Patent ID: 6784424
Filing Date: 2004-08-31
Classification: H01J

Abstract:
Apparatus for the focusing and selecting of gas-phase ions and/or particles at or near atmospheric pressure, the apparatus comprising:a. a dispersive source of ions; b. a means for providing a concentric flow of gas; c. a first conductive high-transmission element composed of a surface populated with a plurality of holes and an entrance lens so that said gas and substantially all said ions pass unobstructed through into an multi-element assembly, the said surface and entrance lens being supplied with an attracting electric potential by connection to a high voltage supply, and generating an electrostatic field between said source of ions and top side of said surface; d. a multi-element assembly for receiving and transmitting gas and focused ions along the z-axis, the said multi-element assembly being supplied with both RF and DC electric potentials by connection to a quadrupole controller so that said multi-element assembly may act as a mass filter for said ions and generating an electrostatic field between backside of said entrance lens and multi-element assembly; e. a second conductive high-transmission element composed of a second surface populated with a plurality of holes and an exit lens so that substantially all said ions exiting said multi-element assembly pass unobstructed through said second element toward a small cross-sectional area on an ion detector, while said gas passes unobstructed pass ion detector and exits out gas exhaust, the said second surface and exit lens being supplied with an attracting electric potential by connection to a high voltage supply, and generating an electrostatic field between said multi-element assembly and top side of said second surface; f. an ion detector for detecting substantially all said ions passing through said exit lens, whereby to provide detection of ions separated at or near atmospheric pressure through said mass filter.