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  • 51. Rathsman, Karin
    et al.
    Reistad, Dag
    Danared, Håkan
    Stockholms universitet, Naturvetenskapliga fakulteten, Manne Siegbahn-laboratoriet.
    Electron Cooling Force Calculations for HESR2008Ingår i: European Particle Accelerator Conference 2008, 2008Konferensbidrag (Övrigt vetenskapligt)
  • 52.
    Reinhed, Peter
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    Orbán, Andrea
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    Rosén, Stefan
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    Thomas, Richard
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    Kashperka, Iryna
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    Johansson, Henrik
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    Misra, Deepankar
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    Fardi, Afshin
    Brännholm, Lars
    Stockholms universitet, Naturvetenskapliga fakulteten, Manne Siegbahn-laboratoriet.
    Björkhage, Mikael
    Stockholms universitet, Naturvetenskapliga fakulteten, Manne Siegbahn-laboratoriet.
    Cederquist, Henrik
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    Schmidt, Henning
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    Cryogenic keV ion-beam storage in ConeTrap - a tool for ion-temperature control2010Ingår i: Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, ISSN 0168-9002, E-ISSN 1872-9576, Vol. 621, nr 1-3, s. 83-90Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We have tested the ion-storage capabilities of the compact triple-electrode electrostatic ion-beam trap, ConeTrap, down to cryogenic temperatures. The low-temperature operation of this electrostatic storage device is an important test for the double electrostatic ion-ring experiment, DESIREE, which is presently under construction at Stockholm University. In the present work we measured the pressure dependent storage lifetimes of 2.5 keV He+ and 2.8 keV Ar+ ion beams in ConeTrap at temperatures down to 28 K and pressures down to 1.3·10-10 mbar. The so far longest measured ion storage lifetime using this system is 21.5±3.8 s for Ar+ ions. The present combination of ConeTrap and the cryogenic experimental chamber was recently applied in the first black-body correction-free measurement of the lifetime of the metastable He- ion at 10 K [Phys. Rev. Lett. 103, 213002(2009)].

  • 53.
    Reinhed, Peter
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    Orbán, Andrea
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    Werner, Josefina
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    Rosén, Stefan
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    Thomas, Richard D.
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    Kashperka, Iryna
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    Johansson, Henrik A. B.
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    Misra, Deepankar
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    Brännholm, Lars
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum, Manne Siegbahn-laboratoriet.
    Björkhage, Mikael
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum, Manne Siegbahn-laboratoriet.
    Cederquist, Henrik
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    Schmidt, Henning T.
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    Precision lifetime measurements of He- in a cryogenic electrostatic ion-beam trap2009Ingår i: Physical Review Letters, ISSN 0031-9007, E-ISSN 1079-7114, Vol. 103, nr 21, s. 213002-Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We have developed a small purely electrostatic ion-beam trap which may be operated in thermal equilibrium at precisely controlled temperatures down to 10 K. Thus, we avoid magnetic field induced mixing of quantum states and may effectively eliminate any influence from absorption of photons from black-body radiation. We report the first correction free measurements of the lifetimes of the 1s2s2p 4PoJ state of 4He- and the high precision result 359.0±0.7 μs for the J=5/2 level. The lifetimes for the J=3/2 and J=1/2 levels are determined to be 12.3±0.5 and 7.8±1.0 μs, respectively.

