Patent ID: 6924479
Filing Date: 2005-08-02
Classification: H01J

Abstract:
1. A method for collecting and releasing ions from an ion barrier mobility spectrometer apparatus, wherein the apparatus comprises: a) a first source shield electrode; b) a second source electrode downstream from said source shield electrode; c) said source electrode and said source shield electrode operating at similar voltages; d) a third collection well electrode downstream from said source electrode; e) a fourth electrode downstream from said third electrode; f) a fifth trigger well electrode downstream from said fourth electrode; g) a plurality of electrodes downstream from said fifth electrode, said plurality of electrodes together comprising a means for creating a decreasing voltage gradient; h) a detector downstream from said plurality of electrodes; and i) means for shielding said detector; and the method comprises: a) first providing a voltage at said third electrode lower than voltages at said second and fourth electrodes; and b) secondly increasing said voltages at said third and fourth electrodes above a voltage at said fifth electrode until the voltage generated across said fifth electrode forms a nearly vertical ion barrier.