Photoelectron source for use in a gas chromatograph detector and mass spectrometer ion source
OwnerRobert A. Younginventor
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Abstract
An ionization source is disclosed for use with mass spectrometers and electron capture species detectors having an ionization light source excited so as to illuminate a fluid sample which flows past the light source whereby electrons are photoelectrically generated by a light source. Means are also provided to accelerate the photoelectrons and to extract heavy ions generated by the accelerated photoelectrons from the fluid sample. Further means are provided to focus the extracted heavy ions so that they may be detected. Also included is a means to maintain a vacuum between the light source and the sample and the detector.
Claims32
An ionization source for a mass spectrometer comprising
- a substantially cylindrical lamp;
- an RF oscillator coil adjacent the outer wall of said lamp;
- a passageway through said lamp;
- a substantially cylindrical window in the wall of said passageway, said window being transparent to VUV ionizing radiation;
- a substantially circular electron acceleration grid in said passageway having a length substantially the same as said window;
- a substantially cylindrical high work function photocathode between said window and said grid, said acceleration grid being at a positive potential relative to said photocathode;
- a gas filling between the wall of said lamp and said wall of said passageway for generating optical photons when said RF oscillator is energized;
- means for passing a sample gas through said passageway, whereby said photons passing through said window illuminate said photocathode to cause ejection of electrons into said passageway, said electrons ionizing said sample gas by electron impact after being accelerated by said grid;
- and
- means for focusing said ions into said mass spectrometer.
The ionization source of claim wherein the wall of said lamp is of a bellows configuration.
An ionization source for mass spectrometers comprising an ionization light source;
- means to power and excite said ionization light source;
- means to connect said excitation means to said light source;
- means to inject a fluid sample past said ionization light source;
- means to photoelectrically generate electrons by said ionization light source;
- means to accelerate said photoelectrons;
- means to extract heavy ions generated by said accelerated photoelectrons from said fluid sample;
- and
- means to focus the extracted heavy ions into a mass spectrometer.
Dependencies are inferred from the claim text.