Patent ID: 8502162

Claim:
An atmospheric pressure ionization apparatus, comprising: a housing comprising a chamber; an ion inlet structure comprising a sampling orifice coaxial with a sampling axis and communicating with the chamber; an electrode spaced from the ion inlet structure, wherein an ionization region is defined between the ion inlet structure and the electrode, the electrode comprising an electrode bore formed through the electrode between two openings into the chamber, wherein the electrode bore has two ends that both open into the chamber, and at least one of the two ends faces the ionization region; a flared structure coaxially disposed about the ion inlet structure and extending along an outward direction that includes a radial component relative to the sampling axis; a sample emitter disposed in the chamber and oriented at an angle to the sampling axis for directing a sample stream toward the ionization region; and a gas passage configured for directing a stream of gas from a gas source to the chamber, wherein the flared structure forms a portion of the gas passage, the portion extending annularly about the sampling axis and along the outward direction, and the gas flows through the portion, around the flared structure, and through the electrode bore toward the ionization region.