Ion guiding, filtering and trapping with a single quadrupole device

This master thesis investigates the characterisation of a quadrupole device in order to include it in an experiment dedicated to the study of the [(CO2)m-(H2O)n]+ ionic clusters using high-resolution rovibrational spectroscopy. The interest of a quadrupolar element is triple: it can be used as an ion guide, as a mass filter or as an ion trapping system. In this work, it is shown that the same quadrupole device can be used in those three different purposes. This master thesis focuses mainly on the development of numerical simulations about the quadrupole. The quadrupole which will be used in the laboratory is noted quadrupole A in this work, and its performances are compared with two other systems, noted quadrupole B and quadrupole C. The quadrupole B is a newly designed quadrupole with round rods reproducing a hyperbolic field shape and the quadrupole C is designed with hyperbolic rods, allowing one to use the formalism of the Mathieu equation. The stability triangle of each system is derived. It is shown, through numerical simulations performed in SIMION and with a self-made Python script, that the quadrupole A can act as an ion guide, as a mass filter and as an ion trapping system. The Python script has been extended, allowing one to simulate ion trajectories in a multipolar system of any order. Those developments are particularly interesting to design future traps in the laboratory. Then, the current experimental setup is briefly presented, followed by a possible design for the future experiment including the quadrupole. With that new experimental setup, the required conditions to perform continuous excitation are discussed. Finally, the design of a miniaturised quadrupole is proposed, opening opportunities for the study of larger molecules.