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First storage of ion beams in the Double Electrostatic Ion-Ring Experiment: DESIREE
Stockholm University, Faculty of Science, Department of Physics.
Stockholm University, Faculty of Science, Department of Physics.
Stockholm University, Faculty of Science, Department of Physics.
Stockholm University, Faculty of Science, Department of Physics.
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2013 (English)In: Review of Scientific Instruments, ISSN 0034-6748, E-ISSN 1089-7623, Vol. 84, no 5, 055115- p.Article in journal (Refereed) Published
Abstract [en]

We report on the first storage of ion beams in the Double ElectroStatic Ion Ring ExpEriment, DESIREE, at Stockholm University. We have produced beams of atomic carbon anions and small carbon anion molecules (C-n(-), n = 1, 2, 3, 4) in a sputter ion source. The ion beams were accelerated to 10 keV kinetic energy and stored in an electrostatic ion storage ring enclosed in a vacuum chamber at 13 K. For 10 keV C-2(-) molecular anions we measure the residual-gas limited beam storage lifetime to be 448 s +/- 18 s with two independent detector systems. Using the measured storage lifetimes we estimate that the residual gas pressure is in the 10(-14) mbar range. When high current ion beams are injected, the number of stored particles does not follow a single exponential decay law as would be expected for stored particles lost solely due to electron detachment in collision with the residual-gas. Instead, we observe a faster initial decay rate, which we ascribe to the effect of the space charge of the ion beam on the storage capacity.

Place, publisher, year, edition, pages
2013. Vol. 84, no 5, 055115- p.
National Category
Accelerator Physics and Instrumentation
Research subject
Physics
Identifiers
URN: urn:nbn:se:su:diva-92036DOI: 10.1063/1.4807702ISI: 000319999300073OAI: oai:DiVA.org:su-92036DiVA: diva2:637133
Funder
Swedish Research Council, 2011-6314, 2011-4047, 2012-3662Knut and Alice Wallenberg Foundation
Note

AuthorCount:34;

Available from: 2013-07-16 Created: 2013-07-15 Last updated: 2017-12-06Bibliographically approved
In thesis
1. Collision Induced Fragmentation of Molecules and Molecular Clusters: Knockout Driven Reactions in Fullerenes and PAHs
Open this publication in new window or tab >>Collision Induced Fragmentation of Molecules and Molecular Clusters: Knockout Driven Reactions in Fullerenes and PAHs
2014 (English)Licentiate thesis, comprehensive summary (Other academic)
Abstract [en]

This licentiate thesis covers experimental and theoretical studies of the fragmentation and sub- sequent reactions of fullerenes or Polycyclic Aromatic Hydrocarbons (PAHs). I present results from experiments where atoms or ions collide with fullerenes, PAHs, or clusters of these mole- cules at energies from 100 eV up to tens of keV.

The results of these experiments are interpreted using quantum chemical calculations, mol- ecular dynamics simulations, and a stopping model that we have developed. With these models I show that different energy transfer processes dominate at different collision energies, from nuclear stopping in low energy (~ 100 eV) collisions to electronic stopping at higher energies (~ 10 keV). I particularly focus on non-statistical fragmentation induced by nuclear stopping which can lead to the formation of exotic new species such as the odd-numbered C119 fullerene- like molecule. 

Place, publisher, year, edition, pages
Stockholm University, 2014
National Category
Atom and Molecular Physics and Optics
Research subject
Physics
Identifiers
urn:nbn:se:su:diva-103501 (URN)
Presentation
2014-06-13, FB53, Roslagstullbacken 21, Stockholm, 14:00 (English)
Opponent
Supervisors
Available from: 2014-07-01 Created: 2014-05-20 Last updated: 2014-07-01Bibliographically approved
2. Time-Resolved Spectroscopy and Intensity Measurements of Singly Charged Ions
Open this publication in new window or tab >>Time-Resolved Spectroscopy and Intensity Measurements of Singly Charged Ions
2015 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

This thesis is mainly concerned with investigations of spontaneous radiatively decaying states in both negative and positive singly charged ions. When possible, the measured lifetime of the state has been combined with branching fractions in order to derive the absolute transition probability (A-value) between different quantum states. The radiative transition probability between two quantum states is a fundamental atomic property. Knowledge of this property can be used as a diagnostic tool in, for example, abundance and temperature determinations with applications in many fields, e.g. astronomy, plasma physics, atomic physics etc.

The focus of the experiments has been on lifetime measurements of long-lived metastable states. Lifetimes of long-lived metastable states are interesting in both theoretical aspects as well as the challenge it poses to the experimentalist. To perform such experiments, impact from the surrounding environment on the stored ions has to be kept to a minimum for extended periods of time. The metastable lifetimes presented here have been measured with time-resolved laser spectroscopic techniques in two different types of ion storage rings. One of them is a new type of unique cryogenically cooled storage ring made of purely electrostatic ion optical elements. As is demonstrated in this thesis, this device opens up a completely new time domain where lifetime measurements now can be performed. In addition, this thesis includes a discussion and preliminary studies of weak interactions otherwise limited by magnetic fields and/or thermal radiation from the environment. When available, the results have been compared to previous measurements and theoretical calculations which enables an evaluation of different methods and theoretical models.

Place, publisher, year, edition, pages
Stockholm: Department of Physics, Stockholm University, 2015. 88 p.
National Category
Atom and Molecular Physics and Optics
Research subject
Physics
Identifiers
urn:nbn:se:su:diva-113503 (URN)978-91-7649-100-3 (ISBN)
Public defence
2015-03-20, sal FB42, AlbaNova universitetscentrum, Roslagstullsbacken 21, Stockholm, 13:00 (English)
Opponent
Supervisors
Note

At the time of the doctoral defense, the following paper was unpublished and had a status as follows: Paper 6: Accepted.

Available from: 2015-02-26 Created: 2015-02-03 Last updated: 2015-02-26Bibliographically approved

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Schmidt, Henning T.Thomas, Richard D.Gatchell, MichaelRosén, StefanReinhed, PeterLöfgren, PatrikBrännholm, LarsBlom, MikaelBjörkhage, MikaelBäckström, ErikAlexander, John D.Leontein, SvenZettergren, HenningLiljeby, LeifKällberg, AndersSimonsson, AnsgarHellberg, FredrikMannervik, SvenLarsson, MatsGeppert, Wolf D.Rensfelt, Karl-GunnarDanared, HåkanMasuda, MasaharuHallden, PerAndler, GuillermoStockett, Mark H.Chen, TaoKällersjö, GunnarWeimer, JanCederquist, Henrik
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