Properties of Ion Beams Formed by a Gridless Two-Electrode Ion Shutter of an Ion Mobility Spectrometer at Atmospheric Pressure. I. Continuous Ion Beam

The properties of the ion flow have been experimentally determined depending on the parameters of a gridless two-electrode ion shutter and the conditions of ion transport in the drift tube. The transverse structure of the ion flow in the plane of the collector is investigated using a collector consisting of concentric rings. The resulting ion current distributions have a radial structure that varies depending on experimental conditions. Theoretical estimates are given to take into account the degree of influence of the space charge on the transverse dimensions of the ion beam in the drift field. The agreement of experimental and theoretical results allows one to conclude that the observed phenomena are caused by a space charge.