Thesis Defence
Adrien Poindron
Aix-Marseille University
Detection of a giant molecule with a trapped ion cloud
Supervisors: Martnina Knoop and Jofre Pedregosa-Gutierrez
Jury composition:
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Rodolphe ANTOINE, Research Professor, Institut Lumière Matière, Examiner
Laurence CHARLES, Professor, Aix Marseille université, Examiner
Laurent HILICO, Professor, Laboratoire Kastler Brosse, Reviewer
Stefan WILLITSCH, Professor, Université de Bâle, Reviewer
Martina KNOOP, Research Professor, Aix Marseille Université, Thesis Director
Jofre PEDREGOSA-GUTIERREZ, assistant professor, Aix-Marseille université, Thesis supervisor
Keywords: Laser spectroscopy,Mass spectrometry,Trapped ions,Giant Molecules
Abstract : A new application for a laser-cooled trapped ion ensemble is proposed for the non-destructive detection of giant molecules. In this application a molecular ion is projected onto an ensemble of calcium+ ions. The detection signal is expected in the fluorescence of the ion set which may vary after the perturbation induced by the molecule. In parallel with the development of a prototype, we demonstrate the feasibility of the principle through numerical simulations. The thesis is organised in three parts: the first part presents the experimental aspects specific to the ion trapping, the second part deals with the experimental aspects specific to the molecular source and the guidance of a charged particle, the third part presents the numerical simulations conducted in order to numerically reproduce the interaction. With the simulations, we highlight the key roles of the coulombic interaction combined with radio-frequency heating in the cloud destabilisation mechanism leading to detection. The conditions favouring detection are studied, as well as certain aspects of ion trapping alone. The essential elements of the prototype are presented and discussed in the first parts. A description of the trapping of an ion set beyond the adiabatic regime is proposed. The essential characteristics of the large ion sets are presented. In particular, radio-frequency heating is discussed. At the molecular level, all the techniques used to deliver a molecular ion are described, taking into account the recent elements that appeared after the development of the prototype. A particular effort has been made to provide the elements necessary for the understanding and proper implementation of the molecular source elements. A detection of light ions by conventional means is implemented and discussed.
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