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US 6,271,527 B1Granted
High-efficiency electron ionizer for a mass spectrometer array
AssigneeCalifornia Institute of Technology
InventorsAra Chutjian, Murray R. Darrach, Otto J. Orient
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Abstract
The present invention provides an improved electron ionizer for use in a quadrupole mass spectrometer. The improved electron ionizer includes a repeller plate that ejects sample atoms or molecules, an ionizer chamber, a cathode that emits an electron beam into the ionizer chamber, an exit opening for excess electrons to escape, at least one shim plate to collimate said electron beam, extraction apertures, and a plurality of lens elements for focusing the extracted ions onto entrance apertures.
Claims4
A method for ionizing sample molecules in a mass spectrometer, comprising:
- emitting an electron beam into an ionizer chamber;
- collimating the electron beam near extraction apertures;
- repelling said sample molecules toward said extraction apertures, where the electron beam intercepts said sample molecules and ionizes the sample molecules into ions;
- providing a plurality of lens elements to focus extracted ions into said extraction apertures;
- and
- detecting said ions.
3 more elements
Dependencies are inferred from the claim text.