Guiding of highly charged ions through insulating nanocapillaries
2010 (English)Doctoral thesis, comprehensive summary (Other academic)
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.
Physical Sciences Atom and Molecular Physics and Optics
Research subject Physics
IdentifiersURN: urn:nbn:se:su:diva-42181ISBN: 978-91-7447-132-8OAI: oai:DiVA.org:su-42181DiVA: diva2:344266
2010-09-20, FA32, AlbaNova universitetscentrum, Roslagstullsbacken 21, Stockholm, 13:00 (English)
Cassimi, Amine, Professor
Schuch, Reinhold, Professor
At the time of the doctoral defense, the following papers were unpublished and had a status as follows: Paper 1: Submitted.2010-08-302010-08-182010-08-20Bibliographically approved
List of papers