiments with gas targets focus on spectroscopic measurements of the K-shell x-rays emitted at the end of radiative cascades following electron capture into Rydberg states of Ar{sup 17+} and Ar{sup 18+} ions as a function of collision energy. The ions are extracted from an Electron Beam Ion Trap at an energy of 2 keVu{sup -1}, charge-selected and then decelerated down to 5 eVu{sup -1} for interaction with an argon gas target. For decreasing collision energies a shift to electron capture into low orbital angular momentum capture states is observed. Comparative measurements of the K-shell x-ray emission following electron capture by Ar{sup 17+} and Ar{sup 18+} ions from background gas in the trap are made and a discrepancy in the results compared with those from the extraction experiments is found. Possible explanations are discussed. For the investigation of electron capture from surfaces, highly charged ions are extracted from an Electron Beam Ion Trap at energies of 2 to 3 keVu{sup -1}, charge-selected and directed onto targets comprising arrays of nanoscale apertures in silicon nitride membranes. The highly charged ions implemented are Ar{sup 16+} and Xe{sup 44+} and the aperture targets are formed by focused ion beam drilling in combination with ion beam assisted thin film deposition, achieving hole diameters of 50 to 300 nm and aspect ratios of 1:5 to 3:2. After transport through the nanoscale apertures the ions pass through an electrostatic charge state analyzer and are detected. The percentage of electron capture from the aperture walls is found to be much lower than model predictions and the results are discussed in terms of a capillary guiding mechanism. (orig.)

  15. Hot electron attenuation of direct and scattered carriers across an epitaxial Schottky interface

    NARCIS (Netherlands)

    Parui, S.; Klandermans, P. S.; Venkatesan, S.; Scheu, C.; Banerjee, T.

    2013-01-01

    Hot electron transport of direct and scattered carriers across an epitaxial NiSi2/n-Si(111) interface, for different NiSi2 thickness, is studied using ballistic electron emission microscopy (BEEM). We find the BEEM transmission for the scattered hot electrons in NiSi2 to be significantly lower than

  16. Non-Maxwellian Electron Velocity Distributions Observed with Thomson Scattering in the Tortur Tokamak

    NARCIS (Netherlands)

    van Lammeren, A. C. A. P.; Barth, C. J.; Vanest, Q. C.; Schüller, F. C.

    1992-01-01

    The Thomson scattering spectrum represents the projection of the three-dimensional electron velocity distribution on the scattering vector. From this the local electron temperature and density can be derived. To determine the three-dimensional electron velocity distribution it is necessary to have

  17. Measurements of scattering processes in negative ion-atom collisions. Technical progress report, 1 September 1991--31 August 1992

    Energy Technology Data Exchange (ETDEWEB)

    Kvale, T.J.

    1992-04-01

    This Technical Progress Report describes the progress made on the research objectives during the past twelve months. This research project is designed to provide measurements of various scattering processes which occur in H{sup {minus}} collisions with atomic (specifically, noble gas and atomic hydrogen) targets at intermediate energies. These processes include: elastic scattering,single- and double-electron detachment, and target excitation/ionization. For the elastic and target inelastic processes where H{sup {minus}} is scattered intact, the experimental technique of Ion Energy-Loss Spectroscopy (IELS) will be employed to identify the final target state(s). In most of the above processes, cross sections are unknown both experimentally and theoretically. The measurements in progress will provide either experimentally-determined cross sections or set upper limits to those cross sections. In either case, these measurements will be stringent tests of our understanding in energetic negative ion-atom collisions. This series of experiments required the construction of a new facility and the initial ion beam was accelerated through the apparatus in April 1991.

  18. Cosmological hydrogen recombination: influence of resonance and electron scattering

    Science.gov (United States)

    Chluba, J.; Sunyaev, R. A.

    2009-08-01

    In this paper we consider the effects of resonance and electron scattering on the escape of Lyman α photons during cosmological hydrogen recombination. We pay particular attention to the influence of atomic recoil, Doppler boosting, and Doppler broadening using a Fokker-Planck approximation of the redistribution function describing the scattering of photons on the Lyman α resonance of moving hydrogen atoms. We extend the computations of our recent paper on the influence of the 3d/3s-1s two-photon channels on the dynamics of hydrogen recombination, simultaneously including the full time dependence of the problem, the thermodynamic corrections factor, leading to a frequency-dependent asymmetry between the emission and absorption profile, and the quantum-mechanical corrections related to the two-photon nature of the 3d/3s-1s emission and absorption process on the exact shape of the Lyman α emission profile. We show here that, because of the redistribution of photons over frequency hydrogen recombination is sped up by Δ N_e/ Ne ~ -0.6% at z ~ 900. For the CMB temperature and polarization power spectra, this results in |Δ C_l/C_l| ~ 0.5-1% at ly ⪆ 1500, which is in turn important for analyzing future CMB data in the context of the Planck Surveyor, Spt, and Act. The main contribution to this correction comes from the atomic recoil effect (Δ N_e/ Ne ~ -1.2% at z ~ 900), while Doppler boosting and Doppler broadening partially cancel this correction, again slowing hydrogen recombination down by Δ N_e/ Ne ~ 0.6% at z ~ 900. The influence of electron scattering close to the maximum of the Thomson visibility function at z ~ 1100 can be neglected. We also give the cumulative results, in addition including the time-dependent correction, the thermodynamic factor, and the correct shape of the emission profile. This amounts to Δ N_e/ Ne ~ -1.8% at z ~ 1160 and |Δ C_l/C_l| ~ 1-3% at l ⪆ 1500.

  19. Cooling force on ions in a magnetized electron plasma

    Directory of Open Access Journals (Sweden)

    Hrachya B. Nersisyan

    2013-07-01

    Full Text Available Electron cooling is a well-established method to improve the phase space quality of ion beams in storage rings. In the common rest frame of the ion and the electron beam, the ion is subjected to a drag force and it experiences a loss or a gain of energy which eventually reduces the energy spread of the ion beam. A calculation of this process is complicated as the electron velocity distribution is anisotropic and the cooling process takes place in a magnetic field which guides the electrons. In this paper the cooling force is calculated in a model of binary collisions (BC between ions and magnetized electrons, in which the Coulomb interaction is treated up to second order as a perturbation to the helical motion of the electrons. The calculations are done with the help of an improved BC theory which is uniformly valid for any strength of the magnetic field and where the second-order two-body forces are treated in the interaction in Fourier space without specifying the interaction potential. The cooling force is explicitly calculated for a regularized and screened potential which is both of finite range and less singular than the Coulomb interaction at the origin. Closed expressions are derived for monochromatic electron beams, which are folded with the velocity distributions of the electrons and ions. The resulting cooling force is evaluated for anisotropic Maxwell velocity distributions of the electrons and ions.

  20. Intrabeam scattering of lead ion LHC type bunches in the SPS

    CERN Document Server

    Vos, L

    1997-01-01

    The classical theory of intrabeam scattering by A. Piwinski [1] has been successfully applied in the past to the Sp S [2] for dense proton and anti-proton bunches. The particle radius is an important ingredient in the scattering process. This parameter becomes very large for heavy ions compared with the radius of protons and intrabeam scattering rates may become troublesome even for modest bunch populations. The injection momentum of the LHC type lead ion bunches will be below transition in the SPS. Applying the theory and computing the growth rates may produce results that are not obvious at first sight. This paper tries to shed some light on the processes involved so that the computed growth rates are less cause for wonder. It does not propose any new element in the theory but only emphasizes a few aspects to clarify intrabeam scattering of relatively dense particle beams below transition.

  1. Electron Acoustic Waves in Pure Ion Plasmas

    Science.gov (United States)

    Anderegg, F.; Affolter, M.; Driscoll, C. F.; O'Neil, T. M.; Valentini, F.

    2012-10-01

    Electron Acoustic Waves (EAWs) are the low-frequency branch of near-linear Langmuir (plasma) waves: the frequency is such that the complex dielectric function (Dr, Di) has Dr= 0; and ``flattening'' of f(v) near the wave phase velocity vph gives Di=0 and eliminates Landau damping. Here, we observe standing axisymmetric EAWs in a pure ion column.footnotetextF. Anderegg, et al., Phys. Rev. Lett. 102, 095001 (2009). At low excitation amplitudes, the EAWs have vph˜1.4 v, in close agreement with near-linear theory. At moderate excitation strengths, EAW waves are observed over a range of frequencies, with 1.3 v vphvph.footnotetextF. Valentini et al., arXiv:1206.3500v1. Large amplitude EAWs have strong phase-locked harmonic content, and experiments will be compared to same-geometry simulations, and to simulations of KEENfootnotetextB. Afeyan et al., Proc. Inertial Fusion Sci. and Applications 2003, A.N.S. Monterey (2004), p. 213. waves in HEDLP geometries.

  2. Angle-differential elastic electron scattering off Mn

    Science.gov (United States)

    Dolmatov, V. K.

    2017-11-01

    Angle-differential elastic electron-scattering cross section, d/σ d Ω , for a 20-eV electron collision with a half-filled-subshell Mn (...3 d54 s2,6S) atom is studied using a semiempirical static polarization potential of the atom in the calculations. The study is in order, primarily due to noticeable discrepancies between results of the only two existing experimental measurements of the differential cross section, as well as discrepancies between the experimental results and available theoretical data. The calculation of d/σ d Ω is performed in the framework of the spin-polarized Hartree-Fock approximation modified by the addition of the Bates static polarization potential Vpol(r ) into the equations. An element of the study is the utilization of individual static dipole polarizabilities, α4 s ↑ and α4 s ↓, of the 4 s electrons with opposite spin orientations (4 s ↑ and 4 s ↓ electrons) from the atomic 4 s2 subshell. They are calculated and used for the subsequent calculation of Vpol(r ) and, finally, d/σ d Ω . The utility of the model is proven by a good agreement between the results of a trial calculation of d/σ d Ω and corresponding trial calculated results obtained in the framework of a sophisticated random phase approximation with exchange. The results of the subsequent final calculation of d/σ d Ω are compared with the experimental data along with the available theoretical results obtained in the framework of a spin-polarized local density approximation. Renewed theoretical and experimental studies of the 20-eV d/σ d Ω of Mn are urged.

  3. Resonances in low-energy electron elastic scattering from Fullerenes C60 through C92

    Science.gov (United States)

    Felfli, Zineb; Msezane, Alfred

    2017-04-01

    The electron affinity (EA) provides a stringent test of theory when the calculated and measured EAs are compared. A strong motivation for the fundamental investigations of low-energy electron elastic scattering from the selected fullerenes C60, C70, C74, C80, C82, C84 and C92 is the availability of high quality measured EAs. The Regge pole calculated electron elastic total cross sections for these fullerenes are found to be characterized generally by Ramsauer-Townsend (R-T) minima, shape resonances and dramatically sharp resonances manifesting stable negative ion formation. The extracted binding energies for the resultant anions agree excellently with the measured EAs of the fullerenes listed above, giving great credence to the Regge pole method and confirming that fullerenes behave like ``big atoms''. Common among all these fullerenes is the appearance of their ground state negative ions at their second R-T minima, similarly to the atomic Au case. This work was supported by U.S. DOE, Basic Energy Sciences, Office of Energy Research.

  4. Angular scattering of 1-50 keV ions through graphene and thin carbon foils: potential applications for space plasma instrumentation.

    Science.gov (United States)

    Ebert, Robert W; Allegrini, Frédéric; Fuselier, Stephen A; Nicolaou, Georgios; Bedworth, Peter; Sinton, Steve; Trattner, Karlheinz J

    2014-03-01

    We present experimental results for the angular scattering of ~1-50 keV H, He, C, O, N, Ne, and Ar ions transiting through graphene foils and compare them with scattering through nominal ~0.5 μg cm(-2) carbon foils. Thin carbon foils play a critical role in time-of-flight ion mass spectrometers and energetic neutral atom sensors in space. These instruments take advantage of the charge exchange and secondary electron emission produced as ions or neutral atoms transit these foils. This interaction also produces angular scattering and energy straggling for the incident ion or neutral atom that acts to decrease the performance of a given instrument. Our results show that the angular scattering of ions through graphene is less pronounced than through the state-of-the-art 0.5 μg cm(-2) carbon foils used in space-based particle detectors. At energies less than 50 keV, the scattering angle half width at half maximum, ψ(1/2), for ~3-5 atoms thick graphene is up to a factor of 3.5 smaller than for 0.5 μg cm(-2) (~20 atoms thick) carbon foils. Thus, graphene foils have the potential to improve the performance of space-based plasma instruments for energies below ~50 keV.

  5. Inversion problem for ion-atom differential elastic scattering.

    Science.gov (United States)

    Rich, W. G.; Bobbio, S. M.; Champion, R. L.; Doverspike, L. D.

    1971-01-01

    The paper describes a practical application of Remler's (1971) method by which one constructs a set of phase shifts from high resolution measurements of the differential elastic scattering of protons by rare-gas atoms. These JWKB phase shifts are then formally inverted to determine the corresponding intermolecular potentials. The validity of the method is demonstrated by comparing an intermolecular potential obtained by direct inversion of experimental data with a fairly accurate calculation by Wolniewicz (1965).

  6. Spin entanglement in elastic electron scattering from quasi-one electron atoms

    Science.gov (United States)

    Fonseca Dos Santos, Samantha; Bartschat, Klaus

    2017-04-01

    We have extended our work on e-Li collisions to investigate low-energy elastic electron collisions with atomic hydrogen and other alkali targets (Na,K,Rb). These systems have been suggested for the possibility of continuously varying the degree of entanglement between the elastically scattered projectile and the valence electron. In order to estimate how well such a scheme may work in practice, we carried out overview calculations for energies between 0 and 10 eV and the full range of scattering angles 0° -180° . In addition to the relative exchange asymmetry parameter that characterizes the entanglement, we present the differential cross section in order to estimate whether the count rates in the most interesting energy-angle regimes are sufficient to make such experiments feasible in practice. Work supported by the NSF under PHY-1403245.

  7. Electron scattering on molecules: search for semi-empirical indications

    Science.gov (United States)

    Fedus, Kamil; Karwasz, Grzegorz P.

    2017-06-01

    Reliable cross-sections for electron-molecule collisions are urgently needed for numerical modeling of various processes important from technological point of view. Unfortunately, a significant progress in theory and experiment over the last decade is not usually accompanied by the convergence of cross-sections measured at different laboratories and calculated with different methods. Moreover the most advanced contemporary theories involve such large basis sets and complicated equations that they are not easily applied to each specific molecule for which data are needed. For these reasons the search for semi-empirical indications in angular and energy dependencies of scattering cross-section becomes important. In this paper we make a brief review of the applicability of the Born-dipole approximation for elastic, rotational, vibrational and ionization processes that can occur during electron-molecule collisions. We take into account the most recent experimental findings as the reference points. Contribution to the Topical Issue "Atomic and Molecular Data and Their Applications", edited by Gordon W.F. Drake, Jung-Sik Yoon, Daiji Kato, and Grzegorz Karwasz.

  8. Electron Scattering From High-Momentum Neutrons in Deuterium

    CERN Document Server

    Klimenko, A V; Ambrozewicz, P; Anghinolo, M; Asryan, G; Avakian, H; Bagdasaryan, H; Baillie, N; Ball, J P; Baltzell, N A; Barrow, S; Batourine, V; Battaglieri, M; Bedlinskiy, I; Bektasoglu, M; Bellis, M; Benmouna, N; Biselli, A S; Bltmann, S; Boiarinov, S; Bouchigny, S; Bradford, R; Branford, D; Brooks, W K; Burkert, V D; Butuceanu, C; Calarco, J R; Careccia, S L; Carman, D S; Cazes, A; Chen, S; Cole, P L; Coltharp, P; Cords, D; Corvisiero, P; Crabb, D; Cummings, J P; Dashyan, N B; De Sanctis, E; De Vita, R; Degtyarenko, P V; Denizli, H; Dennis, L; Dharmawardane, K V; Djalali, C; Dodge, G E; Donnelly, J; Doughty, D; Dugger, M; Dytman, S; Dzyubak, O P; Egiyan, H; Egiyan, K S; Elouadrhiri, L; Eugenio, P; Fatemi, R; Fedotov, G; Fersch, R G; Feuerbach, R J; Funsten, H; Garçon, M; Gavalian, G; Gilfoyle, G P; Giovanetti, K L; Girod, F X; Goetz, J T; Gonenc, A; Gordon, C I O; Gothe, R W; Grioen, K A; Guidal, M; Guillo, M; Guler, N; Guo, L; Gyurjyan, V; Hadjidakis, C; Hakobyan, R S; Hardie, J; Hersman, F W; Hicks, K; Hleiqawi, I; Holtrop, M; Hyde-Wright, C E; Ilieva, Y; Ireland, D G; Ishkhanov, B S; Ito, M M; Jenkins, D; Jo, H S; Joo, K; Jüngst, H G; Kellie, J D; Khandaker, M; Kim, W; Klein, A; Klein, F J; Kossov, M; Kramer, L H; Kubarovski, V; Kuhn, S E; Kuleshov, S V; Kühn, J; Lachniet, J; Laget, J M; Langheinrich, J; Lawrence, D; Li, J; Livingston, K; McAleer, S; McKinnon, B; McNabb, J W C; Mecking, B A; Mehrabyan, S S; Melone, J J; Mestayer, M D; Meyer, C A; Mibe, T; Mikhailov, K; Minehart, R C; Mirazita, M; Miskimen, R; Mokeev, V; Morand, L; Morrow, S A; Mutchler, G S; Müller, J; Nadel-Turonski, P; Napolitano, J; Nasseripour, R; Niccolai, S; Niculescu, G; Niculescu, I; Niczyporuk, B B; Niyazov, R A; Nozar, M; O'Rielly, G V; Osipenko, M; Ostrovidov, A I; Park, K; Pasyuk, E; Paterson, C; Pierce, J; Pivnyuk, N; Pocanic, D; Pogorelko, O I; Pozdniakov, S; Preedom, B M; Price, J W; Prok, Y; Protopopescu, D; Raue, B A; Riccardi, G; Ricco, G; Ripani, M; Ritchie, B G; Ronchetti, F; Rosner, G; Rossi, P; Sabatie, F; Salgado, C; Santoro, J P; Sapunenko, V; Schumacher, R A; Serov, V S; Sharabyan, Yu G; Skabelin, A V; Smith, E S; Smith, L C; Sober, D I; Stavinsky, A V; Stepanyan, S; Stokes, B E; Stoler, P; Strauch, S; Taiuti, M; Tedeschi, D J; Thoma, U; Tkabladze, A; Tkachenko, S I; Todor, L; Tur, C; Ungaro, M; Vineyard, M F; Vlassov, A V; Weinstein, L B; Weygand, D P; Williams, M; Wolin, E; Wood, M H; Yegneswaran, A; Zana, L; Zhang, J; Zhao, B

    2006-01-01

    We report results from an experiment measuring the semi-inclusive reaction $d(e,e'p_s)$ where the proton $p_s$ is moving at a large angle relative to the momentum transfer. If we assume that the proton was a spectator to the reaction taking place on the neutron in deuterium, the initial state of that neutron can be inferred. This method, known as spectator tagging, can be used to study electron scattering from high-momentum (off-shell) neutrons in deuterium. The data were taken with a 5.765 GeV electron beam on a deuterium target in Jefferson Laboratory's Hall B, using the CLAS detector. A reduced cross section was extracted for different values of final-state missing mass $W^{*}$, backward proton momentum $\\vec{p}_{s}$ and momentum transfer $Q^{2}$. The data are compared to a simple PWIA spectator model. A strong enhancement in the data observed at transverse kinematics is not reproduced by the PWIA model. This enhancement can likely be associated with the contribution of final state interactions (FSI) that ...

  9. High resolution electron scattering on {sup 96}Zr

    Energy Technology Data Exchange (ETDEWEB)

    Kremer, Christoph; Bassauer, Sergej; Krugmann, Andreas; Krumbholz, Anna Maria; Pietralla, Norbert; Singer, Maxim; Neumann-Cosel, Peter von [Institut fuer Kernphysik, TU Darmstadt (Germany)

    2015-07-01

    The low-energy structure of the nucleus {sup 96}Zr is interesting for numerous reasons - especially the strong octupole correlation leading to an excitation of the prominent 3{sup -}{sub 1} state with the largest known ground-state transition strength (B(E3, 3{sup +}{sub 1} → 0{sup +}{sub 1}) = 57(4) W.u.) of all nuclei. Even though this nucleus is a good testing ground for nuclear structure theories some low-energy observables are known with insufficient precision. Especially the transition strength of low-lying 2{sup +} states, which are important for the identification of mixed-symmetry states, have large uncertainties. Electron scattering at low impulse transfer has been shown to be capable of obtaining these B(E2) values with high precision. A {sup 96}Zr(e,e{sup '}) experiment has recently been performed at the superconducting electron linear accelerator S-DALINAC at Darmstadt using the high-resolution LINTOTT spectrometer. The experiment and preliminary results are presented.

  10. Computer simulation program for medium-energy ion scattering and Rutherford backscattering spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Nishimura, Tomoaki, E-mail: t-nishi@hosei.ac.jp

    2016-03-15

    A computer simulation program for ion scattering and its graphical user interface (MEISwin) has been developed. Using this program, researchers have analyzed medium-energy ion scattering and Rutherford backscattering spectrometry at Ritsumeikan University since 1998, and at Rutgers University since 2007. The main features of the program are as follows: (1) stopping power can be chosen from five datasets spanning several decades (from 1977 to 2011), (2) straggling can be chosen from two datasets, (3) spectral shape can be selected as Gaussian or exponentially modified Gaussian, (4) scattering cross sections can be selected as Coulomb or screened, (5) simulations adopt the resonant elastic scattering cross section of {sup 16}O({sup 4}He, {sup 4}He){sup 16}O, (6) pileup simulation for RBS spectra is supported, (7) natural and specific isotope abundances are supported, and (8) the charge fraction can be chosen from three patterns (fixed, energy-dependent, and ion fraction with charge-exchange parameters for medium-energy ion scattering). This study demonstrates and discusses the simulations and their results.

  11. A reflective optical transport system for ultraviolet Thomson scattering from electron plasma waves on OMEGAa)

    Science.gov (United States)

    Katz, J.; Boni, R.; Sorce, C.; Follett, R.; Shoup, M. J.; Froula, D. H.

    2012-10-01

    A reflective optical transport system has been designed for the OMEGA Thomson-scattering diagnostic. A Schwarzschild objective that uses two concentric spherical mirrors coupled to a Pfund objective provides diffraction-limited imaging across all reflected wavelengths. This enables the operator to perform Thomson-scattering measurements of ultraviolet (0.263 μm) light scattered from electron plasma waves.

  12. A reflective optical transport system for ultraviolet Thomson scattering from electron plasma waves on OMEGA.

    Science.gov (United States)

    Katz, J; Boni, R; Sorce, C; Follett, R; Shoup, M J; Froula, D H

    2012-10-01

    A reflective optical transport system has been designed for the OMEGA Thomson-scattering diagnostic. A Schwarzschild objective that uses two concentric spherical mirrors coupled to a Pfund objective provides diffraction-limited imaging across all reflected wavelengths. This enables the operator to perform Thomson-scattering measurements of ultraviolet (0.263 μm) light scattered from electron plasma waves.

  13. A reflective optical transport system for ultraviolet Thomson scattering from electron plasma waves on OMEGA

    Energy Technology Data Exchange (ETDEWEB)

    Katz, J.; Boni, R.; Sorce, C.; Follett, R.; Shoup, M. J. III; Froula, D. H. [Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14623-1299 (United States)

    2012-10-15

    A reflective optical transport system has been designed for the OMEGA Thomson-scattering diagnostic. A Schwarzschild objective that uses two concentric spherical mirrors coupled to a Pfund objective provides diffraction-limited imaging across all reflected wavelengths. This enables the operator to perform Thomson-scattering measurements of ultraviolet (0.263 {mu}m) light scattered from electron plasma waves.

  14. Impact of beam ions on α-particle measurements by collective Thomson scattering in ITER

    DEFF Research Database (Denmark)

    Egedal, J.; Bindslev, H.; Budny, R.V.

    2005-01-01

    Collective Thomson scattering (CTS) has been proposed as a viable diagnostic for characterizing fusion born a-distributions in ITER. However, the velocities of the planned 1 MeV deuterium heating beam ions in 1TER are similar to that of fusion born a-particles and may therefore mask the measureme......Collective Thomson scattering (CTS) has been proposed as a viable diagnostic for characterizing fusion born a-distributions in ITER. However, the velocities of the planned 1 MeV deuterium heating beam ions in 1TER are similar to that of fusion born a-particles and may therefore mask...

  15. Comparison Between Path Lengths Traveled by Solar Electrons and Ions in Ground-Level Enhancement Events

    Science.gov (United States)

    Tan, Lun C.; Malandraki, Olga E.; Reames, Donald; NG, Chee K.; Wang, Linghua; Patsou, Ioanna; Papaioannou, Athanasios

    2013-01-01

    We have examined the Wind/3DP/SST electron and Wind/EPACT/LEMT ion data to investigate the path length difference between solar electrons and ions in the ground-level enhancement (GLE) events in solar cycle 23. Assuming that the onset time of metric type II or decameter-hectometric (DH) type III radio bursts is the solar release time of non-relativistic electrons, we have found that within an error range of plus or minus 10% the deduced path length of low-energy (approximately 27 keV) electrons from their release site near the Sun to the 1 AU observer is consistent with the ion path length deduced by Reames from the onset time analysis. In addition, the solar longitude distribution and IMF topology of the GLE events examined are in favor of the coronal mass ejection-driven shock acceleration origin of observed non-relativistic electrons.We have also found an increase of electron path lengths with increasing electron energies. The increasing rate of path lengths is correlated with the pitch angle distribution (PAD) of peak electron intensities locally measured, with a higher rate corresponding to a broader PAD. The correlation indicates that the path length enhancement is due to the interplanetary scattering experienced by first arriving electrons. The observed path length consistency implies that the maximum stable time of magnetic flux tubes, along which particles transport, could reach 4.8 hr.

  16. Electron Bubbles in Superfluid (3) 3 He-A: Exploring the Quasiparticle-Ion Interaction

    Science.gov (United States)

    Shevtsov, Oleksii; Sauls, J. A.

    2017-06-01

    When an electron is forced into liquid ^3He, it forms an "electron bubble", a heavy ion with radius, R˜eq 1.5 nm, and mass, M˜eq 100 m_3, where m_3 is the mass of a ^3He atom. These negative ions have proven to be powerful local probes of the physical properties of the host quantum fluid, especially the excitation spectra of the superfluid phases. We recently developed a theory for Bogoliubov quasiparticles scattering off electron bubbles embedded in a chiral superfluid that provides a detailed understanding of the spectrum of Weyl Fermions bound to the negative ion, as well as a theory for the forces on moving electron bubbles in superfluid ^3He-A (Shevtsov and Sauls in Phys Rev B 94:064511, 2016). This theory is shown to provide quantitative agreement with measurements reported by the RIKEN group (Ikegami et al. in Science 341(6141):59, 2013) for the drag force and anomalous Hall effect of moving electron bubbles in superfluid ^3He-A. In this report, we discuss the sensitivity of the forces on the moving ion to the effective interaction between normal-state quasiparticles and the ion. We consider models for the quasiparticle-ion (QP-ion) interaction, including the hard-sphere potential, constrained random-phase-shifts, and interactions with short-range repulsion and intermediate-range attraction. Our results show that the transverse force responsible for the anomalous Hall effect is particularly sensitive to the structure of the QP-ion potential and that strong short-range repulsion, captured by the hard-sphere potential, provides an accurate model for computing the forces acting on the moving electron bubble in superfluid 3He-A.

  17. Crossed-beam scattering studies of electron-transfer processes between the dication CO2(2+) and neutral CO2: electronic states of reactants and products involved.

    Science.gov (United States)

    Zabka, Jan; Ricketts, Claire L; Schröder, Detlef; Roithová, Jana; Schwarz, Helmut; Thissen, Roland; Dutuit, Odile; Price, Stephen D; Herman, Zdenek

    2010-06-17

    Crossed-beam scattering experiments were carried out at collision energies of 4.51 and 2.71 eV to elucidate the electronic states involved in the nondissociative and dissociative electron-transfer reactions observed following CO(2)(2+)/CO(2) collisions. Specifically, we focus on the observation that, in the dissociative electron-transfer reaction, forming CO(+), the majority of the CO(+) product ions are formed via electron capture by the CO(2)(2+) rather than via ejection of an electron from the neutral CO(2) reaction partner. The main channels resulting in nondissociative electron transfer are reactions of the ground (X(3)Sigma(g)(-)) and excited states of CO(2)(2+) to give different combinations of the ground and excited states of the product pair of CO(2)(+) ions in which the combination AA appears to be significant. The CO(+) ions appear mainly to arise from slow dissociation of CO(2)(+)(b(4)Pi(u)) formed following electron capture by the ground state of the dication reactant (X(3)Sigma(g)(-)), with possible contributions from electron capture by higher triplet excited states of the dication.

  18. Extraction of electron–ion differential scattering cross sections for C2H4 by laser-induced rescattering photoelectron spectroscopy

    DEFF Research Database (Denmark)

    Wang, C.; Okunishi, M.; Lucchese, R. R.

    2012-01-01

    We have measured angle-resolved rescattering electron momentum distributions for C2H4 generated by intense infrared laser pulses and extracted large-angle elastic differential cross sections (DCSs) for electrons scattering from C2H4+. The angle-dependent ionization rate describing the initial...... single-ionization step favours ionization from molecules that have their molecular plane aligned perpendicular to the laser polarization direction. The extracted DCSs are well reproduced by the theoretical calculation. We demonstrate that DCSs for electron–ion scattering of the nonlinear polyatomic...

  19. Solitary waves in asymmetric electron-positron-ion plasmas

    Science.gov (United States)

    Lu, Ding; Li, Zi-Liang; Xie, Bai-Song

    2015-10-01

    > By solving the coupled equations of the electromagnetic field and electrostatic potential, we investigate solitary waves in an asymmetric electron-positron plasma and/or electron-positron-ion plasmas with delicate features. It is found that the solutions of the coupled equations can capture multipeak structures of solitary waves in the case of cold plasma, which are left out by using the long-wavelength approximation. By considering the effect of ion motion with respect to non-relativistic and ultra-relativistic temperature plasmas, we find that the ions' mobility can lead to larger-amplitude solitary waves; especially, this becomes more obvious for a high-temperature plasma. The effects of asymmetric temperature between electrons and positrons and the ion fraction on the solitary waves are also studied and presented. It is shown that the amplitudes of solitary waves decrease with positron temperature in asymmetric temperature electron-positron plasmas and decrease also with ion concentration.

  20. Isotopic anomaly for carbon ions in an electron cyclotron resonance ion source

    NARCIS (Netherlands)

    Drentje, A. G.; Kitagawa, A.; Muramatsu, M.

    In many experiments methods were applied to increase the highly charged ion output from an electron cyclotron resonance ion source; the gas-mixing method is still generally being applied. The dominant role of the masses of the ions in the gas-mixture was apparent. Two basically differing mechanisms

  1. Density-dependent electron scattering in photoexcited GaAs in strongly diffusive regime

    DEFF Research Database (Denmark)

    Mics, Zoltán; D’Angio, Andrea; Jensen, Søren A.

    2013-01-01

    In a series of systematic optical pump–terahertz probe experiments, we study the density-dependent electron scattering rate in photoexcited GaAs in the regime of strong carrier diffusion. The terahertz frequency-resolved transient sheet conductivity spectra are perfectly described by the Drude...... model, directly yielding the electron scattering rates. A diffusion model is applied to determine the spatial extent of the photoexcited electron-hole gas at each moment after photoexcitation, yielding the time-dependent electron density, and hence the density-dependent electron scattering time. We find...

  2. Concurrent in situ ion irradiation transmission electron microscope

    Energy Technology Data Exchange (ETDEWEB)

    Hattar, K., E-mail: khattar@sandia.gov; Bufford, D.C.; Buller, D.L.

    2014-11-01

    An in situ ion irradiation transmission electron microscope has been developed and is operational at Sandia National Laboratories. This facility permits high spatial resolution, real time observation of electron transparent samples under ion irradiation, implantation, mechanical loading, corrosive environments, and combinations thereof. This includes the simultaneous implantation of low-energy gas ions (0.8–30 keV) during high-energy heavy ion irradiation (0.8–48 MeV). Initial results in polycrystalline gold foils are provided to demonstrate the range of capabilities.

  3. Quantitative considerations in medium energy ion scattering depth profiling analysis of nanolayers

    Energy Technology Data Exchange (ETDEWEB)

    Zalm, P.C.; Bailey, P. [International Institute for Accelerator Applications, University of Huddersfield, Queensgate, Huddersfield HD1 3DH (United Kingdom); Reading, M.A. [Physics and Materials Research Centre, University of Salford, Salford M5 4WT (United Kingdom); Rossall, A.K. [International Institute for Accelerator Applications, University of Huddersfield, Queensgate, Huddersfield HD1 3DH (United Kingdom); Berg, J.A. van den, E-mail: j.vandenberg@hud.ac.uk [International Institute for Accelerator Applications, University of Huddersfield, Queensgate, Huddersfield HD1 3DH (United Kingdom)

    2016-11-15

    The high depth resolution capability of medium energy ion scattering (MEIS) is becoming increasingly relevant to the characterisation of nanolayers in e.g. microelectronics. In this paper we examine the attainable quantitative accuracy of MEIS depth profiling. Transparent but reliable analytical calculations are used to illustrate what can ultimately be achieved for dilute impurities in a silicon matrix and the significant element-dependence of the depth scale, for instance, is illustrated this way. Furthermore, the signal intensity-to-concentration conversion and its dependence on the depth of scattering is addressed. Notably, deviations from the Rutherford scattering cross section due to screening effects resulting in a non-coulombic interaction potential and the reduction of the yield owing to neutralization of the exiting, backscattered H{sup +} and He{sup +} projectiles are evaluated. The former mainly affects the scattering off heavy target atoms while the latter is most severe for scattering off light target atoms and can be less accurately predicted. However, a pragmatic approach employing an extensive data set of measured ion fractions for both H{sup +} and He{sup +} ions scattered off a range of surfaces, allows its parameterization. This has enabled the combination of both effects, which provides essential information regarding the yield dependence both on the projectile energy and the mass of the scattering atom. Although, absolute quantification, especially when using He{sup +}, may not always be achievable, relative quantification in which the sum of all species in a layer adds up to 100%, is generally possible. This conclusion is supported by the provision of some examples of MEIS derived depth profiles of nanolayers. Finally, the relative benefits of either using H{sup +} or He{sup +} ions are briefly considered.

  4. TARGET EXCITATION IN BARE ION XE/AR COLLISIONS STUDIED BY ELECTRON TARGET ION COINCIDENCES

    NARCIS (Netherlands)

    DENIJS, G; HOEKSTRA, R; MORGENSTERN, R

    We present electron spectra resulting from collisions of bare ions N-15(7+) and C-13(6+) on Ar and the charge state distribution of target ions resulting from C-13(6+)-Xe collisions. From both type of experiments we find evidence that electron capture accompanied by target excitation is an important

  5. Simulation study of secondary electron images in scanning ion microscopy

    CERN Document Server

    Ohya, K

    2003-01-01

    The target atomic number, Z sub 2 , dependence of secondary electron yield is simulated by applying a Monte Carlo code for 17 species of metals bombarded by Ga ions and electrons in order to study the contrast difference between scanning ion microscopes (SIM) and scanning electron microscopes (SEM). In addition to the remarkable reversal of the Z sub 2 dependence between the Ga ion and electron bombardment, a fine structure, which is correlated to the density of the conduction band electrons in the metal, is calculated for both. The brightness changes of the secondary electron images in SIM and SEM are simulated using Au and Al surfaces adjacent to each other. The results indicate that the image contrast in SIM is much more sensitive to the material species and is clearer than that for SEM. The origin of the difference between SIM and SEM comes from the difference in the lateral distribution of secondary electrons excited within the escape depth.

  6. X-ray, neutron, and electron scattering. Report of a materials sciences workshop

    Energy Technology Data Exchange (ETDEWEB)

    1977-08-01

    The ERDA Workshop on X-ray, Neutron, and Electron Scattering to assess needs and establish priorities for energy-related basic research on materials. The general goals of the Workshop were: (1) to review various energy technologies where x-ray, neutron, and electron scattering techniques might make significant contributions, (2) to identify present and future materials problems in the energy technologies and translate these problems into requirements for basic research by x-ray, neutron, and electron scattering techniques, (3) to recommend research areas utilizing these three scattering techniques that should be supported by the DPR Materials Sciences Program, and (4) to assign priorities to these research areas.

  7. Ion/neutral, ion/electron, ion/photon, and ion/ion interactions in tandem mass spectrometry: do we need them all? Are they enough?

    Science.gov (United States)

    McLuckey, Scott A; Mentinova, Marija

    2011-01-01

    A range of strategies and tools have been developed to facilitate the determination of primary structures of analyte molecules of interest via tandem mass spectrometry (MS/MS). The two main factors that determine the primary structural information present in an MS/MS spectrum are the type of ion generated from the analyte molecule and the dissociation method. The ion type subjected to dissociation is determined by the ionization method/conditions and ion transformation processes that might take place after initial gas-phase ion formation. Furthermore, the range of analyte-related ion types can be expanded via derivatization reactions prior to mass spectrometry. Dissociation methods include those that simply alter the population of internal states of the mass-selected ion (i.e., activation methods like collision-induced dissociation) as well as processes that rely on the transformation of the ion type prior to dissociation (e.g., electron capture dissociation). A variety of ion interactions have been studied for the purpose of ion dissociation and ion transformation, including ion/neutral, ion/photon, ion/electron, and ion/ion interactions. A wide range of phenomena have been observed, many of which have been explored/developed as means for structural analysis. The techniques arising from these phenomena are discussed within the context of the elements of structural determination in tandem mass spectrometry: ion-type definition and dissociation. Unique aspects of the various ion interactions are emphasized along with any barriers to widespread implementation. © American Society for Mass Spectrometry, 2011

  8. 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

  9. Generation of multi-charged high current ion beams using the SMIS 37 gas-dynamic electron cyclotron resonance (ECR) ion source

    Energy Technology Data Exchange (ETDEWEB)

    Dorf, M. A. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Zorin, V. G. [Russian Academy of Sciences (RAS), Nizhny Novgorod (Russian Federation). Inst. of Applied Physics; Sidorov, A. V. [Russian Academy of Sciences (RAS), Nizhny Novgorod (Russian Federation). Inst. of Applied Physics; Bokhanov, A. F. [Russian Academy of Sciences (RAS), Nizhny Novgorod (Russian Federation). Inst. of Applied Physics; Izotov, I. V. [Russian Academy of Sciences (RAS), Nizhny Novgorod (Russian Federation). Inst. of Applied Physics; Razin, S. V. [Russian Academy of Sciences (RAS), Nizhny Novgorod (Russian Federation). Inst. of Applied Physics; Skalyga, V. A. [Russian Academy of Sciences (RAS), Nizhny Novgorod (Russian Federation). Inst. of Applied Physics

    2013-06-02

    A gas-dynamic ECR ion source (GaDIS) is distinguished by its ability to produce high current and high brightness beams of moderately charged ions. Contrary to a classical ECR ion source where the plasma confinement is determined by the slow electron scattering into an empty loss-cone, the higher density and lower electron temperature in a GaDIS plasma lead to an isotropic electron distribution with the confinement time determined by the prompt gas-dynamic flow losses. As a result, much higher ion fluxes are available, however a decrease in the confinement time of the GaDIS plasma lowers the ion charge state. The gas-dynamic ECR ion source concept has been successfully realized in the SMIS 37 experimental facility operated at the Institute of Applied Physics, Russia. The use of high-power (~100 kW) microwave (37.5 GHz) radiation provides a dense plasma (~1013 cm-3) with a relatively low electron temperature (~50- 100 eV) and allows for the generation of high current (~1 A/cm2) beams of multi-charged ions. In this work we report on the present status of the SMIS 37 ion source and discuss the advanced numerical modeling of ion beam extraction using the particle-in-cell code WARP

  10. Intrabeam scattering studies at the Cornell Electron Storage Ring Test Accelerator

    Directory of Open Access Journals (Sweden)

    M. P. Ehrlichman

    2013-10-01

    Full Text Available Intrabeam scattering (IBS limits the emittance and single-bunch current that can be achieved in electron or positron storage ring colliders, damping rings, and light sources. Much theoretical work on IBS exists, and while the theories have been validated in hadron and ion machines, the presence of strong damping makes IBS in lepton machines a different phenomenon. We present the results of measurements at CesrTA of IBS-dominated beams, and compare the data with theory. The beams we study have parameters typical of those specified for the next generation of wiggler-dominated storage rings: low emittance, small bunch length, and an energy of a few GeV. Our measurements are in good agreement with IBS theory, provided a tail-cut procedure is applied.

  11. Nuclear structure functions at a future electron-ion collider

    Science.gov (United States)

    Aschenauer, E. C.; Fazio, S.; Lamont, M. A. C.; Paukkunen, H.; Zurita, P.

    2017-12-01

    The quantitative knowledge of heavy nuclei's partonic structure is currently limited to rather large values of momentum fraction x —robust experimental constraints below x ˜10-2 at low resolution scale Q2 are particularly scarce. This is in sharp contrast to the free proton's structure which has been probed in Deep Inelastic Scattering (DIS) measurements down to x ˜10-5 at perturbative resolution scales. The construction of an electron-ion collider (EIC) with a possibility to operate with a wide variety of nuclei, will allow one to explore the low-x region in much greater detail. In the present paper we simulate the extraction of the nuclear structure functions from measurements of inclusive and charm reduced cross sections at an EIC. The potential constraints are studied by analyzing simulated data directly in a next-to-leading order global fit of nuclear Parton Distribution Functions based on the recent EPPS16 analysis. A special emphasis is placed on studying the impact an EIC would have on extracting the nuclear gluon parton distribution function, the partonic component most prone to nonlinear effects at low Q2. In comparison to the current knowledge, we find that the gluon parton distribution function can be measured at an EIC with significantly reduced uncertainties.

