Ion optical properties of a co-axial Wien filter

Abstract

A new kind of charge/mass separator is described. The separator is based on two co-axial conductors, with the central conductor carrying a large current and the outer conductor DC-biased. The separator has the characteristic properties of a Wien filter. Paraxial trajectory equations appropriate for low-energy heavy-ion beams are obtained and the charge/mass separation behaviour of the filter is derived. The separation behaviour of a purely magnetic co-axial separator is also described as a special case. The filter may be suitable for charge state separation of pulsed hollow beams.