  • 54.
    Richter, B.
    et al.
    Kernforschungszentrum, Universität Karlsruche.
    Adiels, L.
    Stockholms universitet, Naturvetenskapliga fakulteten, Manne Siegbahn-laboratoriet.
    Backenstoss, G.
    Institute for Physics, University of Basle.
    Bergström, I.
    Stockholms universitet, Naturvetenskapliga fakulteten, Manne Siegbahn-laboratoriet.
    Blüm, P.
    Kernforschungszentrum, Universität Karlsruche.
    Fransson, K.
    Stockholms universitet, Naturvetenskapliga fakulteten, Manne Siegbahn-laboratoriet.
    Glöckner, M.
    Kernforschungszentrum, Universität Karlsruche.
    Guigas, R.
    Kernforschungszentrum, Universität Karlsruche.
    Hasinoff, M.
    Institute for Physics, University of Basle.
    Kerek, A.
    Stockholms universitet, Naturvetenskapliga fakulteten, Manne Siegbahn-laboratoriet.
    Koch, H.
    Kernforschungszentrum, Universität Karlsruche.
    Köhler, T.
    Kernforschungszentrum, Universität Karlsruche.
    Meyer, M.
    Kernforschungszentrum, Universität Karlsruche.
    Pavlopoulos, P.
    Institute for Physics, University of Basle.
    Poth, H.
    Kernforschungszentrum, Universität Karlsruche.
    Raich, U.
    Kernforschungszentrum, Universität Karlsruche.
    Repond, J.
    Institute for Physics, University of Basle.
    Suffert, M.
    Centre de recherches nucléaries and Université Louis Pasteur, Strabourg.
    Tauscher, L.
    Institute for Physics, University of Basle.
    Tröster, D.
    Institute for Physics, University of Basle.
    Zioutas, K.
    Dept. of Nuclear Physics, Univerity of Tessaloniki.
    New results in the search for narrow states in the p system below threshold1983Ingår i: Physics Letters B, ISSN 0370-2693, E-ISSN 1873-2445, Vol. 126, nr 3-4, s. 284-288Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The γ-ray spectrum after p annihilation at rest was measured in two independent high-statistics runs. Both spectra show narrow peaks, corresponding to masses of 1210, 1638, 1694 and 1771 MeV.

  • 55.
    Rosén, Stefan
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    Schmidt, Henning
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    Reinhed, Peter
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    Fischer, Daniel
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    Thomas, Richard
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    Cederquist, Henrik
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    Liljeby, Leif
    Stockholms universitet, Naturvetenskapliga fakulteten, Manne Siegbahn-laboratoriet.
    Bagge, Lars
    Stockholms universitet, Naturvetenskapliga fakulteten, Manne Siegbahn-laboratoriet.
    Leontein, Sven
    Stockholms universitet, Naturvetenskapliga fakulteten, Manne Siegbahn-laboratoriet.
    Blom, Mikael
    Stockholms universitet, Naturvetenskapliga fakulteten, Manne Siegbahn-laboratoriet.
    Operating a triple stack microchannel plate-phosphor assembly for single particle counting in the 12-300 K temperature range2007Ingår i: Review of Scientific Instruments, ISSN 0034-6748, E-ISSN 1089-7623, Vol. 78, nr 11, s. 113301-Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    An assembly consisting of a stack of three microchannel plates (MCPs) and a phosphor screen anode has been operated over the temperature range from 300 to 12 K. We report on measurements at 6.4 kHz (using an alpha source) and with dark counts only (15 Hz). Without any particle source,  the MCP bias current decreased by a factor of 2.1×103 when the temperature was lowered from 300 to 12 K. Using the alpha source, and a photomultiplier tube (PMT) to monitor the phosphor screen anode, we first observed an increase in the decay time of the phosphor from 12 to 45 μs when the temperature was decreased from 300 to 100 K while the decay time then decreased and reached a value of 5 μs at 12 K. The pulse height distribution from the PMT was measured between300 and 12 K and shows a spectrum typical for a MCP phosphor setup at 300 K and 12 K but is strongly degraded for intermediate temperatures. We conclude that the present MCP-phosphor detector assembly is well suited for position-sensitive particle counting operation at temperatures down to at least 12 K even for count rates beyond 6 kHz. This result is crucial and an important part of ongoing developments of new instrumentation for investigations of, e.g., interactions involving complex molecular ions with internal quantum state control.

  • 56.
    Schmidt, Henning
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    Fischer, Daniel
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    Berenyi, Zoltan
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    Cocke, Charles Lewis
    Gudmundsson, Magnus
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    Haag, Nicole
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    Johansson, Henrik A. B.
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    Källberg, Anders
    Stockholms universitet, Naturvetenskapliga fakulteten, Manne Siegbahn-laboratoriet.
    Levin, Sergey B.
    Reinhed, Peter
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    Sassenberg, Ulf
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    Schuch, Reinhold
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    Simonsson, Ansgar
    Stockholms universitet, Naturvetenskapliga fakulteten, Manne Siegbahn-laboratoriet.
    Stöchkel, Kristian
    Cederquist, Henrik
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    Evidence of Wave-Particle Duality for Single Fast Hydrogen Atoms2008Ingår i: Physical Review Letters, ISSN 0031-9007, E-ISSN 1079-7114, Vol. 101, nr 8, s. 083201-Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We report the direct observation of interference effects in a Young's double-slit experiment where the interfering waves are two spatially separated components of the de Broglie wave of single 1.3 MeV hydrogen atoms formed close to either target nucleus in H+ + H2 electron-transfer collisions. Quantum interference strongly influences the results even though the hydrogen atoms have a de Broglie wavelength, \lambda_dB, as small as 25 fm.