  12. Monte Carlo study of electron relaxation in graphene with spin polarized, degenerate electron gas in presence of electron-electron scattering

    Science.gov (United States)

    Borowik, Piotr; Thobel, Jean-Luc; Adamowicz, Leszek

    2017-12-01

    The Monte Carlo simulation method is applied to study the relaxation of excited electrons in monolayer graphene. The presence of spin polarized background electrons population, with density corresponding to highly degenerate conditions is assumed. Formulas of electron-electron scattering rates, which properly account for electrons presence in two energetically degenerate, inequivalent valleys in this material are presented. The electron relaxation process can be divided into two phases: thermalization and cooling, which can be clearly distinguished when examining the standard deviation of electron energy distribution. The influence of the exchange effect in interactions between electrons with parallel spins is shown to be important only in transient conditions, especially during the thermalization phase.

  13. Strange quarks in the nucleon and parity violation in polarized electron scattering

    CERN Document Server

    Van de Wiele, J

    2001-01-01

    In this review, we show that the measurement of asymmetry in polarized electron- nucleon scattering provides information about the quark structure of the nucleon.. The formalism of parity-violating electron-nucleon scattering with the theoretical assumptions is presented. An experimental overview of specific experiments with recent results as well as upcoming experiments is discussed.

  14. Self-Consistent Solutions for the Scattering State with Two Free Electrons

    Science.gov (United States)

    Hahn, Y. K.; Gau, J. N.; Zerrad, E.

    2013-11-01

    Wave functions for the scattering states with two free electrons in the field of an ion core are explicitly calculated by the self-consistent, continuum Hartree-Fock (CHF) theory. Typically, such states are associated with the three-body recombination, collisional ionization and photo-double ionization, but have never been directly studied previously. The calculated continuum orbitals are found to be predominantly of the plane-wave forms, as though the system is translation invariant, in the context of many-body HF theory. The symmetry is mildly broken by the presence of the core ion, at about fifteen-percents level, indicating that the orbitals are largely delocalized and the effect of the core potential is an important but minor perturbation. The properties of channel orthogonality and completeness are preserved by the nearly plane wave forms. To test the validity of this finding and the CHF, the continuum orbitals are used to evaluate the amplitudes for the electron impact ionization, and the amputation procedure, that is crucial in the theory, is also critically re-examined.

  15. Ion and electron heating during magnetic reconnection in simulations

    Science.gov (United States)

    Haggerty, Colby C.

    Magnetic reconnection is a fundamental plasma process that converts energy stored in magnetic fields into kinetic energy. Reconnection is believed to occur in astrophysical, heliospheric and laboratory plasma. In this thesis we examine how magnetic energy is converted into electron and ion thermal energy during collisionless magnetic reconnection using fully kinetic 2.5D particle-in-cell (PIC) simulations. We find that both ion and electron heating are reasonably well correlated with the inflowing available magnetic energy per ion electron pair, or more succinctly, to an energy associated with the upstream Alfven speed (micAup 2). We also show that while the upstream Alfven speed is the primary factor controlling the heating, other factors, including the strength of a guide field and the electron to ion temperature ratio, affect the heating as well. Ion heating is found to be inversely proportional to the strength of the guide field relative to the reconnecting field. In anti-parallel reconnection, ion heating is suppressed by an upstream electron to ion temperature ratio greater than unity; conversely, electron heating is found to be enhanced by these upstream parameters. It is also shown that increasing the upstream ion temperature normalized to the Alfven speed squared (beta i) reduces the reconnection outflow velocity in the exhaust for anti-parallel reconnection. The firehose instability in the exhaust limits the field line (and thus the outflow) velocity and it is shown that v0 = ⅓cAr2/√ Ti||/mi, where v 0 is the outflow velocity and Ti|| is the ion parallel temperature in the exhaust. While the upstream temperatures appear to cause the heating to deviate from scaling with mic Aup2, the total heating (ion + electron) is significantly better correlated with micAup 2, giving DeltaTi + Delta Te = 0.14, micAup 2. This implies that the total fraction of magnetic energy released into thermal energy is a constant, and this constant fraction of magnetic energy is

  16. Electron scattering disintegration processes on light nuclei in covariant approach

    Directory of Open Access Journals (Sweden)

    Kuznietsov P.E.

    2016-01-01

    Full Text Available We provide general analysis of electro-break up process of compound scalar system. We use covariant approach with conserved EM current, which gives the ability to include strong interaction into QED. Therefore, we receive the ability to describe disintegration processes on nonlocal matter fields applying standard Feynman rules of QED. Inclusion of phase exponent into wave function receives a physical sense while we deal with the dominance of strong interaction in the process. We apply Green’s function (GF formalism to describe disintegration processes. Generalized gauge invariant electro-break up process amplitude is considered. One is a sum of traditional pole series and the regular part. We explore the deposits of regular part of amplitude, and its physical sense. A transition from virtual to real photon considered in photon point limit. The general analysis for electro-break up process of component scalar system is given. Precisely conserved nuclear electromagnetic currents at arbitrary square of transited momentum are received. The only undefined quantity in theory is vertex function. Therefore, we have the opportunity to describe electron scattering processes taking into account minimal necessary set of parameters.

  17. Electron scattering disintegration processes on light nuclei in covariant approach

    Science.gov (United States)

    Kuznietsov, P. E.; Kasatkin, Yu. A.; Klepikov, V. F.

    2016-07-01

    We provide general analysis of electro-break up process of compound scalar system. We use covariant approach with conserved EM current, which gives the ability to include strong interaction into QED. Therefore, we receive the ability to describe disintegration processes on nonlocal matter fields applying standard Feynman rules of QED. Inclusion of phase exponent into wave function receives a physical sense while we deal with the dominance of strong interaction in the process. We apply Green's function (GF) formalism to describe disintegration processes. Generalized gauge invariant electro-break up process amplitude is considered. One is a sum of traditional pole series and the regular part. We explore the deposits of regular part of amplitude, and its physical sense. A transition from virtual to real photon considered in photon point limit. The general analysis for electro-break up process of component scalar system is given. Precisely conserved nuclear electromagnetic currents at arbitrary square of transited momentum are received. The only undefined quantity in theory is vertex function. Therefore, we have the opportunity to describe electron scattering processes taking into account minimal necessary set of parameters.

  18. Electronic structure of the palladium hydride studied by compton scattering

    CERN Document Server

    Mizusaki, S; Yamaguchi, M; Hiraoka, N; Itou, M; Sakurai, Y

    2003-01-01

    The hydrogen-induced changes in the electronic structure of Pd have been investigated by Compton scattering experiments associated with theoretical calculations. Compton profiles (CPs) of single crystal of Pd and beta phase hydride PdH sub x (x=0.62-0.74) have been measured along the [100], [110] and [111] directions with a momentum resolution of 0.14-0.17 atomic units using 115 keV x-rays. The theoretical Compton profiles have been calculated from the wavefunctions obtained utilizing the full potential linearized augmented plane wave method within the local density approximation for Pd and stoichiometric PdH. The experimental and the theoretical results agreed well with respect to the difference in the CPs between PdH sub x and Pd, and the anisotropy in the CPs of Pd or PdH sub x. This study provides lines of evidence that upon hydride formation the lowest valance band of Pd is largely modified due to hybridization with H 1s-orbitals and the Fermi energy is raised into the sp-band. (author)

  19. Timelike Virtual Compton Scattering from Electron-Positron Radiative Annihilation

    Energy Technology Data Exchange (ETDEWEB)

    Afanasev, Andrei; /Hampton U. /Jefferson Lab; Brodsky, Stanley J.; /SLAC; Carlson, Carl E.; /William-Mary Coll.; Mukherjee, Asmita; /Indian Inst. Tech., Mumbai

    2009-03-31

    We propose measurements of the deeply virtual Compton amplitude (DVCS) {gamma}* {yields} H{bar H}{gamma} in the timelike t = (p{sub H} + p{sub {bar H}}){sup 2} > 0 kinematic domain which is accessible at electron-positron colliders via the radiative annihilation process e{sup +}e{sup -} {yields} H{bar H}{gamma}. These processes allow the measurement of timelike deeply virtual Compton scattering for a variety of H{bar H} hadron pairs such as {pi}{sup +}{pi}{sup -}, K{sup +}K{sup -}, and D{bar D} as well as p{bar p}. As in the conventional spacelike DVCS, there are interfering coherent amplitudes contributing to the timelike processes involving C = - form factors. The interference between the amplitudes measures the phase of the C = + timelike DVCS amplitude relative to the phase of the timelike form factors and can be isolated by considering the forward-backward e{sup +} {leftrightarrow} e{sup -} asymmetry. The J = 0 fixed pole contribution which arises from the local coupling of the two photons to the quark current plays a special role. As an example we present a simple model.

  20. Timelike Virtual Compton Scattering from Electron-Positron Radiative Annihilation

    Energy Technology Data Exchange (ETDEWEB)

    Andrei Afanaciev,Andrei Afanasev, Stanley J. Brodsky, Carl E. Carlson, Asmita Mukherjee

    2010-02-01

    We propose measurements of the deeply virtual Compton amplitude (DVCS), gamma* to H H-bar gamma, in the timelike t = (p_{H} + p_{H-bar})^2 > 0 kinematic domain which is accessible at electron-positron colliders via the radiative annihilation process e+ e- to H H-bar gamma. These processes allow the measurement of timelike deeply virtual Compton scattering for a variety of H H-bar hadron pairs such as pi+ pi-, K+ K-, and D D-bar as well as p p-bar. As in the conventional spacelike DVCS, there are interfering coherent amplitudes contributing to the timelike processes involving C= - form factors. The interference between the amplitudes measures the phase of the C=+ timelike DVCS amplitude relative to the phase of the timelike form factors and can be isolated by considering the forward-backward e+ \\leftrightarrow e- asymmetry. The J=0 fixed pole contribution which arises from the local coupling of the two photons to the quark current plays a special role. As an example we present a simple model.

  1. Scattering of slow ions by various crystallographic planes of tungsten single crystals

    CERN Document Server

    Ermolov, S N; Kortenraad, R; Must, B; Shtinov, E D; Brongersma, K K

    2002-01-01

    The dependence of low-energy ion scattering signal intensity on single crystal surface orientation is investigated, and it is shown that this dependence is not necessarily in direct proportion to atomic density in the uppermost atomic layer. On the basis of comparison of signals from various crystallographic planes of a high purity W single crystal a conclusion is made that the ions scattered from more deep atomic layers contribute considerably to the signal measured for the surface with an open structure. It is shown that reference specimens with a known surface density are needed for quantitative analysis of surface composition by the method of low-energy ion scattering. The best reference specimens are well-oriented single crystals with close-packed planes at the surface, since in this case the low-energy ion scattering signal is proportional to atomic density of the uppermost atomic layer. It single crystals with open surface structure are used as reference specimens the contribution of deeper atomic laye...

  2. A new computer code for quantitative analysis of low-energy ion scattering data

    NARCIS (Netherlands)

    Dorenbos, G; Breeman, M; Boerma, D.O

    We have developed a computer program for the full analysis of low-energy ion scattering (LEIS) data, i.e. an analysis that is equivalent to the full calculation of the three-dimensional trajectories of beam particles through a number of layers in the solid, and ending in the detector. A dedicated

  3. ITER fast ion collective Thomson scattering. Conceptual design of 60 GHz system

    DEFF Research Database (Denmark)

    Meo, Fernando; Bindslev, Henrik; Korsholm, Søren Bang

    The collective Thomson scattering diagnostic for ITER at the 60 GHz range is capable of measuring the fast ion distribution parallel and perpendicular to the magnetic field at different radial locations simultaneously. The design is robust technologically with no moveable components near the plasma...

  4. Growth of CdTe on (100) GaAs and analysis using ion scattering spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Mitrovic, B.; King, B.V. [Newcastle Univ., NSW (Australia). Dept. of Physics

    1993-12-31

    A brief review of Coaxial Impact collision Ion Scattering Spectroscopy (CAICISS) has been presented as well as its advantages in studies of semiconductor surfaces and interfaces. The results that we have gained using fast computer code - SABRE are graphically presented as an incident angular spectrum. The plausible interpretation for the large anomalous peak at 60 deg is given. 14 refs., 1 fig.

  5. Structure determination of surface adsorption and surface alloy phases using medium energy ion scattering

    Energy Technology Data Exchange (ETDEWEB)

    Woodruff, D.P. E-mail: d.p.woodruff@warwick.ac.uk; Brown, D.; Quinn, P.D.; Noakes, T.C.Q.; Bailey, P

    2001-07-01

    Through a series of investigations of the quantitative structure of monolayer surface alloy phases of Cu(1 0 0)/Au, Cu(1 0 0)/Mn, Cu(1 1 1)/Sb and Ni(1 1 1)/Pb a number of aspects of the methodology of medium energy ion scattering (MEIS) have been investigated. These include the form of reliability-factors (R-factors) used to provide an objective test of the fit of experimental blocking curves and those simulated for different model structures, and the criteria used to define the precision and uniqueness of such models. The role of absolute calibration of the scattered ion yields and the appropriate choice of scattering geometry are also discussed in the context of these specific studies. The quantitative results for these surface alloy structures also cast some light on the effective atomic radii in such structures and highlight the general trend for phases with low surface corrugation or rumpling.

  6. Comparison of fast ion collective Thomson scattering measurements at ASDEX Upgrade with numerical simulations

    DEFF Research Database (Denmark)

    Salewski, Mirko; Meo, Fernando; Stejner Pedersen, Morten

    2010-01-01

    Collective Thomson scattering (CTS) experiments were carried out at ASDEX Upgrade to measure the one-dimensional velocity distribution functions of fast ion populations. These measurements are compared with simulations using the codes TRANSP/NUBEAM and ASCOT for two different neutral beam injection...... (NBI) configurations: two NBI sources and only one NBI source. The measured CTS spectra as well as the inferred one-dimensional fast ion velocity distribution functions are clearly asymmetric as a consequence of the anisotropy of the beam ion populations and the selected geometry of the experiment...

  7. Electron detachment from negative carbon and oxygen ions

    Energy Technology Data Exchange (ETDEWEB)

    Serenkov, I.T.; Il' in, R.N.; Oparin, V.A.

    1977-04-01

    The cross sections for electron detachment from negative carbon ions in Mg, N/sub 2/, and CO and from negative oxygen ions in N/sub 2/ and CO are measured over the energy range 20--150 keV for the negative ions. The cross sections for electron detachment from negative carbon ions in the ground and excited states are distinguished on the basis of the decay of weakly bound states of the atomic particles in strong electric fields through the process C/sup -/+Mg..-->..C. The cross sections for electron detachment from the C/sup -/ ions in the bound and excited states behave in different ways as functions of the velocity. The difference is interpreted as evidence for two different detachment mechanisms.

  8. Transport of secondary electrons and reactive species in ion tracks

    CERN Document Server

    Surdutovich, Eugene

    2015-01-01

    The transport of reactive species brought about by ions traversing tissue-like medium is analysed analytically. Secondary electrons ejected by ions are capable of ionizing other molecules; the transport of these generations of electrons is studied using the random walk approximation until these electrons remain ballistic. Then, the distribution of solvated electrons produced as a result of interaction of low-energy electrons with water molecules is obtained. The radial distribution of energy loss by ions and secondary electrons to the medium yields the initial radial dose distribution, which can be used as initial conditions for the predicted shock waves. The formation, diffusion, and chemical evolution of hydroxyl radicals in liquid water are studied as well.

  9. Status report on electron cyclotron resonance ion sources at the Heavy Ion Medical Accelerator in Chiba

    CERN Document Server

    Kitagawa, A; Sekiguchi, M; Yamada, S; Jincho, K; Okada, T; Yamamoto, M; Hattori, T G; Biri, S; Baskaran, R; Sakata, T; Sawada, K; Uno, K

    2000-01-01

    The Heavy Ion Medical Accelerator in Chiba at the National Institute of Radiological Sciences (NIRS) is not only dedicated to cancer therapy, it is also utilized with various ion species for basic experiments of biomedical science, physics, chemistry, etc. Two electron cyclotron resonance (ECR) ion sources are installed for production of gaseous ions. One of them, the NIRS-ECR, is a 10 GHz ECR ion source, and is mainly operated to produce C/sup 4+/ ions for daily clinical treatment. This source realizes good reproducibility and reliability and it is easily operated. The other source, the NIRS-HEC, is an 18 GHz ECR ion source that is expected to produce heavier ion species. The output ion currents of the NIRS-ECR and the NIRS-HEC are 430e mu A for C/sup 4+/ and 1.1e mA for Ar/sup 8+/, respectively. (14 refs).

  10. Axial ion-electron emission microscopy of IC radiation hardness

    Science.gov (United States)

    Doyle, B. L.; Vizkelethy, G.; Walsh, D. S.; Swenson, D.

    2002-05-01

    A new system for performing radiation effects microscopy (REM) has been developed at Sandia National Laboratory in Albuquerque. This system combines two entirely new concepts in accelerator physics and nuclear microscopy. A radio frequency quadrupole (RFQ) linac is used to boost the energy of ions accelerated by a conventional Tandem Van de Graaff-Pelletron to velocities of 1.9 MeV/amu. The electronic stopping power for heavy ions is near a maximum at this velocity, and their range is ˜20 μm in Si. These ions therefore represent the most ionizing form of radiation in nature, and are nearly ideal for performing single event effects testing of integrated circuits. Unfortunately, the energy definition of the RFQ-boosted ions is rather poor (˜ a few %), which makes problematic the focussing of such ions to the submicron spots required for REM. To circumvent this problem, we have invented ion electron emission microscopy (IEEM). One can perform REM with the IEEM system without focussing or scanning the ion beam. This is because the position on the sample where each ion strikes is determined by projecting ion-induced secondary electrons at high magnification onto a single electron position sensitive detector. This position signal is then correlated with each REM event. The IEEM system is now mounted along the beam line in an axial geometry so that the ions pass right through the electron detector (which is annular), and all of the electrostatic lenses used for projection. The beam then strikes the sample at normal incidence which results in maximum ion penetration and removes a parallax problem experienced in an earlier system. Details of both the RFQ-booster and the new axial IEEM system are given together with some of the initial results of performing REM on Sandia-manufactured radiation hardened integrated circuits.

  11. Advanced ion beam analysis of materials using ion-induced fast electron

    Energy Technology Data Exchange (ETDEWEB)

    Kudo, Hiroshi; Tanabe, Atsushi; Ishihara, Toyoyuki [Tsukuba Univ., Ibaraki (Japan)] [and others

    1997-03-01

    Recent progress in the study of high-energy shadowing effect using ion-induced electron spectroscopy is reported with emphasis on a possibility of determination of local electronic structure in solids, which has been a difficult problem to approach with other experimental techniques. We demonstrate real-space determination of covalent-bond electron distribution in Si crystal. The analysis technique may provide a new field of ion beam analysis of solids. (author)

  12. New beam line for time-of-flight medium energy ion scattering with large area position sensitive detector.

    Science.gov (United States)

    Linnarsson, M K; Hallén, A; Åström, J; Primetzhofer, D; Legendre, S; Possnert, G

    2012-09-01

    A new beam line for medium energy ion mass scattering (MEIS) has been designed and set up at the Ångström laboratory, Uppsala University, Sweden. This MEIS system is based on a time-of-flight (ToF) concept and the electronics for beam chopping relies on a 4 MHz function generator. Repetition rates can be varied between 1 MHz and 63 kHz and pulse widths below 1 ns are typically obtained by including beam bunching. A 6-axis goniometer is used at the target station. Scattering angle and energy of backscattered ions are extracted from a time-resolved and position-sensitive detector. Examples of the performance are given for three kinds of probing ions, (1)H(+), (4)He(+), and (11)B(+). Depth resolution is in the nanometer range and 1 and 2 nm thick Pt layers can easily be resolved. Mass resolution between nearby isotopes can be obtained as illustrated by Ga isotopes in GaAs. Taking advantage of the large size detector, a direct imaging (blocking pattern) of crystal channels are shown for hexagonal, 4H-SiC. The ToF-MEIS system described in this paper is intended for use in semiconductor and thin film areas. For example, depth profiling in the sub nanometer range for device development of contacts and dielectric interfaces. In addition to applied projects, fundamental studies of stopping cross sections in this medium energy range will also be conducted.

  13. R-matrix calculation of electron collisions with the BF{sup +} molecular ion

    Energy Technology Data Exchange (ETDEWEB)

    Chakrabarti, K [Department of Mathematics, Scottish Church College, 1 and 3 Urquhart Sq, Kolkata 700006 (India); Tennyson, Jonathan [Department of Physics and Astronomy, University College London, Gower St, London WC1E 6BT (United Kingdom)

    2009-05-28

    Electron collisions with the BF{sup +} molecular ion are studied using the framework of the diatomic version of the UK molecular R-matrix codes. A configuration-interaction calculation is performed for BF{sup +} to obtain potential energy curves and target properties for 14 lowest doublet and quartet states. Scattering calculations are performed which yield resonance parameters and excitation cross sections in the energy range 0-20 eV. Cross sections for rotational excitations and an approximate calculation for the electron impact dissociation cross section for BF{sup +} are also presented.

  14. Towards hot electron mediated charge exchange in hyperthermal energy ion-surface interactions

    DEFF Research Database (Denmark)

    Ray, M. P.; Lake, R. E.; Thomsen, Lasse Bjørchmar

    2010-01-01

    We have made Na + and He + ions incident on the surface of solid state tunnel junctions and measured the energy loss due to atomic displacement and electronic excitations. Each tunnel junction consists of an ultrathin film metal–oxide–semiconductor device which can be biased to create a band of hot...... shows that the primary energy loss mechanism is the atomic displacement of Au atoms in the thin film of the metal–oxide–semiconductor device. We propose that neutral particle detection of the scattered flux from a biased device could be a route to hot electron mediated charge exchange....

  15. Tungsten spectroscopy at the Livermore electron beam ion trap facility

    National Research Council Canada - National Science Library

    Clementson, J; Beiersdorfer, P; Brown, G.V; Gu, M.F; Lundberg, H; Podpaly, Y; Trabert, E

    2011-01-01

    .... In this paper, an overview of recent results from the Livermore WOLFRAM spectroscopy project is presented, which includes experimental investigations at the EBIT-I and SuperEBIT electron beam ion traps...

  16. ULYSSES JUPITER HISCALE LEFS 60 ELECTRON/ION COUNTS

    Data.gov (United States)

    National Aeronautics and Space Administration — This data set consists of HISCALE Low-Energy Foil Spectrometer (LEFS) electron and ion counts at 60 degrees from the spacecraft spin axis. These measurements were...

  17. Accelerator complex of ion and electron storage rings

    CERN Document Server

    Noda, A

    2000-01-01

    An accelerator complex consisting of storage rings of ions and electrons with their booster synchrotron of combined-function type is proposed as one of the candidates of the facility for the new campus of Kyoto University. Maximum energies for ions and electrons are 290 and 1500 MeV, respectively. Aimed beam intensities are 10 sup 1 sup 0 and 4x10 sup 1 sup 1 per pulse for ions and electrons, respectively. With use of this accelerator complex, merging of highly ionized ions and trial of laser beam cooling to ultimate low temperature might be possible. The possibility of laser cooling with use of free electron laser is also to be studied.

  18. Application of compact electron cyclotron resonance ion source

    NARCIS (Netherlands)

    Muramatsu, M.; Kitagawa, A.; Iwata, Y.; Ogawa, H.; Hojo, S.; Kubo, T.; Kato, Y.; Biri, S.; Fekete, E.; Yoshida, Y.; Drentje, A. G.

    The compact electron cyclotron resonance (ECR) ion source with a permanent magnet configuration (Kei2 source) has been developed at National Institute of Radiological Sciences for a new carbon therapy facility. The Kei2 source was designed for production of C(4+) ions; its performance such as beam

  19. Understanding the nuclear initial state with an electron ion collider

    Science.gov (United States)

    Toll, Tobias

    2013-09-01

    In these proceedings I describe how a future electron-ion collider will allow us to directly measure the initial spatial distribution of gluons in heavy ions, as well as its variance ("lumpiness") in exclusive diffraction. I show the feasibility of such a measurement by means of simulated data from the novel event generator Sartre.

  20. Characterization of high-k dielectrics using MeV elastic scattering of He ions

    Energy Technology Data Exchange (ETDEWEB)

    Zoller, C.J. [Dept. of Physics and Astronomy, Ion Physics, Uppsala University, P.O. Box 516, SE 751 20 Uppsala (Sweden); Dentoni Litta, E. [KTH Royal Institute of Technology, School of ICT, Isafjordsgatan 22, SE 164 40 Kista (Sweden); Primetzhofer, D., E-mail: daniel.primetzhofer@physics.uu.se [Dept. of Physics and Astronomy, Ion Physics, Uppsala University, P.O. Box 516, SE 751 20 Uppsala (Sweden)

    2015-03-15

    We present a systematic comparison of two distinct ion-beam based methods for composition analysis of nanometer oxide films: ion-beam channeling and elastic scattering using nuclear resonances, both at MeV energies. Thin films of the technologically highly relevant high-k dielectrics HfO{sub 2} and HfAlO are characterized in the present study, with the additional aim of obtaining a better quantification of the Al content for the latter system. We show that both employed ion scattering methods enable a quantitative determination of the oxygen concentrations with typical uncertainties of about 5–10% in the oxygen fraction. The influence of various kinds of systematic inaccuracies in the evaluation procedure are discussed.

  1. Quantum ion acoustic solitary waves in electron-ion plasmas: A Sagdeev potential approach

    Energy Technology Data Exchange (ETDEWEB)

    Mahmood, S. [Theoretical Plasma Physics Division, PINSTECH, P.O. Nilore, Islamabad (Pakistan)], E-mail: shahzad_mahmoodpk@yahoo.com; Mushtaq, A. [Theoretical Plasma Physics Division, PINSTECH, P.O. Nilore, Islamabad (Pakistan)

    2008-05-05

    Linear and nonlinear ion acoustic waves are studied in unmagnetized electron-ion quantum plasmas. Sagdeev potential approach is employed to describe the nonlinear quantum ion acoustic waves. It is found that density dips structures are formed in the subsonic region in a electron-ion quantum plasma case. The amplitude of the nonlinear structures remains constant and the width is broadened with the increase in the quantization of the system. However, the nonlinear wave amplitude is reduced with the increase in the wave Mach number. The numerical results are also presented.

  2. R-matrix study of electron impact excitation and dissociation of CH+ ions

    Science.gov (United States)

    Chakrabarti, K.; Dora, A.; Ghosh, R.; Choudhury, B. S.; Tennyson, Jonathan

    2017-09-01

    Electron impact excitation and electron impact dissociation of CH+ ions are studied in the framework of the R-matrix method using the diatomic version of the UK molecular R-matrix codes. A configuration interaction calculation is first performed to yield the potential energy curves of the lowest eight singlet and triplet states of CH+. Scattering calculations are then performed to yield vibrationally-resolved electronic excitations to the lowest three bound states, namely the a {}3{{\\Pi }}, A {}1{{\\Pi }} and the b {}3{{{Σ }}}-. Electron impact dissociation cross sections are obtained from the assumption that all electronic excitations above the dissociation threshold result in dissociation. Bound states of CH and resonance positions and widths of Feshbach resonances in the e-CH+ system are also calculated at the CH+ equilibrium bond length 2.137 a0.

  3. Experiments Studying Desorbed Gas and Electron Clouds in Ion Accelerators

    CERN Document Server

    Molvik, Arthur; Barnard, John J; Bieniosek, Frank; Celata, C M; Cohen, Ronald; Covo, Michel K; Friedman, Alex; Lund, Steven M; Seidl, Peter; Vay, Jean-Luc; Vujic, J L; Waldron, William

    2005-01-01

    Electron clouds and gas pressure rise limit the performance of many major accelerator rings. We are studying these issues experimentally with ~1 MeV heavy-ion beams, coordinated with significant efforts in self-consistent simulation and theory.* The experiments use multiple diagnostics, within and between quadrupole magnets, to measure the sources and accumulation of electrons and gas. In support of these studies, we have measured gas desorption and electron emission coefficients for potassium ions impinging on stainless steel targets at angles near grazing incidence.** Our goal is to measure the electron particle balance for each source - ionization of gas, emission from beam tubes, and emission from an end wall - determine the electron effects on the ion beam and apply the increased understanding to mitigation.

  4. Low energy cross sections for electron scattering from tetrafluoroallene

    Science.gov (United States)

    Gupta, Dhanoj; Choi, Heechol; Song, Mi-Young; Chakrabarti, Kalyan; Yoon, Jung-Sik

    2017-08-01

    We report elastic, total, excitation, differential and momentum-transfer cross sections for scattering of low-energy electrons by tetrafluoroallene (C3F4) using the close-coupling (CC) approximation in the R-matrix method with Quantemol-N. We have tested various target models initially to check for the convergence of the result and the final results are provided with the best target model. We have detected shape resonances of symmetry 2 E(2B1,2B2) at 3.08 eV and 3.71 eV with a close-coupling and static exchange models which is seen as a sharp feature in the elastic and momentum transfer cross sections. We also detected other resonances of symmetry 2 E at 11.26 eV and of symmetry 2A2 at 11.12 eV below the ionization threshold of the target respectively. The present elastic and total cross sections are compared with the elastic and total cross sections of allene (C3H4), propene (C3H6) and hexafluoropropene (C3F6) as there were no results available for C3F4. The effect of fluorination is clearly seen with the shape resonance for C3F4 getting slightly shifted to higher energies compared to allene. Finally, we also report the ionization cross section calculated using the Binary-Encounter Bethe (BEB) method. The present calculation is a maiden attempt to find cross sections for C3F4 molecule which could be useful for fluorocarbon plasma modeling.

  5. Investigation of ionospheric stimulated Brillouin scatter generated at pump frequencies near electron gyroharmonics

    Science.gov (United States)

    Mahmoudian, A.; Scales, W. A.; Bernhardt, P. A.; Fu, H.; Briczinski, S. J.; McCarrick, M. J.

    2013-11-01

    Stimulated Electromagnetic Emissions (SEEs), secondary electromagnetic waves excited by high power electromagnetic waves transmitted into the ionosphere, produced by the Magnetized Stimulated Brillouin Scatter (MSBS) process are investigated. Data from four recent research campaigns at the High Frequency Active Auroral Research Program (HAARP) facility is presented in this work. These experiments have provided additional quantitative interpretation of the SEE spectrum produced by MSBS to yield diagnostic measurements of the electron temperature and ion composition in the heated ionosphere. SEE spectral emission lines corresponding to ion acoustic (IA) and electrostatic ion cyclotron (EIC) mode excitation were observed with a shift in frequency up to a few tens of Hz from the pump frequency for heating near the third harmonic of the electron gyrofrequency 3fce. The threshold of each emission line has been measured by changing the pump wave power. The excitation threshold of IA and EIC emission lines originating at the reflection and upper hybrid altitudes is measured for various beam angles relative to the magnetic field. Variation of strength of MSBS emission lines with pump frequency relative to 3fce and 4fce is also studied. A full wave solution has been used to estimate the amplitude of the electric field at the interaction altitude. The estimated instability threshold using the theoretical model is compared with the threshold of MSBS lines in the experiment and possible diagnostic information for the background ionospheric plasma is discussed. Simultaneous formation of artificial field-aligned irregularities (FAIs) and suppression of the MSBS process is investigated. This technique can be used to estimate the growth time of artificial FAIs which may result in determination of plasma waves and physical process involved in the formation of FAIs.

  6. Room scatter effects in Total Skin Electron Irradiation: Monte Carlo simulation study.

    Science.gov (United States)

    Nevelsky, Alexander; Borzov, Egor; Daniel, Shahar; Bar-Deroma, Raquel

    2017-01-01

    Total Skin Electron Irradiation (TSEI) is a complex technique which usually involves the use of large electron fields and the dual-field approach. In this situation, many electrons scattered from the treatment room floor are produced. However, no investigations of the effect of scattered electrons in TSEI treatments have been reported. The purpose of this work was to study the contribution of floor scattered electrons to skin dose during TSEI treatment using Monte Carlo (MC) simulations. All MC simulations were performed with the EGSnrc code. Influence of beam energy, dual-field angle, and floor material on the contribution of floor scatter was investigated. Spectrum of the scattered electrons was calculated. Measurements of dose profile were performed in order to verify MC calculations. Floor scatter dependency on the floor material was observed (at 20 cm from the floor, scatter contribution was about 21%, 18%, 15%, and 12% for iron, concrete, PVC, and water, respectively). Although total dose profiles exhibited slight variation as functions of beam energy and dual-field angle, no dependence of the floor scatter contribution on the beam energy or dual-field angle was found. The spectrum of the scattered electrons was almost uniform between a few hundred KeV to 4 MeV, and then decreased linearly to 6 MeV. For the TSEI technique, dose contribution due to the electrons scattered from the room floor may be clinically significant and should be taken into account during design and commissioning phases. MC calculations can be used for this task. © 2017 The Authors. Journal of Applied Clinical Medical Physics published by Wiley Periodicals, Inc. on behalf of American Association of Physicists in Medicine.

  7. Experimental determination of the electron-avalanche and the electron-ion recombination coefficient

    NARCIS (Netherlands)

    Ernst, G.J.; Boer, A.G.

    1980-01-01

    The electron-ion recombination coefficient γ and the avalanche coefficient δ = (α − a) · vd, where α and a are the ionizat ion and attachment coefficients respectively and vd the drift velocity of the electrons, have been experimentally determined in a self-sustained CO2-laser system (1:1:3 mixture)

  8. Gyrokinetic stability of electron-positron-ion plasmas

    Science.gov (United States)

    Mishchenko, A.; Zocco, A.; Helander, P.; Könies, A.

    2018-02-01

    The gyrokinetic stability of electron-positron plasmas contaminated by an ion (proton) admixture is studied in a slab geometry. The appropriate dispersion relation is derived and solved. Stable K-modes, the universal instability, the ion-temperature-gradient-driven instability, the electron-temperature-gradient-driven instability and the shear Alfvén wave are considered. It is found that the contaminated plasma remains stable if the contamination degree is below some threshold and that the shear Alfvén wave can be present in a contaminated plasma in cases where it is absent without ion contamination.

  9. Shutterless ion mobility spectrometer with fast pulsed electron source

    Science.gov (United States)

    Bunert, E.; Heptner, A.; Reinecke, T.; Kirk, A. T.; Zimmermann, S.

    2017-02-01

    Ion mobility spectrometers (IMS) are devices for fast and very sensitive trace gas analysis. The measuring principle is based on an initial ionization process of the target analyte. Most IMS employ radioactive electron sources, such as 63Ni or 3H. These radioactive materials have the disadvantage of legal restrictions and the electron emission has a predetermined intensity and cannot be controlled or disabled. In this work, we replaced the 3H source of our IMS with 100 mm drift tube length with our nonradioactive electron source, which generates comparable spectra to the 3H source. An advantage of our emission current controlled nonradioactive electron source is that it can operate in a fast pulsed mode with high electron intensities. By optimizing the geometric parameters and developing fast control electronics, we can achieve very short electron emission pulses for ionization with high intensities and an adjustable pulse width of down to a few nanoseconds. This results in small ion packets at simultaneously high ion densities, which are subsequently separated in the drift tube. Normally, the required small ion packet is generated by a complex ion shutter mechanism. By omitting the additional reaction chamber, the ion packet can be generated directly at the beginning of the drift tube by our pulsed nonradioactive electron source with only slight reduction in resolving power. Thus, the complex and costly shutter mechanism and its electronics can also be omitted, which leads to a simple low-cost IMS-system with a pulsed nonradioactive electron source and a resolving power of 90.

  10. Contributions of Mirror and Ion Bernstein Instabilities to the Scattering of Pickup Ions in the Outer Heliosheath

    Science.gov (United States)

    Min, Kyungguk; Liu, Kaijun

    2018-01-01

    Maintaining the stability of pickup ions in the outer heliosheath is a critical element for the secondary energetic neutral atom (ENA) mechanism, a theory put forth to explain the nearly annular band of ENA emission observed by the Interstellar Boundary EXplorer. A recent study showed that a pickup ion ring can remain stable to the Alfvén/ion cyclotron (AC) instability at propagation parallel to the background magnetic field when the parallel thermal spread of the ring is comparable to that of a background population. This study investigates the potential role that the mirror or ion Bernstein (IB) instabilities can play in the stability of pickup ions when conditions are such that the AC instability is suppressed. Linear Vlasov theory predicts relatively fast mirror and IB instability growth even though AC instability growth is suppressed. For a few such cases, two-dimensional hybrid and macroscopic quasi-linear simulations are carried out to examine how the unstable mirror and IB modes evolve and affect the pickup ion ring beyond the linear theory picture. For the parameters used, the mirror mode dominates initially and leads to a rapid parallel heating of the pickup ions in excess of the parallel temperature of the background protons. The heated pickup ions subsequently trigger onset of the AC mode, which grows sufficiently large to be the dominant pitch angle scattering agent after the mirror mode has decayed away. The present results indicate that the pickup ion stability needed may not be guaranteed once the mirror and IB instabilities are taken into account.

  11. Relativistic electromagnetic waves in an electron-ion plasma

    Science.gov (United States)

    Chian, Abraham C.-L.; Kennel, Charles F.

    1987-01-01

    High power laser beams can drive plasma particles to relativistic energies. An accurate description of strong waves requires the inclusion of ion dynamics in the analysis. The equations governing the propagation of relativistic electromagnetic waves in a cold electron-ion plasma can be reduced to two equations expressing conservation of energy-momentum of the system. The two conservation constants are functions of the plasma stream velocity, the wave velocity, the wave amplitude, and the electron-ion mass ratio. The dynamic parameter, expressing electron-ion momentum conversation in the laboratory frame, can be regarded as an adjustable quantity, a suitable choice of which will yield self-consistent solutions when other plasma parameters were specified. Circularly polarized electromagnetic waves and electrostatic plasma waves are used as illustrations.

  12. Quasielastic Diffuse Neutron Scattering from Fluorites in the Fast Ion Phase

    DEFF Research Database (Denmark)

    Clausen, K.; Hayes, W.; Hutchings, M.T

    1981-01-01

    Quasielastic diffuse coherent neutron scattering arising from the dynamically disordered anions in CaF2 and PbF2 has been investigated as the temperature is increased into the fast ion phase. The characteristic variation with scattering vector Image of the integrated intensity, S(Image ), can...... be accounted for by a model in which the most probable instantaneous configuration of the defective anions is a cluster centered at the mid-point of nearest-neighbour regular anion sites. The observed S(Image ,ω) is Lorentzian in ω and the width has a marked increase with temperature....

  13. Enhanced electron/fuel-ion equilibration through impurity ions: Studies applicable to NIF and Omega

    Science.gov (United States)

    Petrasso, R. D.; Sio, H.; Kabadi, N.; Lahmann, B.; Simpson, R.; Parker, C.; Frenje, J.; Gatu Johnson, M.; Li, C. K.; Seguin, F. H.; Rinderknecht, H.; Casey, D.; Grabowski, P.; Graziani, F.; Taitano, W.; Le, A.; Chacon, L.; Hoffman, N.; Kagan, G.; Simakov, A.; Zylstra, A.; Rosenberg, M.; Betti, R.; Srinivasan, B.; Mancini, R.

    2017-10-01

    In shock-driven exploding-pushers, a platform used extensively to study multi-species and kinetic effects, electrons and fuel ions are far out of equilibrium, as reflected by very different temperatures. However, impurity ions, even in small quantities, can couple effectively to the electrons, because of a Z2 dependence, and in turn, impurity ions can then strongly couple to the fuel ions. Through this mechanism, electrons and fuel-ions can equilibrate much faster than they otherwise would. This is a quantitative issue, depending upon the amount and Z of the impurity. For NIF and Omega, we consider the role of this process. Coupled non-linear equations, reflecting the temperatures of the three species, are solved for a range of conditions. Consideration is also given to ablatively driven implosions, since impurities can similarly affect the equilibration. This work was supported in part by DOE/NNSA DE-NA0002949 and DE-NA0002726.

  14. A double-layer based model of ion confinement in electron cyclotron resonance ion source

    Science.gov (United States)

    Mascali, D.; Neri, L.; Celona, L.; Castro, G.; Torrisi, G.; Gammino, S.; Sorbello, G.; Ciavola, G.

    2014-02-01

    The paper proposes a new model of ion confinement in ECRIS, which can be easily generalized to any magnetic configuration characterized by closed magnetic surfaces. Traditionally, ion confinement in B-min configurations is ascribed to a negative potential dip due to superhot electrons, adiabatically confined by the magneto-static field. However, kinetic simulations including RF heating affected by cavity modes structures indicate that high energy electrons populate just a thin slab overlapping the ECR layer, while their density drops down of more than one order of magnitude outside. Ions, instead, diffuse across the electron layer due to their high collisionality. This is the proper physical condition to establish a double-layer (DL) configuration which self-consistently originates a potential barrier; this "barrier" confines the ions inside the plasma core surrounded by the ECR surface. The paper will describe a simplified ion confinement model based on plasma density non-homogeneity and DL formation.

