Patent ID: 8471199

Claim:
A portable mass spectrometer with an atmospheric pressure interface for introducing ions generated at ambient pressure gas conditions into a vacuum of the mass spectrometer, comprising: a vacuum chamber having at least one vacuum section; at least one gas inlet for directing the ambient pressure gas including said ions into said at least one vacuum section, said at least one gas inlet having a gas passage channel of a length L and a limiting cross section S with a ratio of L/S being less than 20,000 cm −1 ; a radio frequency (RF) ion guide in a said at least one vacuum section positioned for collecting said ions from said at least one gas inlet and transmitting the ions further to a mass analyzer; and one or more turbomolecular pumps in gas communication with said at least one vacuum section, said one or more turbomolecular pumps pumping out a majority of the gas directed into said at least one vacuum section by said at least one gas inlet.