  • 57.
    Schmidt, Henning
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    Johansson, Henrik
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    Thomas, Richard
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    Geppert, Wolf
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    Haag, Nicole
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    Reinhed, Peter
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    Rosén, Stefan
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    Larsson, Mats
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    Danared, Håkan
    Stockholms universitet, Naturvetenskapliga fakulteten, Manne Siegbahn-laboratoriet.
    Rensfelt, K.-G
    Stockholms universitet, Naturvetenskapliga fakulteten, Manne Siegbahn-laboratoriet.
    Liljeby, Leif
    Stockholms universitet, Naturvetenskapliga fakulteten, Manne Siegbahn-laboratoriet.
    Bagge, Lars
    Stockholms universitet, Naturvetenskapliga fakulteten, Manne Siegbahn-laboratoriet.
    Björkhage, Mikael
    Stockholms universitet, Naturvetenskapliga fakulteten, Manne Siegbahn-laboratoriet.
    Blom, Mikael
    Stockholms universitet, Naturvetenskapliga fakulteten, Manne Siegbahn-laboratoriet.
    Löfgren, Patrik
    Stockholms universitet, Naturvetenskapliga fakulteten, Manne Siegbahn-laboratoriet.
    Källberg, Anders
    Stockholms universitet, Naturvetenskapliga fakulteten, Manne Siegbahn-laboratoriet.
    Simonsson, Ansgar
    Stockholms universitet, Naturvetenskapliga fakulteten, Manne Siegbahn-laboratoriet.
    Paál, Andras
    Stockholms universitet, Naturvetenskapliga fakulteten, Manne Siegbahn-laboratoriet.
    Zettergren, Henning
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    Cederquist, Henrik
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    DESIREE as a new tool for interstellar ion chemistry2008Ingår i: International Journal of Astrobiology, ISSN 1473-5504, E-ISSN 1475-3006, Vol. 7, nr 3-4, s. 205-208Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A novel cryogenic electrostatic storage device consisting of two ion-beam storage rings with a common straight section for studies of interactions between oppositely charged ions at low and well-defined relative velocities is under construction at Stockholm University. Here we consider the prospect of using this new tool to measure cross-sections and rate coefficients for mutual neutralization reactions of importance in interstellar ion chemistry in general and specifically in cosmic pre-biotic ion chemistry.

  • 58.
    Schuch, R.
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    Bergström, I.
    Stockholms universitet, Naturvetenskapliga fakulteten, Manne Siegbahn-laboratoriet.
    Fritioff, T.
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    Solders, A.
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    Suhonen, M.
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    Nagy, Sz.
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    Precise Atomic Masses for Fundamental Physics Determined at SMILETRAP2008Ingår i: Advances in Quantum Chemistry, ISSN 0065-3276, E-ISSN 2162-8815, Vol. 53, s. 67-81Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In this paper we describe the features of the SMILETRAP Penning trap mass spectrometer and give examples of recently performed precision mass measurements. SMILETRAP is designed for precision mass measurements using the merits of highly-charged ions. We emphasize here the importance of accurate masses of hydrogen-like and lithium-like ions for the evaluation of g-factor measurements of electrons bound to even–even nuclei and test quantum electrodynamics (QED). For these experiments the ion masses of 40Ca17+ and 40Ca19+ were measured at SMILETRAP with 5×10−10 precision. Highly precise mass measurements can also be used for testing atomic structure calculations and determination of atomic and nuclear binding energies. Some Q-values are of fundamental interest, for example, the beta-decay of tritium and the double beta-decay with no neutrinos of several nuclei, in particular 76Ge. These decays are related to properties of the electron neutrino mass and whether this neutrino is a Majorana particle. The reason that Penning traps are so reliable for the determinations of accurate decay Q-values is due to the fact that systematic errors to a great deal cancel in the mass difference between the two atoms defining the Q-value. In this paper we report the most accurate Q-values of these two beta decays namely 18589.8(12) eV for the tritium decay, and 2038.997(46) keV for the neutrinoless double beta-decay of 76Ge.