  15. A double-layer based model of ion confinement in electron cyclotron resonance ion source

    Energy Technology Data Exchange (ETDEWEB)

    Mascali, D., E-mail: davidmascali@lns.infn.it; Neri, L.; Celona, L.; Castro, G.; Gammino, S.; Ciavola, G. [Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali del Sud, via S. Sofia 62, 95123 Catania (Italy); Torrisi, G. [Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali del Sud, via S. Sofia 62, 95123 Catania (Italy); Università Mediterranea di Reggio Calabria, Dipartimento di Ingegneria dell’Informazione, delle Infrastrutture e dell’Energia Sostenibile, Via Graziella, I-89100 Reggio Calabria (Italy); Sorbello, G. [Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali del Sud, via S. Sofia 62, 95123 Catania (Italy); Università degli Studi di Catania, Dipartimento di Ingegneria Elettrica Elettronica ed Informatica, Viale Andrea Doria 6, 95125 Catania (Italy)

    2014-02-15

    The paper proposes a new model of ion confinement in ECRIS, which can be easily generalized to any magnetic configuration characterized by closed magnetic surfaces. Traditionally, ion confinement in B-min configurations is ascribed to a negative potential dip due to superhot electrons, adiabatically confined by the magneto-static field. However, kinetic simulations including RF heating affected by cavity modes structures indicate that high energy electrons populate just a thin slab overlapping the ECR layer, while their density drops down of more than one order of magnitude outside. Ions, instead, diffuse across the electron layer due to their high collisionality. This is the proper physical condition to establish a double-layer (DL) configuration which self-consistently originates a potential barrier; this “barrier” confines the ions inside the plasma core surrounded by the ECR surface. The paper will describe a simplified ion confinement model based on plasma density non-homogeneity and DL formation.

  16. Commissioning of the LEIR electron cooler with Pb$^{+54}$ ions

    CERN Document Server

    Tranquille, G; Carly, Ch; Prieto, V; Sautier, R; Bubley, A; Parkhomchuk, V; Reva, V; Brizgunov, M; Vedenev, M; Panasyuk, V

    2006-01-01

    The new LEIR cooler with a variable profile of the electron beam and electrostatic bending was commissioned in 2005-2006. In this paper we present our experience with the commissioning of the new device as well as the first results of the ion beam Pb +54 cooling with a high-intensity variable-density electron beam.

  17. Probing an Electron Scattering Resonance using Rydberg Molecules within a Dense and Ultracold Gas.

    Science.gov (United States)

    Schlagmüller, Michael; Liebisch, Tara Cubel; Nguyen, Huan; Lochead, Graham; Engel, Felix; Böttcher, Fabian; Westphal, Karl M; Kleinbach, Kathrin S; Löw, Robert; Hofferberth, Sebastian; Pfau, Tilman; Pérez-Ríos, Jesús; Greene, Chris H

    2016-02-05

    We present spectroscopy of a single Rydberg atom excited within a Bose-Einstein condensate. We not only observe the density shift as discovered by Amaldi and Segrè in 1934, but a line shape that changes with the principal quantum number n. The line broadening depends precisely on the interaction potential energy curves of the Rydberg electron with the neutral atom perturbers. In particular, we show the relevance of the triplet p-wave shape resonance in the e^{-}-Rb(5S) scattering, which significantly modifies the interaction potential. With a peak density of 5.5×10^{14}  cm^{-3}, and therefore an interparticle spacing of 1300 a_{0} within a Bose-Einstein condensate, the potential energy curves can be probed at these Rydberg ion-neutral atom separations. We present a simple microscopic model for the spectroscopic line shape by treating the atoms overlapped with the Rydberg orbit as zero-velocity, uncorrelated, pointlike particles, with binding energies associated with their ion-neutral separation, and good agreement is found.

  18. Radiative Recombination and Photoionization Data for Tungsten Ions. Electron Structure of Ions in Plasmas

    Directory of Open Access Journals (Sweden)

    Malvina B. Trzhaskovskaya

    2015-05-01

    Full Text Available Theoretical studies of tungsten ions in plasmas are presented. New calculations of the radiative recombination and photoionization cross-sections, as well as radiative recombination and radiated power loss rate coefficients have been performed for 54 tungsten ions for the range W6+–W71+. The data are of importance for fusion investigations at the reactor ITER, as well as devices ASDEX Upgrade and EBIT. Calculations are fully relativistic. Electron wave functions are found by the Dirac–Fock method with proper consideration of the electron exchange. All significant multipoles of the radiative field are taken into account. The radiative recombination rates and the radiated power loss rates are determined provided the continuum electron velocity is described by the relativistic Maxwell–Jüttner distribution. The impact of the core electron polarization on the radiative recombination cross-section is estimated for the Ne-like iron ion and for highly-charged tungsten ions within an analytical approximation using the Dirac–Fock electron wave functions. The effect is shown to enhance the radiative recombination cross-sections by ≲20%. The enhancement depends on the photon energy, the principal quantum number of polarized shells and the ion charge. The influence of plasma temperature and density on the electron structure of ions in local thermodynamic equilibrium plasmas is investigated. Results for the iron and uranium ions in dense plasmas are in good agreement with previous calculations. New calculations were performed for the tungsten ion in dense plasmas on the basis of the average-atom model, as well as for the impurity tungsten ion in fusion plasmas using the non-linear self-consistent field screening model. The temperature and density dependence of the ion charge, level energies and populations are considered.

  19. Numerical model of electron cyclotron resonance ion source

    Directory of Open Access Journals (Sweden)

    V. Mironov

    2015-12-01

    Full Text Available Important features of the electron cyclotron resonance ion source (ECRIS operation are accurately reproduced with a numerical code. The code uses the particle-in-cell technique to model the dynamics of ions in ECRIS plasma. It is shown that a gas dynamical ion confinement mechanism is sufficient to provide the ion production rates in ECRIS close to the experimentally observed values. Extracted ion currents are calculated and compared to the experiment for a few sources. Changes in the simulated extracted ion currents are obtained with varying the gas flow into the source chamber and the microwave power. Empirical scaling laws for ECRIS design are studied and the underlying physical effects are discussed.

  20. Incident ion charge state dependence of electron emission during slow multicharged ion-surface interactions

    Energy Technology Data Exchange (ETDEWEB)

    Hughes, I.G. (Oak Ridge National Laboratory, Oak Ridge, TN 37831-6372 (United States) Joint Institute for Heavy Ion Research, Holifield Heavy Ion Research, Facility, Oak Ridge, TN 37831-6734 (United States)); Havener, C.C.; Overbury, S.H.; Robinson, M.T.; Zehner, D.M. (Oak Ridge National Laboratory, Oak Ridge, TN 37831-6732 (United States)); Zeijlmans van Emmichoven, P.A. (Oak Ridge National Laboratory, Oak Ridge, TN 37831-6732 (United States) Joint Institute for Heavy Ion Research, Holifield Heavy Ion Research Facility, Oak Ridge, TN 37821-6734 (United States)); Meyer, F.W. (Oak Ridge National Laboratory, Oak Ridge, TN 37831-6732 (United States))

    1993-06-05

    Characteristic variations in the total electron yield [gamma] as a function of crystal azimuthal orientation are reported for slow N[sup 2+], N[sup 5+] and N[sup 6+] ions incident on a Au(011) single crystal, together with measurements of [gamma] as a function of incident ion velocity. Kinetic electron emission is shown to arise predominantly in close collisions between incident ions and target atoms, and potential electron emission is found to be essentially constant within our present velocity range. The incident ion charge state is shown to play no role in kinetic electron emission. Extremely fast neutralization times of the order of 10[sup [minus]15] secs are needed to explain the observations.

  1. Selective minority-ion heating in the afterglow of an electron cyclotron resonance ion source

    NARCIS (Netherlands)

    Nadzeyka, A; Meyer, D; Barzangy, F; Drentje, AG; Wiesemann, K

    We report first experimental results on selective minority-ion heating in the afterglow mode of electron cyclotron resonance ion sources in Bochum and at the KVI (Groningen) in mixtures of Ar/O/He and in pure nitrogen. In addition we measured time resolved vacuum ultraviolet-line intensities of

  2. An Organic Mixed Ion-Electron Conductor for Power Electronics

    DEFF Research Database (Denmark)

    Malti, Abdellah; Edberg, Jesper; Granberg, Hjalmar

    2016-01-01

    A mixed ionic–electronic conductor based on nanofibrillated cellulose composited with poly(3,4-ethylene-dioxythio­phene):­poly(styrene-sulfonate) along with high boiling point solvents is demonstrated in bulky electrochemical devices. The high electronic and ionic conductivities of the resulting...

  3. Increasing positive ion number densities below the peak of ion-electron pair production in Titan's ionosphere

    Energy Technology Data Exchange (ETDEWEB)

    Vigren, E.; Galand, M. [Department of Physics, Imperial College London, London SW7 2AZ (United Kingdom); Shebanits, O.; Wahlund, J.-E. [Swedish Institute of Space Physics, P.O. Box 537, SE-751 21 Uppsala (Sweden); Geppert, W. D. [Department of Physics, Stockholm University, SE-10691 Stockholm (Sweden); Lavvas, P. [Groupe de Spectrométrie Moléculaire et Atmosphérique, Université Reims Champagne-Ardenne, UMR 7331, F-51687 Reims (France); Vuitton, V. [Institut de Planétologie et d' Astrophysique de Grenoble (IPAG), UJF-Grenoble/CNRS-INSU, UMR 5274, F-38041 Grenoble (France); Yelle, R. V., E-mail: erik.vigren@irfu.se [Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ 85721-0092 (United States)

    2014-05-01

    We combine derived ion-electron pair formation rates with Cassini Radio Plasma Wave Science Langmuir Probe measurements of electron and positive ion number densities in Titan's sunlit ionosphere. We show that positive ion number densities in Titan's sunlit ionosphere can increase toward significantly lower altitudes than the peak of ion-electron pair formation despite that the effective ion-electron recombination coefficient increases. This is explained by the increased mixing ratios of negative ions, which are formed by electron attachment to neutrals. While such a process acts as a sink for free electrons, the positive ions become longer-lived as the rate coefficients for ion-anion neutralization reactions are smaller than those for ion-electron dissociative recombination reactions.

  4. Absolute cross section measurements for the scattering of low- and intermediate-energy electrons from PF3. I. Elastic scattering

    Science.gov (United States)

    Hishiyama, N.; Hoshino, M.; Blanco, F.; García, G.; Tanaka, H.

    2017-12-01

    We report absolute elastic differential cross sections (DCSs) for electron collisions with phosphorus trifluoride, PF3, molecules (e- + PF3) in the impact energy range of 2.0-200 eV and over a scattering angle range of 10°-150°. Measured angular distributions of scattered electron intensities were normalized by reference to the elastic DCSs of He. Corresponding integral and momentum-transfer cross sections were derived by extrapolating the angular range from 0° to 180° with the help of a modified phase-shift analysis. In addition, due to the large dipole moment of the considered molecule, the dipole-Born correction for the forward scattering angles has also been applied. As a part of this study, independent atom model calculations in combination with screening corrected additivity rule were also performed for elastic and inelastic (electronic excitation plus ionization) scattering using a complex optical potential method. Rotational excitation cross sections have been estimated with a dipole-Born approximation procedure. Vibrational excitations are not considered in this calculation. Theoretical data, at the differential and integral levels, were found to reasonably agree with the present experimental results. Furthermore, we explore the systematics of the elastic DCSs for the four-atomic trifluoride molecules of XF3 (X = B, N, and P) and central P-atom in PF3, showing that, owing to the comparatively small effect of the F-atoms, the present angular distributions of elastic DCSs are essentially dominated by the characteristic of the central P-atom at lower impact energies. Finally, these quantitative results for e- - PF3 collisions were compiled together with the previous data available in the literature in order to obtain a cross section dataset for modeling purposes. To comprehensively describe such a considerable amount of data, we proceed by first discussing, in this paper, the vibrationally elastic scattering processes whereas vibrational and electronic

  5. High-magnetic-field-assisted scattering of electrons with atomic hydrogen

    Energy Technology Data Exchange (ETDEWEB)

    Chakraborty, Ajoy [Laban Hrad Vidyapith, AD-369, Salt Lake City, Kolkata 700064 (India)

    2007-04-28

    We have investigated quantum mechanically the scattering of electrons off atomic hydrogen in a strong magnetic field. Elastic, inelastic, backward and total scattering cross sections are reported. Near-resonance behaviour of the system is analysed. Results are presented after evaluating and summing all-order Born series under suitable physical conditions.

  6. Determination of Rest Mass Energy of the Electron by a Compton Scattering Experiment

    Science.gov (United States)

    Prasannakumar, S.; Krishnaveni, S.; Umesh, T. K.

    2012-01-01

    We report here a simple Compton scattering experiment which may be carried out in graduate and undergraduate laboratories to determine the rest mass energy of the electron. In the present experiment, we have measured the energies of the Compton scattered gamma rays with a NaI(Tl) gamma ray spectrometer coupled to a 1 K multichannel analyzer at…

  7. Development of electron optical system using annular pupils for scanning transmission electron microscope by focused ion beam

    Energy Technology Data Exchange (ETDEWEB)

    Matsutani, Takaomi, E-mail: matutani@ele.kindai.ac.jp [Kinki University, 3-4-1 Kowakae, Higashiosaka, Osaka 577-8502 (Japan); Yasumoto, Tsuchika; Tanaka, Takeo [Osaka Sangyo University, 3-1-1 Nakagaito, Daito, Osaka 574-8530 (Japan); Kawasaki, Tadahiro; Ichihashi, Mikio [Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8603 (Japan); Ikuta, Takashi [Osaka Electro-Communication University, 18-8 Hatsu-cho, Neyagawa, Osaka 572-8530 (Japan)

    2012-02-01

    Annular pupils for electron optics were produced using a focused ion beam (FIB), enabling an increase in the depth of focus and allowing for aberration-free imaging and separation of the amplitude and phase images in a scanning transmission electron microscope (STEM). Simulations demonstrate that an increased focal depth is advantageous for three-dimensional tomography in the STEM. For a 200 kV electron beam, the focal depth is increased to approximately 100 nm by using an annular pupil with inner and outer semi-angles of 29 and 30 mrad, respectively. Annular pupils were designed with various outer diameters of 40-120 {mu}m and the inner diameter was designed at 80% of the outer diameter. A taper angle varying from 1 Degree-Sign to 20 Degree-Sign was applied to the slits of the annular pupils to suppress the influence of high-energy electron scattering. The fabricated annular pupils were inspected by scanning ion beam microscopy and scanning electron microscopy. These annular pupils were loaded into a STEM and no charge-up effects were observed in the scintillator projection images recorded by a CCD camera.

  8. Electron transfer processes of atomic and molecular doubly charged ions: information from beam experiments

    Science.gov (United States)

    Herman, Zdenek

    2013-07-01

    Single-electron transfer reactions in collisions of atomic and molecular doubly charged ions, with atoms and molecules, were investigated in a series of crossed-beam scattering, translational spectroscopy and product luminescence experiments. Investigation of a series of atomic dication-atom electron transfer at collision energies of 0.1-10 eV provided data on differential and relative total cross sections of state-to-state processes. Populations of electronic and vibrational states and rotational temperatures of molecular product ions were obtained from studies of non-dissociative electron transfer in systems containing simple molecular dications and/or molecular targets. The product electronic states populated with highest probability were those for which the translational energy release was 3-5 eV, indicating that the 'reaction window' concept, based on the Landau-Zener formalism, is applicable also to molecular systems. Population of the vibrational states of the molecular products could be described by Franck-Condon factors of the vertical transitions between the reactant and product states, especially at higher (keV) collision energies. Rotational temperature of the product molecular cations was found to be surprisingly low, mostly 400-500 K, practically the temperature of the ion source.

  9. Degradation of Methylammonium Lead Iodide Perovskite Structures through Light and Electron Beam Driven Ion Migration

    Science.gov (United States)

    2016-01-01

    Organometal halide perovskites show promising features for cost-effective application in photovoltaics. The material instability remains a major obstacle to broad application because of the poorly understood degradation pathways. Here, we apply simultaneous luminescence and electron microscopy on perovskites for the first time, allowing us to monitor in situ morphology evolution and optical properties upon perovskite degradation. Interestingly, morphology, photoluminescence (PL), and cathodoluminescence of perovskite samples evolve differently upon degradation driven by electron beam (e-beam) or by light. A transversal electric current generated by a scanning electron beam leads to dramatic changes in PL and tunes the energy band gaps continuously alongside film thinning. In contrast, light-induced degradation results in material decomposition to scattered particles and shows little PL spectral shifts. The differences in degradation can be ascribed to different electric currents that drive ion migration. Moreover, solution-processed perovskite cuboids show heterogeneity in stability which is likely related to crystallinity and morphology. Our results reveal the essential role of ion migration in perovskite degradation and provide potential avenues to rationally enhance the stability of perovskite materials by reducing ion migration while improving morphology and crystallinity. It is worth noting that even moderate e-beam currents (86 pA) and acceleration voltages (10 kV) readily induce significant perovskite degradation and alter their optical properties. Therefore, attention has to be paid while characterizing such materials using scanning electron microscopy or transmission electron microscopy techniques. PMID:26804213

  10. Study of CuAl(100) by using He ion scattering

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, L.; Zur Muhlen, E.; O`Connor, D.J. [Newcastle Univ., NSW (Australia). Dept. of Physics

    1993-12-31

    The clean CuAl (100) surface has been investigated by using He{sup +} ion scattering. The polar scans show that Al atoms randomly replace the Cu atoms but sit (0.15{+-}0.05) Angstroms higher than the Cu atoms. The outmost layer concentration of Al is about (17{+-}3)%. The aluminium concentration on the outmost layer is sensitive to the sample temperature up to 300 deg C. 7 refs., 5 figs.

  11. Study of electron impact inelastic scattering of chlorine molecule (Cl2)

    Science.gov (United States)

    Yadav, Hitesh; Vinodkumar, Minaxi; Limbachiya, Chetan; Vinodkumar, P. C.

    2018-02-01

    A theoretical study is carried out for electron interactions with the chlorine molecule (Cl2) for incident energies ranging from 0.01 to 5000 eV. This wide range of energy has allowed us to investigate a variety of processes and report data on symmetric excitation energies, dissociative electron attachment (DEA), total excitation cross sections, and ionization cross section (Q ion) along with total inelastic cross sections (Q inel). The present study is important since Cl2 is a prominent gas for plasma etching and its anionic atoms are important in the etching of semiconductor wafers. In order to compute the total inelastic cross sections, we have employed the ab initio R-matrix method (0.01 to 15 eV) together with the spherical complex optical potential method (∼15 to 5000 eV). The R-matrix calculations are performed using a close coupling method, and we have used DEA estimator via Quantemol-N to calculate the DEA fragmentation and cross sections. The present study finds overall good agreement with the available experimental data. Total excitation and inelastic cross sections of e-{{{Cl}}}2 scattering for a wide energy range (0.01 to 5 keV) are reported for the first time, to the best of our knowledge.

  12. Competition between outer zone electron scattering by plasmaspheric hiss and magnetosonic waves

    Science.gov (United States)

    Ni, Binbin; Hua, Man; Zhou, Ruoxian; Yi, Juan; Fu, Song

    2017-04-01

    We quantify the electron scattering effects of simultaneous plasmaspheric hiss and magnetosonic waves that occurred in two neighboring time intervals but with distinct wave intensity profiles on 21 August 2013. Their combined scattering is found capable of causing electron distribution variations largely distinguishable from the consequences of individual waves. The net effect of electron diffusion relies strongly on the relative dominance of the two wave intensities, which also controls the relative contribution of each wave mode. In combination, MS waves slow down the hiss-induced loss of 100 keV electrons, and hiss efficiently inhibits the electron butterfly distribution caused by MS waves to produce a gradual acceleration process. Our results strongly suggest that comprehensive simulations of the radiation belt electron dynamics should carefully incorporate the combined scattering and complex competition resulting from simultaneous occurrences of various magnetospheric emissions, including, but not limited to, plamaspheric hiss and magnetosonic waves.

  13. Resonant scattering of energetic electrons by unusual low-frequency hiss

    Science.gov (United States)

    Ni, Binbin; Li, Wen; Thorne, Richard M.; Bortnik, Jacob; Ma, Qianli; Chen, Lunjin; Kletzing, Craig A.; Kurth, William S.; Hospodarsky, George B.; Reeves, Geoffrey D.; Spence, Harlan E.; Bernard Blake, J.; Fennell, Joseph F.; Claudepierre, Seth G.

    2014-03-01

    We quantify the resonant scattering effects of the unusual low-frequency dawnside plasmaspheric hiss observed on 30 September 2012 by the Van Allen Probes. In contrast to normal (~100-2000 Hz) hiss emissions, this unusual hiss event contained most of its wave power at ~20-200 Hz. Compared to the scattering by normal hiss, the unusual hiss scattering speeds up the loss of ~50-200 keV electrons and produces more pronounced pancake distributions of ~50-100 keV electrons. It is demonstrated that such unusual low-frequency hiss, even with a duration of a couple of hours, plays a particularly important role in the decay and loss process of energetic electrons, resulting in shorter electron lifetimes for ~50-400 keV electrons than normal hiss, and should be carefully incorporated into global modeling of radiation belt electron dynamics during periods of intense injections.

  14. Spin–spin correlations and entanglement in elastic electron scattering from hydrogen atoms

    Science.gov (United States)

    Bartschat, Klaus

    2017-11-01

    In two recent papers, Blum and Lohmann (2016 Phys. Rev. Lett. 116 033201) and Lohmann et al (2016 Phys. Rev. A 94 032331), the possibility of continuously varying the degree of entanglement between an elastically scattered electron and the valence electron of quasi-one electron targets was discussed. Here we present results for elastic electron scattering from atomic hydrogen in the energy regime of 1‑10 eV and the full range of scattering angles 0^\\circ -180^\\circ . We confirm previous calculations at very low energies, which predicted that the hydrogen target is not a promising candidate for Bell correlations through electron collisions. This finding remains unchanged in the near-resonance regime of incident electron energies just below 10 eV. In addition to the spin-correlation parameter P, we present the angle-integrated total cross section, as well as the angle-differential cross section at a few representative collision energies.

  15. Transferable Pseudo-Classical Electrons for Aufbau of Atomic Ions

    Science.gov (United States)

    Ekesan, Solen; Kale, Seyit; Herzfeld, Judith

    2014-01-01

    Generalizing the LEWIS reactive force field from electron pairs to single electrons, we present LEWIS• in which explicit valence electrons interact with each other and with nuclear cores via pairwise interactions. The valence electrons are independently mobile particles, following classical equations of motion according to potentials modified from Coulombic as required to capture quantum characteristics. As proof of principle, the aufbau of atomic ions is described for diverse main group elements from the first three rows of the periodic table, using a single potential for interactions between electrons of like spin and another for electrons of unlike spin. The electrons of each spin are found to distribute themselves in a fashion akin to the major lobes of the hybrid atomic orbitals, suggesting a pointillist description of the electron density. The broader validity of the LEWIS• force field is illustrated by predicting the vibrational frequencies of diatomic and triatomic hydrogen species. PMID:24752384

  16. Transferable pseudoclassical electrons for aufbau of atomic ions.

    Science.gov (United States)

    Ekesan, Solen; Kale, Seyit; Herzfeld, Judith

    2014-06-05

    Generalizing the LEWIS reactive force field from electron pairs to single electrons, we present LEWIS• in which explicit valence electrons interact with each other and with nuclear cores via pairwise interactions. The valence electrons are independently mobile particles, following classical equations of motion according to potentials modified from Coulombic as required to capture quantum characteristics. As proof of principle, the aufbau of atomic ions is described for diverse main group elements from the first three rows of the periodic table, using a single potential for interactions between electrons of like spin and another for electrons of unlike spin. The electrons of each spin are found to distribute themselves in a fashion akin to the major lobes of the hybrid atomic orbitals, suggesting a pointillist description of the electron density. The broader validity of the LEWIS• force field is illustrated by predicting the vibrational frequencies of diatomic and triatomic hydrogen species. Copyright © 2014 Wiley Periodicals, Inc.

  17. Investigation of ion capture in an electron beam ion trap charge-breeder for rare isotopes

    Science.gov (United States)

    Kittimanapun, Kritsada

    Charge breeding of rare isotope ions has become an important ingredient for providing reaccelerated rare isotope beams for science. At the National Superconducting Cyclotron Laboratory (NSCL), a reaccelerator, ReA, has been built that employs an advanced Electron Beam Ion Trap (EBIT) as a charge breeder. ReA will provide rare-isotope beams with energies of a few hundred keV/u up to tens of MeV/u to enable the study of properties of rare isotopes via low energy Coulomb excitation and transfer reactions, and to investigate nuclear reactions important for nuclear astrophysics. ReA consists of an EBIT charge breeder, a charge-over-mass selector, a room temperature radio-frequency quadrupole accelerator, and a superconducting radio-frequency linear accelerator. The EBIT charge breeder features a high-current electron gun, a long trap structure, and a hybrid superconducting magnet to reach both high acceptance for injected low-charge ions as well as high-electron beam current densities for fast charge breeding. In this work, continuous ion injection and capture in the EBIT have been investigated with a dedicated Monte-Carlo simulation code and in experimental studies. The Monte-Carlo code NEBIT considers the electron-impact ionization cross sections, space charge due to the electron beam current, ion dynamics, electric field from electrodes, and magnetic field from the superconducting magnet. Experiments were performed to study the capture efficiency as a function of injected ion beam current, electron beam current, trap size, and trap potential depth. The charge state evolution of trapped ions was studied, providing information about the effective current density of the electron beam inside the EBIT. An attempt was made to measure the effective space-charge potential of the electron beam by studying the dynamics of a beam injected and reflected inside the trap.

  18. Heavy ion-acoustic rogue waves in electron-positron multi-ion plasmas.

    Science.gov (United States)

    Chowdhury, N A; Mannan, A; Hasan, M M; Mamun, A A

    2017-09-01

    The nonlinear propagation of heavy-ion-acoustic (HIA) waves (HIAWs) in a four-component multi-ion plasma (containing inertial heavy negative ions and light positive ions, as well as inertialess nonextensive electrons and positrons) has been theoretically investigated. The nonlinear Schrödinger (NLS) equation is derived by employing the reductive perturbation method. It is found that the NLS equation leads to the modulational instability (MI) of HIAWs, and to the formation of HIA rogue waves (HIARWs), which are due to the effects of nonlinearity and dispersion in the propagation of HIAWs. The conditions for the MI of HIAWs and the basic properties of the generated HIARWs are identified. It is observed that the striking features (viz., instability criteria, growth rate of MI, amplitude and width of HIARWs, etc.) of the HIAWs are significantly modified by the effects of nonextensivity of electrons and positrons, the ratio of light positive ion mass to heavy negative ion mass, the ratio of electron number density to light positive ion number density, the ratio of electron temperature to positron temperature, etc. The relevancy of our present investigation to the observations in space (viz., cometary comae and earth's ionosphere) and laboratory (viz., solid-high intense laser plasma interaction experiments) plasmas is pointed out.

  19. Electron beam ion sources for student education at universities

    Energy Technology Data Exchange (ETDEWEB)

    Ritter, Erik [DREEBIT GmbH, Dresden (Germany); Zschornack, Guenter [TU Dresden, Dresden (Germany)

    2014-07-01

    Ion beams have become essential tools used in many fields of fundamental research as well as industrial applications. Thus, it is important for todays physics students to understand the basics of ion beam creation, transportation as well as ion-surface interactions. We present results from laboratory training courses using table-top sized electron beam ion sources of the Dresden EBIT type which is able to produce a large spectrum of ions with low or high charge states. The initial ion beam is guided through several ion optical elements like Einzel lenses and deflectors, is separated by the charge-to-mass ratio of its components with a Wien-Filter or dipole analyzing magnet and is detected in a Faraday Cup. A specific assembly for laboratory training as used at the Technische Universitaet Dresden and the Jagiellonian University in Krakow, Poland, is introduced. In typical experiments, students analyze the charge-to-mass ratio spectrum from a Dresden EBIT measured using a Wien Filter. The composition of the extracted ion beam can be manipulated by the gas pressure or the ionisation time. In a wider context, the atomic physics processes occurring especially during the production of highly charged ions also appear in nuclear fusion facilities as well as in many astrophysical phenomena, for example supernovas. Such aspects can be discussed in order to help students connect to modern research carried out at large international facilities.

  20. Accelerator physics in ERL based polarized electron ion collider

    Energy Technology Data Exchange (ETDEWEB)

    Hao, Yue [Brookhaven National Lab. (BNL), Upton, NY (United States). Collider-Accelerator Dept.

    2015-05-03

    This talk will present the current accelerator physics challenges and solutions in designing ERL-based polarized electron-hadron colliders, and illustrate them with examples from eRHIC and LHeC designs. These challenges include multi-pass ERL design, highly HOM-damped SRF linacs, cost effective FFAG arcs, suppression of kink instability due to beam-beam effect, and control of ion accumulation and fast ion instabilities.

  1. Ion streaming instabilities in pair ion plasma and localized structure with non-thermal electrons

    Energy Technology Data Exchange (ETDEWEB)

    Khattak, M. Nasir; Qamar, A., E-mail: mnnasirphysics@gmail.com [Department of Physics, University of Peshawar (Pakistan); Mushtaq, A. [Department of Physics, Abdul Wali Khan University Mardan, National Center for Physics, Mardan (Pakistan)

    2015-12-15

    Pair ion plasma with a fraction of non-thermal electrons is considered. We investigate the effects of the streaming motion of ions on linear and nonlinear properties of unmagnetized, collisionless plasma by using the fluid model. A dispersion relation is derived, and the growth rate of streaming instabilities with effect of streaming motion of ions and non-thermal electrons is calculated. A quasi-potential approach is adopted to study the characteristics of ion acoustic solitons. An energy integral equation involving Sagdeev potential is derived during this process. The presence of the streaming term in the energy integral equation affects the structure of the solitary waves significantly along with non-thermal electrons. Possible application of the work to the space and laboratory plasmas are highlighted. (author)

  2. Initial commissioning results with the NSCL Electron Beam Ion Trap

    Energy Technology Data Exchange (ETDEWEB)

    Schwarz, S.; Kittimanapun, K.; Lapierre, A.; Leitner, D.; Ottarson, J.; Portillo, M. [National Superconducting Cyclotron Laboratory, NSCL, Michigan State University, East Lansing, Michigan 48824 (United States); Bollen, G. [National Superconducting Cyclotron Laboratory, NSCL, Michigan State University, East Lansing, Michigan 48824 (United States); Department of Physics and Astronomy, Michigan State University, East Lansing, Michigan 48824 (United States); Lopez-Urrutia, J. R. Crespo [Max-Planck Institut fuer Kernphysik, Saupfercheckweg 1, 69117 Heidelberg (Germany); Kester, O. [GSI Helmholtzzentrum fuer Schwerionenforschung, Planckstr. 1, 64291 Darmstadt (Germany)

    2012-02-15

    The ReA reaccelerator is being added to the National Superconducting Cyclotron Laboratory (NSCL) fragmentation facility in order to provide exotic rare-isotope beams, not available at the Isotope Separation On-Line facilities, in the several-MeV/u energy range. The first stage of the NSCL reaccelerator complex, consisting of an EBIT charge breeder, a room-temperature radiofrequency quadrupole (RFQ) accelerator, and superconducting linear accelerator modules, has been completed and is being put into operation. Commissioning of the EBIT has started by extracting charge-bred residual gas ions, ions created from a Ne gas jet directed across the EBIT's electron beam and ions captured from an external test ion source. Charge-bred ions from the Ne gas jet have been extracted as a pulse and accelerated through the RFQ and the two cryomodules.

  3. Determination of the electron temperature in the modified ionosphere over HAARP using the HF pumped Stimulated Brillouin Scatter (SBS emission lines

    Directory of Open Access Journals (Sweden)

    P. A. Bernhardt

    2009-12-01

    Full Text Available An ordinary mode electromagnetic wave can decay into an ion acoustic wave and a scattered electromagnetic wave by a process called stimulated Brillouin scatter (SBS. The first detection of this process during ionospheric modification with high power radio waves was reported by Norin et al. (2009 using the HAARP transmitter in Alaska. Subsequent experiments have provided additional verification of this process and quantitative interpretation of the scattered wave frequency offsets to yield measurements of the electron temperatures in the heated ionosphere. Using the SBS technique, electron temperatures between 3000 and 4000 K were measured over the HAARP facility. The matching conditions for decay of the high frequency pump wave show that in addition to the production of an ion-acoustic wave, an electrostatic ion cyclotron wave may also be produced by the generalized SBS processes. Based on the matching condition theory, the first profiles of the scattered wave amplitude are produced using the stimulated Brillouin scatter (SBS matching conditions. These profiles are consistent with maximum ionospheric interactions at the upper-hybrid resonance height and at a region just below the plasma resonance altitude where the pump wave electric fields reach their maximum values.

  4. Ion and electron angular distributions in the Io torus region of the Jovian magnetosphere

    Science.gov (United States)

    Lanzerotti, L. J.; Maclennan, C. G.; Armstrong, T. P.; Krimigis, S. M.; Lepping, R. P.; Ness, N. F.

    1981-01-01

    Angular distributions are presented of ion (about 0.5-2 MeV) and electron (greater than 10 MeV) fluxes measured during the Voyager 1 spacecraft passage through the inner regions of the Jovian magnetosphere. In the regions of peak flux intensities, just outside the orbit of Io, the ion angular distributions are most sharply peaked at 90 deg local pitch angle, a configuration consistent with diffusion of the particles inward from large radial distances. Inside the orbit of Io the lower-energy ions exhibit angular distributions depleted at 90 deg local pitch angles, suggesting the possibility of charge-exchange scattering loss of these particles. In the vicinity of the Io flux tube, no significant effect is observed in the flux or pitch angle distributions of the ions. The relativistic electrons are depleted in the flux tube region and exhibit an asymmetrical pitch angle distribution, with more electrons appearing to arrive from the equatorial region (the direction of Io) than from the low-altitude mirror point.

  5. Differential Cross Sections Of Electron Silver Scattering At Varying

    African Journals Online (AJOL)

    dimensional space, a central potential does not depend on the angular variable and . Therefore, in a scattering experiment it is easier to work in the Centre of mass frame, where a spherically symmetric potential has the form V(r) with = | ⃗|, due to the quantum mechanical uncertainty (i.e we can only predict the probability of ...

  6. Ion and electron heating in ICRF heating experiments on LHD

    Energy Technology Data Exchange (ETDEWEB)

    Saito, K. [Nagoya Univ. (Japan). Faculty of Engineering; Kumazawa, R.; Mutoh, T. [National Inst. for Fusion Science, Toki, Gifu (Japan)] [and others

    2001-02-01

    This paper reports on the Ion Cyclotron Range of Frequency (ICRF) heating conducted in 1999 in the 3rd experimental campaign on the Large Helical Device (LHD) with an emphasis on the optimization of the heating regime. Specifically, an exhaustive study of seven different heating regimes was carried out by changing the RF frequency relative to the magnetic field intensity, and the dependence of the heating efficiency on H-minority concentration was investigated. It was found in the experiment that both ion and electron heating are attainable with the same experimental setup by properly choosing the frequency relative to the magnetic field intensity. In the cases of both electron heating and ion heating, the power absorption efficiency depends on the minority ion concentration. An optimum minority concentration exists in the ion heating case while, in the electron heating case, the efficiency increases with concentration monotonically. A simple model calculation is introduced to provide a heuristic understanding of these experimental results. Among the heating regimes examined in this experiment, one of the ion heating regimes was finally chosen as the optimized heating regime and various high performance discharges were realized with it. (author)

  7. MUNU: study of the neutrino-electron scattering; MUNU: etude de la diffusion neutrino-electron

    Energy Technology Data Exchange (ETDEWEB)

    Cerna, C

    2000-11-01

    MUNU is an experiment dedicated to electron-neutrino scattering studies and in particular to neutrino magnetic moment search at a nuclear power plant in Bugey (France). MUNU is based on a gaseous time projection chamber (TPC) immersed in 8 tons of liquid scintillator acting as an active anti-Compton shielding. A preliminary analysis of the first results of this experiment corresponding to about 24 days of data collecting draws a line on the value of the neutrino magnetic moment: {mu}{sub {nu}}-bar{sub {sub e}} {<=} 1.97 10{sup -10} {mu}{sub B} (68% confidence level). All along this work, it is shown that the combined use of a TPC and of a light detection system is valuable for discriminating particles and for discarding signals from background noise.

  8. Head-on collision of dust-ion-acoustic solitons in electron-dust-ion ...

    Indian Academy of Sciences (India)

    3Physics and Applied Mathematics, Indian Statistical Institute, Kolkata 700 009, India. ∗ ... electrons. The electron-dust-ion plasma behaves like Fermi gas and the quantum mechanical effect plays a significant role in the behaviour of charge particles ... cal and numerical perspectives by employing the two-fluid QHD model.

  9. The effect of the electron scattering phase shifts upon the computational outcomes of the Low-Energy Electron Diffraction technique

    Science.gov (United States)

    Adas, Sonya; Meyers, Lisa; Caragiu, Mellita

    2009-04-01

    In a typical Low-Energy Electron Diffraction (LEED) investigation of a crystal surface, the electrons probing the surface are scattered by the atoms in the sample. The scattering process introduces phase shifts in the waves associated to the incoming electrons. An investigation of how these phase shifts influence the results of a LEED calculation are presented for the fairly complicated Cu(511) stepped surface. The phase shifts have been calculated using the Barbieri/Van Hove Phase Shift Package. The phase shifts considered correspond to copper atoms arranged in various planes of the copper crystal: (100), (111), and a close approximation of the (511) plane.

  10. Electron and ion heating characteristics during magnetic reconnection in MAST

    CERN Document Server

    Tanabe, H; Watanabe, T; Gi, K; Kadowaki, K; Inomoto, M; Imazawa, R; Gryaznevich, M; Michael, C; Crowley, B; Conway, N; Scannell, R; Harrison, J; Fitzgerald, I; Meakins, A; Hawkes, N; Cheng, C Z; Ono, Y

    2015-01-01

    Local electron and ion heating characteristics during merging reconnection startup on the MAST spherical tokamak have been revealed for the first time using a 130 channel YAG-TS system and a new 32 chord ion Doppler tomography diagnostic. 2D local profile measurement of $T_e$, $n_e$ and $T_i$ detect highly localized electron heating at the X point and bulk ion heating downstream. For the push merging experiment under high guide field condition, thick layer of closed flux surface formed by reconnected field sustains the heating profile for more than electron and ion energy relaxation time $\\tau^E_{ei}\\sim4-10$ms, both heating profiles finally form triple peak structure at the X point and downstream. Toroidal guide field mostly contributes the formation of peaked electron heating profile at the X point. The localized heating increases with higher guide field, while bulk downstream ion heating is unaffected by the change in the guide field under MAST conditions ($B_t>3B_{rec}$).

  11. Analytical Schwartz density applied to heavy two-electron ions

    Energy Technology Data Exchange (ETDEWEB)

    Romera, E.; Dehesa, J.S. [Universidad de Granada (Spain); Koga, Toshikatsu [Muroran Institute of Technology (Japan)

    1997-01-20

    An analytical expression of the electron density function p(r) due to Schwartz for two-electron atomic systems is applied to a detailed study of density-dependent properties of relatively heavy two-electron ions. Comparison of the Schwartz results with those from accurate Hartree-Fock and Hylleraas wave functions shows that despite its simple yet analytical form, the Schwartz density has a quantitative applicability in the density study of two-electron atoms within the nonrelativistic framework. 13 refs., 4 tabs.

  12. Electron and ion kinetics in a micro hollow cathode discharge

    Energy Technology Data Exchange (ETDEWEB)

    Kim, G J; Iza, F; Lee, J K [Electronics and Electrical Engineering Department, Pohang University of Science and Technology, Pohang, 790-784 (Korea, Republic of)

    2006-10-21

    Electron and ion kinetics in a micro hollow cathode discharge are investigated by means of two-dimensional axisymmetric particle-in-cell Monte Carlo collision simulations. Argon discharges at 10 and 300 Torr are studied for various driving currents. Electron and ion energy probability functions (IEPF) are shown at various times and locations to study the spatio-temporal behaviour of the discharge. The electron energy probability function (EEPF) evolves from the Druyvesteyn type in the early stages of the discharge into a two (or three) temperature distribution when steady state is reached. In steady state, secondary electrons accelerated across the cathode fall populate the high energy tail of the EEPF while the low energy region is populated by trapped electrons. The IEPF evolves from a Maxwellian in the negative glow (bulk) to a two temperature distribution on the cathode surface. The overpopulation of low energy ions near the cathode surface is attributed to a larger collision cross section for low energy ions and ionization within the cathode fall.

  13. Electron pitch-angle diffusion: resonant scattering by waves vs. nonadiabatic effects

    Directory of Open Access Journals (Sweden)

    A. V. Artemyev

    2013-09-01

    Full Text Available In this paper we investigate the electron pitch-angle diffusion coefficients in the night-side inner magnetosphere around the geostationary orbit (L ~ 7 due to magnetic field deformation. We compare the effects of resonant wave–particle scattering by lower band chorus waves and the adiabaticity violation of electron motion due to the strong curvature of field lines in the vicinity of the equator. For a realistic magnetic field configuration, the nonadiabatic effects are more important than the wave–particle interactions for high energy (> 1 MeV electrons. For smaller energy, the scattering by waves is more effective than nonadiabatic one. Moreover, the role of nonadiabatic effects increases with particle energy. Therefore, to model electron scattering and transport in the night-side inner magnetosphere, it is important to take into account the peculiarities of high-energy electron dynamics.

  14. Electron Accelerators for Radioactive Ion Beams

    Energy Technology Data Exchange (ETDEWEB)

    Lia Merminga

    2007-10-10

    The summary of this paper is that to optimize the design of an electron drive, one must: (a) specify carefully the user requirements--beam energy, beam power, duty factor, and longitudinal and transverse emittance; (b) evaluate different machine options including capital cost, 10-year operating cost and delivery time. The author is convinced elegant solutions are available with existing technology. There are several design options and technology choices. Decisions will depend on system optimization, in-house infrastructure and expertise (e.g. cryogenics, SRF, lasers), synergy with other programs.

  15. The Electron-Ion Collider Science Case

    CERN Document Server

    Milner, Richard G

    2014-01-01

    For the first time, physicists are in the position to precisely study a fully relativistic quantum field theory: Quantum ChromoDynamics (QCD). QCD is a central element of the Standard Model and provides the theoretical framework for understanding the strong interaction. This demands a powerful new electron microscope to probe the virtual particles of QCD. Ab initio calculations using lattice gauge theory on the world's most powerful supercomputers are essential for comparison with the data. The new accelerator and computing techniques demand aggressive development of challenging, innovative technologies.

