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US 2008/0073530 A1Published application
Method and apparatus for detecting positively charged and negatively charged ionized particles
AssigneeIonics Mass Spectrometry Group Inc.
InventorsCharles Jolliffe, Lisa Cousins, Gholamreza Javahery
Life of this patent
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Abstract
An ion detector includes collision surfaces for converting both positively and negatively charged ions into emitted secondary electrons. Secondary electrons may be detected using an electron detector, than may, for example include an electron multiplier. Conveniently, secondary electrons (or electrons emitted by the multiplier) may be detected using an electron pulse counter.
Claims31
A method of detecting charged particles, comprising
- guiding said charged particles toward first and second electrodes;
- biasing said first and second electrodes, at potentials with said first electrode biased to attract positive ones of said charged particles, and said second electrode biased to attract negatively charged ones of said charged particles;
- wherein said first and second electrodes each emit secondary electrons in response to collisions by ones of said charged particles;
- attracting said secondary electrons to an electron multiplier, and causing said electron multiplier to emit electrons in response thereto;
- and
- detecting said electrons emitted by said electron multiplier, at a detection surface biased at a potential above said first and second electrodes, to detect said electrons emitted by said electron multiplier, and thereby said charged particles.
3 more elements
An ion detector, comprising
- a first electrode that emits secondary electrons when collided by a charged ion;
- a second electrode that emits secondary electrons when collided by a charged ion;
- an electron detector for detecting emitted secondary electrons, said electron detector having a detection surface;
- and
- at least one voltage source to bias said first electrode at a potential above ground, said second electrode at a potential below ground, and said detection surface of said detector at a potential above said first electrode.
2 more elements
A charged particle detector, comprising
- a first conversion electrode that emits electrons when collided by a charged particle;
- a second conversion electrode that emits electrons when collided by a charged particle;
- an electron multiplying detector for multiplying said emitted electrons, said multiplying detector having a detection surface;
- and
- at least one voltage source to bias said first electrode at a potential above ground, said second electrode at a potential below ground, and said detection surface of said electron multiplier at a potential above said first and second electrodes.
2 more elements
A method of detecting charged particles, comprising
- guiding said charged particles toward first and second collision surfaces;
- biasing said first and second collision surfaces, at potentials with said first collision surface biased to attract positive ones of said charged particles, and said second collision surface biased to attract negatively charged ones of said charged particles;
- wherein said first and second collision surfaces each emit secondary electrons in response to collisions by ones of said charged particles;
- and
- detecting emission of said electrons by said collision surfaces to detect said charged particles.
2 more elements
A method of detecting charged particles, comprising
- biasing first and second collision surfaces, at potentials with said first collision surface biased to attract positive ones of said charged particles, and said second collision surface biased to attract negatively charged ones of said charged particles;
- wherein said first and second collision surfaces each emit secondary electrons in response to collisions by ones of said charged particles;
- and
- guiding charged particles of a single first polarity toward first and second collision surfaces;
- detecting emission of said electrons by said collision surfaces to detect said charged particles of said first polarity;
- after said detecting, guiding charged particles of a second, opposite, polarity toward first and second collision surfaces;
- detecting emission of said electrons by said collision surfaces to detect said charged particles of said second polarity.
4 more elements
Dependencies are inferred from the claim text.