An ion lens is used to focus ions produced by various types of ion sources
which are substantially at atmospheric pressure. The ions are focused to
the inlet of a downstream mass spectrometer or other devices which
require a larger and more stable ion flux improved performance. The ion
lens is mounted in close proximity to the sprayer tip. The ion lens
increases the total ion count rate summed over all of the generated ions.
The ion lens may also be employed to vary the degree of ion fragmentation
and the charge state pattern of the generated ions. The ion lens may also
result in a more stable ion signal. Furthermore, more than one ion lens
may be used. This invention may also be extended to multisprayer ion
sources.