  16. Optical modeling of plasma-deposited ZnO films: Electron scattering at different length scales

    Energy Technology Data Exchange (ETDEWEB)

    Knoops, Harm C. M., E-mail: H.C.M.Knoops@tue.nl; Loo, Bas W. H. van de; Smit, Sjoerd; Ponomarev, Mikhail V.; Weber, Jan-Willem; Sharma, Kashish [Department of Applied Physics, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven (Netherlands); Kessels, Wilhelmus M. M.; Creatore, Mariadriana, E-mail: M.Creatore@tue.nl [Department of Applied Physics, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven, The Netherlands and Solliance, High Tech Campus 5, 5656 AE Eindhoven (Netherlands)

    2015-03-15

    In this work, an optical modeling study on electron scattering mechanisms in plasma-deposited ZnO layers is presented. Because various applications of ZnO films pose a limit on the electron carrier density due to its effect on the film transmittance, higher electron mobility values are generally preferred instead. Hence, insights into the electron scattering contributions affecting the carrier mobility are required. In optical models, the Drude oscillator is adopted to represent the free-electron contribution and the obtained optical mobility can be then correlated with the macroscopic material properties. However, the influence of scattering phenomena on the optical mobility depends on the considered range of photon energy. For example, the grain-boundary scattering is generally not probed by means of optical measurements and the ionized-impurity scattering contribution decreases toward higher photon energies. To understand this frequency dependence and quantify contributions from different scattering phenomena to the mobility, several case studies were analyzed in this work by means of spectroscopic ellipsometry and Fourier transform infrared (IR) spectroscopy. The obtained electrical parameters were compared to the results inferred by Hall measurements. For intrinsic ZnO (i-ZnO), the in-grain mobility was obtained by fitting reflection data with a normal Drude model in the IR range. For Al-doped ZnO (Al:ZnO), besides a normal Drude fit in the IR range, an Extended Drude fit in the UV-vis range could be used to obtain the in-grain mobility. Scattering mechanisms for a thickness series of Al:ZnO films were discerned using the more intuitive parameter “scattering frequency” instead of the parameter “mobility”. The interaction distance concept was introduced to give a physical interpretation to the frequency dependence of the scattering frequency. This physical interpretation furthermore allows the prediction of which Drude models can be used in a specific

  17. Resonance estimates for single spin asymmetries in elastic electron-nucleon scattering

    Energy Technology Data Exchange (ETDEWEB)

    Barbara Pasquini; Marc Vanderhaeghen

    2004-07-01

    We discuss the target and beam normal spin asymmetries in elastic electron-nucleon scattering which depend on the imaginary part of two-photon exchange processes between electron and nucleon. We express this imaginary part as a phase space integral over the doubly virtual Compton scattering tensor on the nucleon. We use unitarity to model the doubly virtual Compton scattering tensor in the resonance region in terms of {gamma}* N {yields} {pi} N electroabsorption amplitudes. Taking those amplitudes from a phenomenological analysis of pion electroproduction observables, we present results for beam and target normal single spin asymmetries for elastic electron-nucleon scattering for beam energies below 1 GeV and in the 1-3 GeV region, where several experiments are performed or are in progress.

  18. Ground- and excited-state scattering potentials for the stopping of protons in an electron gas

    Science.gov (United States)

    Matias, F.; Fadanelli, R. C.; Grande, P. L.; Koval, N. E.; Díez Muiño, R.; Borisov, A. G.; Arista, N. R.; Schiwietz, G.

    2017-09-01

    The self-consistent electron-ion potential V(r) is calculated for H+ ions in an electron gas system as a function of the projectile energy to model the electronic stopping power for conduction-band electrons. The results show different self-consistent potentials at low projectile-energies, related to different degrees of excitation of the electron cloud surrounding the intruder ion. This behavior can explain the abrupt change of velocity dependent screening-length of the potential found by the use of the extended Friedel sum rule and the possible breakdown of the standard free electron gas model for the electronic stopping at low projectile energies. A dynamical interpolation of V(r) is proposed and used to calculate the stopping power for H+ interacting with the valence electrons of Al. The results are in good agreement with the TDDFT benchmark calculations as well as with experimental data.

  19. Electronic Raman scattering in cuprate superconductors and parent insulating phases

    Energy Technology Data Exchange (ETDEWEB)

    Klein, M.V.; Liu, R.; Salamon, D.; Blumberg, G.; Reznik, D.; Cooper, S.L.; Lee, W.C.; Ginsberg, D.M. [Univ. of Illinois, Urbana, IL (United States); Cheong, S.W. [AT and T Labs., Murray Hill, NJ (United States)

    1994-12-31

    Raman scattering from charge and spin excitations in cuprates is reviewed. The two-magnon resonance Raman profile is used to determine the most probable energy for photon-assisted charge transfer leading to exchange between two spins. The difference between this energy and that for absorption is attributed to spin relaxation (spin polaron) effects. Two-magnon spectra in superconducting cuprates are presented. It is argued that their presence is evidence that the antiferromagnetic correlation length is equal to or greater than three lattice constants. The recently-discovered Raman-active excitons are described and possible assignments of them are discussed. It is pointed out that in highly correlated metals and insulators, the mechanisms for fight scattering that are familiar for doped semiconductors or conventional metals are not necessarily the only ones that are operative.

  20. A simple model for electron dissipation in trapped ion turbulence

    Science.gov (United States)

    Lesur, M.; Cartier-Michaud, T.; Drouot, T.; Diamond, P. H.; Kosuga, Y.; Réveillé, T.; Gravier, E.; Garbet, X.; Itoh, S.-I.; Itoh, K.

    2017-01-01

    Trapped ion resonance-driven turbulence is investigated in the presence of electron dissipation in a simplified tokamak geometry. A reduced gyrokinetic bounce-averaged model for trapped ions is adopted. Electron dissipation is modeled by a simple phase-shift δ between density and electric potential perturbations. The linear eigenfunction features a peak at the resonant energy, which becomes stronger with increasing electron dissipation. Accurately resolving this narrow peak in numerical simulation of the initial-value problem yields a stringent lower bound on the number of grid points in the energy space. Further, the radial particle flux is investigated in the presence of electron dissipation, including kinetic effects. When the density gradient is higher than the temperature gradient, and the phase-shift is finite but moderate ( δ≈0.02 ), the particle flux peaks at an order-of-magnitude above the gyro-Bohm estimate. Slight particle pinch is observed for δ<0.003 .

  1. Rotational excitation of interstellar molecular ions by electrons

    Energy Technology Data Exchange (ETDEWEB)

    Faure, A [Laboratoire d' Astrophysique, UMR 5571 CNRS, Universite Joseph-Fourier, B.P. 53, 38041 Grenoble cedex 09 (France); Tennyson, J [Department of Physics and Astronomy, University College London, Gower Street, London WC1E 6BT (United Kingdom); Kokoouline, V [Department of Physics, University of Central Florida, Orlando, Florida 32816 (United States); Greene, Chris H, E-mail: afaure@obs.ujf-grenoble.f [Department of Physics and JILA, University of Colorado, Boulder, Colorado 80309-0440 (United States)

    2009-11-15

    Electrons are known to be efficient in rotationally exciting molecular ions in cold ionized media. Rotational effects have also been shown to affect the dissociative recombination (DR) process. Electron collisions are thus expected to play a significant role in the thermalization and dissociation dynamics of molecular ions, both in the laboratory and in space. Using the molecular R-matrix method combined with the Adiabatic-Nuclei-Rotation (ANR) approximation corrected for threshold and closed-channel effects, we have computed new rate coefficients for the rotational excitation of H{sup +}{sub 3} and HCO{sup +} by electrons at temperatures from 10 to 1 000K. At temperatures above rotational thresholds, rotational rates are found to compete or even dominate those of dissociative recombination, suggesting that electron collisions provide a possible source of rotational (de)excitation in DR measurements.

  2. Multiple electron capture in close ion-atom collisions

    Energy Technology Data Exchange (ETDEWEB)

    Schlachter, A.S.; Stearns, J.W.; Berkner, K.H.; Bernstein, E.M.; Clark, M.W.; DuBois, R.D.; Graham, W.G.; Morgan, T.J.; Mueller, D.W.; Stockli, M.P.; Tanis, J.A.; Woodland, W.T. (Lawrence Berkeley Lab., CA (USA); Western Michigan Univ., Kalamazoo, MI (USA); Pacific Northwest Lab., Richland, WA (USA); Queen' s Univ., Belfast, Northern Ireland (UK); Wesleyan Univ., Middletown, CT (USA); University of North Tex

    1989-07-24

    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.

  3. Structure and electron-ion correlation of liquid germanium

    Energy Technology Data Exchange (ETDEWEB)

    Kawakita, Y. [Faculty of Sciences, Kyushu University, 4-2-1 Ropponmatsu, Fukuoka 810-8560 (Japan)]. E-mail: kawakita@rc.kyushu-u.ac.jp; Fujita, S. [Graduate School of Sciences, Kyushu University, 4-2-1 Ropponmatsu, Fukuoka 810-8560 (Japan); Kohara, S. [Japan Synchrotron Radiation Research Institute, 1-1-1 Kouto Mikazuki-cho, Hyogo 679-5198 (Japan); Ohshima, K. [Graduate School of Sciences, Kyushu University, 4-2-1 Ropponmatsu, Fukuoka 810-8560 (Japan); Fujii, H. [Graduate School of Sciences, Kyushu University, 4-2-1 Ropponmatsu, Fukuoka 810-8560 (Japan); Yokota, Y. [Graduate School of Sciences, Kyushu University, 4-2-1 Ropponmatsu, Fukuoka 810-8560 (Japan); Takeda, S. [Faculty of Sciences, Kyushu University, 4-2-1 Ropponmatsu, Fukuoka 810-8560 (Japan)

    2005-08-15

    Structure factor of liquid germanium (Ge) has a shoulder at {theta} = 3.2 A{sup -1} in the high-momentum-transfer region of the first peak. To investigate the origin of such a non-simplicity in the structure, high energy X-ray diffraction measurements have been performed using 113.26 keV incident X-ray, at BL04B2 beamline of SPring-8. By a combination of the obtained structure factor with the reported neutron diffraction data, charge density function and electron-ion partial structure factor have been deduced. The peak position of the charge distribution is located at about 1 A, rather smaller r value than the half value of nearest neighbor distance ({approx}2.7 A), which suggests that valence electrons of liquid Ge play a role of screening electrons around a metallic ion rather than covalently bonding electrons.

  4. Enhanced Physicochemical and Biological Properties of Ion-Implanted Titanium Using Electron Cyclotron Resonance Ion Sources

    Directory of Open Access Journals (Sweden)

    Csaba Hegedűs

    2016-01-01

    Full Text Available The surface properties of metallic implants play an important role in their clinical success. Improving upon the inherent shortcomings of Ti implants, such as poor bioactivity, is imperative for achieving clinical use. In this study, we have developed a Ti implant modified with Ca or dual Ca + Si ions on the surface using an electron cyclotron resonance ion source (ECRIS. The physicochemical and biological properties of ion-implanted Ti surfaces were analyzed using various analytical techniques, such as surface analyses, potentiodynamic polarization and cell culture. Experimental results indicated that a rough morphology was observed on the Ti substrate surface modified by ECRIS plasma ions. The in vitro electrochemical measurement results also indicated that the Ca + Si ion-implanted surface had a more beneficial and desired behavior than the pristine Ti substrate. Compared to the pristine Ti substrate, all ion-implanted samples had a lower hemolysis ratio. MG63 cells cultured on the high Ca and dual Ca + Si ion-implanted surfaces revealed significantly greater cell viability in comparison to the pristine Ti substrate. In conclusion, surface modification by electron cyclotron resonance Ca and Si ion sources could be an effective method for Ti implants.

  5. Efficient scattering of electrons below few keV by Time Domain Structures around injection fronts

    Science.gov (United States)

    Vasko, I.; Agapitov, O. V.; Mozer, F.; Artemyev, A.; Krasnoselskikh, V.

    2016-12-01

    Van Allen Probes observations show an abundance of non-linear large-amplitude electrostatic spikes around injection fronts in the outer radiation belt. These spikes referred to as Time Domain Structures (TDS) include electron holes, double layers and more complicated solitary waves. The electron scattering driven by TDS may not be evaluated via the standard quasi-linear theory, since TDS are in principle non-linear plasma modes. In this paper we analyze the scattering of electrons by three-dimensional TDS (with non-negligible perpendicular electric field) around injection fronts. We derive the analytical formulas describing the local scattering by single TDS and show that the most efficiently scattered electrons are those in the first cyclotron resonance (electrons crossing TDS on a time scale comparable with their gyroperiod). The analytical formulas are verified via the test-particle simulation. We compute the bounce-averaged diffusion coefficients and demonstrate their dependence on the TDS spatial distribution, individual TDS parameters and L shell. We show that TDS are able to provide the pitch-angle scattering of electrons at rate 10-2-10-4 s-1 and, thus, can be responsible for driving loss of electrons out of injections fronts on a time scale from few minutes to few hours. TDS can be, thus, responsible for driving diffuse aurora precipitations conjugated to injection fronts. We show that the pitch-angle scattering rates driven by TDS are comparable with those due to chorus waves and exceed those due to electron cyclotron harmonics. For injections fronts with no significant wave activity in the frequency range corresponding to chorus waves, TDS can be even dominant mechanism for losses of below few keV electrons.

  6. A Literature Survey on Inverse Scattering for Electron Density Profile Determination. Volume II.

    Science.gov (United States)

    1981-09-24

    THE INVERSE SCATTERING PROBLEM4 FOR THE EQUAT ION Of ACOUSTIC$ AVILA, G.S.S. DEPT. DE MATEMATICA . INST. DE CIENCIAS EXATAS. UNIV. Of BRASILIA...of Colict support Portinari. Joao C. Departamento do Matematica . Pontificia Universidade Catolica do Rio de Janeiro, Rio do Janeiro. Brasil J. Math

  7. Electron Impact Ionization of Stored Highly Charged Ions

    CERN Document Server

    Hahn, Michael

    2014-01-01

    Accurate cross section data for electron impact ionization (EII) are needed in order to interpret the spectra of collisionally ionized plasmas both in astrophysics and in the laboratory. Models and spectroscopic diagnostics of such plasmas rely on accurate ionization balance calculations, which depend, in turn, on the underlying rates for EII and electron-ion recombination. EII measurements have been carried out using the TSR storage ring located at the Max-Planck-Institut fuer Kernphysik in Heidelberg, Germany. Storage ring measurements are largely free of metastable contamination, resulting in unambiguous EII data, unlike what is encountered with other experimental geometries. As it is impractical to perform experiments for every ion, theory must provide the bulk of the necessary EII data. In order to guide theory, TSR experiments have focused on providing at least one measurement for every isoelectronic sequence. EII data have been measured for ions from 13 isoelectronic sequences: Li-like silicon and chlo...

  8. Electron-Ion Collider : The next QCD frontier

    NARCIS (Netherlands)

    Accardi, A.; Albacete, J. L.; Anselmino, M.; Armesto, N.; Aschenauer, E. C.; Bacchetta, A.; Boer, D.; Brooks, W. K.; Burton, T.; Chang, N. -B.; Deng, W. -T.; Deshpande, A.; Diehl, M.; Dumitru, A.; Dupre, R.; Ent, R.; Fazio, S.; Guzey, V.; Hakobyan, H.; Hao, Y.; Hasch, D.; Holt, R.; Horn, T.; Huang, M.; Hutton, A.; Hyde, C.; Jalilian-Marian, J.; Klein, S.; Kopeliovich, B.; Kovchegov, Y.; Kumar, K.; Kumericki, K.; Lamont, M. A. C.; Lappi, T.; Lee, J. -H.; Lee, Y.; Levin, E. M.; Lin, F. -L.; Litvinenko, V.; Ludlam, T. W.; Marquet, C.; Meziani, Z. -E.; McKeown, R.; Metz, A.; Milner, R.; Morozov, V. S.; Mueller, A. H.; Muller, B.; Mueller, D.; Nadel-Turonski, P.; Paukkunen, H.; Prokudin, A.; Ptitsyn, V.; Qian, X.; Qiu, J. -W.; Ramsey-Musolf, M.; Roser, T.; Sabatie, F.; Sassot, R.; Schnell, G.; Schweitzer, P.; Sichtermann, E.; Stratmann, M.; Strikman, M.; Sullivan, M.; Taneja, S.; Toll, T.; Trbojevic, D.; Ullrich, T.; Venugopalan, R.; Vigdor, S.; Vogelsang, W.; Weiss, C.; Xiao, B. -W.; Yuan, F.; Zhang, Y. -H.; Zheng, L.

    2016-01-01

    This White Paper presents the science case of an Electron-Ion Collider (EIC), focused on the structure and interactions of gluon-dominated matter, with the intent to articulate it to the broader nuclear science community. It was commissioned by the managements of Brookhaven National Laboratory (BNL)

  9. An Electron-Ion Collider at Jefferson lab

    Energy Technology Data Exchange (ETDEWEB)

    A.W. Thomas

    2009-10-01

    Long term plans for the investigation of the quark and gluon structure of matter have for some time focussed on the possibility of an electron-ion collider, with the nuclear physics communities associated with JLab and BNL being particularly active. We briefly outline the current thinking on this subject at Jefferson lab.

  10. Modeling of Electron Temperature in H- Ion Source

    Science.gov (United States)

    Morishita, Takatoshi; Ogasawara, Masatada; Hatayama, Akiyoshi

    2000-05-01

    The equation of electron temperature is included in a two point numerical code for a high power hydrogen negative ion source. The calculated results of the electron temperature are in good agreement with Japan Atomic Energy Research Institute (JAERI)’s experimental results. The scaling law of electron temperature is estimated as a function of input power and gas pressure. Energy input by arc discharge, energy loss by ionization, dissociation and loss on the wall are considered in the electron energy equation. The leak width on the wall at the cusp magnet is also calculated numerically. Energy loss on the wall is dominant, and is larger than the ionization loss. In a similarly enlarged JAERI’s Kamaboko source, electron density increases and electron temperature decreases under a constant energy input per unit volume. In this situation, H- extraction current increases despite the decrease in H- density because of the enlargement of the H- extraction area.

  11. Interatomic Coulombic Decay as a New Source of Low Energy Electrons in slow Ion-Dimer Collisions

    CERN Document Server

    Iskandar, W; Leredde, A; Flechard, X; Gervais, B; Guillous, S; Hennecart, D; Mery, A; Rangama, J; Zhou, C L; Shiromaru, H; Cassimi, A

    2014-01-01

    We provide the experimental evidence that the single electron capture process in slow collisions between O$^{3+}$ ions and neon dimer targets leads to an unexpected production of low-energy electrons. This production results from the interatomic Coulombic decay process, subsequent to inner shell single electron capture from one site of the neon dimer. Although pure one-electron capture from inner shell is expected to be negligible in the low collision energy regime investigated here, the electron production due to this process overtakes by one order of magnitude the emission of Auger electrons by the scattered projectiles after double-electron capture. This feature is specific to low charge states of the projectile: similar studies with Xe$^{20+}$ and Ar$^{9+}$ projectiles show no evidence of inner shell single-electron capture. The dependence of the process on the projectile charge state is interpreted using simple calculations based on the classical over the barrier model.

  12. On the electron-scattering power of protein structures in the spinach chloroplast

    NARCIS (Netherlands)

    Bustraan, M.; Goedheer, J.C.; Thomas, J.B.

    1952-01-01

    The relative electron-scattering power of chromidia and interchromidia in protein structures of the spinach chloroplast was examined with the aid of the electron microscope. It has been demonstrated that: 1. 1. The technique of Marton and Schiff holds for WO3 crystals and silica films

  13. Bibliography on electron transfer processes in ion-ion/atom/molecule collisions. Updated 1997

    Energy Technology Data Exchange (ETDEWEB)

    Tawara, H.

    1997-04-01

    Following our previous compilations (IPPJ-AM-45 (1986), NIFS-DATA-7 (1990), NIFS-DATA-20 (1993)), bibliographic information on experimental and theoretical studies on electron transfer processes in ion-ion/atom/molecule collisions is up-dated. The references published through 1954-1996 are listed in the order of the publication year. For easy finding of the references for a combination of collision partners, a simple list is provided. (author)

  14. The Brookhaven National Laboratory electron beam ion source for RHIC.

    Science.gov (United States)

    Alessi, J G; Barton, D; Beebe, E; Bellavia, S; Gould, O; Kponou, A; Lambiase, R; Lockey, R; McNerney, A; Mapes, M; Marneris, Y; Okamura, M; Phillips, D; Pikin, A I; Raparia, D; Ritter, J; Snydstrup, L; Theisen, C; Wilinski, M

    2010-02-01

    As part of a new heavy ion preinjector that will supply beams for the Relativistic Heavy Ion Collider and the National Aeronautics and Space Administration Space Radiation Laboratory, construction of a new electron beam ion source (EBIS) is now being completed. This source, based on the successful prototype Brookhaven National Laboratory Test EBIS, is designed to produce milliampere level currents of all ion species, with q/m=(1/6)-(1/2). Among the major components of this source are a 5 T, 2-m-long, 204 mm diameter warm bore superconducting solenoid, an electron gun designed to operate at a nominal current of 10 A, and an electron collector designed to dissipate approximately 300 kW of peak power. Careful attention has been paid to the design of the vacuum system, since a pressure of 10(-10) Torr is required in the trap region. The source includes several differential pumping stages, the trap can be baked to 400 C, and there are non-evaporable getter strips in the trap region. Power supplies include a 15 A, 15 kV electron collector power supply, and fast switchable power supplies for most of the 16 electrodes used for varying the trap potential distribution for ion injection, confinement, and extraction. The EBIS source and all EBIS power supplies sit on an isolated platform, which is pulsed up to a maximum of 100 kV during ion extraction. The EBIS is now fully assembled, and operation will be beginning following final vacuum and power supply tests. Details of the EBIS components are presented.

  15. Spin dynamics in Kapitza-Dirac scattering of electrons from bichromatic laser fields

    CERN Document Server

    Dellweg, Matthias M; Müller, Carsten

    2016-01-01

    Kapitza-Dirac scattering of nonrelativistic electrons from counterpropagating bichromatic laser waves of linear polarization i s studied. The focus lies on the electronic spin dynamics in the Bragg regime when the laser fields possess a frequency ratio of two. To this end, the time-dependent Pauli equation is solved numerically, both in coordinate space and momentum space. Our numerical results are corroborated by analytical derivations. We demonstrate that, for certain incident electron momenta, the scattering crucially relies on the electron spin which undergo es characteristic Rabi-like oscillations. A parameter regime is identified where the Rabi oscillations reach maximum amplitude. We also briefly discuss spin-dependent Kapitza-Dirac scattering of protons.

  16. Parity violation in deep inelastic electron scattering. [19. 4 to 22. 2 GeV

    Energy Technology Data Exchange (ETDEWEB)

    Taylor, R.E.

    1979-11-01

    Neutral currents in electron scattering and the Weinberg-Salam model are reviewed. This generally accepted model is consistent with experimental results from neutrino interactions; an appropriate deep inelastic electron scattering experiment would measure couplings that don't involve neutrinos to see if they are also correctly described by the theory. The SLAC-Yale experiment measures a difference in the e-d inelastic cross section for right- and left-handed electrons. The polarized source, beam monitors, scattering experiment, checks of helicity dependence, and results are described. It is concluded that the data obtained are in agreement with the Weinberg-Salam model, and that the best value of sin/sup 2/theta/sub W/ for these data is in excellent agreement with the average values of that parameter deduced from neutrino experiments. Future experiments with polarized electrons are discussed. 12 figures, 2 tables. (RWR)

  17. Enhanced negative ion formation via electron attachment to electronically-excited states

    Energy Technology Data Exchange (ETDEWEB)

    Pinnaduwage, L.A. [Oak Ridge National Lab., TN (United States). Health Sciences Research Div.]|[Univ. of Tennessee, Knoxville, TN (United States). Dept. of Physics

    1995-12-31

    Recent basic studies on electron attachment to laser-excited molecules show that electron attachment to electronically-excited states can have orders of magnitude larger cross sections compared to the respective ground electronic states. Even though systematic studies have not been conducted, there are indications that electronically-excited states may play a significant role in negative ion formation in gas discharges. The high-lying Rydberg states could be of particular significance since, (i) their production efficiencies are high, and (ii) they have comparatively long lifetimes. Such states could be populated in discharge sources via direct electron impact or via excitation transfer from metastable states of inert gases.

  18. Accessibility condition of wave propagation and multicharged ion production in electron cyclotron resonance ion source plasma.

    Science.gov (United States)

    Kato, Yushi; Yano, Keisuke; Nishiokada, Takuya; Nagaya, Tomoki; Kimura, Daiju; Kumakura, Sho; Imai, Youta; Hagino, Shogo; Otsuka, Takuro; Sato, Fuminobu

    2016-02-01

    A new tandem type source of electron cyclotron resonance (ECR) plasmas has been constructing for producing synthesized ion beams in Osaka University. Magnetic mirror field configuration with octupole magnets can be controlled to various shape of ECR zones, namely, in the 2nd stage plasma to be available by a pair mirror and a supplemental coil. Noteworthy correlations between these magnetic configurations and production of multicharged ions are investigated in detail, as well as their optimum conditions. We have been considering accessibility condition of electromagnetic and electrostatic waves propagating in ECR ion source plasma, and then investigated their correspondence relationships with production of multicharged ions. It has been clarified that there exits efficient configuration of ECR zones for producing multicharged ion beams experimentally, and then has been suggested from detail accessibility conditions on the ECR plasma that new resonance, i.e., upper hybrid resonance, must have occurred.

  19. Focused ion beam (FIB)/scanning electron microscopy (SEM) in tissue structural research.

    Science.gov (United States)

    Leser, Vladka; Milani, Marziale; Tatti, Francesco; Tkalec, Ziva Pipan; Strus, Jasna; Drobne, Damjana

    2010-10-01

    The focused ion beam (FIB) and scanning electron microscope (SEM) are commonly used in material sciences for imaging and analysis of materials. Over the last decade, the combined FIB/SEM system has proven to be also applicable in the life sciences. We have examined the potential of the focused ion beam/scanning electron microscope system for the investigation of biological tissues of the model organism Porcellio scaber (Crustacea: Isopoda). Tissue from digestive glands was prepared as for conventional SEM or as for transmission electron microscopy (TEM). The samples were transferred into FIB/SEM for FIB milling and an imaging operation. FIB-milled regions were secondary electron imaged, back-scattered electron imaged, or energy dispersive X-ray (EDX) analyzed. Our results demonstrated that FIB/SEM enables simultaneous investigation of sample gross morphology, cell surface characteristics, and subsurface structures. The same FIB-exposed regions were analyzed by EDX to provide basic compositional data. When samples were prepared as for TEM, the information obtained with FIB/SEM is comparable, though at limited magnification, to that obtained from TEM. A combination of imaging, micro-manipulation, and compositional analysis appears of particular interest in the investigation of epithelial tissues, which are subjected to various endogenous and exogenous conditions affecting their structure and function. The FIB/SEM is a promising tool for an overall examination of epithelial tissue under normal, stressed, or pathological conditions.

  20. Effect of secondary ions on the electron beam optics in the Recycler Electron Cooler

    Energy Technology Data Exchange (ETDEWEB)

    Shemyakin, A.; Prost, L.; Saewert, G.; /Fermilab

    2010-05-01

    Antiprotons in Fermilab's Recycler ring are cooled by a 4.3 MeV, 0.1-0.5 A DC electron beam (as well as by a stochastic cooling system). The unique combination of the relativistic energy ({gamma} = 9.49), an Ampere-range DC beam, and a relatively weak focusing makes the cooling efficiency particularly sensitive to ion neutralization. A capability to clear ions was recently implemented by way of interrupting the electron beam for 1-30 {micro}s with a repetition rate of up to 40 Hz. The cooling properties of the electron beam were analyzed with drag rate measurements and showed that accumulated ions significantly affect the beam optics. For a beam current of 0.3 A, the longitudinal cooling rate was increased by factor of {approx}2 when ions were removed.

  1. Electron and Ion Acceleration Associated with Magnetotail Reconnection

    Science.gov (United States)

    Liang, Haoming

    This dissertation is dedicated to understanding electron and ion acceleration associated with magnetotail reconnection during substorms by using numerical simulations. Electron dynamics were investigated by using the UCLA global magnetohydrodynamic (MHD) model and large scale kinetic (LSK) simulations. The neutral line configurations and magnetotail flows modify the amounts of the adiabatic and non-adiabatic acceleration that electrons undergo. This causes marked differences in the temperature anisotropy for different substorms. In particular, one substorm event analyzed shows T⊥ > T∥ (T⊥ / T ∥ ≈ 2.3)at -10RE while another shows T ∥ > T⊥ (T ⊥ / T∥ ≈ 0.8), where T⊥ and T∥ (second order moments of the distribution functions) are defined with respect to the magnetic field. These differences determine the subsequent acceleration of the energetic electrons in the inner magnetosphere. Whether the acceleration is mostly parallel or perpendicular is determined by the location of dayside reconnection. A 2.5D implicit Particle-in-Cell simulation was used to study the effects produced by oxygen ions on magnetotail reconnection, and the associated acceleration of protons and oxygen ions. The inertia of oxygen ions reduces the reconnection rate and slows down the earthward propagation of dipolarization fronts (DFs). An ambipolar electric field in the oxygen diffusion region contributes to the smaller reconnection rate. This change in the reconnection rate affects the ion acceleration. In particular 67% of protons and 58% of oxygen ions were accelerated in the exhaust (between the X-point and the DF) in a simulation corresponding to a magnetic storm in which there was a 50% concentration of oxygen ions. In addition, 42% of lobe oxygen-ions are accelerated locally by the Hall electric field, far away from the X-point without entering the exhaust. Protons at the same locations experience Ex B drift. This finding extends previous knowledge that oxygen and

  2. Doubly versus Singly Positively Charged Oxygen Ions Back-Scattering from a Silicon Surface under Dynamic O2+ Bombardment

    Czech Academy of Sciences Publication Activity Database

    Franzreb, K.; Williams, P.; Lörinčík, Jan; Šroubek, Zdeněk

    203-204, 1/4 (2003), s. 39-42 ISSN 0169-4332 Institutional research plan: CEZ:AV0Z2067918; CEZ:AV0Z4040901 Keywords : low-energy ion scattering * doubly charged ions * molecular orbital Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 1.284, year: 2003

  3. Calculation of ion scattering yields from simulated crystal surfaces: theory and application to melting and non-melting Al surfaces

    NARCIS (Netherlands)

    Denier van der Gon, A.W.; Frenkel, D.; Frenken, J.W.M.; Smith, R.J.; Stolze, P.

    1991-01-01

    We present a formalism for the calculation of medium-energy ion scattering yields from crystal surfaces that are simulated using the Monte Carlo or molecular-dynamics method. Input in the calculations is the interatomic potential of the atoms in the crystal and the ion-atom interaction potential. We

  4. INTERACTION REGION DESIGN FOR THE ELECTRON-ION COLLIDER ERHIC.

    Energy Technology Data Exchange (ETDEWEB)

    MONTAG, C.; PARKER, B.; TEPIKIAN, S.; ET AL.

    2005-05-16

    To facilitate the study of collisions between 10 GeV polarized electrons and 100 GeV/u heavy ions or 250 GeV polarized protons at luminosities in the 10{sup 33} cm{sup -2} sec{sup -1} range (e-p case), adding a 10 GeV electron storage ring to the existing RHIC complex has been proposed. The interaction region of this electron-ion collider eRHIC has to provide the required low-beta focusing, while simultaneously accommodating the synchrotron radiation fan generated by beam separation close to the interaction point, which is particularly challenging. The latest design status of the eRHIC interaction region will be presented.

  5. ENERGETIC PHOTON AND ELECTRON INTERACTIONS WITH POSITIVE IONS

    Energy Technology Data Exchange (ETDEWEB)

    Phaneuf, Ronald A. [UNR

    2013-07-01

    The objective of this research is a deeper understanding of the complex multi-electron interactions that govern inelastic processes involving positive ions in plasma environments, such as those occurring in stellar cares and atmospheres, x-ray lasers, thermonuclear fusion reactors and materials-processing discharges. In addition to precision data on ionic structure and transition probabilities, high resolution quantitative measurements of ionization test the theoretical methods that provide critical input to computer codes used for plasma modeling and photon opacity calculations. Steadily increasing computational power and a corresponding emphasis on simulations gives heightened relevance to precise and accurate benchmark data. Photons provide a highly selective probe of the internal electronic structure of atomic and molecular systems, and a powerful means to better understand more complex electron-ion interactions.

  6. Scattering of near-zero-energy electrons and positrons by H2

    KAUST Repository

    Zhang, J.-Y.

    2014-04-15

    The parameters for S-wave elastic scattering of near-zero-energy electrons and positrons by H2 molecules are calculated using the stabilization method with explicitly correlated Gaussians. The confined variational method is applied to optimize the Gaussians to describe the short-range interaction of incident e± with H2 in the fixed-nuclei approximation. For e+-H2 scattering the scattering length of previous work [Phys. Rev. Lett. 103, 223202 (2009)] is substantially improved. More importantly, for e−-H2 scattering, from first principles, the scattering length is computed as a function of the internuclear distance. In the case that the two nuclei are at the equilibrium distance the results are in a good agreement with values derived from fitting experimental total and diffusion cross sections to the modified effective range theory.

  7. New theoretical methods for studies on electrons and positrons scattering involving multichannel processes

    CERN Document Server

    Lara, O

    1995-01-01

    continued fractions are now in progress. It is well known that multichannel effects strongly influence the low-energy electron scattering by atoms and molecules. Nevertheless, the inclusion of such effects on the calculations of scattering cross sections remains a considerable task for the area researches due to the complexity of the problem. In the present study we aim to develop a new theoretical method which can be efficiently applied to the multichannel scattering studies. Two new theoretical formalisms namely the Multichannel sup - C-Functional Method have been proposed. Both methods were developed on the base of well-known distorted-wave method combined with Schwinger variational principle. In addition, an integrative method proposed by Horacek and Sasakawa in 1983, the method of continued fractions is adapted by the first time to multichannel scatterings. Numerical test of these three methods were carried out through applications to solve the multichannel scattering problems involving the interaction o...

  8. Probing the Quark Sea and Gluons: the Electron-Ion Collider Projects

    Energy Technology Data Exchange (ETDEWEB)

    Rolf Ent

    2012-04-01

    EIC is the generic name for the nuclear science-driven Electron-Ion Collider presently considered in the US. Such an EIC would be the world’s first polarized electron-proton collider, and the world’s first e-A collider. Very little remains known about the dynamical basis of the structure of hadrons and nuclei in terms of the fundamental quarks and gluons of Quantum Chromodynamics (QCD). A large community effort to sharpen a compelling nuclear science case for an EIC occurred during a ten-week program taking place at the Institute for Nuclear Theory (INT) in Seattle from September 13 to November 19, 2010. The critical capabilities of a stage-I EIC are a range in center-of-mass energies from 20 to 70 GeV and variable, full polarization of electrons and light ions (the latter both longitudinal and transverse), ion species up to A=200 or so, multiple interaction regions, and a high luminosity of about 10{sup 34} electron-nucleons per cm{sup 2} and per second. The physics program of such a stage-I EIC encompass inclusive measurements (ep/A{yields}e'+X), which require detection of the scattered lepon and/or the full scattered hadronic debris with high precision, semi-inclusive processes (ep/A{yields}e'+h+X), which require detection in coincidence with the scattered lepton of at least one (current or target region) hadron; and exclusive processes (ep/A{yields}e'+N'/A'+{gamma}/m), which require detection of all particles in the reaction. The main science themes of an EIC are to i) map the spin and spatial structure of quarks and gluons in nucleons, ii) discover the collective effects of gluons in atomic nuclei, and (iii) understand the emergence of hadronic matter from color charge. In addition, there are opportunities at an EIC for fundamental symmetry and nucleon structure measurements using the electroweak probe. To truly make headway to image the sea quarks and gluons in nucleons and nuclei, the EIC needs high luminosity over a range of

  9. Three-dimensional simulations of ion dynamics in the plasma of an electron cyclotron resonance ion source

    NARCIS (Netherlands)

    Mironov, V.; Beijers, J.P.M.

    The ion production in an electron cyclotron resonance ion source (ECRIS) is modeled using a particle-in-cell Monte-Carlo-collision code in a three-dimensional geometry. Only the heavy particles (ions and atoms) are tracked, while the electrons are represented using a Maxwell-Boltzmann energy

  10. Modified stimulated Raman scattering of a laser induced by trapped electrons in a plasma

    Science.gov (United States)

    Baliyan, Sweta; Rafat, Mohd.; Ahmad, Nafis; Sajal, Vivek

    2017-10-01

    The plasma wave, generated in stimulated Raman scattering process by an intense laser in the plasmas, traps a significant number of electrons in its potential energy minima. These electrons travel with the phase velocity of plasma wave and oscillate with bounce frequency. When the bounce frequency of electrons becomes equal to the growth rate of Raman process, resonance takes place. Now, Raman scattering gets modified by parametrically exciting a trapped electron mode and an electromagnetic sideband. The ponderomotive force due to the pump and sideband drives the plasma wave, whereas the density perturbation due to the trapped electron mode couples with the oscillating velocity of electrons due to the laser to produce a nonlinear current, driving the sideband.

  11. Ion distributions at charged aqueous surfaces: Synchrotron X-ray scattering studies

    Energy Technology Data Exchange (ETDEWEB)

    Bu, Wei [Iowa State Univ., Ames, IA (United States)

    2009-01-01

    Surface sensitive synchrotron X-ray scattering studies were performed to obtain the distribution of monovalent ions next to a highly charged interface at room temperature. To control surface charge density, lipids, dihexadecyl hydrogen-phosphate (DHDP) and dimysteroyl phosphatidic acid (DMPA), were spread as monolayer materials at the air/water interface, containing CsI at various concentrations. Five decades in bulk concentrations (CsI) are investigated, demonstrating that the interfacial distribution is strongly dependent on bulk concentration. We show that this is due to the strong binding constant of hydronium H3O+ to the phosphate group, leading to proton-transfer back to the phosphate group and to a reduced surface charge. Using anomalous reflectivity off and at the L3 Cs+ resonance, we provide spatial counterion (Cs+) distributions next to the negatively charged interfaces. The experimental ion distributions are in excellent agreement with a renormalized surface charge Poisson-Boltzmann theory for monovalent ions without fitting parameters or additional assumptions. Energy Scans at four fixed momentum transfers under specular reflectivity conditions near the Cs+ L3 resonance were conducted on 10-3 M CsI with DHDP monolayer materials on the surface. The energy scans exhibit a periodic dependence on photon momentum transfer. The ion distributions obtained from the analysis are in excellent agreement with those obtained from anomalous reflectivity measurements, providing further confirmation to the validity of the renormalized surface charge Poisson-Boltzmann theory for monovalent ions. Moreover, the dispersion corrections f0 and f00 for Cs+ around L3 resonance, revealing the local environment of a Cs+ ion in the solution at the interface, were extracted simultaneously with output of ion distributions.

  12. Study of Dislocation Loops in Ion-Irradiated Tungsten Using X-Ray Diffuse Scattering

    Science.gov (United States)

    Sun, Peihao; Heimann, Philip; Wang, Yongqiang; Frost, Mungo; Schonwalder, Christopher; Levitan, Abraham; Mo, Mianzhen; Chen, Zhijiang; Hastings, Jerome; Glenzer, Siegfried

    2017-10-01

    As the material of choice for the divertor wall in tokamak fusion reactors, tungsten is exposed to high levels of radiation. As a result, a large amount of defects form inside the crystal, leading to significant changes in its thermal-mechanical properties. Therefore, it is important to understand the types and sizes of radiation-induces defects. X-ray diffuse scattering around Bragg peaks has been developed as a technique to solve this problem. By applying this technique to ion-irradiated tungsten, we have obtained quantitative data on the size-distribution of dislocation loops under different radiation levels. This work is supported by DOE FES under FWP 100182.

  13. Oxygen adsorption on Cu(111) using low energy ion scattering spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, F.M.; Yao, J.; Shen, Y.G.; King, B.V.; O`Connor, D.J. [Newcastle Univ., NSW (Australia). Dept. of Physics

    1993-12-31

    The surface structure and oxygen adsorption of Cu(l 11) have been studied by 2 keV Li{sup +}, He{sup +} and Ar{sup +} ion scattering . Incident and azimuthal dependences were measured for the clean and O-covered surfaces, and the surface geometry was analysed on the basis of the shadowing features. Experimental results under different oxygen exposures at room temperature showed that the Cu(l 11) surface undergoes a roughening transition and results in a reconstruction where Cu atoms are vertically displaced by about 0.23 Angstroms. 4 refs., 4 figs.

  14. Switchable resonant x-ray Bragg scattering on a magnetic grating patterned by ion bombardment

    Science.gov (United States)

    Höink, V.; Sacher, M. D.; Schmalhorst, J.; Reiss, G.; Engel, D.; Weis, T.; Ehresmann, A.

    2006-09-01

    A local manipulation of the exchange bias coupling between antiferromagnetic and ferromagnetic layers by ion bombardment induced magnetic patterning enables a patterning of the magnetization direction of the ferromagnetic layer without considerable structural changes. We show that a magnetic line grating with alternating antiparallel orientations of the magnetization of the ferromagnetic layer acts as a magnetically switchable reflective grating for soft x-ray radiation. A common rotational direction of the magnetization at all boundaries between bombarded and not bombarded lines is shown by magnetic force microscopy measurements. Scattering at the edges of the bombarded lines might be responsible for the observed interference pattern.

