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Guiding of highly charged ions through insulating nanocapillaries
Stockholm University, Faculty of Science, Department of Physics. (Atomic physics)
2010 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

This thesis contains experimental work on guiding of highly charged ions through insulating nanocapillaries. We have studied the time evolution of angular distributions of transmitted ions under well defined initial conditions: already charged, as well as fully discharged nanocapillaries, by using a two-dimensional position sensitive Micro Channel Plate detector with a data acquisition system working in event mode. Time-dependent features in the ion-guiding properties have been found. For the initially discharged capillaries, a shift and broadening of transmitted angular distribution have been observed in the charge-up process. This is interpreted by the formation of charged patches downstream of the entrance patch. We have, with the help of a model calculation, quantitatively derived distinct charge patterns, resulting in the time evolution of the transmitted angular distributions. We show that all charge patches are maintained in the stationary state of transmission by the followed discharging and recharging measurements. For already charged nanocapillaries, a double peak structure in the angular distribution has been found, which is attributed to a memory effect and the re-arrangement of charge patches. When the tilt angle of the capillaries is changed, the existing charge patches from the previous tilt angle can affect the ion trajectories and the formation of new patches.

The preliminary results of highly charged ions transmitted through muscovite mica capillaries of rhombic cross section are also presented in this thesis. We have shown the transmission profiles for various orientations of the rhombi. A rectangular shape of the transmission profile has been found. We have performed a simulation by considering the image force from the four sides of the rhombus. To our surprise, this effect gives an angular distribution that agrees well with the transmission profile obtained by the experiment.

Place, publisher, year, edition, pages
Stockholm: Department of Physics, Stockholm University , 2010. , 64 p.
National Category
Physical Sciences Atom and Molecular Physics and Optics
Research subject
Physics
Identifiers
URN: urn:nbn:se:su:diva-42181ISBN: 978-91-7447-132-8 (print)OAI: oai:DiVA.org:su-42181DiVA: diva2:344266
Public defence
2010-09-20, FA32, AlbaNova universitetscentrum, Roslagstullsbacken 21, Stockholm, 13:00 (English)
Opponent
Supervisors
Note
At the time of the doctoral defense, the following papers were unpublished and had a status as follows: Paper 1: Submitted.Available from: 2010-08-30 Created: 2010-08-18 Last updated: 2010-08-20Bibliographically approved
List of papers
1. Dynamics of Guiding Highly Charged Ions through SiO2 Nanocapillaries
Open this publication in new window or tab >>Dynamics of Guiding Highly Charged Ions through SiO2 Nanocapillaries
2010 (English)In: Physical Review A. Atomic, Molecular, and Optical Physics, ISSN 1050-2947, E-ISSN 1094-1622, Vol. 82, no 052901Article in journal (Refereed) Published
Abstract [en]

Time evolution of angular distributions of transmitted ions through SiO2 nanocapillaries wasmeasured under defined initial conditions: already charged, as well as fully dischargedcapillaries. We find distinct charge patterns and describe them quantitatively with the help of amodel calculation. This results in a pattern of a few number of charge patches, guiding ions inthe stationary state of transmission. For the already charged capillary membrane, we show a“memory effect” in the form of a double peak structure in the transmitted angulardistributions. The time evolution of these structures reflects charge relaxation andrearrangement of the charge patches. The re-arrangement of the charge patches is much fasterthan the discharge, suggesting that the charge relaxation inside the capillaries can be drivenby the incident charges, such as a Frenkel-Poole process.

National Category
Physical Sciences Atom and Molecular Physics and Optics
Research subject
Physics
Identifiers
urn:nbn:se:su:diva-42180 (URN)10.1103/PhysRevA.82.052901 (DOI)000283838000005 ()
Available from: 2010-08-18 Created: 2010-08-18 Last updated: 2017-12-12Bibliographically approved
2. Guiding of slow highly charged ions through insulating nano-capillaries
Open this publication in new window or tab >>Guiding of slow highly charged ions through insulating nano-capillaries
2009 (English)In: Journal of Physics, Conference Series, ISSN 1742-6588, E-ISSN 1742-6596, Vol. 163, no 1Article in journal (Refereed) Published
Abstract [en]

The guiding of highly charged ions through SiO2 nano-capillaries has been investigated by our group, using 7 keV Ne7+-ions. We studied in particular the transmission of ions incident at angles greater than the angle given by the capillary aspect ratio as a function of charge incident on the capillary membrane. In this report we show the re-arrangement of charge patches inside the capillary by observing the evolution of the two-dimensional angular distributions of the transmitted ions.

National Category
Physical Sciences Atom and Molecular Physics and Optics
Research subject
Physics
Identifiers
urn:nbn:se:su:diva-42179 (URN)10.1088/1742-6596/163/1/012092 (DOI)
Available from: 2010-08-18 Created: 2010-08-18 Last updated: 2017-12-12Bibliographically approved
3. Evidence of Sequentially Formed Charge Patches Guiding Ions through Nanocapillaries
Open this publication in new window or tab >>Evidence of Sequentially Formed Charge Patches Guiding Ions through Nanocapillaries
2008 (English)In: Physical Review Letters, ISSN 0031-9007, E-ISSN 1079-7114, Vol. 101, no 22, 223202- p.Article in journal (Refereed) Published
Abstract [en]

We investigated the time evolution of the dynamically shifting distribution of 7 keV Ne7+ ions guided through nanocapillaries in SiO2. We present evidence for a small number of charge patches, formed sequentially in the charging-up process, guiding the ions. We show that the charge patches are distributed along the whole length of the capillaries and that they are maintained in the equilibrium state of transmission. The interpretations are supported by model calculations.

National Category
Physical Sciences Atom and Molecular Physics and Optics
Research subject
Physics
Identifiers
urn:nbn:se:su:diva-42175 (URN)10.1103/PhysRevLett.101.223202 (DOI)000261214400020 ()
Available from: 2010-08-18 Created: 2010-08-18 Last updated: 2017-12-12Bibliographically approved
4. Guiding of highly charged ions through insulating nanocapillaries
Open this publication in new window or tab >>Guiding of highly charged ions through insulating nanocapillaries
Show others...
2008 (English)In: Canadian journal of physics (Print), ISSN 0008-4204, E-ISSN 1208-6045, Vol. 86, no 1, 327-330 p.Article in journal (Refereed) Published
Abstract [en]

The guiding of highly charged ions through nanocapillaries in different insulating materials, such as polyethylene terephthalate, SiO<sub>2</sub>, and Al<sub>2</sub>O<sub>3</sub> has been investigated by our group, using 7 keV Ne<sup>7+</sup> ions. We find transmission of ions incident at angles larger than the angle given by the capillary aspect ratio in all these materials. The measured angular distributions, however, vary with the membrane material. In this report we compare the experimental findings with the different membranes.

Keyword
ions, insulating materials, polyethylene terephthalate, angular distribution (nuclear physics), electrons, nuclear reactions, electric insulators & insulation
National Category
Physical Sciences Atom and Molecular Physics and Optics
Research subject
Physics
Identifiers
urn:nbn:se:su:diva-42264 (URN)10.1139/P07-169 (DOI)000253774700034 ()
Available from: 2010-08-20 Created: 2010-08-20 Last updated: 2017-12-12Bibliographically approved

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