  • 59.
    Schuch, Reinhold
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    Bergström, Ingmar
    Stockholms universitet, Naturvetenskapliga fakulteten, Manne Siegbahn-laboratoriet.
    Blaum, K.
    Johannes Gutenberg-University Mainz.
    Fritioff, Tomas
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    Solders, Andreas
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    Suhonen, Markus
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    Nagy, Szilárd
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    Q value related mass determinations using a Penning trap2007Ingår i: Hyperfine Interactions, ISSN 0304-3843, E-ISSN 1572-9540, Vol. 173, nr 1-3, s. 73-83Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We report here about measurements of reaction and decay Q values by precise determination of pairs of atomic masses. These were performed with the Penning trap mass spectrometer SMILETRAP. Measurements with Penning traps give reliable and accurate masses, in particular Q values, due to the fact that certain systematic errors to a great deal cancel in the mass difference between the two atoms defining the Q value. Some Q values that are of fundamental interest will be discussed here, for example, a new Q value for the 6Li (n,γ) 7Li reaction, for the β-decay of tritium, related to properties of the electron neutrino mass, and for the neutrino-less double β-decay of 76Ge, related to the question of whether the neutrino is a Majorana particle or not. In case of the latter two we report the most accurate Q values, namely 18,589.8(12) eV for the tritium decay and 2,038.997(46) keV for the neutrino-less double β-decay of 76Ge.

  • 60.
    Solders, Andreas
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    Bergström, Ingmar
    Stockholms universitet, Naturvetenskapliga fakulteten, Manne Siegbahn-laboratoriet.
    Nagy, Szilard
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    Suhonen, Markus
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    Schuch, Reinhold
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    Determination of the proton mass from a measurement of the cyclotron frequencies of D+ and H2+ in a Penning trap2008Ingår i: Physical Review A. Atomic, Molecular, and Optical Physics, ISSN 1050-2947, E-ISSN 1094-1622, Vol. 78, nr 1, s. 2514-2520Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We determine the cyclotron frequency ratio of H2+ and D+, applying the two-pulse Ramsey-excitation technique in the Penning-trap mass spectrometer SMILETRAP. The final result, based on probing more than 100 000 ions, is a frequency ratio of 0.999 231 659 33(17). Using a value of the D+ mass recently measured by the Seattle group, we obtain so far the most precise experimental H2+ mass value of 2.015 101 497 16(34) u. From this value a proton mass value of 1.007 276 466 95(18) u (0.18 ppb relative uncertainty) could be derived, in good agreement with the value of 1.007 276 466 89(14) u published by Van Dyck et al.

  • 61. Stefanesco, I
    et al.
    Liljeby, Leif
    Stockholms universitet, Naturvetenskapliga fakulteten, Manne Siegbahn-laboratoriet.
    et, al.
    Coulomb Excitation of Cu-68, Cu-70: First Use of Post-Accelerated Isomeric Beams2007Ingår i: Physical Review Letters, Vol. 98, nr 12Artikel i tidskrift (Refereegranskat)
  • 62.
    Suhonen, Markus
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    Bergström, Ingmar
    Stockholms universitet, Naturvetenskapliga fakulteten, Manne Siegbahn-laboratoriet.
    Fritioff, Tomas
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    Nagy, Szilard
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    Solders, Andreas
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    Schuch, Reinhold
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    High-frequency Ramsey excitation in a Penning trap2007Ingår i: Journal of instrumentation, ISSN 1748-0221, Vol. 2, nr P06003, s. 1-14Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The Ramsey excitation method for high-precision mass-measurements of highly-charged ions has been investigated and benchmarked using H2+ ions in the Penning-trap mass-spectrometer SMILETRAP. The reason for using H2+ ions are their high cyclotron frequency which is typical for the highly-charged ions usually used at SMILETRAP. Two-, three- and four-pulse Ramsey excitation data are analyzed with the help of recent theoretical work and are compared with the previously used single-pulse excitation data. An improvement factor of 2.9 in the statistical uncertainty is achieved. Furthermore the mass of 76Se, included in the previous Q-value measurement of the 76Ge neutrinoless double beta decay, is checked using 76Se25+ ions and a three-pulse Ramsey excitation. The results show a convincing agreement with the measurement when using single-pulse excitation and therefore our Q-value of 2039.006(50) keV, performed with single-pulse excitation, is confirmed.