  15. Laser-ion acceleration via anomalous electron heating

    CERN Document Server

    Yogo, A; Iwata, N; Tosaki, S; Morace, A; Arikawa, Y; Fujioka, S; Nishimura, H; Sagisaka, A; Johzaki, T; Matsuo, K; Kamitsukasa, N; Kojima, S; Nagatomo, H; Nakai, M; Shiraga, H; Murakami, M; Tokita, S; Kawanaka, J; Miyanaga, N; Yamanoi, K; Norimatsu, T; Sakagami, H; Bulanov, S V; Kondo, K; Azechi, H

    2016-01-01

    Using a kilojoule class laser, we demonstrate for the first time that high-contrast picosecond pulses are advantageous for ion acceleration. We show that a laser pulse with optimum duration and a large focal spot accelerates electrons beyond the ponderomotive energy. This anomalous electron heating enables efficient ion acceleration reaching 52 MeV at an intensity of 1.2X10^19 Wcm^-2. The proton energy observed agrees quantitatively with a one-dimensional plasma expansion model newly developed by taking the anomalous heating effect into account. The heating process is confirmed by both measurements with an electron spectrometer and a one-dimensional particle-in-cell simulation. By extending the pulse duration to 6 ps, 5% energy conversion efficiency to protons (50 J out of 1 kJ laser energy) is achieved with an intensity of 10^18-Wcm^-2. The present results are quite encouraging for realizing ion-driven fast ignition and novel ion beamlines.

  16. On novel mechanisms of slow ion induced electron emission

    CERN Document Server

    Eder, H

    2000-01-01

    impact of singly and doubly charged ions on poly- and monocrystalline aluminum surfaces were performed. From the results we conclude that direct plasmon excitation by slow ions occurs due to the potential energy of the projectile in a quasi-resonant fashion. The highest relative plasmon intensities were found for impact of 5 keV Ne+ on Al(111) with 5 % of the total yield. For impact of H + and H sub 2 + characteristical differences were observed for Al(111) and polycrystalline aluminum. We show that structures in the spectrum for monocrystalline aluminum arise from diffraction of ejected electrons instead of plasmon excitation as previously assumed. The present work has contributed in new ways to the field of slow ion induced electron emission. First, measurements of the total electron yield gamma for impact of slow singly and multiply charged ions on atomically clean polycrystalline gold and graphite have been made. The respective yields were determined by current measurements and measurements of the electro...

  17. 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.)

  18. Measurement of electron neutrino quasielastic and quasielastic-like scattering on hydrocarbon at $\\langle E_{\

    CERN Document Server

    Wolcott, J; Bellantoni, L; Bercellie, A; Betancourt, M; Bodek, A; Bravar, A; Budd, H; Carneiro, M F; Chvojka, J; da Motta, H; Devan, J; Dytman, S A; Diaz, G A; Eberly, B; Felix, J; Fields, L; Fine, R; Galindo, R; Gallagher, H; Ghosh, A; Golan, T; Gran, R; Harris, D A; Higuera, A; Kiveni, M; Kleykamp, J; Kordosky, M; Le, T; Maher, E; Manly, S; Mann, W A; Marshall, C M; Caicedo, D A Martinez; McFarland, K S; McGivern, C L; McGowan, A M; Messerly, B; Miller, J; Mislivec, A; Morfin, J G; Mousseau, J; Muhlbeier, T; Naples, D; Nelson, J K; Norrick, A; Osta, J; Paolone, V; Park, J; Patrick, C E; Perdue, G N; Rakotondravohitra, L; Ransome, R D; Ray, H; Ren, L; Rimal, D; Rodrigues, P A; Ruterbories, D; Schellman, H; Schmitz, D W; Salinas, C J Solano; Tagg, N; Tice, B G; Valencia, E; Walton, T; Wospakrik, M; Zavala, G; Zhang, D; Ziemer, B P

    2015-01-01

    The first direct measurement of electron-neutrino quasielastic and quasielastic-like scattering on hydrocarbon in the few-GeV region of incident neutrino energy has been carried out using the MINERvA detector in the NuMI beam at Fermilab. The flux-integrated differential cross sections in electron production angle, electron energy and $Q^{2}$ are presented. The ratio of the quasielastic, flux-integrated differential cross section in $Q^{2}$ for $\

  19. The two-photon exchange contribution to elastic electron-nucleon scattering at large momentum transfer

    Energy Technology Data Exchange (ETDEWEB)

    Andrei V. Afanasev; Stanley J. Brodsky; Carl E. Carlson; Yu-Chun Chen; Marc Vanderhaeghen

    2005-01-01

    We estimate the two-photon exchange contribution to elastic electron-proton scattering at large momentum transfer by using a quark-parton representation of virtual Compton scattering. We thus can relate the two-photon exchange amplitude to the generalized parton distributions which also enter in other wide angle scattering processes. We find that the interference of one- and two-photon exchange contribution is able to substantially resolve the difference between electric form factor measurements from Rosenbluth and polarization transfer experiments.

  20. Ion Scattering Spectrometry: A Versatile Technique for a Variety of Materials.

    Science.gov (United States)

    1982-02-01

    SCATTERING AND EQUIPMENT 1 III USE OF ISS FOR SURFACE CHEMISTRY CHARACTERIZATION 2 IV USE OF ISS FOR CRYSTALLOGRAPHY 4 V ISS FOR ELECTRONIC STRUCTURE...e U n for single crystal applications, but space does not permit Tb 2 further treatment. Table 2. Clases of satered lo yild curveb for venow in- atom...interactions CoseI Cie" It Cl&. M Ci.e" IV ISS FOR ELECTRONIC STRUCTURE ee’--. He-. He-. H ’-. DETERMINATION At, Si. Cu. Zn, GA, Go. In, As, S. Hf

  1. Interplay between magnetic and electric excitations for backward electron scattering

    Energy Technology Data Exchange (ETDEWEB)

    Nojarov, R.; Faessler, A.; Dingfelder, M. [Tuebingen Univ. (Germany). Inst. fuer Theoretische Physik

    1994-10-01

    It is found that the M1 (e,e`) cross sections of low-lying orbital I{sup {pi}} K = 1{sup +}1 excitations in heavy deformed nuclei contain E2 admixtures from the (predominantly longtitudinal) excitation of the accompanying 2{sup +}1 states. This happens even for backward scattering angles as large as {theta} = 165{sup o}, where the E2 excitation is strongly quenched. For small momentum transfer q the E2 cross section is negligible; however, it provides significant corrections to the theoretical M1 cross section for 0.4 < q < 0.6 fm{sup -1} and substantially improves the agreement with experiment in heavy deformed nuclei. (author).

  2. Transverse Beam Spin Asymmetries at Backward Angles in Elastic Electron-Proton and Quasi-elastic Electron-Deuteron Scattering

    Energy Technology Data Exchange (ETDEWEB)

    Androic, D; Armstrong, D S; Bailey, S L; Beck, D H; Beise, E J; Benesch, J; Benmokhtar, F; Bimbot, L; Birchall, J; Bosted, P; Breuer, K; Capuano, C L; Chao, Y -C; Coppens, A; Davis, C A; Ellis, C; Flores, G; Franklin, G; Furget, C; Gaskell, D; Gericke, M.T.W.; Grames, J; Guillard, G; Hansknecht, J; Horn, T; Jones, M K; King, P M; Korsch, W; Kox, S; Lee, L; Liu, J; Lung, A; Mammei, J; Martin, J W; McKeown, R D; Micherdzinska, A; Mihovilovic, M; Mkrtchyan, H; Muether, M; Page, S A; Papavassiliou, V; Pate, S F; Phillips, S K; Pillot, P; Pitt, M L; Poelker, M; Quinn, B; Ramsay, W D; Real, J -S; Roche, J; Roos, P; Schaub, J; Seva, T; Simicevic, N; Smith, G R; Spayde, D T; Stutzman, M; Suleiman, R; Tadevosyan, V; van Oers, W.T.H.; Versteegen, M; Voutier, E; Vulcan, W; Wells, S P; Williamson, S E; Wood, S A; Pasquini, B

    2011-07-01

    We have measured the beam-normal single-spin asymmetries in elastic scattering of transversely polarized electrons from the proton, and performed the first measurement in quasi-elastic scattering on the deuteron, at backward angles (lab scattering angle of 108 degrees) for Q2 = 0.22 GeV^2/c^2 and 0.63 GeV^2/c^2 at beam energies of 362 MeV and 687 MeV, respectively. The asymmetry arises due to the imaginary part of the interference of the two-photon exchange amplitude with that of single photon exchange. Results for the proton are consistent with a model calculation which includes inelastic intermediate hadronic (piN) states. An estimate of the beam-normal single-spin asymmetry for the scattering from the neutron is made using a quasi-static deuterium approximation, and is also in agreement with theory.

  3. Photoinduced Electron Transfer Based Ion Sensing within an Optical Fiber

    Science.gov (United States)

    Englich, Florian V.; Foo, Tze Cheung; Richardson, Andrew C.; Ebendorff-Heidepriem, Heike; Sumby, Christopher J.; Monro, Tanya M.

    2011-01-01

    We combine suspended-core microstructured optical fibers with the photoinduced electron transfer (PET) effect to demonstrate a new type of fluorescent optical fiber-dip sensing platform for small volume ion detection. A sensor design based on a simple model PET-fluoroionophore system and small core microstructured optical fiber capable of detecting sodium ions is demonstrated. The performance of the dip sensor operating in a high sodium concentration regime (925 ppm Na+) and for lower sodium concentration environments (18.4 ppm Na+) is explored and future approaches to improving the sensor’s signal stability, sensitivity and selectivity are discussed. PMID:22163712

  4. Photoinduced Electron Transfer Based Ion Sensing within an Optical Fiber

    Directory of Open Access Journals (Sweden)

    Tanya M. Monro

    2011-10-01

    Full Text Available We combine suspended-core microstructured optical fibers with the photoinduced electron transfer (PET effect to demonstrate a new type of fluorescent optical fiber-dip sensing platform for small volume ion detection. A sensor design based on a simple model PET-fluoroionophore system and small core microstructured optical fiber capable of detecting sodium ions is demonstrated. The performance of the dip sensor operating in a high sodium concentration regime (925 ppm Na+ and for lower sodium concentration environments (18.4 ppm Na+ is explored and future approaches to improving the sensor’s signal stability, sensitivity and selectivity are discussed.

  5. Quantitative surface-enhanced Raman scattering ultradetection of atomic inorganic ions: the case of chloride.

    Science.gov (United States)

    Tsoutsi, Dionysia; Montenegro, Jose Maria; Dommershausen, Fabian; Koert, Ulrich; Liz-Marzán, Luis M; Parak, Wolfgang J; Alvarez-Puebla, Ramon A

    2011-09-27

    Surface-enhanced Raman scattering (SERS) spectroscopy can be used for the determination and quantification of biologically representative atomic ions. In this work, the detection and quantification of chloride is demonstrated by monitoring the vibrational changes occurring at a specific interface (a Cl-sensitive dye) supported on a silver-coated silica microbead. The engineered particles play a key role in the detection, as they offer a stable substrate to support the dye, with a dense collection of SERS hot spots. These results open a new avenue toward the generation of microsensors for fast ultradetection and quantification of relevant ions inside living organisms such as cells. Additionally, the use of discrete particles rather than rough films, or other conventional SERS supports, will also enable a safe remote interrogation of highly toxic sources in environmental problems or biological fluids. © 2011 American Chemical Society

  6. Parity violation in electron scattering; Violation de parite en diffusion d'electrons

    Energy Technology Data Exchange (ETDEWEB)

    Lhuillier, D

    2007-09-15

    The elaboration of the electroweak standard model from the discovery of parity violation to the weak neutral current is described in the first chapter. In the second chapter the author discusses the 2 experimental approaches of the parity violation experiments. In the first approach the weak neutral current can be assumed to be well known and can be used as a probe for the hadronic matter. The second approach consists in measuring the weak neutral current between 2 particles with known internal structure in order to test the predictions of the standard model in the low energy range. The chapters 3 and 4 are an illustration of the first approach through the HAPPEx series of experiments that took place in the Jefferson Laboratory from 1998 to 2005. The HAPPEx experiments aimed at measuring the contribution of strange quarks in the electromagnetic form factors of the nucleon through the violation of parity in the elastic scattering at forward angles. The last chapter is dedicated to the E158 experiment that was performed at the Slac (California) between 2000 and 2003. The weak neutral current was measured between 2 electrons and the high accuracy obtained allowed the physics beyond the standard model to be indirectly constraint up to a few TeV. (A.C.)

  7. Thomson-Scattering Measurements of Ion-Acoustic Wave Amplitudes Driven by the Two-Plasmon-Decay Instability

    Science.gov (United States)

    Follett, R. K.; Michel, D. T.; Myatt, J. F.; Hu, S. X.; Yaakobi, B.; Froula, D. H.

    2012-10-01

    Thomson scattering was used to measure enhanced ion-acoustic waves (IAW's) driven by the two-plasmon-decay (TPD) instability. The IAW amplitude scales with the 3/2φ emission (a TPD signature). Up to 20 beams with 860-μm-diam laser spots generated by 2-ns-long pulses of 3φ (0.351-μm) light with overlapped intensities up to 4 x 10^14 W/cm^2 were used to produce ˜300-μm density-scale lengths. The IAW amplitudes were measured using 4φ Thomson scattering near 3φ quarter-critical densities. Time-resolved 3/2φ spectroscopy was used to compare the amplitude of 3/2φ emission to the IAW amplitude. QZAKfootnotetext K. Y. Sanbonmatsu et al., Phys. Rev. Lett. 82, 932 (1999).^,footnotetext K. Y. Sanbonmatsu et al., Phys. Plasmas 7, 2824 (2000). modeling shows a similar onset threshold and wave amplitude as the experiments. The model suggests that the source of the IAW growth is from the beating of electron-plasma waves, which drive density perturbations through the ponderomotive force. This conclusion is supported by the experimental geometry. This process is shown to be a saturation mechanism for TPD from simulations.footnotetext R. Yan et al., Phys. Rev. Lett. 103, 175002 (2009). This work was supported by the U.S. Department of Energy Office of Inertial Confinement Fusion under Cooperative Agreement No. DE-FC52-08NA28302.

  8. Intense highly charged ion beam production and operation with a superconducting electron cyclotron resonance ion source

    Directory of Open Access Journals (Sweden)

    H. W. Zhao

    2017-09-01

    Full Text Available The superconducting electron cyclotron resonance ion source with advanced design in Lanzhou (SECRAL is a superconducting-magnet-based electron cyclotron resonance ion source (ECRIS for the production of intense highly charged heavy ion beams. It is one of the best performing ECRISs worldwide and the first superconducting ECRIS built with an innovative magnet to generate a high strength minimum-B field for operation with heating microwaves up to 24–28 GHz. Since its commissioning in 2005, SECRAL has so far produced a good number of continuous wave intensity records of highly charged ion beams, in which recently the beam intensities of ^{40}Ar^{12+} and ^{129}Xe^{26+} have, for the first time, exceeded 1 emA produced by an ion source. Routine operations commenced in 2007 with the Heavy Ion accelerator Research Facility in Lanzhou (HIRFL, China. Up to June 2017, SECRAL has been providing more than 28,000 hours of highly charged heavy ion beams to the accelerator demonstrating its great capability and reliability. The great achievement of SECRAL is accumulation of numerous technical advancements, such as an innovative magnetic system and an efficient double-frequency (24+18  GHz heating with improved plasma stability. This article reviews the development of SECRAL and production of intense highly charged ion beams by SECRAL focusing on its unique magnet design, source commissioning, performance studies and enhancements, beam quality and long-term operation. SECRAL development and its performance studies representatively reflect the achievements and status of the present ECR ion source, as well as the ECRIS impacts on HIRFL.

  9. Intense highly charged ion beam production and operation with a superconducting electron cyclotron resonance ion source

    Science.gov (United States)

    Zhao, H. W.; Sun, L. T.; Guo, J. W.; Lu, W.; Xie, D. Z.; Hitz, D.; Zhang, X. Z.; Yang, Y.

    2017-09-01

    The superconducting electron cyclotron resonance ion source with advanced design in Lanzhou (SECRAL) is a superconducting-magnet-based electron cyclotron resonance ion source (ECRIS) for the production of intense highly charged heavy ion beams. It is one of the best performing ECRISs worldwide and the first superconducting ECRIS built with an innovative magnet to generate a high strength minimum-B field for operation with heating microwaves up to 24-28 GHz. Since its commissioning in 2005, SECRAL has so far produced a good number of continuous wave intensity records of highly charged ion beams, in which recently the beam intensities of 40Ar+ and 129Xe26+ have, for the first time, exceeded 1 emA produced by an ion source. Routine operations commenced in 2007 with the Heavy Ion accelerator Research Facility in Lanzhou (HIRFL), China. Up to June 2017, SECRAL has been providing more than 28,000 hours of highly charged heavy ion beams to the accelerator demonstrating its great capability and reliability. The great achievement of SECRAL is accumulation of numerous technical advancements, such as an innovative magnetic system and an efficient double-frequency (24 +18 GHz ) heating with improved plasma stability. This article reviews the development of SECRAL and production of intense highly charged ion beams by SECRAL focusing on its unique magnet design, source commissioning, performance studies and enhancements, beam quality and long-term operation. SECRAL development and its performance studies representatively reflect the achievements and status of the present ECR ion source, as well as the ECRIS impacts on HIRFL.

  10. Validation of COSMIC radio occultation electron density profiles by incoherent scatter radar data

    Science.gov (United States)

    Cherniak, Iurii; Zakharenkova, Irina

    The COSMIC/FORMOSAT-3 is a joint US/Taiwan radio occultation mission consisting of six identical micro-satellites. Each microsatellite has a GPS Occultation Experiment payload to operate the ionospheric RO measurements. FS3/COSMIC data can make a positive impact on global ionosphere study providing essential information about height electron density distribu-tion. For correct using of the RO electron density profiles for geophysical analysis, modeling and other applications it is necessary to make validation of these data with electron density distributions obtained by another measurement techniques such as proven ground based facili-ties -ionosondes and IS radars. In fact as the ionosondes provide no direct information on the profile above the maximum electron density and the topside ionosonde profile is obtained by fitting a model to the peak electron density value, the COSMIC RO measurements can make an important contribution to the investigation of the topside part of the ionosphere. IS radars provide information about the whole electron density profile, so we can estimate the agreement of topside parts between two independent measurements. To validate the reliability of COS-MIC data we have used the ionospheric electron density profiles derived from IS radar located near Kharkiv, Ukraine (geographic coordinates: 49.6N, 36.3E, geomagnetic coordinates: 45.7N, 117.8E). The Kharkiv radar is a sole incoherent scatter facility on the middle latitudes of Eu-ropean region. The radar operates with 100-m zenith parabolic antenna at 158 MHz with peak transmitted power 2.0 MW. The Kharkiv IS radar is able to determine the heights-temporal distribution of ionosphere parameters in height range of 70-1500 km. At the ionosphere in-vestigation by incoherent scatter method there are directly measured the power spectrum (or autocorrelation function) of scattered signal. With using of rather complex procedure of the received signal processing it is possible to estimate the

  11. ITER fast ion collective Thomson scattering, conceptual design of 60 GHz system

    Energy Technology Data Exchange (ETDEWEB)

    Meo, F.; Bindslev, H.; Korsholm, S.B.

    2007-08-15

    The collective Thomson scattering diagnostic for ITER at the 60 GHz range is capable of measuring the fast ion distribution parallel and perpendicular to the magnetic field at different radial locations simultaneously. The design is robust technologically with no moveable components near the plasma. The fast ion CTS diagnostic consists of two separate systems. Each system has its own RF launcher and separate set of detectors. The first system measures the perpendicular component of the fast ion velocity distribution. It consists of radially directed RF launcher and receiver, both located in the equatorial port on the low field side (LFS). This system will be referred to by the acronym LFS-BS system referring to the location of the receiver and the fact that it measures backscattered radiation. The second part of the CTS diagnostic measures the parallel component of the fast ion distribution. It consists of an RF launcher located in the mid-plane port on the LFS and a receiver mounted on the inner vacuum vessel wall that views the plasma from between two blanket modules. This system will be referred to as HFS-FS referring to the location of the receivers and that they measure forward scattered radiation. The design of both LFS-BS and HFS-FS receivers is aimed at measuring at different spatial locations simultaneously with no moveable components near the plasma. This report is a preliminary study of the hardware design and engineering constraints for this frequency range. Section 2 conceptually describes the two systems and their main components. Section 3 clarifies the impact of design parameters such as beam widths and scattering angle on the CTS measurements. With this in hand, the ITER measurement requirements are translated into constraints on the CTS system designs. An important result in this section is that systems can be designed inside these constraints. Section 4 outlines the technical feasibility and describes in more detail the design and the engineering

  12. First test of BNL electron beam ion source with high current density electron beam

    Energy Technology Data Exchange (ETDEWEB)

    Pikin, Alexander, E-mail: pikin@bnl.gov; Alessi, James G., E-mail: pikin@bnl.gov; Beebe, Edward N., E-mail: pikin@bnl.gov [Brookhaven National Laboratory, Upton, NY 11973 (United States); Shornikov, Andrey; Mertzig, Robert; Wenander, Fredrik; Scrivens, Richard [CERN, CH-1211 Geneva 23 (Switzerland)

    2015-01-09

    A new electron gun with electrostatic compression has been installed at the Electron Beam Ion Source (EBIS) Test Stand at BNL. This is a collaborative effort by BNL and CERN teams with a common goal to study an EBIS with electron beam current up to 10 A, current density up to 10,000 A/cm{sup 2} and energy more than 50 keV. Intensive and pure beams of heavy highly charged ions with mass-to-charge ratio < 4.5 are requested by many heavy ion research facilities including NASA Space Radiation Laboratory (NSRL) at BNL and HIE-ISOLDE at CERN. With a multiampere electron gun, the EBIS should be capable of delivering highly charged ions for both RHIC facility applications at BNL and for ISOLDE experiments at CERN. Details of the electron gun simulations and design, and the Test EBIS electrostatic and magnetostatic structures with the new electron gun are presented. The experimental results of the electron beam transmission are given.

  13. Phonons in a magnetized Coulomb crystal of ions with polarizable electron background

    Science.gov (United States)

    Baiko, D. A.; Kozhberov, A. A.

    2017-11-01

    We have studied phonon modes of a body-centered cubic (bcc) Coulomb crystal of ions in the presence of a uniform magnetic field B taking into account the polarizability of the electron background (electron screening) described by the Thomas-Fermi formalism. For k ≫κTF (k and κTF are the phonon wavevector and Thomas-Fermi wavenumber, respectively), electron polarizability is not important. At k ≪κTF , the electron response results in a pronounced effect. One of the three available modes is acoustic. For orthogonal propagation ( k ⊥B ), its frequency Ω is independent of B and κTF . For k ∥B , Ω∝1 /κTF and is independent of B. Another mode is quadratic. Its frequency is ∝1 /(B κTF) for orthogonal propagation and ∝1 /B and independent of κTF for the parallel case. The third mode is optic with Ω≈ωB ( ωB is the ion cyclotron frequency). A general expression is derived for the dynamic matrix of a Coulomb crystal with a polarizable background and more than one ion in the primitive cell. It is employed for a study of a magnetized hexagonal close-packed Coulomb crystal. We have also presented an analysis of phonon polarization vectors in a magnetized bcc crystal with or without screening. The results obtained can be used for realistic calculations of electron-phonon scattering rates and electron thermal and electrical conductivities in neutron star crusts.

  14. Inelastic electron-dipole-molecule scattering at sub-milli-electron-volt energies: Possible role of dipole-supported states

    Science.gov (United States)

    Frey, M. T.; Hill, S. B.; Ling, X.; Smith, K. A.; Dunning, F. B.; Fabrikant, I. I.

    1994-10-01

    Studies of collisions between Rydberg atoms with values of principal quantum number n in the range 100<~n<~400 and H2S and C6H5NO2 are reported. These targets were selected because they have very different dipole moments: 0.97 and 4.22 D, respectively. Analysis of the data using the essentially-free-electron model shows that at micro-electron-volt energies the cross sections for rotationally inelastic electron scattering by these targets have very different energy dependences. This difference suggests that, in the case of C6H5NO2, dipole-supported states might be important in the scattering. To examine this further, the data are compared with the results of calculations using a free-electron cross section that assumes the presence of dipole-supported states, and it is demonstrated that, with a reasonable choice of parameters, it is possible to reproduce the experimental observations.

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

  16. Laser Thomson scattering measurements of electron temperature and density in a hall-effect plasma

    Science.gov (United States)

    Washeleski, Robert L.

    Hall-effect thrusters (HETs) are compact electric propulsion devices with high specific impulse used for a variety of space propulsion applications. HET technology is well developed but the electron properties in the discharge are not completely understood, mainly due to the difficulty involved in performing accurate measurements in the discharge. Measurements of electron temperature and density have been performed using electrostatic probes, but presence of the probes can significantly disrupt thruster operation, and thus alter the electron temperature and density. While fast-probe studies have expanded understanding of HET discharges, a non-invasive method of measuring the electron temperature and density in the plasma is highly desirable. An alternative to electrostatic probes is a non-perturbing laser diagnostic technique that measures Thomson scattering from the plasma. Thomson scattering is the process by which photons are elastically scattered from the free electrons in a plasma. Since the electrons have thermal energy their motion causes a Doppler shift in the scattered photons that is proportional to their velocity. Like electrostatic probes, laser Thomson scattering (LTS) can be used to determine the temperature and density of free electrons in the plasma. Since Thomson scattering measures the electron velocity distribution function directly no assumptions of the plasma conditions are required, allowing accurate measurements in anisotropic and non-Maxwellian plasmas. LTS requires a complicated measurement apparatus, but has the potential to provide accurate, non-perturbing measurements of electron temperature and density in HET discharges. In order to assess the feasibility of LTS diagnostics on HETs non-invasive measurements of electron temperature and density in the near-field plume of a Hall thruster were performed using a custom built laser Thomson scattering diagnostic. Laser measurements were processed using a maximum likelihood estimation method

  17. Electron scattering at surfaces and grain boundaries in thin Au films

    Energy Technology Data Exchange (ETDEWEB)

    Henriquez, Ricardo [Departamento de Física, Universidad Técnica Federico Santa María, Av. España 1680, Casilla 110-V, Valparaíso (Chile); Flores, Marcos; Moraga, Luis [Departamento de Física, Facultad de Ciencias Físicas y Matemáticas, Universidad de Chile, Blanco Encalada 2008, Casilla 487-3, Santiago 8370449 (Chile); Kremer, German [Bachillerato, Universidad de Chile, Las Palmeras 3425, Santiago 7800024 (Chile); González-Fuentes, Claudio [Departamento de Física, Universidad Técnica Federico Santa María, Av. España 1680, Casilla 110-V, Valparaíso (Chile); Munoz, Raul C., E-mail: ramunoz@ing.uchile.cl [Departamento de Física, Facultad de Ciencias Físicas y Matemáticas, Universidad de Chile, Blanco Encalada 2008, Casilla 487-3, Santiago 8370449 (Chile)

    2013-05-15

    The electron scattering at surfaces and grain boundaries is investigated using polycrystalline Au films deposited onto mica substrates. We vary the three length scales associated with: (i) electron scattering in the bulk, that at temperature T is characterized by the electronic mean free path in the bulk ℓ{sub 0}(T); (ii) electron-surface scattering, that is characterized by the film thickness t; (iii) electron-grain boundary scattering, that is characterized by the mean grain diameter D. We varied independently the film thickness from approximately 50 nm to about 100 nm, and the typical grain size making up the samples from 12 nm to 160 nm. We also varied the scale of length associated with electron scattering in the bulk by measuring the resistivity of each specimen at temperatures T, 4 K < T < 300 K. Cooling the samples to 4 K increases ℓ{sub 0}(T) by approximately 2 orders of magnitude. Detailed measurements of the grain size distribution as well as surface roughness of each sample were performed with a Scanning Tunnelling Microscope (STM). We compare, for the first time, theoretical predictions with resistivity data employing the two theories available that incorporate the effect of both electron-surface as well as electron-grain boundary scattering acting simultaneously: the theory of A.F. Mayadas and M. Shatzkes, Phys. Rev. 1 1382 (1970) (MS), and that of G. Palasantzas, Phys. Rev. B 58 9685 (1998). We eliminate adjustable parameters from the resistivity data analysis, by using as input the grain size distribution as well as the surface roughness measured with the STM on each sample. The outcome is that both theories provide a fair representation of both the temperature as well as the thickness dependence of the resistivity data, but yet there are marked differences between the resistivity predicted by these theories. In the case of the MS theory, when the average grain diameter D is significantly smaller than ℓ{sub 0}(300) = 37 nm, the electron mean

  18. Measurement of multiple scattering of 13 and 20 MeV electrons by thin foils

    Science.gov (United States)

    Ross, C. K.; McEwen, M. R.; McDonald, A. F.; Cojocaru, C. D.; Faddegon, B. A.

    2008-01-01

    To model the transport of electrons through material requires knowledge of how the electrons lose energy and scatter. Theoretical models are used to describe electron energy loss and scatter and these models are supported by a limited amount of measured data. The purpose of this work was to obtain additional data that can be used to test models of electron scattering. Measurements were carried out using 13 and 20 MeV pencil beams of electrons produced by the National Research Council of Canada research accelerator. The electron fluence was measured at several angular positions from 0° to 9° for scattering foils of different thicknesses and with atomic numbers ranging from 4 to 79. The angle, θ1∕e, at which the fluence has decreased to 1∕e of its value on the central axis was used to characterize the distributions. Measured values of θ1∕e ranged from 1.5° to 8° with a typical uncertainty of about 1%. Distributions calculated using the EGSnrc Monte Carlo code were compared to the measured distributions. In general, the calculated distributions are narrower than the measured ones. Typically, the difference between the measured and calculated values of θ1∕e is about 1.5%, with the maximum difference being 4%. The measured and calculated distributions are related through a simple scaling of the angle, indicating that they have the same shape. No significant trends with atomic number were observed. PMID:18841865

  19. A study of electron scattering through noise spectroscopy

    NARCIS (Netherlands)

    Kumar, Manohar

    2012-01-01

    Charge counting statistics (C.S.) of traversing electron in quantum devices like atomic-molecular junctions is sensitive to the local perturbation in the charge field at the contact and in the quantum channels. The first cumulant of C.S. i.e. current-voltage characteristic of such devices has been

  20. Increase of the performances of electron cyclotron resonance ion sources by using cold electron emission

    CERN Document Server

    Schaechter, I; Badescu-Singureanu, A I; Stiebing, K E; Runkel, S; Hohn, O; Schmidt, L; Schmidt-Böcking, H; Drentje, A; Rodríguez, G

    2003-01-01

    The possibility of a significant increase of the high charge state ion beams delivered by electron cyclotron resonance (ECR) ion sources was approached in IFIN-HH, Bucharest, Romania by a new method. It consists in the introduction in the plasma chamber of the ECR ion source of a metal-dielectric (MD) structure characterized by very high secondary electron emission properties. The intensities of argon ion beams extracted from the 14 GHz ECR ion sources of IKF, Frankfurt/Main, Germany and KVI, Groningen, Netherlands were measured both in the standard mode of operation of the sources and in the presence of a MD structure. Similar results were obtained in both experiments when the MD structure was used showing a net shift of the beam intensity towards higher charge states as compared with the usual standard plasma chamber of the ECR ion sources. Ion current enhancement factors of up to two orders of magnitude were obtained for Ar sup 1 sup 6 sup + ions. (authors)

  1. A novel cyanide ion sensing approach based on Raman scattering for the detection of environmental cyanides.

    Science.gov (United States)

    Yan, Fei; Gopal Reddy, C V; Zhang, Yan; Vo-Dinh, Tuan

    2010-09-01

    This paper describes a direct optical approach based on Raman scattering for selective and sensitive detection of cyanide ions in aqueous environment without requiring time-consuming sample pretreatment and the formation of hydrogen cyanide. Due to the strong affinity between copper (I) and cyanide ion, evaporated copper (I) iodide (CuI) thin films are shown to be excellent substrates for selective recognition of free cyanide ions in aqueous matrices. The amount of cyanide ion retained by the copper (I) in the CuI thin films reflects its actual concentration in tested samples, and the subsequent Raman measurements of the substrate are shown to be capable of detecting toxic cyanide content at levels under international drinking water standard and environmental regulatory concentrations. Measurements obtained from the same batch of evaporated CuI thin films (approximately 100-nm thickness) show excellent linearity over a variety of cyanide concentrations ranging from 1.5 microM to 0.15 mM. This detection method offers the advantage of selectively detecting cyanides causing a health hazard while avoiding detection of other common interfering anions such as Cl-, Br-, PO4(3-), SO4(2-), NO2-, S2- and SCN-. Coupled with portable Raman systems that are commercially available, our detection approach will provide on-site monitoring capability with little sample preparation or instrument supervision, which will greatly expedite the assessment of potential environmental cyanide risks. Copyright (c) 2010 Elsevier Inc. All rights reserved.

  2. Production and decay of chlorine ion excited species in an electron cyclotron resonance ion source plasma

    Energy Technology Data Exchange (ETDEWEB)

    Santos, J P; Martins, M C; Parente, F [Centro de Fisica Atomica, CFA, Departamento de Fisica, Faculdade de Ciencias e Tecnologia, FCT, Universidade Nova de Lisboa, 2829-516 Caparica (Portugal); Costa, A M; Marques, J P [Centro de Fisica Atomica, CFA, Departamento de Fisica, Faculdade de Ciencias, FCUL, Universidade de Lisboa, Campo Grande, 1749-016 Lisboa (Portugal); Indelicato, P, E-mail: jps@fct.unl.pt [Laboratoire Kastler Brossel, Ecole Normale Superieure, CNRS, Universite P et M Curie-Paris 6, Case 74, 4 place Jussieu, 75252 Paris Cedex 05 (France)

    2011-06-15

    The most important processes for the creation of chlorine ion excited states from the ground configurations of Cl{sup 10+} to Cl{sup 15+} ions in an electron cyclotron resonance ion source, leading to the emission of K x-ray lines, were studied. Theoretical values for inner-shell excitation and ionization cross-sections, including double KL and triple KLL ionization, transition probabilities and energies for the de-excitation processes, were calculated in the framework of the multi-configuration Dirac-Fock method. With reasonable assumptions about the electron energy distribution, a theoretical K{alpha} x-ray spectrum was obtained, which was then compared with recent experimental data.

  3. Abrupt variation in ion current with biased disk voltage in the electron cyclotron resonance ion source

    NARCIS (Netherlands)

    Taki, GS; Sarma, PR; Chakraborty, DK; Lhandari, RK; Ray, PK; Drentje, AG; Bhandari, R.K.

    The performance of the biased disk in the 6.4 GHz electron cyclotron resonance ion source at VECC, Kolkata was studied at a pressure of similar to 1 X 10(-7) Torr. We observed an abrupt variation of beam current with bias voltage. For low negative bias voltages (from 0 to -5 V) the beam current

  4. The Radiation Belt Electron Scattering by Magnetosonic Wave: Dependence on Key Parameters

    Science.gov (United States)

    Lei, Mingda; Xie, Lun; Li, Jinxing; Pu, Zuyin; Fu, Suiyan; Ni, Binbin; Hua, Man; Chen, Lunjin; Li, Wen

    2017-12-01

    Magnetosonic (MS) waves have been found capable of creating radiation belt electron butterfly distributions in the inner magnetosphere. To investigate the physical nature of the interactions between radiation belt electrons and MS waves, and to explore a preferential condition for MS waves to scatter electrons efficiently, we performed a comprehensive parametric study of MS wave-electron interactions using test particle simulations. The diffusion coefficients simulated by varying the MS wave frequency show that the scattering effect of MS waves is frequency insensitive at low harmonics (f butterfly distributions in the inner part of the plasmasphere where the ratio of electron plasma-to-gyrofrequency (fpe/fce) is large, while they may essentially form a two-peak distribution outside the plasmapause and in the inner radiation belt where fpe/fce is small.

  5. Total and elastic electron scattering cross sections from Xe at intermediate and high energies

    Energy Technology Data Exchange (ETDEWEB)

    Garcia, G [Instituto de Matematicas y Fisica Fundamental, CSIC, Serrano 123, 28006 Madrid (Spain); Pablos, J L de [Departamento de Fusion y Particulas Elementales, CIEMAT, Avenida Complutense 22, 28040 Madrid (Spain); Blanco, F [Departamento de Fisica Atomica Molecular y Nuclear, Universidad Complutense de Madrid, 28040 Madrid (Spain); Williart, A [Departamento de Fisica de los Materiales, UNED, Senda del Rey 9, 28040 Madrid (Spain)

    2002-11-28

    Experimental total electron scattering cross sections from Xe in the energy range 300-5000 eV have been obtained with experimental errors of about 3%. The method was based on the measurement of the attenuation of a linear electron beam through a Xe gas cell in combination with an electron spectroscopy technique to analyse the energy of the transmitted electrons. Differential and integral elastic cross sections have been calculated using a scattering potential method which includes relativistic effects. The consistency of our theoretical and experimental results is also discussed in the paper. Finally, analytical formulae depending on two parameters, namely the number of target electrons and the atomic polarizability, are given to reproduce the experimental data for Ne, Ar, Kr and Xe in the energy range 500-10 000 eV.

  6. Effects of model approximations for electron, hole, and photon transport in swift heavy ion tracks

    Science.gov (United States)

    Rymzhanov, R. A.; Medvedev, N. A.; Volkov, A. E.

    2016-12-01

    The event-by-event Monte Carlo code, TREKIS, was recently developed to describe excitation of the electron subsystems of solids in the nanometric vicinity of a trajectory of a nonrelativistic swift heavy ion (SHI) decelerated in the electronic stopping regime. The complex dielectric function (CDF) formalism was applied in the used cross sections to account for collective response of a matter to excitation. Using this model we investigate effects of the basic assumptions on the modeled kinetics of the electronic subsystem which ultimately determine parameters of an excited material in an SHI track. In particular, (a) effects of different momentum dependencies of the CDF on scattering of projectiles on the electron subsystem are investigated. The 'effective one-band' approximation for target electrons produces good coincidence of the calculated electron mean free paths with those obtained in experiments in metals. (b) Effects of collective response of a lattice appeared to dominate in randomization of electron motion. We study how sensitive these effects are to the target temperature. We also compare results of applications of different model forms of (quasi-) elastic cross sections in simulations of the ion track kinetics, e.g. those calculated taking into account optical phonons in the CDF form vs. Mott's atomic cross sections. (c) It is demonstrated that the kinetics of valence holes significantly affects redistribution of the excess electronic energy in the vicinity of an SHI trajectory as well as its conversion into lattice excitation in dielectrics and semiconductors. (d) It is also shown that induced transport of photons originated from radiative decay of core holes brings the excess energy faster and farther away from the track core, however, the amount of this energy is relatively small.

  7. Relativistic, QED and nuclear effects in highly charged ions revealed by resonant electron-ion recombination in storage rings

    OpenAIRE

    Schippers, Stefan

    2008-01-01

    Dielectronic recombination (DR) of few-electron ions has evolved into a sensitive spectroscopic tool for highly charged ions. This is due to technological advances in electron-beam preparation and ion-beam cooling techniques at heavy-ion storage rings. Recent experiments prove unambiguously that DR collision spectroscopy has become sensitive to 2nd order QED and to nuclear effects. This review discusses the most recent developments in high-resolution spectroscopy of low-energy DR resonances, ...

  8. High mass-resolution electron-ion-ion coincidence measurements on core-excited organic molecules

    CERN Document Server

    Tokushima, T; Senba, Y; Yoshida, H; Hiraya, A

    2001-01-01

    Total electron-ion-ion coincidence measurements on core excited organic molecules have been carried out with high mass resolution by using multimode (reflectron/linear) time-of-flight mass analyzer. From the ion correlation spectra of core excited CH sub 3 OH and CD sub 3 OH, the reaction pathway to form H sub 3 sup + (D sub 3 sup +) is identified as the elimination of three H (D) atoms from the methyl group, not as the inter-group (-CH sub 3 and -OH) interactions. In a PEPIPICO spectrum of acetylacetone (CH sub 3 COCH sub 2 COCH sub 3) measured by using a reflectron TOF, correlations between ions up to mass number 70 with one-mass resolution was recorded.

  9. Electronic transport in a one-dimensional random array of scatterers

    CERN Document Server

    Filinov, V S; Varga, I; Meier, T; Bonitz, M; Fortov, V E; Koch, S W

    2003-01-01

    The quantum dynamics of an ensemble of interacting electrons in an array of random scatterers is treated using a new numerical approach for the calculation of average values of quantum operators and time correlation functions in the Wigner representation. This approach combines both molecular dynamics and Monte Carlo methods and computes numerical traces and spectra of the relevant dynamical quantities such as momentum-momentum correlation functions and spatial dispersions. Considering, as an application, a system with fixed scatterers, the results clearly demonstrate that the many-particle interaction between the electrons can lead to an enhancement of the conductivity at intermediate densities.

  10. Kapitza-Dirac scattering of electrons from a bichromatic standing laser wave

    CERN Document Server

    Dellweg, Matthias M

    2015-01-01

    Coherent scattering of an electron beam by the Kapitza-Dirac effect from a standing laser wave which comprises two frequency components is studied. To this end, the Schr\\"odinger equation is solved numerically with a suitable ponderomotive potential. Besides, an analytical solution for electron diffraction in the asymptotic domain of large field amplitudes is obtained and a mathematical model in reduced dimensionality for the scattering amplitude in the Bragg regime is presented. We demonstrate distinct interference signatures and relative phase effects when the standing wave contains a fundamental frequency and its second harmonic. The influence of the relative field intensities on the Rabi oscillation dynamics is also discussed.

  11. Elastic scattering of low energy electrons in partially ionized dense semiclassical plasma

    Energy Technology Data Exchange (ETDEWEB)

    Dzhumagulova, K. N., E-mail: dzhumagulova.karlygash@gmail.com; Shalenov, E. O.; Ramazanov, T. S. [IETP, Al Farabi Kazakh National University, 71al Farabi Street, Almaty 050040 (Kazakhstan)

    2015-08-15

    Elastic scattering of electrons by hydrogen atoms in a dense semiclassical hydrogen plasma for low impact energies has been studied. Differential scattering cross sections were calculated within the effective model of electron-atom interaction taking into account the effect of screening as well as the quantum mechanical effect of diffraction. The calculations were carried out on the basis of the phase-function method. The influence of the diffraction effect on the Ramsauer–Townsend effect was studied on the basis of a comparison with results made within the effective polarization model of the Buckingham type.

