Transport of ions through tubes in a stream of flowing gas

Abstract

The theoretical analysis and experimental investigations of phenomena connected with the transport of ions in regions devoid of external electric field were performed. The movement of ions in such regions is caused by gas flow. Due to diffusion, recombination and mutual repulsion the concentration of transported ions in the space outside the ionization source drops. The influence of these phenomena was analyzed using simplified ions balance equations taking into account a specific mechanisms of ion losses. A full system of balance equations describing a combined effect of diffusion, recombination and repulsion was also solved. The results of theoretical considerations were confirmed experimentally by measuring currents, for which the charge carriers were ions transported through metal tubes. The measurements were performed for the case when the ions of both polarities were present in the gas as well as for swarms consisting of positive ions only. The possibility of ion transport between parts of the measurement system connected to different potentials was also investigated. The method used for this purpose involved the application of the metal tubes connected to variable potential as an intermediate element.