  • 63.
    Tauscher, L.
    et al.
    Institute for Physics, University of Basle.
    Backenstoss, G.
    Institute for Physics, University of Basle.
    Hasinoff, M.
    Institute for Physics, University of Basle.
    Pavlopoulos, P.
    Institute for Physics, University of Basle.
    Repond, J.
    Institute for Physics, University of Basle.
    Tröster, D.
    Institute for Physics, University of Basle.
    Blüm, P.
    Kernforschungszentrum, Universität Karlsruche.
    Glöckner, M.
    Kernforschungszentrum, Universität Karlsruche.
    Guigas, R.
    Kernforschungszentrum, Universität Karlsruche.
    Koch, H.
    Kernforschungszentrum, Universität Karlsruche.
    Köhler, T
    Meyer, M.
    Kernforschungszentrum, Universität Karlsruche.
    Poth, H.
    Kernforschungszentrum, Universität Karlsruche.
    Raich, U.
    Kernforschungszentrum, Universität Karlsruche.
    Richter, B.
    Kernforschungszentrum, Universität Karlsruche.
    Adiels, Lars
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum, Manne Siegbahn-laboratoriet.
    Bergström, I.
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum, Manne Siegbahn-laboratoriet.
    Fransson, Kjell
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum, Manne Siegbahn-laboratoriet.
    Kerek, A.
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum, Manne Siegbahn-laboratoriet.
    Suffert, M.
    Centre de recherches nucléaries and Université Louis Pasteur, Strabourg.
    Zioutas, K.
    Dept. of Nuclear Physics, Univerity of Tessaloniki.
    $øverlinep$p annihilations at rest into two neutral mesons1983Ingår i: Ann. Fí­s., A, Vol. 79, s. 24-28Artikel i tidskrift (Refereegranskat)
  • 64.
    Vigren, Erik
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    Hamberg, Mathias
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    Zhaunerchyk, Vitali
    Kaminska, Magdalena
    Thomas, Richard D.
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    Trippel, Sebastian
    Wester, Roland
    Zhang, Mingwu
    Kashperka, Iryna
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    af Ugglas, Magnus
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum, Manne Siegbahn-laboratoriet.
    Semaniak, Jacek
    Larsson, Mats
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    Geppert, Wolf D.
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    Dissociative Recombination of Protonated Propionitrile, CH3CH2CNH+: Implications for Titan's Upper Atmosphere2010Ingår i: Astrophysical Journal, ISSN 0004-637X, E-ISSN 1538-4357, Vol. 722, nr 1, s. 847-850Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The dissociative recombination of protonated propionitrile, CH3CH2CNH+, has been investigated at the heavy ion storage ring, CRYRING, at the Manne Siegbahn Laboratory, Stockholm University, Sweden. The thermal rate coefficient has been deduced to follow k(T) = (1.5 ± 0.2) × 10–6 (T/300)–0.76 ± 0.02 cm3 s–1 for electron temperatures ranging from ~10 to ~1000 K. Measurements of the branching fractions were performed at ~0 eV relative kinetic energy. It has been found that in 43% ± 2% of the reactions the four heavy atoms remain in the same product fragment. An equal portion of the reactions leads to products where one of the heavy atoms is split off from the other three and 14% ± 1% result in a breakup into two heavy fragments containing two heavy atoms each. We discuss the significance of the data to Titan's upper atmosphere.

  • 65. Xiao, J.
    et al.
    Fei, Z.
    Yang, Y.
    Jin, X.
    Lu, D.
    Shen, Y.
    Liljeby, Leif
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum, Manne Siegbahn-laboratoriet.
    Hutton, R.
    Zou, Y.
    A very low energy compact electron beam ion trap for spectroscopic research in Shanghai2012Ingår i: Review of Scientific Instruments, ISSN 0034-6748, E-ISSN 1089-7623, Vol. 83, nr 1, s. 013303-Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In this paper, a new compact low energy electron beam ion trap, SH-PermEBIT, is reported. This electron beam ion trap (EBIT) can operate in the electron energy range of 60-5000 eV, with a current density of up to 100 A/cm(2). The low energy limit of this machine sets the record among the reported works so far. The magnetic field in the central drift tube region of this EBIT is around 0.5 T, produced by permanent magnets and soft iron. The design of this EBIT allows adjustment of the electron gun's axial position in the fringe field of the central magnetic field. This turned out to be very important for optimizing the magnetic field in the region of the electron gun and particularly important for low electron beam energy operation, since the magnetic field strength is not tunable with permanent magnets. In this work, transmission of the electron beam as well as the upper limit of the electron beam width under several conditions are measured. Spectral results from test operation of this EBIT at the electron energies of 60, 315, 2800, and 4100 eV are also reported.