  12. Neutrino-Electron Scattering in MINERvA for Constraining the NuMI Neutrino Flux

    Energy Technology Data Exchange (ETDEWEB)

    Park, Jaewon [Univ. of Rochester, NY (United States)

    2013-01-01

    Neutrino-electron elastic scattering is used as a reference process to constrain the neutrino flux at the Main Injector (NuMI) beam observed by the MINERvA experiment. Prediction of the neutrino flux at accelerator experiments from other methods has a large uncertainty, and this uncertainty degrades measurements of neutrino oscillations and neutrino cross-sections. Neutrino-electron elastic scattering is a rare process, but its cross-section is precisely known. With a sample corresponding to $3.5\\times10^{20}$ protons on target in the NuMI low-energy neutrino beam, a sample of $120$ $\

  13. Creation, destruction, and transfer of atomic multipole moments by electron scattering: Quantum-mechanical treatment

    Science.gov (United States)

    Csanak, G.; Kilcrease, D. P.; Fursa, D. V.; Bray, I.

    2008-12-01

    Using the wave-packet propagation method of Rodberg and Thaler and the density matrix method of Fano and Blum, we have defined by completely quantum-mechanical methods the cross sections for the creation, destruction, and transfer of atomic multipole moments by both elastic and inelastic scattering of electrons by atomic targets. All cross sections obtained quantum mechanically, except for the coherence transfer cross sections, agree in form with those obtained semiclassically by Fujimoto and co-workers. We also used the converged close-coupling (CCC) method to calculate numerically some of the above cross sections for selected transitions in electron scattering from hydrogen and barium atoms.

  14. Focusing effects in laser-electron Thomson scattering

    Directory of Open Access Journals (Sweden)

    Chris Harvey

    2016-09-01

    Full Text Available We study the effects of laser pulse focusing on the spectral properties of Thomson scattered radiation. Modeling the laser as a paraxial beam we find that, in all but the most extreme cases of focusing, the temporal envelope has a much bigger effect on the spectrum than the focusing itself. For the case of ultrashort pulses, where the paraxial model is no longer valid, we adopt a subcycle vector beam description of the field. It is found that the emission harmonics are blue shifted and broaden out in frequency space as the pulse becomes shorter. Additionally the carrier envelope phase becomes important, resulting in an angular asymmetry in the spectrum. We then use the same model to study the effects of focusing beyond the limit where the paraxial expansion is valid. It is found that fields focussed to subwavelength spot sizes produce spectra that are qualitatively similar to those from subcycle pulses due to the shortening of the pulse with focusing. Finally, we study high-intensity fields and find that, in general, the focusing makes negligible difference to the spectra in the regime of radiation reaction.

  15. Focussing effects in laser-electron Thomson scattering

    CERN Document Server

    Harvey, C; Holkundkar, A R

    2016-01-01

    We study the effects of laser pulse focussing on the spectral properties of Thomson scattered radiation. Modelling the laser as a paraxial beam we find that, in all but the most extreme cases of focussing, the temporal envelope has a much bigger effect on the spectrum than the focussing itself. For the case of ultra-short pulses where the paraxial model is no longer valid, we adopt a sub-cycle vector beam description of the field. It is found that the emission harmonics are blue shifted and broaden out in frequency space as the pulse becomes shorter. Additionally the carrier envelope phase becomes important, resulting in an angular asymmetry in the spectrum. We then use the same model to study the effects of focussing beyond the limit where the paraxial expansion is valid. It is found that fields focussed to sub-wavelength spot sizes produce spectra that are qualitatively similar to those from sub-cycle pulses due to the shortening of the pulse with focussing. Finally, we study high-intensity fields and find ...

  16. Measurement of Deuteron Tensor Polarization in Elastic Electron Scattering

    Energy Technology Data Exchange (ETDEWEB)

    Gustafsson, Kenneth K. [Univ. of Maryland, College Park, MD (United States)

    2000-01-01

    Nuclear physics traces it roots back to the very beginning of the last century. The concept of the nuclear atom was introduced by Rutherford around 1910. The discovery of the neutron Chadwick in 1932 gave us the concept of two nucleons: the proton and the neutron. The Jlab electron accelerator with its intermediate energy high current continuous wave beam combined with the Hall C high resolution electron spectrometer and a deutron recoil polarimeter provided experiment E94018 with the opportunity to study the deuteron electomagnetic structure, in particular to measure the tensor polarization observable t20, at high four momentum transfers than ever before. This dissertation presents results of JLab experiment E94018.

  17. Electron scattering from molecules and molecular aggregates of biological relevance

    Science.gov (United States)

    Gorfinkiel, Jimena D.; Ptasinska, Sylwia

    2017-09-01

    In this Topical Review we survey the current state of the art in the study of low energy electron collisions with biologically relevant molecules and molecular clusters. We briefly describe the methods and techniques used in the investigation of these processes and summarise the results obtained so far for DNA constituents and their model compounds, amino acids, peptides and other biomolecules. The applications of the data obtained is briefly described as well as future required developments.

  18. Electron beam final focus system for Thomson scattering at ELBE

    Energy Technology Data Exchange (ETDEWEB)

    Krämer, J.M., E-mail: jmkr@danfysik.dk [Danfysik A/S, Gregersensvej 8, 2630 Taastrup (Denmark); Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiation Physics, Bautzner Landstrasse 400, 01328 Dresden (Germany); Technische Universität Dresden, 01069 Dresden (Germany); Budde, M.; Bødker, F. [Danfysik A/S, Gregersensvej 8, 2630 Taastrup (Denmark); Irman, A.; Jochmann, A. [Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiation Physics, Bautzner Landstrasse 400, 01328 Dresden (Germany); Kristensen, J.P. [Danfysik A/S, Gregersensvej 8, 2630 Taastrup (Denmark); Lehnert, U.; Michel, P. [Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiation Physics, Bautzner Landstrasse 400, 01328 Dresden (Germany); Schramm, U. [Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiation Physics, Bautzner Landstrasse 400, 01328 Dresden (Germany); Technische Universität Dresden, 01069 Dresden (Germany)

    2016-09-11

    The design of an electron beam final focus system (FFS) aiming for high-flux laser-Thomson backscattering X-ray sources at ELBE is presented. A telescope system consisting of four permanent magnet based quadrupoles was found to have significantly less chromatic aberrations than a quadrupole doublet or triplet as commonly used. Focusing properties like the position of the focal plane and the spot size are retained for electron beam energies between 20 and 30 MeV by adjusting the position of the quadrupoles individually on a motorized stage. The desired ultra-short electron bunches require an increased relative energy spread up to a few percent and, thus, second order chromatic effects must be taken into account. We also present the design and test results of the permanent magnet quadrupoles. Adjustable shunts allow for correction of the field strength and compensation of deviations in the permanent magnet material. For a beam emittance of 13 mm mrad, we predict focal spot sizes of about 40 μm (rms) and divergences of about 10 mrad using the FFS.

  19. Electron beam final focus system for Thomson scattering at ELBE

    Science.gov (United States)

    Krämer, J. M.; Budde, M.; Bødker, F.; Irman, A.; Jochmann, A.; Kristensen, J. P.; Lehnert, U.; Michel, P.; Schramm, U.

    2016-09-01

    The design of an electron beam final focus system (FFS) aiming for high-flux laser-Thomson backscattering X-ray sources at ELBE is presented. A telescope system consisting of four permanent magnet based quadrupoles was found to have significantly less chromatic aberrations than a quadrupole doublet or triplet as commonly used. Focusing properties like the position of the focal plane and the spot size are retained for electron beam energies between 20 and 30 MeV by adjusting the position of the quadrupoles individually on a motorized stage. The desired ultra-short electron bunches require an increased relative energy spread up to a few percent and, thus, second order chromatic effects must be taken into account. We also present the design and test results of the permanent magnet quadrupoles. Adjustable shunts allow for correction of the field strength and compensation of deviations in the permanent magnet material. For a beam emittance of 13 mm mrad, we predict focal spot sizes of about 40 μm (rms) and divergences of about 10 mrad using the FFS.

  20. Electron Beam Final Focus System For Thomson Scattering At Elbe

    CERN Document Server

    Krämer, J.M.; Bødkera, F.; Irman, A.; Jochmann, A.; Kristensena, J.P.; Lehnert, U.; Michel, P.; Schramm, U.; 10.1016/j.nima.2015.10.067

    2016-01-01

    The design of an electron beam final focus system (FFS) aiming for high-flux laser-Thomson backscattering X-ray sources at ELBE is presented. A telescope system consisting of four permanent magnet based quadrupoles was found to have significantly less chromatic aberrations than a quadrupole doublet or triplet as commonly used. Focusing properties like the position of the focal plane and the spot size are retained for electron beam energies between 20 and 30 MeV by adjusting the position of the quadrupoles individually on a motorized stage. The desired ultra-short electron bunches require an increased relative energy spread up to a few percent and, thus, second order chromatic effects must be taken into account. We also present the design and test results of the permanent magnet quadrupoles. Adjustable shunts allow for correction of the field strength and compensation of deviations in the permanent magnet material. For a beam emittance of 13 mm mrad, we predict focal spot sizes of about 40 μm (rms) and diverg...

  1. Electron beam final focus system for Thomson scattering at ELBE

    CERN Document Server

    Krämer, J.M.; Bødker, F.; Irman, A.; .Jochmann A.; Kristensen, J.P.; Lehnert U., HZDR; Michel, P.; Schrammb, U.; 10.1016/j.nima.2015.10.067

    2016-01-01

    The design of an electron beam final focus system (FFS) aiming for high-flux laser-Thomson backscattering X-ray sources at ELBE is presented. A telescope system consisting of four permanent magnet based quadrupoles was found to have significantly less chromatic aberrations than a quadrupole doublet or triplet as commonly used. Focusing properties like the position of the focal plane and the spot size are retained for electron beam energies between 20 and 30 MeV by adjusting the position of the quadrupoles individually on a motorized stage. The desired ultra-short electron bunches require an increased relative energy spread up to a few percent and, thus, second order chromatic effects must be taken into account. We also present the design and test results of the permanent magnet quadrupoles. Adjustable shunts allow for correction of the field strength and compensation of deviations in the permanent magnet material. For a beam emittance of 13 mm mrad, we predict focal spot sizes of about 40 μm (rms) and diverg...

  2. ELECTRON BEAM ION SOURCE PREINJECTOR PROJECT (EBIS) CONCEPTUAL DESIGN REPORT.

    Energy Technology Data Exchange (ETDEWEB)

    ALESSI, J.; BARTON, D.; BEEBE, E.; GASSNER, D.; ET AL.

    2005-02-28

    This report describes a new heavy ion pre-injector for the Relativistic Heavy Ion Collider (RHIC) based on a high charge state Electron Beam Ion Source (EBIS), a Radio Frequency Quadrupole (RFQ) accelerator, and a short Linac. The highly successful development of an EBIS at BNL now makes it possible to replace the present pre-injector that is based on an electrostatic Tandem with a reliable, low maintenance Linac-based pre-injector. Linac-based pre-injectors are presently used at most accelerator and collider facilities with the exception of RHIC, where the required gold beam intensities could only be met with a Tandem until the recent EBIS development. EBIS produces high charge state ions directly, eliminating the need for the two stripping foils presently used with the Tandem. Unstable stripping efficiencies of these foils are a significant source of luminosity degradation in RHIC. The high reliability and flexibility of the new Linac-based pre-injector will lead to increased integrated luminosity at RHIC and is an essential component for the long-term success of the RHIC facility. This new pre-injector, based on an EBIS, also has the potential for significant future intensity increases and can produce heavy ion beams of all species including uranium beams and, as part of a future upgrade, might also be used to produce polarized {sup 3}He beams. These capabilities will be critical to the future luminosity upgrades and electron-ion collisions in RHIC. The new RFQ and Linac that are used to accelerate beams from the EBIS to an energy sufficient for injection into the Booster are both very similar to existing devices already in operation at other facilities. Injection into the Booster will occur at the same location as the existing injection from the Tandem.

  3. Electron-ion thermal equilibration after spherical shock collapse

    Energy Technology Data Exchange (ETDEWEB)

    Rygg, J R; Frenje, J A; Li, C K; Seguin, F H; Petrasso, R D; Meyerhofer, D D; Stoeckl, C

    2009-08-14

    A comprehensive set of dual nuclear product observations provides a snapshot of imploding inertial confinement fusion capsules at the time of shock collapse, shortly before the final stages of compression. The collapse of strong convergent shocks at the center of spherical capsules filled with D{sub 2} and {sup 3}He gas induces D-D and D-{sup 3}He nuclear production. Temporal and spectral diagnostics of products from both reactions are used to measure shock timing, temperature, and capsule areal density. The density and temperature inferred from these measurements are used to estimate the electron-ion thermal coupling, and demonstrate a lower electron-ion relaxation rate for capsules with lower initial gas density.

  4. Lifetime measurements of nuclei in few-electron ions

    CERN Document Server

    Faestermann, Thomas

    2015-01-01

    In this review lifetime measurements of ions with at most two electrons are summarized. Such highly ionized systems have been studied - until now - only in the Experimental Storage Ring of the GSI in Darmstadt. Emphasis is put on decays via the weak interaction. The first observations of beta-decay into bound atomic states are described as well as its time mirrored counterpart, the electron-capture decay. In the latter case the decays of hydrogen- and helium-like ions are compared with a surprising result. Further on, the observation of sinusoidal modulations of the decay rate in two-body decays is summarized. As a possible cause an interference due to the emission of neutrinos with different rest mass is discussed.

  5. Bounce Resonance Scattering of Radiation Belt Electrons by Low-Frequency Hiss: Comparison With Cyclotron and Landau Resonances

    Science.gov (United States)

    Cao, Xing; Ni, Binbin; Summers, Danny; Zou, Zhengyang; Fu, Song; Zhang, Wenxun

    2017-10-01

    Bounce resonant interactions with magnetospheric waves have been proposed as an important contributing mechanism for scattering near-equatorially mirroring electrons by violating the second adiabatic invariant associated with the electron bounce motion along a geomagnetic field line. This study demonstrates that low-frequency plasmaspheric hiss with significant wave power below 100 Hz can bounce resonate efficiently with radiation belt electrons. By performing quantitative calculations of pitch angle scattering rates, we show that low-frequency hiss-induced bounce resonant scattering of electrons has a strong dependence on equatorial pitch angle αeq. For electrons with αeq close to 90°, the timescale associated with bounce resonance scattering can be comparable to or even less than 1 h. Cyclotron and Landau resonant interactions between low-frequency hiss and electrons are also investigated for comparisons. It is found that while the bounce and Landau resonances are responsible for the diffusive transport of near-equatorially mirroring electrons to lower αeq, pitch angle scattering by cyclotron resonance could take over to further diffuse electrons into the atmosphere. Bounce resonance provides a more efficient pitch angle scattering mechanism of relativistic (≥1 MeV) electrons than Landau resonance due to the stronger scattering rates and broader resonance coverage of αeq, thereby demonstrating that bounce resonance scattering by low-frequency hiss can contribute importantly to the evolution of the electron pitch angle distribution and the loss of radiation belt electrons.

  6. ELECTRON BEAM ION SOURCE PREINJECTOR PROJECT (EBIS) CONCEPTUAL DESIGN REPORT.

    Energy Technology Data Exchange (ETDEWEB)

    ALESSI, J.; BARTON, D.; BEEBE, E.; GASSNER, D.; GRANDINETTI, R.; HSEUH, H.; JAVIDFAR, A.; KPONOU, A.; LAMBIASE, R.; LESSARD, E.; LOCKEY, R.; LODESTRO, V.; MAPES, M.; MIRABELLA, D.; NEHRING, T.; OERTER, B.; PENDZICK, A.; PIKIN, A.; RAPARIA, D.; RITTER, J.; ROSER, T.; RUSSO, T.; SNYDSTRUP, L.; WILINSKI, M.; ZALTSMAN, A.; ZHANG, S.

    2005-09-01

    This report describes a new heavy ion pre-injector for the Relativistic Heavy Ion Collider (RHIC) based on a high charge state Electron Beam Ion Source (EBIS), a Radio Frequency Quadrupole (RFQ) accelerator, and a short Linear accelerator (Linac). The highly successful development of an EBIS at Brookhaven National Laboratory (BNL) now makes it possible to replace the present pre-injector that is based on an electrostatic Tandem with a reliable, low maintenance Linac-based pre-injector. Linac-based preinjectors are presently used at most accelerator and collider facilities with the exception of RHIC, where the required gold beam intensities could only be met with a Tandem until the recent EBIS development. EBIS produces high charge state ions directly, eliminating the need for the two stripping foils presently used with the Tandem. Unstable stripping efficiencies of these foils are a significant source of luminosity degradation in RHIC. The high reliability and flexibility of the new Linac-based pre-injector will lead to increased integrated luminosity at RHIC and is an essential component for the long-term success of the RHIC facility. This new pre-injector, based on an EBIS, also has the potential for significant future intensity increases and can produce heavy ion beams of all species including uranium beams and, as part of a future upgrade, might also be used to produce polarized {sup 3}He beams. These capabilities will be critical to the future luminosity upgrades and electron-ion collisions in RHIC. The proposed pre-injector system would also provide for a major enhancement in capability for the NASA Space Radiation Laboratory (NSRL), which utilizes heavy-ion beams from the RHIC complex. EBIS would allow for the acceleration of all important ion species for the NASA radiobiology program, such as, helium, argon, and neon which are unavailable with the present Tandem injector. In addition, the new system would allow for very rapid switching of ion species for

  7. Ionic fragmentation channels in electron collisions of small molecular ions

    Energy Technology Data Exchange (ETDEWEB)

    Hoffmann, Jens

    2009-01-28

    Dissociative Recombination (DR) is one of the most important loss processes of molecular ions in the interstellar medium (IM). Ion storage rings allow to investigate these processes under realistic conditions. At the Heidelberg test storage ring TSR a new detector system was installed within the present work in order to study the DR sub-process of ion pair formation (IPF). The new detector expands the existing electron target setup by the possibility to measure strongly deflected negative ionic fragments. At the TSR such measurements can be performed with a uniquely high energy resolution by independently merging two electron beams with the ion beam. In this work IPF of HD{sup +}, H{sub 3}{sup +} and HF{sup +} has been studied. In the case of HD{sup +} the result of the high resolution experiment shows quantum interferences. Analysis of the quantum oscillations leads to a new understanding of the reaction dynamics. For H{sub 3}{sup +} it was for the first time possible to distinguish different IPF channels and to detect quantum interferences in the data. Finally the IPF of HF{sup +} was investigated in an energy range, where in previous experiments no conclusive results could be obtained. (orig.)

  8. Electron impact ionization of highly charged lithiumlike ions

    Energy Technology Data Exchange (ETDEWEB)

    Wong, K L

    1992-10-01

    Electron impact ionization cross sections can provide valuable information about the charge-state and power balance of highly charged ions in laboratory and astrophysical plasmas. In the present work, a novel technique based on x-ray measurements has been used to infer the ionization cross section of highly charged lithiumlike ions on the Livermore electron beam ion trap. In particular, a correspondence is established between an observed x ray and an ionization event. The measurements are made at one energy corresponding to approximately 2.3 times the threshold energy for ionization of lithiumlike ions. The technique is applied to the transition metals between Z=22 (titanium, Ti[sup 19+]) and Z=26 (iron, Fe[sup 23+]) and to Z=56 (barium, Ba[sup 53+]). The results for the transition metals, which have an estimated 17-33% uncertainty, are in good overall agreement with a relativistic distorted-wave calculation. However, less good agreement is found for barium, which has a larger uncertainty. Methods for properly accounting for the polarization in the x-ray intensities and for inferring the charge-state abundances from x-ray observations, which were developed for the ionization measurements, as well as an x-ray model that assists in the proper interpretation of the data are also presented.

  9. Ion beam polishing for three-dimensional electron backscattered diffraction

    DEFF Research Database (Denmark)

    Saowadee, Nath; Agersted, Karsten; Ubhi, H.S.

    2013-01-01

    Serial sectioning by focused ion beam milling for three-dimensional electron backscatter diffraction (3D-EBSD) can create surface damage and amorphization in certain materials and consequently reduce the EBSD signal quality. Poor EBSD signal causes longer data acquisition time due to signal avera.......3% of normal 3D-EBSD mapping compared to a significant increase of indexing percentage and pattern quality. The polishing performance in this investigation is discussed, and two potential methods for further improvement are presented....

  10. Electron paramagnetic resonance parameters of Mn4+ ion in h ...

    Indian Academy of Sciences (India)

    569–575. Electron paramagnetic resonance parameters of Mn4+ ion in h-BaTiO3 crystal from a two-mechanism model. WU XIAO-XUAN1,4,∗, FANG WANG2, FENG WEN-LIN2,3 and. ZHENG WEN-CHEN2,4. 1Department of Physics, Civil Aviation Flight University of China, Guanghan 618307,. People's Republic of China.

  11. Glow plasma trigger for electron cyclotron resonance ion sources.

    Science.gov (United States)

    Vodopianov, A V; Golubev, S V; Izotov, I V; Nikolaev, A G; Oks, E M; Savkin, K P; Yushkov, G Yu

    2010-02-01

    Electron cyclotron resonance ion sources (ECRISs) are particularly useful for nuclear, atomic, and high energy physics, as unique high current generators of multicharged ion beams. Plasmas of gas discharges in an open magnetic trap heated by pulsed (100 micros and longer) high power (100 kW and higher) high-frequency (greater than 37.5 GHz) microwaves of gyrotrons is promising in the field of research in the development of electron cyclotron resonance sources for high charge state ion beams. Reaching high ion charge states requires a decrease in gas pressure in the magnetic trap, but this method leads to increases in time, in which the microwave discharge develops. The gas breakdown and microwave discharge duration becomes greater than or equal to the microwave pulse duration when the pressure is decreased. This makes reaching the critical plasma density initiate an electron cyclotron resonance (ECR) discharge during pulse of microwave gyrotron radiation with gas pressure lower than a certain threshold. In order to reduce losses of microwave power, it is necessary to shorten the time of development of the ECR discharge. For fast triggering of ECR discharge under low pressure in an ECRIS, we initially propose to fill the magnetic trap with the plasmas of auxiliary pulsed discharges in crossed ExB fields. The glow plasma trigger of ECR based on a Penning or magnetron discharge has made it possible not only to fill the trap with plasma with density of 10(12) cm(-3), required for a rapid increase in plasma density and finally for ECR discharge ignition, but also to initially heat the plasma electrons to T(e) approximately = 20 eV.

  12. High resolution EUV spectroscopy of xenon ions with a compact electron beam ion trap

    Science.gov (United States)

    Ali, Safdar; Nakamura, Nobuyuki

    2017-09-01

    We performed high resolution extreme ultraviolet (EUV) spectroscopy measurements of highly charged xenon ions with a compact electron beam ion trap. The spectra were recorded with a flat-field grazing incidence spectrometer while varying the electron beam energy between 200 and 890 eV. We measured the wavelengths for several lines of Rh-like Xe9+ - Cd-like Xe6+ and Cu-like Xe25+- Se-like Xe20+ in the range of 150-200 Å with an uncertainty of 0.05 Å. Previously, most of these lines have been reported from EBITs with a wavelength uncertainty of 0.2 Å. Additionally, based on the electron beam energy dependence of the observed spectra we tentatively identified three new lines, which were reported as unidentified lines in the previous studies.

  13. Positive and Negative Ion Formation Following Electron Impact on Uracil

    Science.gov (United States)

    Becker, K.; Feil, S.; Gluch, K.; Matt-Leubner, S.; Probst, M.; Scheier, P.; Maerk, T. D.; Stamatovic, A.; Deutsch, H.; Limtrakul, J.

    2004-05-01

    We report absolute partial cross sections for the formation of selected positive and negative ions resulting from electron interactions with the biologically important molecule uracil. Absolute calibration of the measured partial cross sections for the formation of the three most intense positive ions, the parent C_4H_4N_2O_2^+ ion and the C_3H_2NO^+ and OCN^+ fragment ions, was achieved by normalization of the total single uracil ionization cross section to a calculated cross section based on the semi-classical Deutsch-Märk (DM) formalism at 100 eV. Subsequently, we used the OCN^+ cross section in conjunction with the known sensitivity ratio for positive and negative ion detection in our apparatus (obtained from the well-known cross sections for SF_4^+ and SF_4^- formation from SF_6) to determine the dissociative attachment cross section for OCN^- formation from uracil. This work was partially supported by the FWF, ÖNB, and ÖAW, Wien, Austria and the EU Commission, Brussels. We acknowledge financial support from the US Department of Energy to KB.

  14. Imaging Near-Earth Electron Densities Using Thomson Scattering

    Science.gov (United States)

    2009-01-15

    telescopes (left and right squares). In these simulated images, we have assumed an input aperture diameter of 23.5 cm and a pixel plate scale of 270...diameter of 23.8 cm and a pixel plate scale of 120 km. The inner field of view begins near 320 km in altitude, which Imaging Near-Earth Electron...LFM) Global MHD Magnetospheric Simulation Code,” J. Atmos. Sol. Terres . Phys. 66, 1333. Meier, R.R., 1991. “Ultraviolet Spectroscopy and Remote

  15. Investigation on the electron flux to the wall in the VENUS ion source

    Energy Technology Data Exchange (ETDEWEB)

    Thuillier, T., E-mail: thuillier@lpsc.in2p3.fr; Angot, J. [LPSC, Université Grenoble-Alpes, CNRS/IN2P3, 53 rue des Martyrs, 38026 Grenoble Cedex (France); Benitez, J. Y.; Hodgkinson, A.; Lyneis, C. M.; Todd, D. S.; Xie, D. Z. [Nuclear Science Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States)

    2016-02-15

    The long-term operation of high charge state electron cyclotron resonance ion sources fed with high microwave power has caused damage to the plasma chamber wall in several laboratories. Porosity, or a small hole, can be progressively created in the chamber wall which can destroy the plasma chamber over a few year time scale. A burnout of the VENUS plasma chamber is investigated in which the hole formation in relation to the local hot electron power density is studied. First, the results of a simple model assuming that hot electrons are fully magnetized and strictly following magnetic field lines are presented. The model qualitatively reproduces the experimental traces left by the plasma on the wall. However, it is too crude to reproduce the localized electron power density for creating a hole in the chamber wall. Second, the results of a Monte Carlo simulation, following a population of scattering hot electrons, indicate a localized high power deposited to the chamber wall consistent with the hole formation process. Finally, a hypervapotron cooling scheme is proposed to mitigate the hole formation in electron cyclotron resonance plasma chamber wall.

  16. Investigation on the electron flux to the wall in the VENUS ion source.

    Science.gov (United States)

    Thuillier, T; Angot, J; Benitez, J Y; Hodgkinson, A; Lyneis, C M; Todd, D S; Xie, D Z

    2016-02-01

    The long-term operation of high charge state electron cyclotron resonance ion sources fed with high microwave power has caused damage to the plasma chamber wall in several laboratories. Porosity, or a small hole, can be progressively created in the chamber wall which can destroy the plasma chamber over a few year time scale. A burnout of the VENUS plasma chamber is investigated in which the hole formation in relation to the local hot electron power density is studied. First, the results of a simple model assuming that hot electrons are fully magnetized and strictly following magnetic field lines are presented. The model qualitatively reproduces the experimental traces left by the plasma on the wall. However, it is too crude to reproduce the localized electron power density for creating a hole in the chamber wall. Second, the results of a Monte Carlo simulation, following a population of scattering hot electrons, indicate a localized high power deposited to the chamber wall consistent with the hole formation process. Finally, a hypervapotron cooling scheme is proposed to mitigate the hole formation in electron cyclotron resonance plasma chamber wall.

  17. Investigation of the clinical potential of scattering foil free electron beams.

    Science.gov (United States)

    Eldib, Ahmed; Jin, Lihui; Li, Jinsheng; Ma, C-M Charlie

    2014-02-21

    Electron beam therapy has been an important radiation therapy modality for many decades. Studies have been conducted recently for more efficient and advanced delivery of electron beam radiation therapy. X-ray contamination is a common problem that exists with all of the advanced electron beam therapy techniques such as Bolus Electron conformal therapy, segmented electron conformal therapy, and modulated electron arc therapy. X-ray contamination could add some limitations to the advancement and clinical utility of those electron modalities. It was previously shown in the literature that the scattering foil is one of the major accelerator parts contributing to the generation of bremsstrahlung photons. Thus, in this work we investigate the dosimetric characteristics of scattering foil free (SFF) electron beams and the feasibility of using those beams for breast cancer boosts. The SFF electron beams were modeled and simulated using the Monte Carlo method. CT scans of six previously treated breast patients were used for the treatment plan generation utilizing our in-house Monte Carlo-based treatment planning system. Electron boost plans with conventional beams and the SFF beams were generated, respectively, for all patients. A significant reduction of the photon component was observed with the removal of the primary scattering foil for beam energies higher than 12 MeV. Flatness was greatly affected but the difference in flatness between conventional and SFF beams was much reduced for small cone sizes, which were often used clinically for breast boosts. It was found that the SFF electron beams could deliver high-quality dose distributions as conventional electron beams for boost treatments of the breast with an added advantage of a further reduced dose to the lung and the heart.

  18. Heat-Flux Measurements in Laser-Produced Plasmas Using Thomson Scattering from Electron Plasma Waves

    Science.gov (United States)

    Henchen, R. J.; Goncharov, V. N.; Cao, D.; Katz, J.; Froula, D. H.; Rozmus, W.

    2017-10-01

    An experiment was designed to measure heat flux in coronal plasmas using collective Thomson scattering. Adjustments to the electron distribution function resulting from heat flux affect the shape of the collective Thomson scattering features through wave-particle resonance. The amplitude of the Spitzer-Härm electron distribution function correction term (f1) was varied to match the data and determines the value of the heat flux. Independent measurements of temperature and density obtained from Thomson scattering were used to infer the classical heat flux (q = - κ∇Te) . Time-resolved Thomson-scattering data were obtained at five locations in the corona along the target normal in a blowoff plasma formed from a planar Al target with 1.5 kJ of 351-nm laser light in a 2-ns square pulse. The flux measured through the Thomson-scattering spectra is a factor of 5 less than the κ∇Te measurements. The lack of collisions of heat-carrying electrons suggests a nonlocal model is needed to accurately describe the heat flux. This material is based upon work supported by the Department of Energy National Nuclear Security Administration under Award Number DE-NA0001944.

  19. Electron-phonon scattering rates in complex polar crystals from ab initio calculations

    Energy Technology Data Exchange (ETDEWEB)

    Prange, Micah P.; Campbell, Luke W.; Kerisit, Sebastien N.

    2017-09-17

    The thermalization of fast electrons by phonons is studied in CsI, NaI, SrI2, and YAP. This numerical study uses an improvement to a recently developed ab initio method based on a density functional perturbation theoretical description of the phonon modes that provides a way to go beyond widely used phonon models based on binary crystals. Improvements to this method are described, and scattering rates are presented and discussed. The results here treat polar and nonpolar scattering on equal footing and allow an assessment of the relative importance of the two types of scattering. The relative activity of the numerous phonon modes in materials with complicated structures is discussed, and a simple criterion for finding the modes that scatter strongly is presented.

  20. Low energy RBS-channeling measurement system with the use of a time-of-flight scattered ion detector

    Energy Technology Data Exchange (ETDEWEB)

    Hasegawa, Masataka; Kobayashi, Naoto; Hayashi, Nobuyuki [Electrotechnical Lab., Tsukuba, Ibaraki (Japan)

    1996-07-01

    We have developed a low energy Rutherford backscattering spectrometry-ion channeling measurement system for the analysis of thin films and solid surfaces with the use of several tens keV hydrogen ions and a time-of-flight particle energy spectrometer. For the detection of the scattered ions new TOF spectrometer has been developed, which consists of two micro-channel-plate detectors. The pulsing of the primary ion beam is not necessary for this type of TOF measurement, and it is possible to observe continues scattered ion beams. The dimension of whole system is very compact compared to the conventional RBS-channeling measurement system with the use of MeV He ions. The energy resolution, {delta} E/E, for 25 keV H{sup +} was 4.1%, which corresponds to the depth resolution of 4.8 nm for silicon. The depth resolution of our system is better than that of conventional RBS system with MeV helium ions and solid state detectors. We have demonstrated the ion channeling measurement by this system with 25 keV hydrogen ions. The system can be available well to the analysis of thin films and solid surfaces with the use of the ion channeling effect. The observation of the reaction between Fe and hydrogen terminated silicon surface was also demonstrated. (J.P.N.)

  1. Beam Energy Scaling of Ion-Induced Electron Yield from K+ Ions Impact on Stainless Steel Surfaces

    CERN Document Server

    Kireeff-Covo, Michel; Barnard, John J; Bieniosek, Frank; Celata, C M; Cohen, Ronald; Friedman, Alex; Grote, D P; Kwan, Joe W; Lund, Steven M; Molvik, Arthur; Seidl, Peter; Vay, Jean-Luc; Vujic, Jasmina L; Westenskow, Glen

    2005-01-01

    The cost of accelerators for heavy-ion inertial fusion energy (HIF) can be reduced by using the smallest possible clearance between the beam and the wall from the beamline. This increases beam loss to the walls, generating ion-induced electrons that could be trapped by beam space charge potential into an "electron cloud," which can cause degradation or loss of the ion beam. In order to understand the physical mechanism of production of ion-induced electrons we have measured impact of K+ ions with energies up to 400 KeV on stainless steel surfaces near grazing incidence, using the ion source test stand (STS-500) at LLNL. The electron yield will be discussed and compared with experimental measurements from 1 MeV K+ ions in the High-Current Experiment at LBNL.*

  2. Anomalously Hot Electrons due to Rescatter of Stimulated Raman Scattering in the Kinetic Regime

    CERN Document Server

    Winjum, B J; Tsung, F S; Mori, W B

    2012-01-01

    Using particle-in-cell simulations, we examine hot electron generation from electron plasma waves excited by stimulated Raman scattering and rescattering in the kinetic regime where the wavenumber times the Debye length (k\\lambda_D) is greater than 0.3 for backscatter. We find that for laser and plasma conditions of possible relevance to experiments at the National Ignition Facility (NIF), anomalously energetic electrons can be produced through the interaction of a discrete spectrum of plasma waves generated from SRS (back and forward scatter), rescatter, and the Langmuir decay of the rescatter-generated plasma waves. Electrons are bootstrapped in energy as they propagate into plasma waves with progressively higher phase velocities.

  3. An experimental and theoretical investigation into positron and electron scattering from formaldehyde

    Energy Technology Data Exchange (ETDEWEB)

    Zecca, A; Trainotti, E; Chiari, L [Department of Physics, University of Trento, Povo, I-38123 Trento (Italy); GarcIa, G [Instituto de Matematicas y Fisica Fundamental, CSIC, Serrano 121, 28006 Madrid (Spain); Blanco, F [Facultad de Ciencias Fisicas, Departamento de Fisica Atomica, Molecular y Nuclear, Universidad Complutense, Avda. Complutense s/n, E-28040 Madrid (Spain); Bettega, M H F [Departamento de Fisica, Universidade Federal do Parana, Caixa Postal 19044, 81531-990 Curitiba, Parana (Brazil); Varella, M T do N [Instituto de Fisica, Universidade de Sao Paulo, Caixa Postal 66318, 05315-970 Sao Paulo, SP (Brazil); Lima, M A P [Instituto de Fisica ' Gleb Wataghin' , Universidade Estadual de Campinas, Caixa Postal 6165, 13083-970 Campinas, Sao Paulo (Brazil); Laboratorio Nacional de Ciencia e Tecnologia do Bioetanol (CTBE), Centro Nacional de Pesquisa em Energia e Materiais (CNPEM), Caixa Postal 6170, 13083-970 Campinas, Sao Paulo (Brazil); Brunger, M J, E-mail: Michael.Brunger@flinders.edu.au [ARC Centre for Antimatter-Matter Studies, School of Chemical and Physical Sciences, Flinders University, GPO Box 2100, Adelaide, South Australia 5001 (Australia)

    2011-10-14

    We report on measurements of total cross sections (TCSs) for positron scattering from the fundamental organic molecule formaldehyde (CH{sub 2}O). The energy range of these measurements was 0.26-50.3 eV, whereas the energy resolution was {approx}260 meV. To assist us in interpreting these data, Schwinger multichannel level calculations for positron elastic scattering from CH{sub 2}O were also undertaken (0.5-50 eV). These calculations, incorporating an accurate model for the target polarization, are found to be in good qualitative agreement with our measured data. In addition, in order to compare the behaviour of positron and electron scattering from this species, independent atom model-screened additivity rule theoretical electron TCSs, now for energies in the range 1-10 000 eV, are also reported.

  4. 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.)

  5. Closed form S matrix in terms of matter distributions and nucleon-nucleon interaction for heavy ion scattering

    Energy Technology Data Exchange (ETDEWEB)

    Gambhir, Y.K.; Shastry, C.S.

    1984-10-01

    We derive an approximate analytical expression for the S matrix in terms of the parameters of the nuclear matter distributions and nucleon-nucleon interaction in the framework of folding model for heavy ion scattering. The numerical calculations carried out for /sup 18/O+ /sup 58/Ni scattering (E/sub lab/ = 60 MeV), a test case, agree well with the corresponding results of the phenomenological optical model.

  6. Laser scattering method in studies of the turbulence excited by a relativistic electron beam in plasma

    Energy Technology Data Exchange (ETDEWEB)

    Vyacheslavov, L.N.; Kandaurov, I.V.; Kruglyakov, E.P.; Losev, M.V.; Meshkov, O.I.; Sanin, A.L.

    1992-02-01

    Scattering radiation from a CO{sub 2} laser is used to carry out direct observations of Langmuir oscillations associated with the interaction between a high-power relativistic electron beam and a plasma. Experimental data on the frequency spectrum of the turbulence and the first results on studies of the spatial spectra of the oscillations are presented. 4 refs., 2 figs.

  7. A Large-Acceptance Detector System for Electron Scattering from Polarized Internal targets.

    NARCIS (Netherlands)

    Passchier, E.; Bouwhuis, M.; Choi, S.; Zhou, Z.L.; Alarcon, R.; Anghinolfi, M.; Botto, T.; van den Brand, J.F.J.; Bulten, H.J.; Dimitroyannis, D.; Doets, M.; Ent, R.; Ferro Luzzi, M.M.E.; Higinbotham, D.W.; de Jager, C.W.; Lang, J.; de Lange, D.J.; Nikolenko, D.; Nooren, G.J.; Papadakis, N.; Passchier, I.; Popov, S.G.; Rachek, I.; Ripani, M.; Steijger, J.J.M.; Taiuti, M.; Vodinas, N.; de Vries, H.

    1997-01-01

    The design and the performance of a non-magnetic detector setup for internal target physics at the NIKHEF electron-scattering facility is described. The detector setup, used in the first internal-target experiment at the AmPS ring, measures the spin dependence in the elastic and break-up reaction

  8. Measuring the Weak Charge of the Proton via Elastic Electron-Proton Scattering

    Energy Technology Data Exchange (ETDEWEB)

    Jones, Donald C. [Univ. of Virginia, Charlottesville, VA (United States)

    2015-10-01

    The Qweak experiment which ran in Hall C at Jefferson Lab in Newport News, VA, and completed data taking in May 2012, measured the weak charge of the proton QpW via elastic electron-proton scattering. Longitudinally polarized electrons were scattered from an unpolarized liquid hydrogen target. The helicity of the electron beam was flipped at approximately 1 kHz between left and right spin states. The Standard Model predicts a small parity-violating asymmetry of scattering rates between right and left helicity states due to the weak interaction. An initial result using 4% of the data was published in October 2013 [1] with a measured parity-violating asymmetry of -279 ± 35(stat) ± 31 (syst) ppb. This asymmetry, along with other data from parity-violating electron scattering experiments, provided the world's first determination of the weak charge of the proton. The weak charge of the proton was found to be pW = 0.064 ± 0.012, in good agreement with the Standard Model prediction of pW(SM) = 0.0708 ± 0.0003[2].

  9. Electron-phonon scattering from Green’s function transport combined with molecular dynamics

    DEFF Research Database (Denmark)

    Markussen, Troels; Palsgaard, Mattias Lau Nøhr; Stradi, Daniele

    2017-01-01

    We present a conceptually simple method for treating electron-phonon scattering and phonon limited mobilities. By combining Green’s function based transport calculations and molecular dynamics, we obtain a temperature dependent transmission from which we evaluate the mobility. We validate our...

  10. Electron kinetic effects on interferometry, polarimetry and Thomson scattering measurements in burning plasmas (invited)a)

    Science.gov (United States)

    Mirnov, V. V.; Brower, D. L.; Hartog, D. J. Den; Ding, W. X.; Duff, J.; Parke, E.

    2014-11-01

    At anticipated high electron temperatures in ITER, the effects of electron thermal motion on Thomson scattering (TS), toroidal interferometer/polarimeter (TIP), and poloidal polarimeter (PoPola) diagnostics will be significant and must be accurately treated. The precision of the previous lowest order linear in τ = Te/mec2 model may be insufficient; we present a more precise model with τ2-order corrections to satisfy the high accuracy required for ITER TIP and PoPola diagnostics. The linear model is extended from Maxwellian to a more general class of anisotropic electron distributions that allows us to take into account distortions caused by equilibrium current, ECRH, and RF current drive effects. The classical problem of the degree of polarization of incoherent Thomson scattered radiation is solved analytically exactly without any approximations for the full range of incident polarizations, scattering angles, and electron thermal motion from non-relativistic to ultra-relativistic. The results are discussed in the context of the possible use of the polarization properties of Thomson scattered light as a method of Te measurement relevant to ITER operational scenarios.

