Patent ID: 6452167
Filing Date: 2002-09-17
Classification: H01J

Abstract:
An improved multipole mass spectrometer, comprising:a low voltage field emission array comprising a plurality of emission tips, wherein each of said emission tips is surrounded by an emission gate; a means for applying an electrical potential difference between said plurality of emission tips and said emission gates, said potential difference sufficient to initiate quantum tunneling at said emission tips thereby generating a flux of electrons; an acceleration tube for directing said electrons into an ionization cage, said ionization cage in communication with said field emission array, said acceleration tube held at a potential sufficient to prevent electrons emitted from said tips from shorting to said gates; a first drift region comprising said ionization cage, said field emission array and said acceleration tube; a means for introducing molecules of an analyte material sample into said ionization cage, wherein at least some of said molecules are ionized by said electrons in said ionization cage to provide one or more analyte ions of said analyte molecule; an ion focus electrode for directing and focusing said analyte ions into a multipole mass filter; an ion detector in communication with said ionization cage and said mass filter; and a second drift region comprising said ionization cage, said ion focus electrode, and said mass filter, wherein said first and said second drift regions share a common atmosphere.