  • 66. Xiao, J.
    et al.
    Fei, Z.
    Yang, Y.
    Jin, X.
    Lu, D.
    Shen, Y.
    Liljeby, Leif
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum, Manne Siegbahn-laboratoriet.
    Hutton, R.
    Zou, Y.
    Progress of the permanent magnetic electron beam ion trap in Shanghai2011Ingår i: Physica Scripta, ISSN 0031-8949, E-ISSN 1402-4896, Vol. T144, s. 014061-Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In this paper, a brief description of the progress of the Shanghai permanent magnetic electron beam ion trap is presented. Some test results regarding the electron beam current versus beam energy are presented. The electron beam width was measured and compared with our simulations, and good agreement was found.

  • 67.
    Zhaunerchyk, Vitali
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    Hellberg, Fredrik
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    Thomas, Richard D.
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    Ehlerding, Anneli
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    Geppert, Wolf D.
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    Larsson, Mats
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    Vane, C. Randy
    Bannister, Mark E.
    Bahati, Eric M.
    Österdahl, Fabian
    af Ugglas, Magnus
    Stockholms universitet, Naturvetenskapliga fakulteten, Manne Siegbahn-laboratoriet.
    Dissociative recombination study of PD2+ at CRYRING: absolute cross section, chemical branching ratios and three-body fragmentation dynamics2005Ingår i: Molecular Physics, ISSN 0026-8976, E-ISSN 1362-3028, Molecular Physics, ISSN 0026-8976, Vol. 103, nr 20, s. 2735-2745Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The paper reports an investigation of the dissociative recombination of   at the heavy-ion storage ring CRYRING. The absolute cross-section has been measured as a function of centre-of-mass energy ranging from 1 meV to 0.1 eV. The experiment performed has shown the dissociative recombination of   to be dominated by three-body break-up, with a branching ratio of about 78%. Competition between the available three-body channels producing the ground state, P(4S), and the first two excited states, P(2D) and P(2P), is observed. The formation of the first excited state dominates over the other two almost equally probable channels with about 75% of all three-body events. The results indicate that the kinetic energy released in the three-body break-up of   is randomly shared between the deuterium atoms. The intra-molecular angle on dissociation has also been investigated. A comparative analysis of the dissociative recombination dynamics for the two isovalent systems,   and  , is undertaken.

  • 68. Zhu, Xiaofeng
    et al.
    Liljeby, Leif
    Stockholms universitet, Naturvetenskapliga fakulteten, Manne Siegbahn-laboratoriet.
    et al.,
    Status of the Shanghai EBIT2005Ingår i: Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, Vol. 266, nr 1, s. 509-513Artikel i tidskrift (Refereegranskat)
  • 69. Öjekull, J
    et al.
    Andersson, P.U
    Någård, M.B
    Pettersson, J.B.C
    Neau, A
    Rosén, S
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    Thomas, R.D
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    Larsson, M
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    Semaniak, J
    Österdahl, F
    Danared, Håkan
    Manne Siegbahn-laboratoriet.
    Källberg, Anders
    Manne Siegbahn-laboratoriet.
    af Ugglas., M
    Dissociative recombination of ammonia clusters studied by storage ring experiments2006Ingår i: The journal of chemical physics, Vol. 125, s. 194306-Artikel i tidskrift (Refereegranskat)
  • 70. Öjekull, Jenny
    et al.
    Andersson, Patrik U
    Någård, Mats B
    Pettersson, Jan B C
    Markovic, Nicola
    Derkatch, Alik M
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    Neau, Anita
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    Al-Khalili, Ahmed
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    Rosén, Stefan
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    Larsson, Mats
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    Semaniak, Jacec
    Danared, Håkan
    Manne Siegbahn-laboratoriet.
    Källberg, Anders
    Manne Siegbahn-laboratoriet.
    Österdahl, Fabian
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    af Ugglas, Magnus
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    Dissociative recombination of H+(H2O)3 and D+(D2O)3 water cluster ions with electrons: cross sections and branching ratios,2007Ingår i: Journal of Chemical Physics, Vol. 127, nr 194301Artikel i tidskrift (Refereegranskat)
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