  11. Electron kinetic effects on interferometry, polarimetry and Thomson scattering measurements in burning plasmas (invited)

    Energy Technology Data Exchange (ETDEWEB)

    Mirnov, V. V.; Hartog, D. J. Den; Duff, J.; Parke, E. [Physics Department, University of Wisconsin - Madison and the Center for Magnetic Self-Organization in Laboratory and Astrophysical Plasmas, Madison, Wisconsin 53706 (United States); Brower, D. L.; Ding, W. X. [Department of Physics and Astronomy, University of California Los Angeles, Los Angeles, California 90095 (United States)

    2014-11-15

    At anticipated high electron temperatures in ITER, the effects of electron thermal motion on Thomson scattering (TS), toroidal interferometer/polarimeter (TIP), and poloidal polarimeter (PoPola) diagnostics will be significant and must be accurately treated. The precision of the previous lowest order linear in τ = T{sub e}/m{sub e}c{sup 2} model may be insufficient; we present a more precise model with τ{sup 2}-order corrections to satisfy the high accuracy required for ITER TIP and PoPola diagnostics. The linear model is extended from Maxwellian to a more general class of anisotropic electron distributions that allows us to take into account distortions caused by equilibrium current, ECRH, and RF current drive effects. The classical problem of the degree of polarization of incoherent Thomson scattered radiation is solved analytically exactly without any approximations for the full range of incident polarizations, scattering angles, and electron thermal motion from non-relativistic to ultra-relativistic. The results are discussed in the context of the possible use of the polarization properties of Thomson scattered light as a method of T{sub e} measurement relevant to ITER operational scenarios.

  12. A hollow cathode ion source for production of primary ions for the BNL electron beam ion source

    Energy Technology Data Exchange (ETDEWEB)

    Alessi, James, E-mail: alessi@bnl.gov; Beebe, Edward; Carlson, Charles; McCafferty, Daniel; Pikin, Alexander; Ritter, John [Collider-Accelerator Department, Brookhaven National Laboratory, Upton, New York 11973 (United States)

    2014-02-15

    A hollow cathode ion source, based on one developed at Saclay, has been modified significantly and used for several years to produce all primary 1+ ions injected into the Relativistic Heavy Ion Collider Electron Beam Ion Source (EBIS) at Brookhaven. Currents of tens to hundreds of microamperes have been produced for 1+ ions of He, C, O, Ne, Si, Ar, Ti, Fe, Cu, Kr, Xe, Ta, Au, and U. The source is very simple, relying on a glow discharge using a noble gas, between anode and a solid cathode containing the desired species. Ions of both the working gas and ionized sputtered cathode material are extracted, and then the desired species is selected using an ExB filter before being transported into the EBIS trap for charge breeding. The source operates pulsed with long life and excellent stability for most species. Reliable ignition of the discharge at low gas pressure is facilitated by the use of capacitive coupling from a simple toy plasma globe. The source design, and operating experience for the various species, is presented.

  13. Study of nonlinear ion- and electron-acoustic waves in multi-component space plasmas

    Directory of Open Access Journals (Sweden)

    G. S. Lakhina

    2008-11-01

    Full Text Available Large amplitude ion-acoustic and electron-acoustic waves in an unmagnetized multi-component plasma system consisting of cold background electrons and ions, a hot electron beam and a hot ion beam are studied using Sagdeev pseudo-potential technique. Three types of solitary waves, namely, slow ion-acoustic, ion-acoustic and electron-acoustic solitons are found provided the Mach numbers exceed the critical values. The slow ion-acoustic solitons have the smallest critical Mach numbers, whereas the electron-acoustic solitons have the largest critical Mach numbers. For the plasma parameters considered here, both type of ion-acoustic solitons have positive potential whereas the electron-acoustic solitons can have either positive or negative potential depending on the fractional number density of the cold electrons relative to that of the ions (or total electrons number density. For a fixed Mach number, increases in the beam speeds of either hot electrons or hot ions can lead to reduction in the amplitudes of the ion-and electron-acoustic solitons. However, the presence of hot electron and hot ion beams have no effect on the amplitudes of slow ion-acoustic modes. Possible application of this model to the electrostatic solitary waves (ESWs observed in the plasma sheet boundary layer is discussed.

  14. Relativistic Shear Flow between Electron-Ion and Electron-Positron Plasmas and Astrophysical Applications

    Science.gov (United States)

    Liang, Edison; Fu, Wen; Böttcher, Markus

    2017-10-01

    We present particle-in-cell simulation results of relativistic shear boundary layers between electron-ion and electron-positron plasmas and discuss their potential applications to astrophysics. Specifically, we find that in the case of a fast electron-positron spine surrounded by a slow-moving or stationary electron-ion sheath, lepton acceleration proceeds in a highly anisotropic manner due to electromagnetic fields created at the shear interface. While the highest-energy leptons still produce a beaming pattern (as seen in the quasi-stationary frame of the sheath) of order 1/Γ, where Γ is the bulk Lorentz factor of the spine, for lower-energy particles, the beaming is much less pronounced. This is in stark contrast to the case of pure electron-ion shear layers, in which anisotropic particle acceleration leads to significantly narrower beaming patterns than 1/Γ for the highest-energy particles. In either case, shear-layer acceleration is expected to produce strongly angle-dependent lepton (hence, emanating radiation) spectra, with a significantly harder spectrum in the forward direction than viewed from larger off-axis angles, much beyond the regular Doppler boosting effect from a co-moving isotropic lepton distribution. This may solve the problem of the need for high (and apparently arbitrarily chosen) minimum Lorentz factors of radiating electrons, often plaguing current blazar and GRB jet modeling efforts.

  15. Electron Scattering by High-Frequency Whistler Waves at Earth's Bow Shock

    Science.gov (United States)

    Oka, M.; Wilson, L. B., III; Phan, T. D.; Hull, A. J.; Amano, T.; Hoshino, M.; Argall, M. R.; Le Contel, O.; Agapitov, O.; Gersham, D. J.; hide

    2017-01-01

    Electrons are accelerated to non-thermal energies at shocks in space and astrophysical environments. While different mechanisms of electron acceleration have been proposed, it remains unclear how non-thermal electrons are produced out of the thermal plasma pool. Here, we report in situ evidence of pitch-angle scattering of non-thermal electrons by whistler waves at Earths bow shock. On 2015 November 4, the Magnetospheric Multiscale (MMS) mission crossed the bow shock with an Alfvn Mach number is approximately 11 and a shock angle of approximately 84deg. In the ramp and overshoot regions, MMS revealed bursty enhancements of non-thermal (0.52 keV) electron flux, correlated with high-frequency (0.2 - 0.4 Omega(sub ce), where Omega(sub ce) is the cyclotron frequency) parallel-propagating whistler waves. The electron velocity distribution (measured at 30 ms cadence) showed an enhanced gradient of phase-space density at and around the region where the electron velocity component parallel to the magnetic field matched the resonant energy inferred from the wave frequency range. The flux of 0.5 keV electrons (measured at 1ms cadence) showed fluctuations with the same frequency. These features indicate that non-thermal electrons were pitch-angle scattered by cyclotron resonance with the high-frequency whistler waves. However, the precise role of the pitch-angle scattering by the higher-frequency whistler waves and possible nonlinear effects in the electron acceleration process remains unclear.

  16. Electron Scattering by High-frequency Whistler Waves at Earth’s Bow Shock

    Science.gov (United States)

    Oka, M.; Wilson, L. B., III; Phan, T. D.; Hull, A. J.; Amano, T.; Hoshino, M.; Argall, M. R.; Le Contel, O.; Agapitov, O.; Gershman, D. J.; Khotyaintsev, Y. V.; Burch, J. L.; Torbert, R. B.; Pollock, C.; Dorelli, J. C.; Giles, B. L.; Moore, T. E.; Saito, Y.; Avanov, L. A.; Paterson, W.; Ergun, R. E.; Strangeway, R. J.; Russell, C. T.; Lindqvist, P. A.

    2017-06-01

    Electrons are accelerated to non-thermal energies at shocks in space and astrophysical environments. While different mechanisms of electron acceleration have been proposed, it remains unclear how non-thermal electrons are produced out of the thermal plasma pool. Here, we report in situ evidence of pitch-angle scattering of non-thermal electrons by whistler waves at Earth’s bow shock. On 2015 November 4, the Magnetospheric Multiscale (MMS) mission crossed the bow shock with an Alfvén Mach number ˜11 and a shock angle ˜84°. In the ramp and overshoot regions, MMS revealed bursty enhancements of non-thermal (0.5-2 keV) electron flux, correlated with high-frequency (0.2-0.4 {{{Ω }}}{ce}, where {{{Ω }}}{ce} is the cyclotron frequency) parallel-propagating whistler waves. The electron velocity distribution (measured at 30 ms cadence) showed an enhanced gradient of phase-space density at and around the region where the electron velocity component parallel to the magnetic field matched the resonant energy inferred from the wave frequency range. The flux of 0.5 keV electrons (measured at 1 ms cadence) showed fluctuations with the same frequency. These features indicate that non-thermal electrons were pitch-angle scattered by cyclotron resonance with the high-frequency whistler waves. However, the precise role of the pitch-angle scattering by the higher-frequency whistler waves and possible nonlinear effects in the electron acceleration process remains unclear.

  17. Mixed oxygen ion/electron-conducting ceramics for oxygen separation

    Energy Technology Data Exchange (ETDEWEB)

    Stevenson, J.W.; Armstrong, T.R.; Armstrong, B.L. [Pacific Northwest National Lab., Richland, WA (United States)

    1996-08-01

    Mixed oxygen ion and electron-conducting ceramics are unique materials that can passively separate high purity oxygen from air. Oxygen ions move through a fully dense ceramic in response to an oxygen concentration gradient, charge-compensated by an electron flux in the opposite direction. Compositions in the system La{sub 1{minus}x}M{sub x}Co{sub 1{minus}y{minus}z}Fe{sub y}N{sub z}O{sub 3{minus}{delta}}, perovskites where M=Sr, Ca, and Ba, and N=Mn, Ni, Cu, Ti, and Al, have been prepared and their electrical, oxygen permeation, oxygen vacancy equilibria, and catalytic properties evaluated. Tubular forms, disks, and asymmetric membrane structures, a thin dense layer on a porous support of the same composition, have been fabricated for testing purposes. In an oxygen partial gradient, the passive oxygen flux through fully dense structures was highly dependent on composition. An increase in oxygen permeation with increased temperature is attributed to both enhanced oxygen vacancy mobility and higher vacancy populations. Highly acceptor-doped compositions resulted in oxygen ion mobilities more than an order of magnitude higher than yttria-stabilized zirconia. The mixed conducting ceramics have been utilized in a membrane reactor configuration to upgrade methane to ethane and ethylene. Conditions were established to balance selectivity and throughput in a catalytic membrane reactor constructed from mixed conducting ceramics.

  18. Analytic description of elastic electron-atom scattering in an elliptically polarized laser field

    Science.gov (United States)

    Flegel, A. V.; Frolov, M. V.; Manakov, N. L.; Starace, Anthony F.; Zheltukhin, A. N.

    2013-01-01

    An analytic description of laser-assisted electron-atom scattering (LAES) in an elliptically polarized field is presented using time-dependent effective range (TDER) theory to treat both electron-laser and electron-atom interactions nonperturbatively. Closed-form formulas describing plateau features in LAES spectra are derived quantum mechanically in the low-frequency limit. These formulas provide an analytic explanation for key features of the LAES differential cross section. For the low-energy region of the LAES spectrum, our result generalizes the Kroll-Watson formula to the case of elliptic polarization. For the high-energy (rescattering) plateau in the LAES spectrum, our result generalizes prior results for a linearly polarized field valid for the high-energy end of the rescattering plateau [Flegel , J. Phys. BJPAPEH0953-407510.1088/0953-4075/42/24/241002 42, 241002 (2009)] and confirms the factorization of the LAES cross section into three factors: two field-free elastic electron-atom scattering cross sections (with laser-modified momenta) and a laser field-dependent factor (insensitive to the scattering potential) describing the laser-driven motion of the electron in the elliptically polarized field. We present also approximate analytic expressions for the exact TDER LAES amplitude that are valid over the entire rescattering plateau and reduce to the three-factor form in the plateau cutoff region. The theory is illustrated for the cases of e-H scattering in a CO2-laser field and e-F scattering in a midinfrared laser field of wavelength λ=3.5μm, for which the analytic results are shown to be in good agreement with exact numerical TDER results.

  19. Time evolution of bremsstrahlung and ion production of an electron cyclotron resonance ion source

    Energy Technology Data Exchange (ETDEWEB)

    Tarvainen, Ollie [Los Alamos National Laboratory; Ropponen, Tommi [UNIV OF JYVASKYLA; Jones, Peter [UNIV OF JYVASKYLA; Peura, Pauli [UNIV OF JYVASKYLA

    2008-01-01

    Bremsstrahlung radiation measurement is one of the most commonly used plasma diagnostics methods. Most of the bremsstrahlung measurements with electron cyclotron resonance (ECR) ion sources have been performed in continuous operation mode yielding information only on the steady state bremsstrahlung emission. This article describes the results of bremsstrahlung and ion current measurement with the JYFL 14 GHz ECRIS operated in pulsed mode. The experiments reveal information about the bremsstrahlung radiation in plasma conditions before reaching the equilibrium. The time scale of bremsstrahlung production is compared to ion production time scale for different charge states. The bremsstrahlung data is presented with 2 millisecond time intervals as a function of neutral gas pressure and microwave power. Data from hundreds of microwave pulses is combined in order to have a sufficient amount of events at each time step. The relevant plasma physics phenomena during both, the leading and the trailing edge of the RF pulse, are discussed.

  20. Ion Behavior and Gas Mixing in electron cyclotron resonance plasmas as sources of highly charged ions (concept

    NARCIS (Netherlands)

    Melin, G.; Drentje, A. G.; Girard, A.; Hitz, D.

    1999-01-01

    Abstract: An ECR ion source is basically an ECR heated plasma confinement machine, with hot electrons and cold ions. The main parameters of the ion population have been analyzed, including temperature, losses, and confinement time. The "gas mixing" effect has been studied in this context. An

  1. Molecular Dynamics Simulation of Electron-Ion Temperature Relaxation in Dense Hydrogen: Electronic Quantum Effects

    Science.gov (United States)

    Ma, Qian; Dai, Jiayu; Zhao, Zengxiu

    2016-10-01

    The electron-ion temperature relaxation is an important non-equilibrium process in the generation of dense plasmas, particularly in Inertial Confinement Fusion. Classical molecular dynamics considers electrons as point charges, ignoring important quantum processes. We use an Electron Force Field (EFF) method to study the temperature relaxation processes, considering the nuclei as semi-classical point charges and assume electrons as Gaussian wave packets which includes the influences of the size and the radial motion of electrons. At the same time, a Pauli potential is used to describe the electronic exchange effect. At this stage, quantum effects such as exchange, tunneling can be included in this model. We compare the results from EFF and classical molecular dynamics, and find that the relaxation time is much longer with including quantum effects, which can be explained directly by the deference of collision cross sections between quantum particles and classical particles. Further, the final thermal temperature of electron and ion is different compared with classical results that the electron quantum effects cannot be neglected.

  2. Online ion-exchange chromatography for small-angle X-ray scattering.

    Science.gov (United States)

    Hutin, Stephanie; Brennich, Martha; Maillot, Benoit; Round, Adam

    2016-10-01

    Biological small-angle X-ray scattering (BioSAXS) is a powerful technique to determine the solution structure, particle size, shape and surface-to-volume ratio of macromolecules. However, a drawback is that the sample needs to be monodisperse. To ensure this, size-exclusion chromatography (SEC) has been implemented on many BioSAXS beamlines. Here, the integration of ion-exchange chromatography (IEC) using both continuous linear and step gradients on a beamline is described. Background subtraction for continuous gradients by shifting a reference measurement and two different approaches for step gradients, which are based on interpolating between two background measurements, are discussed. The results presented here serve as a proof of principle for online IEC and subsequent data treatment.

  3. Surfactant-mediated growth of Cu on Co(0001) investigated using medium-energy ion scattering

    Science.gov (United States)

    Noakes, T. C.; Bailey, P.; Dekadjevi, D. T.; Howson, M. A.

    2003-10-01

    Experiments were carried out using medium energy ion scattering (MEIS) to compare the structural properties of Cu films deposited on Co(0001) both with and without surfactant and before and after annealing to 300 °C. Films of 10-ML thickness were deposited onto the clean Co surface and onto a surface pre-dosed with 1 ML of Pb surfactant. MEIS data revealed a twinned fcc structure in all the deposited films irrespective of the presence of surfactant or the use of post deposition annealing. In the case of the Pb deposited surfaces the majority of surfactant was seen to float on the surface during growth but with a small quantity becoming distributed throughout the film. In addition to allowing 1-2 extra monolayers to grow epitaxially, the MEIS data provided evidence of improved crystallinity for films grown with the surfactant. Annealing the sample to 300 °C appeared to have little or no effect on the deposited films.

  4. Status and Perspectives of Ion Track Electronics for Advanced Biosensing

    Science.gov (United States)

    Fink, D.; Muñoz, H. Gerardo; Alfonta, L.; Mandabi, Y.; Dias, J. F.; de Souza, C. T.; Bacakova, L. E.; Vacík, J.; Hnatowicz, V.; Kiv, A. E.; Fuks, D.; Papaleo, R. M.

    New multifunctional ion irradiation-based three-dimensional electronic structures are developed for biotechnological applications, specifically for sensing of biomaterials, bacteria and mammalian cells. This is accomplished by combined micrometric surface and nanometric bulk microstructuring of insulators (specifically of polymer foils and SiO2/Si hybride structures) by adequate ion beams. Our main goal is the production of a cheap small universal generic working platform with multifunctional properties for biomedical analysis. Surface engineering of this platform enables cell bonding and its bulk engineering enables the extraction of cell secrets, for the sake of intercepting and analyzing the biomolecules used in cell communication. The exact knowledge of the spectrum of these cell-secreted signalling molecules should enable one to identify unambiguously the cell type. This knowledge will help developing strategies for preventive quorum sensing of bacteria, with the aim of fighting bacterial infections in an ecologically secure way.

  5. Utilizing of the medium-energy ion scattering spectrometry for the composition investigation of graphene oxide films on silicon surface

    OpenAIRE

    AFROSIMOV V.V.; Dideykin, A. T.; SAKHAROV V.I.; SERENKOV I.T.; VUL S.P.

    2014-01-01

    The possibilities of Medium-Energy Ion Scattering (MEIS) spectrometry combined with ion channeling for the estimation of the composition of single layer graphene oxide films and produced graphene layers deposited on the surface of standard silicon substrates was investigated. It was found that the oxygen amount in the natural surface silicon oxide ranges from 2-8 times the possible oxygen content in a graphene oxide layer. This causes difficulties in the estimation of the oxygen concentration...

  6. Electron scattering filter design for a single field rotational total skin irradiation.

    Science.gov (United States)

    Pham, Y T; Bubb, I F; Cramb, J A

    2005-09-01

    The aim of radiotherapy treatment of cutaneous T-cell lymphoma is to irradiate the skin with an appropriately homogeneous dose distribution up to a few millimetres in depth. This can be achieved by applying one of the total skin electron irradiation techniques. An aluminium/polystyrene foam electron scattering filter was designed so that the incident beam is broadened and degraded sufficiently to achieve a mean dose uniformity in a rectangular field of 180 cm height and 40 cm width. This paper reports on the development and construction of the electron scattering filter for use with a Varian 2100C accelerator, without MLCs, with a dose uniformity, over a useful field dimension of 180 cm height and 40 cm width, of +/- 7% about the mean, and an x-ray contamination of less than 2.4% beyond a depth of 3 cm.

  7. An investigation into electron scattering from pyrazine at intermediate and high energies

    Energy Technology Data Exchange (ETDEWEB)

    Sanz, A. G.; Fuss, M. C. [Instituto de Física Fundamental, Consejo Superior de Investigaciones Científicas, Serrano 113-bis, 28006 Madrid (Spain); Blanco, F. [Departamento de Física Atómica, Molecular y Nuclear, Universidad Complutense de Madrid, Ciudad Universitaria, 28040 Madrid (Spain); Gorfinkiel, J. D. [Department of Physical Sciences, The Open University, Walton Hall, Milton Keynes MK7 6AA (United Kingdom); Almeida, D.; Ferreira da Silva, F.; Limão-Vieira, P. [Laboratório de Colisões Atómicas e Moleculares, CEFITEC, Departamento de Física, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2829-516 Caparica (Portugal); Brunger, M. J. [ARC Centre for Antimatter-Matter Studies, School of Chemical and Physical Sciences, Flinders University, GPO Box 2100, Adelaide, SA 5001 (Australia); Institute of Mathematical Sciences, University of Malaya, 50603 Kuala Lumpur (Malaysia); García, G., E-mail: g.garcia@iff.csic.es [Instituto de Física Fundamental, Consejo Superior de Investigaciones Científicas, Serrano 113-bis, 28006 Madrid (Spain); Centre for Medical Radiation Physics, University of Wollongong, NSW 2522 (Australia)

    2013-11-14

    Total electron scattering cross sections for pyrazine in the energy range 10–500 eV have been measured with a new magnetically confined electron transmission-beam apparatus. Theoretical differential and integral elastic, as well as integral inelastic, cross sections have been calculated by means of a screening-corrected form of the independent-atom representation (IAM-SCAR) from 10 to 1000 eV incident electron energies. The present experimental and theoretical total cross sections show a good level of agreement, to within 10%, in the overlapping energy range. Consistency of these results with previous calculations (i.e., the R-matrix and Schwinger Multichannel methods) and elastic scattering measurements at lower energies, below 10 eV, is also discussed.

  8. Total and elastic electron scattering cross sections from ozone at intermediate and high energies

    Energy Technology Data Exchange (ETDEWEB)

    Pablos, J.L. de; Garcia, G. [Departamento de Fusion y Particulas Elementales, CIEMAT, Madrid (Spain); Kendall, P.A.; Mason, N.J.; Tegeder, P. [Department of Physics and Astronomy, University College London, London (United Kingdom); Williart, A. [Departamento de Fisica de los Materiales, UNED, Madrid (Spain); Blanco, F. [Departamento de Fisica Atomica Molecular y Nuclear, Universidad Complutense de Madrid, Madrid (Spain)

    2002-02-28

    Total cross sections for electron scattering from O{sub 3} molecules in the energy range 350-5000 eV have been measured for the first time. The experimental method used was based on the measurement of the attenuation of a collimated electron beam through an O{sub 3}-O{sub 2} mixture in combination with use of an electron energy loss technique to determine the purity of the ozone sample. Differential and integral elastic cross sections have also been calculated using a scattering potential in the framework of the independent-atom model. The present theoretical and experimental results are compared with earlier calculations available in the literature. (author)

  9. Calculation of dipole polarizability derivatives of adamantane and their use in electron scattering computations

    DEFF Research Database (Denmark)

    Sauer, Stephan P. A.; Paidarová, Ivana; Čársky, Petr

    2016-01-01

    In this paper we present calculations of the static polarizability and its derivatives for the adamantane molecule carried out at the density functional theory level using the B3LYP exchange correlation functional and Sadlej’s polarized valence triple zeta basis set. It is shown that the polariza......In this paper we present calculations of the static polarizability and its derivatives for the adamantane molecule carried out at the density functional theory level using the B3LYP exchange correlation functional and Sadlej’s polarized valence triple zeta basis set. It is shown...... that the polarizability tensor is necessary to correct long-range behavior of DFT functionals used in electron-molecule scattering calculations. The impact of such a long-range correction is demonstrated on elastic and vibrationally inelastic electron collisions with adamantane, a molecule representing a large polyatomic...... target for electron scattering calculations....

  10. Modeling and theoretical study of electronic anti-Stokes Raman scattering in quantum cascade lasers

    Science.gov (United States)

    Yousefvand, Hossein Reza

    2017-04-01

    This paper presents a self-consistent model for studying the electronic anti-Stokes (AS) Raman scattering in quantum cascade lasers (QCLs). The model is developed by employing a five-level rate-equation for the carrier dynamics in whole of the device and a two-level energy balance equations to adopt the electron-temperature in the pump and AS active regions. Using the presented model, the effect of temperature on the steady and transient characteristics of the device is investigated. Because of considering the parametric interaction between the incident and the scattered lights in the stimulated Raman process, the model accurately predicts the existence of Raman gain's saturation in both the steady and transient regimes. Additionally, using a steady-state analysis of the rate equations in the nonlinear region, an expression for the threshold current of the AS Raman laser is derived and the effects of pump power and temperature are examined. It is found that the electronic AS Raman scattering is affected by interplay between the various temperature-dependent parameters such as the pump intensity, the intrinsic gain of the nonlinear optical medium, and the longitudinal optical (LO) phonon scattering times between the states involved in the stimulated Raman process.

  11. On the role of inelastic scattering in phase-plate transmission electron microscopy.

    Science.gov (United States)

    Hettler, Simon; Wagner, Jochen; Dries, Manuel; Oster, Marco; Wacker, Christian; Schröder, Rasmus R; Gerthsen, Dagmar

    2015-08-01

    The phase contrast of Au nanoparticles on amorphous-carbon films with different thicknesses is analyzed using an electrostatic Zach phase plate in a Zeiss 912 Ω transmission electron microscope with in-column energy filter. Specifically, unfiltered and plasmon-filtered phase-plate transmission electron microscopy (PP TEM) images are compared to gain insight in the role of coherence after inelastic scattering processes. A considerable phase-contrast contribution resulting from a combined elastic-inelastic scattering process is found in plasmon-filtered PP TEM images. The contrast reduction compared to unfiltered images mainly originates from zero-order beam broadening caused by the inelastic scattering process. The effect of the sequence of the elastic and inelastic scattering processes is studied by varying the position of the nanoparticles, which can be either located on top or at the bottom of the amorphous-carbon film with respect to the incident electron beam direction. Copyright © 2015 Elsevier B.V. All rights reserved.

  12. Factors affecting the performance of detectors that use secondary electron emission from a thin foil to determine ion impact position

    CERN Document Server

    Shapira, D; Hulett, L D; Ciao, Z

    2000-01-01

    The factors affecting the performance of a Position-Sensitive Timing Detector (PSTD), based on the detection of secondary electrons ejected from a thin foil by the passing ion, were investigated. Different contributions to the observed (generally poor) position resolution were investigated. The effects of multiple scattering in the foil were determined first. We then measured the contribution of the position-sensitive detector and signal-handling electronics. Finally, the effect of electron transport, from the point of emission at the foil surface to the micro-channel plate detector (MCP) surface, was measured and evaluated. Our measurements, as well as a simulation of the electron transport, lead us to conclude that for detectors with foil-to-MCP distance >=5 cm, electron transport limits the devices currently in use to resolution worse than 2 mm (FWHM).

  13. Construction and Commissioning of a New Scattering Chamber at the Union College Ion Beam Analysis Laboratory

    Science.gov (United States)

    Turley, Colin; Moore, Robert; Johnson, Christopher; Battaglia, Maria; Vineyard, Michael; Labrake, Scott

    2011-10-01

    We have constructed a new scattering chamber in the Union College Ion Beam Analysis Laboratory to improve our experimental capabilities. The new chamber was constructed from a ten-inch, conflat, multi-way cross. We fitted the chamber with an eight-inch, Leybold turbomolecular pump so that it can be evacuated quickly. A target manipulator with stepper motors that provide x, y, and z-positioning of the target with micron precision is mounted atop the chamber. A target ladder was constructed for the manipulator that allows us to analyze multiple samples without breaking the vacuum. The chamber has a door with an O-ring seal mounted on one of the ten-inch ports that provides easy access to the interior of the chamber. An Amptek silicon-drift X-ray detector is mounted close to the target ladder, inside the vacuum so that low-energy X-rays can be detected. A new Faraday cup was also installed to provide more accurate current measurements. Finally, a new collimator system was developed and installed in the beam-line to the scattering chamber to provide a well-defined beam spot. A proton induced X-ray emission analysis of aerosol samples has been performed as the commissioning experiment for the chamber. Here, we report on the construction and commissioning of this new chamber.

  14. Thermal Relaxation in Titanium Nanowires: Signatures of Inelastic Electron-Boundary Scattering in Heat Transfer

    Science.gov (United States)

    Elo, Teemu; Lähteenmäki, Pasi; Golubev, Dmitri; Savin, Alexander; Arutyunov, Konstantin; Hakonen, Pertti

    2017-11-01

    We have employed noise thermometry for investigations of thermal relaxation between the electrons and the substrate in nanowires patterned from 40-nm-thick titanium film on top of silicon wafers covered by a native oxide. By controlling the electronic temperature T_e by Joule heating at the base temperature of a dilution refrigerator, we probe the electron-phonon coupling and the thermal boundary resistance at temperatures T_e= 0.5-3 K. Using a regular T^5-dependent electron-phonon coupling of clean metals and a T^4-dependent interfacial heat flow, we deduce a small contribution for the direct energy transfer from the titanium electrons to the substrate phonons due to inelastic electron-boundary scattering.

  15. Effect of electron correlation on positronium formation in positron-helium scattering

    Energy Technology Data Exchange (ETDEWEB)

    Chaudhuri, P.; Adhikari, S.K. [Universidad Estadual Paulista, Sao Paulo (Brazil). Inst. de Fisica Teorica; Talukdar, B.; Bhattacharyya, S. [Department of Physics, Visva Bharati University, Santiniketan 731235 (India)

    1999-02-01

    A three-parameter correlated wave function for the helium ground state is used to study the scattering reaction e{sup +}+He{yields}He{sup +}+Ps, where Ps stands for positronium atom. An exact analytical expression is constructed for the first Born scattering amplitude for Ps formation from helium. Based on this numerical results are presented for both differential and total cross-sections. It is demonstrated that the inner electronic correlation of the target atom plays a crucial role in explaining the discrepancy between theory and experiment. (orig.) 13 refs.

  16. Laser-Compton scattering from a 20 MeV electron beam

    CERN Document Server

    Chouffani, K; Harmon, F; Jones, J; Lancaster, G

    2002-01-01

    Laser-Compton scattering (LCS) experiments were carried out at the Idaho Accelerator Center. A 20 MeV electron beam was brought to a head-on collision with a 100 MW 7 ns Nd:YAG laser. We observed clear narrow LCS X-ray spectral peaks resulting from the interaction of the electron beam with the two Nd:YAG laser photon lines of 1064 and 532 nm. The LCS X-ray energy lines and widths were measured as a function of the electron beam energy and energy spread, respectively. The results recorded showed good agreement with the predicted values.

  17. Saturation Physics and the Electron-Ion Collider

    Science.gov (United States)

    Gonçalves, V. P.; Kugeratski, M. S.; Navarra, F. S.

    Using an extension of the Iancu-Itakura-Munier model to nuclear targets we look for saturation effects in electron-ion collisions. In previous publications we have made definite predictions. Here we try to compare our results with already existing experimental data on structure functions and on total and diffractive cross sections. Strictly speaking such a comparison is not well justified because the present data are not yet in the saturation domain. Nevertheless our results agree qualitatively with data and, in some cases, even quantitatively.

  18. Calibrating the DARHT Electron Spectrometer with Negative Ions

    Energy Technology Data Exchange (ETDEWEB)

    R. Trainham (STL), A. P. Tipton (LAO), and R. R. Bartech (LANL)

    2005-11-01

    Negative ions of hydrogen and oxygen have been used to calibrate the DARHT electron spectrometer over the momentum range of 2 to 20 MeV/c. The calibration was performed on September 1, 3, and 8, 2004, and it is good to 0.5% absolute, provided that instrument alignment is carefully controlled. The momentum in MeV/c as a function of magnetic field (B in Gauss) and position in the detector plane (X in mm) is: P = (B-6.28)/(108.404-0.1935*X)

  19. Electromagnetic solitary structures in dense electron-positron-ion magnetoplasmas

    Energy Technology Data Exchange (ETDEWEB)

    Masood, W; Hussain, S; Rizvi, H; Mushtaq, A [TPPD, PINSTECH, PO Nilore, Islamabad (Pakistan); Ayub, M, E-mail: waqasmas@gmail.co [Government College University (GCU), Lahore (Pakistan)

    2010-12-15

    The linear and nonlinear propagation characteristics of low-frequency obliquely propagating magnetoacoustic waves in dense electron-positron-ion magnetoplasmas are studied in this paper by using the quantum magnetohydrodynamic (QMHD) model. A quantum Kadomtsev-Petviashvili (KP) equation is derived by using the reductive perturbation technique. The dependence of the fast and slow magnetoacoustic solitary waves on the positron concentration, the obliqueness parameter {theta} and the magnetic field is also investigated. The present investigation may have relevance to dense astrophysical environments where the quantum effects are expected to dominate.

  20. Monte Carlo simulation of heavy ion induced kinetic electron emission from an Al surface

    CERN Document Server

    Ohya, K

    2002-01-01

    A Monte Carlo simulation is performed in order to study heavy ion induced kinetic electron emission from an Al surface. In the simulation, excitation of conduction band electrons by the projectile ion and recoiling target atoms is treated on the basis of the partial wave expansion method, and the cascade multiplication process of the excited electrons is simulated as well as collision cascade of the recoiling target atoms. Experimental electron yields near conventional threshold energies of heavy ions are simulated by an assumption of a lowering in the apparent surface barrier for the electrons. The present calculation derives components for electron excitations by the projectile ion, the recoiling target atoms and the electron cascades, from the calculated total electron yield. The component from the recoiling target atoms increases with increasing projectile mass, whereas the component from the electron cascade decreases. Although the components from the projectile ion and the electron cascade increase with...

  1. Electronic excitation effects in ion-irradiated high- Tc superconductors

    Science.gov (United States)

    Ishikawa, N.; Chimi, Y.; Iwase, A.; Maeta, H.; Tsuru, K.; Michikami, O.; Kambara, T.; Mitamura, T.; Awaya, Y.; Terasawa, M.

    1998-02-01

    We have measured the fluence dependence of the c-axis lattice parameter in EuBa 2Cu 3O y (EBCO) irradiated with various ions from He to Au over the wide energy range from 0.85 MeV to 3.80 GeV. We have observed a linear increase of the c-axis lattice parameter with increasing fluence for all irradiations. The slope of c-axis lattice parameter against fluence, which corresponds to the defect production rate, is separated into two contributions; the effect via elastic displacement and the effect via electronic excitation. The former contribution exhibits a linear increase against the nuclear stopping power, Sn. The latter contribution is scaled by the primary ionization rate, d J/d x, rather than by the electronic stopping power, Se, and is nearly proportional to (d J/d x) 4.

  2. ITER Plasma at Ion Cyclotron Frequency Domain: The Fusion Alpha Particles Diagnostics Based on the Stimulated Raman Scattering of Fast Magnetosonic Wave off High Harmonic Ion Bernstein Modes

    Science.gov (United States)

    Stefan, V. Alexander

    2014-10-01

    A novel method for alpha particle diagnostics is proposed. The theory of stimulated Raman scattering, SRS, of the fast wave and ion Bernstein mode, IBM, turbulence in multi-ion species plasmas, (Stefan University Press, La Jolla, CA, 2008). is utilized for the diagnostics of fast ions, (4)He (+2), in ITER plasmas. Nonlinear Landau damping of the IBM on fast ions near the plasma edge leads to the space-time changes in the turbulence level, (inverse alpha particle channeling). The space-time monitoring of the IBM turbulence via the SRS techniques may prove efficient for the real time study of the fast ion velocity distribution function, spatial distribution, and transport. Supported by Nikola Tesla Labs., La Jolla, CA 92037.

  3. Towards a Resolution of the Proton Form Factor Problem: New Electron and Positron Scattering Data

    Science.gov (United States)

    Adikaram, D.; Rimal, D.; Weinstein, L. B.; Raue, B.; Khetarpal, P.; Bennett, R. P.; Arrington, J.; Brooks, W. K.; Adhikari, K. P.; Afanasev, A. V.; Amaryan, M. J.; Anderson, M. D.; Anefalos Pereira, S.; Avakian, H.; Ball, J.; Battaglieri, M.; Bedlinskiy, I.; Biselli, A. S.; Bono, J.; Boiarinov, S.; Briscoe, W. J.; Burkert, V. D.; Carman, D. S.; Careccia, S.; Celentano, A.; Chandavar, S.; Charles, G.; Colaneri, L.; Cole, P. L.; Contalbrigo, M.; Crede, V.; D'Angelo, A.; Dashyan, N.; De Vita, R.; De Sanctis, E.; Deur, A.; Djalali, C.; Dodge, G. E.; Dupre, R.; Egiyan, H.; El Alaoui, A.; El Fassi, L.; Elouadrhiri, L.; Eugenio, P.; Fedotov, G.; Fegan, S.; Filippi, A.; Fleming, J. A.; Fradi, A.; Garillon, B.; Gilfoyle, G. P.; Giovanetti, K. L.; Girod, F. X.; Goetz, J. T.; Gohn, W.; Golovatch, E.; Gothe, R. W.; Griffioen, K. A.; Guegan, B.; Guidal, M.; Guo, L.; Hafidi, K.; Hakobyan, H.; Hanretty, C.; Harrison, N.; Hattawy, M.; Hicks, K.; Holtrop, M.; Hughes, S. M.; Hyde, C. E.; Ilieva, Y.; Ireland, D. G.; Ishkhanov, B. S.; Jenkins, D.; Jiang, H.; Jo, H. S.; Joo, K.; Joosten, S.; Kalantarians, N.; Keller, D.; Khandaker, M.; Kim, A.; Kim, W.; Klein, A.; Klein, F. J.; Koirala, S.; Kubarovsky, V.; Kuhn, S. E.; Livingston, K.; Lu, H. Y.; MacGregor, I. J. D.; Markov, N.; Mattione, P.; Mayer, M.; McKinnon, B.; Mestayer, M. D.; Meyer, C. A.; Mirazita, M.; Mokeev, V.; Montgomery, R. A.; Moody, C. I.; Moutarde, H.; Movsisyan, A.; Camacho, C. Munoz; Nadel-Turonski, P.; Niccolai, S.; Niculescu, G.; Osipenko, M.; Ostrovidov, A. I.; Park, K.; Pasyuk, E.; Peña, C.; Pisano, S.; Pogorelko, O.; Price, J. W.; Procureur, S.; Prok, Y.; Protopopescu, D.; Puckett, A. J. R.; Ripani, M.; Rizzo, A.; Rosner, G.; Rossi, P.; Roy, P.; Sabatié, F.; Salgado, C.; Schott, D.; Schumacher, R. A.; Seder, E.; Sharabian, Y. G.; Simonyan, A.; Skorodumina, I.; Smith, E. S.; Smith, G. D.; Sober, D. I.; Sokhan, D.; Sparveris, N.; Stepanyan, S.; Stoler, P.; Strauch, S.; Sytnik, V.; Taiuti, M.; Tian, Ye; Trivedi, A.; Ungaro, M.; Voskanyan, H.; Voutier, E.; Walford, N. K.; Watts, D. P.; Wei, X.; Wood, M. H.; Zachariou, N.; Zana, L.; Zhang, J.; Zhao, Z. W.; Zonta, I.; CLAS Collaboration

    2015-02-01

    There is a significant discrepancy between the values of the proton electric form factor, GEp, extracted using unpolarized and polarized electron scattering. Calculations predict that small two-photon exchange (TPE) contributions can significantly affect the extraction of GEp from the unpolarized electron-proton cross sections. We determined the TPE contribution by measuring the ratio of positron-proton to electron-proton elastic scattering cross sections using a simultaneous, tertiary electron-positron beam incident on a liquid hydrogen target and detecting the scattered particles in the Jefferson Lab CLAS detector. This novel technique allowed us to cover a wide range in virtual photon polarization (ɛ ) and momentum transfer (Q2) simultaneously, as well as to cancel luminosity-related systematic errors. The cross section ratio increases with decreasing ɛ at Q2=1.45 GeV2 . This measurement is consistent with the size of the form factor discrepancy at Q2≈1.75 GeV2 and with hadronic calculations including nucleon and Δ intermediate states, which have been shown to resolve the discrepancy up to 2 - 3 GeV2 .

  4. Towards a resolution of the proton form factor problem: new electron and positron scattering data

    CERN Document Server

    Adikaram, D; Weinstein, L B; Raue, B; Khetarpal, P; Bennett, R P; Arrington, J; Brooks, W K; Adhikari, K P; Afanasev, A V; Amaryan, M J; Anderson, M D; Ball, J; Battaglieri, M; Bedlinskiy, I; Biselli, A S; Bono, J; Boiarinov, S; Briscoe, W J; Burkert, V D; Carman, D S; Celentano, A; Chandavar, S; Charles, G; Colaneri, L; Cole, P L; Contalbrigo, M; D'Angelo, A; Dashyan, N; De Vita, R; De Sanctis, E; Deur, A; Djalali, C; Dodge, G E; Dupre, R; Egiyan, H; Alaoui, A El; Fassi, L El; Eugenio, P; Fedotov, G; Fegan, S; Filippi, A; Fleming, J A; Fradi, A; Gilfoyle, G P; Giovanetti, K L; Girod, F X; Goetz, J T; Gohn, W; Golovatch, E; Gothe, R W; Griffioen, K A; Guidal, M; Guo, L; Hafidi, K; Hakobyan, H; Harrison, N; Hattawy, M; Hicks, K; Holtrop, M; Hughes, S M; Hyde, C E; Ilieva, Y; Ireland, D G; Ishkhanov, B S; Jenkins, D; Jiang, H; Joo, K; Joosten, S; Khandaker, M; Kim, W; Klein, A; Klein, F J; Koirala, S; Kubarovsky, V; Kuhn, S E; Lu, H Y; MacGregor, I J D; Markov, N; Mayer, M; McKinnon, B; Mestayer, M D; Meyer, C A; Mirazita, M; Mokeev, V; Montgomery, R A; Moody, C I; Moutarde, H; Movsisyan, A; Camacho, C Munoz; Nadel-Turonski, P; Niccolai, S; Niculescu, G; Osipenko, M; Ostrovidov, A I; Park, K; Pasyuk, E; Pisano, S; Pogorelko, O; Procureur, S; Prok, Y; Protopopescu, D; Puckett, A J R; Ripani, M; Rizzo, A; Rosner, G; Rossi, P; Sabatié, F; Schott, D; Schumacher, R A; Sharabian, Y G; Simonyan, A; Skorodumina, I; Smith, E S; Smith, G D; Sober, D I; Sparveris, N; Stepanyan, S; Strauch, S; Sytnik, V; Taiuti, M; Tian, Ye; Trivedi, A; Ungaro, M; Voskanyan, H; Voutier, E; Walford, N K; Watts, D P; Wei, X; Wood, M H; Zachariou, N; Zana, L; Zhang, J; Zhao, Z W; Zonta, I

    2014-01-01

    There is a significant discrepancy between the values of the proton electric form factor, $G_E^p$, extracted using unpolarized and polarized electron scattering. Calculations predict that small two-photon exchange (TPE) contributions can significantly affect the extraction of $G_E^p$ from the unpolarized electron-proton cross sections. We determined the TPE contribution by measuring the ratio of positron-proton to electron-proton elastic scattering cross sections using a simultaneous, tertiary electron-positron beam incident on a liquid hydrogen target and detecting the scattered particles in the Jefferson Lab CLAS detector. This novel technique allowed us to cover a wide range in virtual photon polarization ($\\varepsilon$) and momentum transfer ($Q^2$) simultaneously, as well as to cancel luminosity-related systematic errors. The cross section ratio increases with decreasing $\\varepsilon$ at $Q^2 = 1.45 \\text{ GeV}^2$. This measurement is consistent with the size of the form factor discrepancy at $Q^2\\approx...

