Image Number 2 for United States Patent #5756995.
A heated capillary tube is axially supported in center of a housing under cuum. One end of the capillary tube receives ions from an ion source. The other end of the capillary tube terminates adjacent to the inner side of a flat plate having an orifice. A transport tube is connected to the outer side of the flat plate and has an open outer end. A first electrical field exists between the capillary tube and the plate to control the flow of ions. A second electrical field exists downstream of the plate, and the tube is disposed within the second electrical field. The transport tube allows for more efficient focusing of ions by the electrical and aerodynamic means to the mass spectrometer. A mechanical valve may be coupled to the capillary tube to independently control the flow of ions and the entire probe may be removed without compromising the vacuum in the mass spectrometer.