Patent ID: 6998605

Claim:
An apparatus for delivering ions to a vacuum chamber comprising: an enclosing ionization chamber including an ionization region and a vacuum interface at a vacuum interface voltage, wherein the vacuum interface allows the ionization chamber to communicate with the vacuum chamber; first, second, and third electric field regions in the ionization chamber for transporting the ions through first, second, and third electric field regions and into the vacuum chamber; an electrospray assembly at approximately ground potential having a dispensing end disposed within the ionization chamber; a first electrode disposed sufficiently close to the dispensing end at a first electrode voltage of sufficiently high magnitude to form ions in the ionization region and to attract the ions from the ionization region; a second electrode disposed in the ionization chamber at a second electrode voltage that repels the ion to a greater degree than the first electrode voltage; and means for generating a gaseous stream in a gas flow path extending from the first electrode to the second electrode, wherein the gaseous stream provides the ion with sufficient velocity to overcome repulsion by the second electrode, wherein the vacuum interface voltage is more attractive to the ion than the second electrode voltage.