  5. Benchmark and combined velocity-space tomography of fast-ion D-alpha spectroscopy and collective Thomson scattering measurements

    DEFF Research Database (Denmark)

    Jacobsen, Asger Schou; Salewski, Mirko; Geiger, B.

    2016-01-01

    We demonstrate the combination of fast-ion D-alpha spectroscopy (FIDA) and collective Thomson scattering (CTS) measurements to determine a common best estimate of the fastion velocity distribution function by velocity-space tomography. We further demonstrate a benchmark of FIDA tomography and CTS...... measurements without using a numerical simulation as common reference. Combined velocity-space tomographies from FIDA and CTS measurements confirm that sawtooth crashes reduce the fast-ion phase-space densities in the plasma center and affect ions with pitches close to one more strongly than those with pitches...

  6. Relativistic electron dropouts by pitch angle scattering in the geomagnetic tail

    Directory of Open Access Journals (Sweden)

    J. J. Lee

    2006-11-01

    Full Text Available Relativistic electron dropout (RED events are characterized by fast electron flux decrease at the geostationary orbit. It is known that the main loss process is non adiabatic and more effective for the high energy particles. RED events generally start to occur at midnight sector and propagate to noon sector and are correlated with magnetic field stretching. In this paper, we discuss this kind of event can be caused from pitch angle diffusion induced when the gyro radius of the electrons is comparable to the radius of curvature of the magnetic field and the magnetic moment is not conserved any more. While this process has been studied theoretically, the question is whether electron precipitation could be explained with this process for the real field configuration. This paper will show that this process can successfully explain the precipitation that occurred on 14 June 2004 observed by the low-altitude (680 km polar orbiting Korean satellite, STSAT-1. In this precipitation event, the energy dispersion showed higher energy electron precipitation occurred at lower L values. This feature is a good indicator that precipitation was caused by the magnetic moment scattering in the geomagnetic tail. This interpretation is supported by the geosynchronous satellite GOES observations that showed significant magnetic field distortion occurred on the night side accompanying the electron flux depletion. Tsyganenko-01 model also shows the magnetic moment scattering could occur under the geomagnetic conditions existing at that time. We suggest the pitch angle scattering by field curvature violating the first adiabatic invariant as a possible candidate for loss mechanism of relativistic electrons in radiation belt.

  7. Cooling of ions and antiprotons with magnetized electrons

    CERN Document Server

    Mollers, B; Walter, M; Zwicknagel, G; Carli, Christian; Nersisyan, H

    2004-01-01

    Electron cooling is a well-established method to improve the phase space quality of ion beams in storage rings. More recently antiprotons have been cooled in traps, first by electrons and then by positrons in order to produce antihydrogen atoms as simplest form of antimatter for CPT-tests. During these cooling processes the light particles are guided by strong external magnetic fields which imposes a challenge to the theoretical description. Within the binary collision model we treat the Coulomb interaction as second-order perturbation to the helix motion of the light particles and also by numerical simulations. In the complementary dielectric theory we calculate the polarization of the light particles by solving the nonlinear Vlasov-Poisson equation as well as linear response. It turns out that the linearization becomes dubious at low ion velocities. In the presence of a strong magnetic field the numerically expensive solution of the Vlasov-Poisson equation is the method of choice, alternatively one may empl...

  8. New DMSP Database of Precipitating Auroral Electrons and Ions.

    Science.gov (United States)

    Redmon, Robert J; Denig, William F; Kilcommons, Liam M; Knipp, Delores J

    2017-08-01

    Since the mid 1970's, the Defense Meteorological Satellite Program (DMSP) spacecraft have operated instruments for monitoring the space environment from low earth orbit. As the program evolved, so to have the measurement capabilities such that modern DMSP spacecraft include a comprehensive suite of instruments providing estimates of precipitating electron and ion fluxes, cold/bulk plasma composition and moments, the geomagnetic field, and optical emissions in the far and extreme ultraviolet. We describe the creation of a new public database of precipitating electrons and ions from the Special Sensor J (SSJ) instrument, complete with original counts, calibrated differential fluxes adjusted for penetrating radiation, estimates of the total kinetic energy flux and characteristic energy, uncertainty estimates, and accurate ephemerides. These are provided in a common and self-describing format that covers 30+ years of DMSP spacecraft from F06 (launched in 1982) through F18 (launched in 2009). This new database is accessible at the National Centers for Environmental Information (NCEI) and the Coordinated Data Analysis Web (CDAWeb). We describe how the new database is being applied to high latitude studies of: the co-location of kinetic and electromagnetic energy inputs, ionospheric conductivity variability, field aligned currents and auroral boundary identification. We anticipate that this new database will support a broad range of space science endeavors from single observatory studies to coordinated system science investigations.

  9. New DMSP database of precipitating auroral electrons and ions

    Science.gov (United States)

    Redmon, Robert J.; Denig, William F.; Kilcommons, Liam M.; Knipp, Delores J.

    2017-08-01

    Since the mid-1970s, the Defense Meteorological Satellite Program (DMSP) spacecraft have operated instruments for monitoring the space environment from low Earth orbit. As the program evolved, so have the measurement capabilities such that modern DMSP spacecraft include a comprehensive suite of instruments providing estimates of precipitating electron and ion fluxes, cold/bulk plasma composition and moments, the geomagnetic field, and optical emissions in the far and extreme ultraviolet. We describe the creation of a new public database of precipitating electrons and ions from the Special Sensor J (SSJ) instrument, complete with original counts, calibrated differential fluxes adjusted for penetrating radiation, estimates of the total kinetic energy flux and characteristic energy, uncertainty estimates, and accurate ephemerides. These are provided in a common and self-describing format that covers 30+ years of DMSP spacecraft from F06 (launched in 1982) to F18 (launched in 2009). This new database is accessible at the National Centers for Environmental Information and the Coordinated Data Analysis Web. We describe how the new database is being applied to high-latitude studies of the colocation of kinetic and electromagnetic energy inputs, ionospheric conductivity variability, field-aligned currents, and auroral boundary identification. We anticipate that this new database will support a broad range of space science endeavors from single observatory studies to coordinated system science investigations.

  10. Phonon-Electron Scattering Limits Free Charge Mobility in Methylammonium Lead Iodide Perovskites.

    Science.gov (United States)

    Karakus, Melike; Jensen, Søren A; D'Angelo, Francesco; Turchinovich, Dmitry; Bonn, Mischa; Cánovas, Enrique

    2015-12-17

    The nature of the photoconductivity in solution-processed films of methylammonium lead iodide perovskite is investigated by determining the variation of the photoconductive response with temperature. Ultrabroadband terahertz (THz) photoconductivity spectra in the 0.3-10 THz range can be reproduced well by a simple Drude-like response at room temperature, where free charge carrier motion is characterized by an average scattering time. The scattering time determined from Drude fits in the 0.3-2THz region increases from ∼4 fs at 300 K (tetragonal phase; mobility of ∼27 cm(2) V(-1) s(-1)) to almost ∼25 fs at 77 K (orthorhombic phase, mobility of ∼150 cm(2) V(-1) s(-1)). For the tetragonal phase (temperature range 150 < T < 300 K) the scattering time shows a ∼T(-3/2) dependence, approaching the theoretical limit for pure acoustic phonon (deformation potential) scattering. Hence, electron-phonon, rather than impurity scattering, sets the upper limit on free charge transport for this perovskite.

  11. Inclusive Electron Scattering From Nuclei at x >1 and High Q2

    Energy Technology Data Exchange (ETDEWEB)

    Arrington, John [California Inst. of Technology (CalTech), Pasadena, CA (United States)

    1998-06-02

    CEBAF experiment e89-008 measured inclusive electron scattering from nuclei in a Q2 range between 0.8 and 7.3 (GeV/c)2 for xBjorken approximately greater than 1. The cross sections for scattering from D C, Fe, and Au were measured. The C, Fe, and Au data have been analyzed in terms of F(y) to examine y-scaling of the quasielastic scattering, and to study the momentum distribution of the nucleons in the nucleus. The data have also been analyzed in terms of the structure function vW2 to examine scaling of the inelastic scattering in x and xi and to study the momentum distribution of the quarks. In the regions where quasielastic scattering dominates the cross section (low Q2 or large negative values of y), the data are shown to exhibit y-scaling. However, the y-scaling breaks down once the inelastic contributions become large. The data do not exhibit x-scaling, except at the lowest values of x, while the structure function does appear to scale in the Nachtmann variable, xi.

  12. Quantum multiscattering interferences in collision-induced coherent electron emission from diatomic molecules by swift ion impact

    Science.gov (United States)

    Agueny, H.; Hansen, J. P.

    2016-11-01

    In the intramolecular scattering process, the interference between the rescattered electron waves emanating from each atomic center gives rise to additional oscillations superimposed on the Young-type oscillatory structure in the observed electron intensity. Here we explore numerically this behavior for coherent electron emission from the dimer Rb2 + by fast-moving highly charged ions, which is achieved by solving the two-dimensional time-dependent Schrödinger equation. Well-defined modulations with higher frequency are observed in the momentum distribution of the ejected electron, which are well reproduced by additional quantitative calculations based on the third-order Born series. This demonstrates without ambiguity the dynamic interference induced by multiple scattering paths of the electron prior to emission. Furthermore, the dependence of the phenomenon on the emission direction of the electron and the orientation of the molecular axis also is investigated. The phenomenon is not specific to Rb2 + as investigated in the present study, but is broadly applicable to other systems with sufficiently large internuclear distances, thus opening new prospects for the investigation of electron emission process from large systems.

  13. Photoionization and electron-ion recombination of P II

    Science.gov (United States)

    Nahar, Sultana N.

    2017-08-01

    A study of the inverse processes of photoionization and electron-ion recombination of P II is reported. Phosphorus, a little studied cosmic element, requires atomic parameters such as those presented here for spectral analysis. The unified method of Nahar and Pradhan, which incorporates two methods of recombination - radiative recombination (RR) and dielectronic recombination (DR) - and the interference between them, is used to obtain the total electron-ion recombination. This method implements the framework of the {R}-matrix close-coupling approximation. The present results include the partial photoionization cross-sections σPI(Jπ) leaving the residual ion in the ground level and level-specific recombination rate coefficients, αRC(Jπ), of 475 fine-structure levels of P II with n ≤10. In photoionization of the ground and many excited levels, a sharp resonance is found to form at the ionization threshold from couplings of relativistic fine-structure channels. These, with other resonances in the near-threshold energy region, yield a slight curvature, in contrast to typical smooth decay, at a very low temperature of about 330 K in the total recombination rate coefficient αRC. The presence of other Rydberg and Seaton resonances in the photoionization cross-section introduces features in the level-specific recombination rate coefficients and a DR bump at high temperature at 105 K for the total recombination rate coefficient. Considerable interference between RR and DR is noted around 6700 K. The recombination spectrum with respect to photoelectron energy αRC(E) is also presented. The results are expected to provide accurate models for astrophysical plasmas up to ˜1 MK.

  14. First results of electron temperature measurements by the use of multi-pass Thomson scattering system in GAMMA 10

    Energy Technology Data Exchange (ETDEWEB)

    Yoshikawa, M., E-mail: yosikawa@prc.tsukuba.ac.jp; Nagasu, K.; Shimamura, Y.; Shima, Y.; Kohagura, J.; Sakamoto, M.; Nakashima, Y.; Imai, T.; Ichimura, M. [Plasma Research Center, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8577 (Japan); Yasuhara, R.; Yamada, I.; Funaba, H.; Kawahata, K. [National Institute for Fusion Science, 322-6 Oroshi-cho, Toki, Gifu 509-5292 (Japan); Minami, T. [Institute of Advanced Energy, Kyoto University, Gokasho, Uji, Kyoto 611-0011 (Japan)

    2014-11-15

    A multi-pass Thomson scattering (TS) has the advantage of enhancing scattered signals. We constructed a multi-pass TS system for a polarisation-based system and an image relaying system modelled on the GAMMA 10 TS system. We undertook Raman scattering experiments both for the multi-pass setting and for checking the optical components. Moreover, we applied the system to the electron temperature measurements in the GAMMA 10 plasma for the first time. The integrated scattering signal was magnified by approximately three times by using the multi-pass TS system with four passes. The electron temperature measurement accuracy is improved by using this multi-pass system.

  15. Three-dimensional simulations of ion dynamics in the plasma of an electron cyclotron resonance ion source

    Directory of Open Access Journals (Sweden)

    V. Mironov

    2009-07-01

    Full Text Available The ion production in an electron cyclotron resonance ion source (ECRIS is modeled using a particle-in-cell Monte-Carlo-collision code in a three-dimensional geometry. Only the heavy particles (ions and atoms are tracked, while the electrons are represented using a Maxwell-Boltzmann energy distribution with the electron density determined from the requirement of quasineutrality, and the electron temperature considered as a free parameter. It is found that experimentally observed features of ECRIS plasma are closely reproduced by the code, including the charge-state distributions of extracted ion beams and sputtering patterns inside the source. The isotope anomaly is observed for the mixture of ^{20}Ne+^{22}Ne isotopes, and a possible explanation is proposed. Finally, the wall-coating effect is treated by modeling the neutralization of ions impinging on the walls of the plasma chamber.

  16. Transverse Beam Spin Asymmetries in Forward-Angle Elastic Electron-Proton Scattering

    CERN Document Server

    Armstrong, D S; Asaturyan, R; Averett, T; Bailey, S L; Batigne, G; Beck, D H; Beise, E J; Benesch, J; Bimbot, L; Birchall, J; Biselli, A; Bosted, P; Boukobza, E; Breuer, H; Carlini, R; Carr, R; Chant, N; Chao, Y C; Chattopadhyay, S; Clark, R; Covrig, S; Cowley, A; Dale, D; Davis, C; Falk, W; Finn, J M; Forest, T; Franklin, G; Furget, C; Gaskell, D; Grames, J; Griffioen, K A; Grimm, K; Guillon, B; Guler, H; Hannelius, L; Hasty, R; Hawthorne Allen, A; Horn, T; Johnston, K; Jones, M; Kammel, P; Kazimi, R; King, P M; Kolarkar, A; Korkmaz, E; Korsch, W; Kox, S; Kühn, J; Lachniet, J; Lee, L; Lenoble, J; Liatard, E; Liu, J; Loupias, B; Lung, A; Marchand, D; Martin, J W; McFarlane, K W; McKee, D W; McKeown, R D; Merchez, F; Mkrtchyan, H; Moffit, B; Morlet, M; Nakagawa, I; Nakahara, K; Neveling, R; Niccolai, S; Ong, S; Page, S; Papavassiliou, V; Pate, S F; Phillips, S K; Pitt, M L; Poelker, M; Porcelli, T A; Quéméner, G; Quinn, B; Ramsay, W D; Rauf, A W; Real, J S; Roche, J; Roos, P; Rutledge, G A; Secrest, J; Simicevic, N; Smith, G R; Spayde, D T; Stepanyan, S; Stutzman, M; Sulkosky, V; Tadevosyan, V; Tieulent, R; Van de Wiele, J; Van Oers, W T H; Voutier, E; Vulcan, W; Warren, G; Wells, S P; Williamson, S E; Wood, S A; Yan, C; Yun, J; Zeps, V

    2007-01-01

    We have measured the beam-normal single-spin asymmetry in elastic scattering of transversely-polarized 3 GeV electrons from unpolarized protons at Q^2 values of 0.15 and 0.25 (GeV/c)^2 with results of A_n = -4.06 +- 0.99 (stat) +- 0.63 (syst) and A_n = -4.82 +- 1.87 (stat) +- 0.98 (syst) ppm. These results are inconsistent with calculations solely using the elastic nucleon intermediate state, and generally agree with calculations with significant inelastic hadronic intermediate state contributions. A_n provides a direct probe of the imaginary component of the 2-gamma exchange amplitude, the complete description of which is important in the interpretation of data from precision electron-scattering experiments.

  17. Cascade emission in electron beam ion trap plasma of W$^{25+}$ ion

    CERN Document Server

    Jonauskas, V; Kučas, S; Masys, Š; Kynienė, A; Gaigalas, G; Kisielius, R; Radžiūtė, L; Rynkun, P; Merkelis, G

    2015-01-01

    Spectra of the W$^{25+}$ ion are studied using the collisional-radiative model (CRM) with an ensuing cascade emission. It is determined that the cascade emission boosts intensities only of a few lines in the $10 - 3$ nm range. The cascade emission is responsible for the disappearance of structure of lines at about 6 nm in the electron beam ion trap plasma. Emission band at 4.5 to 5.3 nm is also affected by the cascade emission. The strongest lines in the CRM spectrum correspond to $4d^{9} 4f^{4} \\rightarrow 4f^{3}$ transitions, while $4f^{2} 5d \\rightarrow 4f^{3}$ transitions arise after the cascade emission is taken into account.

  18. Propagation of ion-acoustic solitary waves in a relativistic electron-positron-ion plasma

    CERN Document Server

    Saberian, E; Akbari-Moghanjoughi, M

    2011-01-01

    Propagation of large amplitude ion-acoustic solitary waves (IASWs) in a fully relativistic plasma consisting of cold ions and ultrarelativistic hot electrons and positrons is investigated using the Sagdeev's pseudopotential method in a relativistic hydrodynamics model. Effects of streaming speed of plasma fluid, thermal energy, positron density and positron temperature on large amplitude IASWs are studied by analysis of the pseudopotential structure. It is found that in regions that the streaming speed of plasma fluid is larger than that of solitary wave, by increasing the streaming speed of plasma fluid the depth and width of potential well increases and resulting in narrower solitons with larger amplitude. This behavior is opposite for the case where the streaming speed of plasma fluid is smaller than that of solitary wave. On the other hand, increase of the thermal energy results in wider solitons with smaller amplitude, because the depth and width of potential well decreases in that case. Additionally, th...

  19. Estimating electron affinity from the lifetime of negative molecular ions: Cycloheptatriene derivatives

    Science.gov (United States)

    Asfandiarov, N. L.; Pshenichnyuk, S. A.; Vorob'ev, A. S.; Nafikova, E. P.; Mavrodiev, V. K.; Furlei, I. I.; Dokichev, V. A.; Platonov, D. N.; Belyy, A. Yu.

    2017-05-01

    Cycloheptatriene derivatives are studied by means of resonance electron capture negative ion mass spectrometry (REC NIMS). The average lifetimes of molecular negative ions (NIs) are measured with respect to electron autodetachment. Using the Arrhenius approach, electron affinity EAa of the molecules under study is estimated, and the effective temperature of the resulting negative molecular ions is determined as a function of the electron energy. It is assumed that the dissociation of negative molecular ions in the ground electronic state is a process similar to that of the thermal degradation of molecules.

  20. Electron transport in a one dimensional conductor with inelastic scattering by self-consistent reservoirs

    OpenAIRE

    Roy, Dibyendu; Dhar, Abhishek

    2006-01-01

    We present an extension of the work of D'Amato and Pastawski on electron transport in a one-dimensional conductor modeled by the tight binding lattice Hamiltonian and in which inelastic scattering is incorporated by connecting each site of the lattice to one-dimensional leads. This model incorporates B\\"uttiker's original idea of dephasing probes. Here we consider finite temperatures and study both electrical and heat transport across a chain with applied chemical potential and temperature gr...

  1. Longitudinal response functions for quasielastic electron scattering in relativistic non-linear models

    CERN Document Server

    Caillon, J C

    2002-01-01

    The longitudinal response functions for quasielastic electron scattering on sup 1 sup 2 C, sup 4 sup 0 Ca and sup 5 sup 6 Fe have been calculated in relativistic non-linear models taking into account RPA correlations. For these calculations, a covariant, consistent, calculation of the nuclear matter linear response has been performed. The effect of the non-linear terms on the longitudinal response has been discussed.

  2. Materials analysis fast ions

    CERN Document Server

    Denker, A; Rauschenberg, J; Röhrich, J; Strub, E

    2006-01-01

    Materials analysis with ion beams exploits the interaction of ions with the electrons and nuclei in the sample. Among the vast variety of possible analytical techniques available with ion beams we will restrain to ion beam analysis with ion beams in the energy range from one to several MeV per mass unit. It is possible to use either the back-scattered projectiles (RBS – Rutherford Back Scattering) or the recoiled atoms itself (ERDA – Elastic Recoil Detection Analysis) from the elastic scattering processes. These techniques allow the simultaneous and absolute determination of stoichiometry and depth profiles of the detected elements. The interaction of the ions with the electrons in the sample produces holes in the inner electronic shells of the sample atoms, which recombine and emit X-rays characteristic for the element in question. Particle Induced X-ray Emission (PIXE) has shown to be a fast technique for the analysis of elements with an atomic number above 11.

  3. Bremsstrahlung from relativistic bare heavy ions: Nuclear and electronic contributions in amorphous and crystalline materials

    DEFF Research Database (Denmark)

    Jensen, Tue Vissing; Sørensen, Allan Hvidkjær

    2013-01-01

    A charged particle emits bremsstrahlung while traversing matter. We calculate the radiation cross section for bare heavy ions penetrating amorphous materials and single crystals at highly relativistic energies. The main component originates in scattering of the virtual photons of screened target...... in a pronounced directional dependence of the energy loss of bare heavy ions at extreme relativistic energies....

  4. Ab-initio electron scattering cross-sections and transport in liquid xenon

    CERN Document Server

    Boyle, Greg; Cocks, Daniel; Brunger, Michael; Buckman, Steve; Dujko, Sasa; White, Ron

    2016-01-01

    Ab-initio electron - liquid phase xenon fully differential cross-sections for electrons scattering in liquid xenon are developed from a solution of the Dirac-Fock scattering equations, using a recently developed framework [1] which considers multipole polarizabilities, a non-local treatment of exchange, and screening and coherent scattering effects. A multi-term solution of Boltzmann's equation accounting for the full anisotropic nature of the differential cross-section is used to calculate transport properties of excess electrons in liquid xenon. The results were found to agree to within 25% of the measured mobilities and characteristic energies over the reduced field range of 10^{-4} to 1 Td. The accuracies are comparable to those achieved in the gas phase. A simple model, informed by highly accurate gas-phase cross-sections, is presented to transform highly accurate gas-phase cross-sections to improve the liquid cross-sections, which was found to enhance the accuracy of the transport coefficient calculatio...

  5. Spin-resolved inelastic electron scattering by spin waves in noncollinear magnets

    Science.gov (United States)

    dos Santos, Flaviano José; dos Santos Dias, Manuel; Guimarães, Filipe Souza Mendes; Bouaziz, Juba; Lounis, Samir

    2018-01-01

    Topological noncollinear magnetic phases of matter are at the heart of many proposals for future information nanotechnology, with novel device concepts based on ultrathin films and nanowires. Their operation requires understanding and control of the underlying dynamics, including excitations such as spin waves. So far, no experimental technique has attempted to probe large wave-vector spin waves in noncollinear low-dimensional systems. In this paper, we explain how inelastic electron scattering, being suitable for investigations of surfaces and thin films, can detect the collective spin-excitation spectra of noncollinear magnets. To reveal the particularities of spin waves in such noncollinear samples, we propose the usage of spin-polarized electron-energy-loss spectroscopy augmented with a spin analyzer. With the spin analyzer detecting the polarization of the scattered electrons, four spin-dependent scattering channels are defined, which allow us to filter and select specific spin-wave modes. We take as examples a topological nontrivial skyrmion lattice, a spin-spiral phase, and the conventional ferromagnet. Then we demonstrate that, counterintuitively and in contrast to the ferromagnetic case, even non-spin-flip processes can generate spin waves in noncollinear substrates. The measured dispersion and lifetime of the excitation modes permit us to fingerprint the magnetic nature of the substrate.

  6. Influence of the angular scattering of electrons on the runaway threshold in air

    DEFF Research Database (Denmark)

    Chanrion, O.; Bonaventura, Z.; Bourdon, A.

    2016-01-01

    The runaway electron mechanism is of great importance for the understanding of the generation of x- and gamma rays in atmospheric discharges. In 1991, terrestrial gamma-ray flashes (TGFs) were discovered by the Compton Gamma-Ray Observatory. Those emissions are bremsstrahlung from high energy ele...... scattering is not valid below 1 MeV where the runaway threshold usually is defined. These results are important for the thermal runaway and the runaway electron avalanche discharge mechanisms suggested to participate in the TGF generation....

  7. Tensor Analyzing Powers for Quasi-Elastic Electron Scattering from Deuterium

    CERN Document Server

    Zhou, Z L; Ferro-Luzzi, M; Passchier, E; Alarcon, R; Anghinolfi, M; Arenhövel, H; Van Bommel, R; Botto, T; Van den Brand, J F J; Bulten, H J; Choi, S; Comfort, J; Dolfini, S M; Ent, R; Gaulard, C; Higinbotham, D W; De Jager, C W; Konstantinov, E S; Lang, J; Leidemann, W; De Lange, D J; Miller, M A; Lenko, D N; Papadakis, N H; Passchier, I; Poolman, H R; Popov, S G; Rachek, Igor A; Ripani, M; Six, E; Steijger, J J M; Taiuti, M; Unal, O; Vodinas, N P; De Vries, H

    1999-01-01

    We report on a first measurement of tensor analyzing powers in quasi-elastic electron-deuteron scattering at an average three-momentum transfer of 1.7 fm$^{-1}$. Data sensitive to the spin-dependent nucleon density in the deuteron were obtained for missing momenta up to 150 MeV/$c$ with a tensor polarized $^2$H target internal to an electron storage ring. The data are well described by a calculation that includes the effects of final-state interaction, meson-exchange and isobar currents, and leading-order relativistic contributions.

  8. Probing the O(6) character of {sup 196}Pt with inelastic electron scattering

    Energy Technology Data Exchange (ETDEWEB)

    Aslanidou, Simela; Bassauer, Sergej; Hufnagel, Alexander; Kremer, Christoph; Krugmann, Andreas; Neumann-Cosel, Peter von; Pietralla, Norbert; Singer, Maxim [Institut fuer Kernphysik, Technische Universitaet Darmstadt (Germany)

    2015-07-01

    The Interacting-Boson-Model provides an elegant tool to classify low-lying collective states in medium and heavy mass even-even nuclei. One of its dynamical symmetries is O(6) and a crucial test of this theory is to investigate the monopole transition to the band head of the K=0, σ=N-2 band. A powerful tool to investigate monopole transitions is inelastic electron scattering. An experiment on {sup 196}Pt -claimed to be a perfect O(6) nucleus - has been performed at the superconducting electron linear accelerator S-DALINAC at Darmstadt using the high resolution LINTOTT spectrometer. The experiment and analysis results are presented.

  9. Imaging partons in exclusive scattering processes

    Energy Technology Data Exchange (ETDEWEB)

    Diehl, Markus

    2012-06-15

    The spatial distribution of partons in the proton can be probed in suitable exclusive scattering processes. I report on recent performance estimates for parton imaging at a proposed Electron-Ion Collider.

  10. The dynamics of electron and ion holes in a collisionless plasma

    Directory of Open Access Journals (Sweden)

    B. Eliasson

    2005-01-01

    Full Text Available We present a review of recent analytical and numerical studies of the dynamics of electron and ion holes in a collisionless plasma. The new results are based on the class of analytic solutions which were found by Schamel more than three decades ago, and which here work as initial conditions to numerical simulations of the dynamics of ion and electron holes and their interaction with radiation and the background plasma. Our analytic and numerical studies reveal that ion holes in an electron-ion plasma can trap Langmuir waves, due the local electron density depletion associated with the negative ion hole potential. Since the scale-length of the ion holes are on a relatively small Debye scale, the trapped Langmuir waves are Landau damped. We also find that colliding ion holes accelerate electron streams by the negative ion hole potentials, and that these streams of electrons excite Langmuir waves due to a streaming instability. In our Vlasov simulation of two colliding ion holes, the holes survive the collision and after the collision, the electron distribution becomes flat-topped between the two ion holes due to the ion hole potentials which work as potential barriers for low-energy electrons. Our study of the dynamics between electron holes and the ion background reveals that standing electron holes can be accelerated by the self-created ion cavity owing to the positive electron hole potential. Vlasov simulations show that electron holes are repelled by ion density minima and attracted by ion density maxima. We also present an extension of Schamel's theory to relativistically hot plasmas, where the relativistic mass increase of the accelerated electrons have a dramatic effect on the electron hole, with an increase in the electron hole potential and in the width of the electron hole. A study of the interaction between electromagnetic waves with relativistic electron holes shows that electromagnetic waves can be both linearly and nonlinearly

  11. Modeling and simulation of low-energy electron scattering in organic and inorganic EUV photoresists

    Science.gov (United States)

    Vaglio Pret, Alessandro; Graves, Trey; Blankenship, David; Biafore, John J.

    2017-03-01

    Alternative photoresist platforms are being developed with the goal of meeting Resolution, Roughness and Sensitivity requirements for EUV lithography. Metal-based materials appear promising due to the high etch resistance, high absorption, and high resolution. However, the exposure mechanism of these materials is quite different from that of organic chemically amplified resists. The current electron-scattering model built into PROLITHTM X6.0 allows a direct comparison of the exposure mechanisms for different resist platforms: in particular, it is now possible to estimate the intrinsic resist uncertainty by evaluating electron, acid shot noise and spatial blurring, while forcing the photon shot noise contribution to zero. A comparison between organic resists and metal-based platforms reveals how the denser nature of the latter help containing the electron scattering in a much closer radius around the absorption event. The consequent electron-reaction (acid generation for photo-active-generator-containing organic materials, ligand dissociation for the metal-oxides) reflects the electron shot noise of the different platforms. The higher absorption combined with lower blur of the metaloxide materials seem to become of crucial importance for the 5 nm technology node and beyond.

  12. Ion Behavior and Gas Mixing in electron cyclotron resonance plasmas as sources of highly charged ions (concept)

    CERN Document Server

    Melin, G; Girard, A; Hitz, D

    1999-01-01

    An ECR ion source is basically an ECR heated plasma confinement machine, with hot electrons and cold ions. The main parameters of the ion population have been analyzed, including temperature, losses, and confinement time. The "gas mixing" effect has been studied in this context. An expression is derived for determining the ion temperature from the values of all extracted ion currents. One aim is to study the ion temperature behavior in argon plasmas without and with mixing different gases into the plasma. For that purpose a series of experiments has been performed where systematically one or a few parameters where changed. One conclusion is that the ion temperature indeed is decreasing due to gas mixing. A second conclusion is that the decreasing ion temperature is not a sufficient requirement for the beneficial effect of gas mixing to the production of highest charge states of argon.

  13. Effect of pulse-modulated microwaves on fullerene ion production with electron cyclotron resonance ion source.

    Science.gov (United States)

    Asaji, T; Uchida, T; Minezaki, H; Oshima, K; Racz, R; Muramatsu, M; Biri, S; Kitagawa, A; Kato, Y; Yoshida, Y

    2012-02-01

    Fullerene plasmas generated by pulse-modulated microwaves have been investigated under typical conditions at the Bio-Nano electron cyclotron resonance ion source. The effect of the pulse modulation is distinct from that of simply structured gases, and then the density of the fullerene plasmas increased as decreasing the duty ratio. The density for a pulse width of 10 μs at the period of 100 μs is 1.34 times higher than that for CW mode. We have studied the responses of fullerene and argon plasmas to pulsed microwaves. After the turnoff of microwave power, fullerene plasmas lasted ∼30 times longer than argon plasmas.

  14. Nuclear-polarization correction to the bound-electron g factor in heavy hydrogenlike ions.

    Science.gov (United States)

    Nefiodov, A V; Plunien, G; Soff, G

    2002-08-19

    The influence of nuclear polarization on the bound-electron g factor in heavy hydrogenlike ions is investigated. Numerical calculations are performed for the K- and L-shell electrons taking into account the dominant virtual nuclear excitations. This determines the ultimate limit for tests of QED utilizing measurements of the bound-electron g factor in highly charged ions.

  15. Nuclear-polarization correction to the bound-electron g factor in heavy hydrogenlike ions

    OpenAIRE

    Nefiodov, A. V.; Plunien, G.; Soff, G.

    2002-01-01

    The influence of nuclear polarization on the bound-electron $g$ factor in heavy hydrogenlike ions is investigated. Numerical calculations are performed for the K- and L-shell electrons taking into account the dominant virtual nuclear excitations. This determines the ultimate limit for tests of QED utilizing measurements of the bound-electron $g$ factor in highly charged ions.

  16. Experiments with biased cylinder in electron cyclotron resonance ion source (plenary)

    NARCIS (Netherlands)

    Drentje, AG; Kitagawa, A; Muramatsu, M; Ogawa, H; Sakamoto, Y

    The shape of the magnetic field of an electron cyclotron resonance ion source (ECRIS) gives rise to different particle fluxes (losses) from the plasma to the end plates (mainly diffusion of electrons), and to the side walls (mainly ions). The electron fluxes to the injection end plate can be reduced

  17. Measurement of parity-violating asymmetry in electron-deuteron inelastic scattering

    Energy Technology Data Exchange (ETDEWEB)

    Wang, D.; Pan, K.; Subedi, R.; Ahmed, Z.; Allada, K.; Aniol, K. A.; Armstrong, D. S.; Arrington, J.; Bellini, V.; Beminiwattha, R.; Benesch, J.; Benmokhtar, F.; Bertozzi, W.; Camsonne, A.; Canan, M.; Cates, G. D.; Chen, J. -P.; Chudakov, E.; Cisbani, E.; Dalton, M. M.; de Jager, C. W.; De Leo, R.; Deconinck, W.; Deng, X.; Deur, A.; Dutta, C.; Fassi, L. El; Erler, J.; Flay, D.; Franklin, G. B.; Friend, M.; Frullani, S.; Garibaldi, F.; Gilad, S.; Giusa, A.; Glamazdin, A.; Golge, S.; Grimm, K.; Hafidi, K.; Hansen, J. -O.; Higinbotham, D. W.; Holmes, R.; Holmstrom, T.; Holt, R. J.; Huang, J.; Hyde, C. E.; Jen, C. M.; Jones, D.; Kang, Hoyoung; King, P. M.; Kowalski, S.; Kumar, K. S.; Lee, J. H.; LeRose, J. J.; Liyanage, N.; Long, E.; McNulty, D.; Margaziotis, D. J.; Meddi, F.; Meekins, D. G.; Mercado, L.; Meziani, Z. -E.; Michaels, R.; Mihovilovic, M.; Muangma, N.; Mesick, K. E.; Nanda, S.; Narayan, A.; Nelyubin, V.; Nuruzzaman,; Oh, Y.; Parno, D.; Paschke, K. D.; Phillips, S. K.; Qian, X.; Qiang, Y.; Quinn, B.; Rakhman, A.; Reimer, P. E.; Rider, K.; Riordan, S.; Roche, J.; Rubin, J.; Russo, G.; Saenboonruang, K.; Saha, A.; Sawatzky, B.; Shahinyan, A.; Silwal, R.; Širca, S.; Souder, P. A.; Suleiman, R.; Sulkosky, V.; Sutera, C. M.; Tobias, W. A.; Urciuoli, G. M.; Waidyawansa, B.; Wojtsekhowski, B.; Ye, L.; Zhao, B.; Zheng, X.

    2015-04-01

    The parity-violating asymmetries between a longitudinally polarized electron beam and an unpolarized deuterium target have been measured recently. The measurement covered two kinematic points in the deep-inelastic scattering region and five in the nucleon resonance region. We provide here details of the experimental setup, data analysis, and results on all asymmetry measurements including parity-violating electron asymmetries and those of inclusive pion production and beam-normal asymmetries. The parity-violating deep-inelastic asymmetries were used to extract the electron-quark weak effective couplings, and the resonance asymmetries provided the first evidence for quark-hadron duality in electroweak observables. These electron asymmetries and their interpretation were published earlier, but are presented here in more detail.

  18. Measurement of Parity-Violating Asymmetry in Electron-Deuteron Inelastic Scattering

    CERN Document Server

    Wang, D; Subedi, R; Ahmed, Z; Allada, K; Aniol, K A; Armstrong, D S; Arrington, J; Bellini, V; Beminiwattha, R; Benesch, J; Benmokhtar, F; Bertozzi, W; Camsonne, A; Canan, M; Cates, G D; Chen, J -P; Chudakov, E; Cisbani, E; Dalton, M M; de Jager, C W; De Leo, R; Deconinck, W; Deng, X; Deur, A; Dutta, C; Fassi, L El; Erler, J; Flay, D; Franklin, G B; Friend, M; Frullani, S; Garibaldi, F; Gilad, S; Giusa, A; Glamazdin, A; Golge, S; Grimm, K; Hafidi, K; Hansen, J -O; Higinbotham, D W; Holmes, R; Holmstrom, T; Holt, R J; Huang, J; Hyde, C E; Jen, C M; Jones, D; Kang, Hoyoung; King, P M; Kowalski, S; Kumar, K S; Lee, J H; LeRose, J J; Liyanage, N; Long, E; McNulty, D; Margaziotis, D J; Meddi, F; Meekins, D G; Mercado, L; Meziani, Z -E; Michaels, R; Mihovilovic, M; Muangma, N; Mesick, K E; Nanda, S; Narayan, A; Nelyubin, V; Nuruzzaman, A; Oh, Y; Parno, D; Paschke, K D; Phillips, S K; Qian, X; Qiang, Y; Quinn, B; Rakhman, A; Reimer, P E; Rider, K; Riordan, S; Roche, J; Rubin, J; Russo, G; Saenboonruang, K; Saha, A; Sawatzky, B; Shahinyan, A; Silwal, R; Širca, S; Souder, P A; Suleiman, R; Sulkosky, V; Sutera, C M; Tobias, W A; Urciuoli, G M; Waidyawansa, B; Wojtsekhowski, B; Ye, L; Zhao, B; Zheng, X

    2014-01-01

    The parity-violating asymmetries between a longitudinally-polarized electron beam and an unpolarized deuterium target have been measured recently. The measurement covered two kinematic points in the deep inelastic scattering region and five in the nucleon resonance region. We provide here details of the experimental setup, data analysis, and results on all asymmetry measurements including parity-violating electron asymmetries and those of inclusive pion production and beam-normal asymmetries. The parity-violating deep-inelastic asymmetries were used to extract the electron-quark weak effective couplings, and the resonance asymmetries provided the first evidence for quark-hadron duality in electroweak observables. These electron asymmetries and their interpretation were published earlier, but are presented here in more detail.

  19. Elastic scattering by hot electrons and apparent lifetime of longitudinal optical phonons in gallium nitride

    Energy Technology Data Exchange (ETDEWEB)

    Khurgin, Jacob B., E-mail: jakek@jhu.edu [Department of Electrical and Computer Engineering, Johns Hopkins University, Baltimore, Maryland 21218 (United States); Bajaj, Sanyam; Rajan, Siddharth [Department of Electrical and Computer Engineering, The Ohio State University, Columbus, Ohio 43210 (United States)

    2015-12-28

    Longitudinal optical (LO) phonons in GaN generated in the channel of high electron mobility transistors (HEMT) are shown to undergo nearly elastic scattering via collisions with hot electrons. The net result of these collisions is the diffusion of LO phonons in the Brillouin zone causing reduction of phonon and electron temperatures. This previously unexplored diffusion mechanism explicates how an increase in electron density causes reduction of the apparent lifetime of LO phonons, obtained from the time resolved Raman studies and microwave noise measurements, while the actual decay rate of the LO phonons remains unaffected by the carrier density. Therefore, the saturation velocity in GaN HEMT steadily declines with increased carrier density, in a qualitative agreement with experimental results.

  20. Electron Raman scattering in a double quantum well tuned by an external nonresonant intense laser field

    Science.gov (United States)

    Tiutiunnyk, A.; Mora-Ramos, M. E.; Morales, A. L.; Duque, C. M.; Restrepo, R. L.; Ungan, F.; Martínez-Orozco, J. C.; Kasapoglu, E.; Duque, C. A.

    2017-02-01

    In this work we shall present a study of inelastic light scattering involving inter-subband electron transitions in coupled GaAs-(Ga,Al)As quantum wells. Calculations include the electron related Raman differential cross section and Raman gain. The effects of an external nonresonant intense laser field are used in order to tune these output properties. The confined electron states will be described by means of a diagonalization procedure within the effective mass and parabolic band approximations. It is shown that the application of the intense laser field can produce values of the intersubband electron Raman gain above 400 cm-1. The system proposed here is an alternative choice for the development of AlxGa1-xAs semiconductor laser diodes that can be tuned via an external nonresonant intense laser field.