Patent US3774028A successfully refreshed from Google Patents.
US3774028A
Expired / Lapsed
US
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Ion beam intensity measuring apparatus
Assignee: United Kingdom Atomic Energy Authority
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Filing: 1971-06-01
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Granted: 1973-11-20
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Expires: 1991-06-01
Abstract
Abstract In a known energy-selective ion measuring apparatus, mainly for mass spectrometers, the ions pass through an apertured electrode towards an electrode to which a variable retarding voltage is applied. The centre of the latter electrode is occupied by a scintillator beyond which is located a photomultiplier. When the retarding voltage equals or exceeds the ion source voltage, all ions are repelled to the apertured electrode to produce secondary electrons which are accelerated to the scintillator to produce an output. When the retarding voltage is less than the source voltage, only ions of lesser energy, such as metastable fragments, are so repelled. In the present invention the aforesaid apertured electrode, instead of being earthed or earthy, is held at a high voltage opposite in sign to that of the retarding voltage, which increases the sensitivity. Optionally a transverse field is provided by an assymetrical projection of the apertured electrode, in order to prevent ions being repelled through the aperture, thereby further increasing the sensitivity.
Inventors
- 👤 N Daly
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 20:05
CPC Classifications
G; G01; G01T; G01T1/00; G01T1/16; G01T1/28; H; H01; H01J; H01J49/00; H01J49/02; H01J49/025
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
148 words
Ion beam intensity measuring apparatus suitable for use with a mass spectrometer comprising an apertured resolving electrode connected to a fixed reference potential, a first apertured electrode located beyond said apertured resolving electrode for admitting the ion beam and capable of emitting secondary electrons from a surface thereof, a first retarding electrode located beyond said first apertured electrode to apply a retarding electric field to ions passing through the aperture, a detector mounted on said first retarding electrode facing said first apertured electrode for detecting secondary electrons emitted from said first apertured electrode by ions repelled to said first apertured electrode by said field, means for applying a variable high potential to said first retarding electrode, and means for applying to said first apertured electrode a high potential which is of opposite polarity to said variable high potential relative to the fixed potential of said apertured resolving electrode.
Claim 2
Dependent Claim
148 words
Ion beam intensity measuring apparatus suitable for use with a mass spectrometer comprising an apertured resolving electrode connected to a fixed reference potential, a first apertured electrode located beyond said apertured resolving electrode for admitting the ion beam and capable of emitting secondary electrons from a surface thereof, a first retarding electrode located beyond said first apertured electrode to apply a retarding electric field to ions passing through the aperture, a detector mounted on said first retarding electrode facing said first apertured electrode for detecting secondary electrons emitted from said first apertured electrode by ions repelled to said first apertured electrode by said field, means for applying a variable high potential to said first retarding electrode, and means for applying to said first apertured electrode a high potential which is of opposite polarity to said variable high potential relative to the fixed potential of said apertured resolving electrode.
Claim 3
Dependent Claim
36 words
Apparatus as claimed in claim 1 wherein said first apertured electrode is preceded by a further apertured electrode capable of being maintained at a potential which is slightly lower than that of said first apertured electrode.
Claim 4
Dependent Claim
64 words
Apparatus as claimed in claim 1 comprising means located between said first retarding electrode and said first apertured electrode for providing an electric field component whose direction is transverse to the axis of the aperture, whereby the ion paths between said two electrodes are displaced away from said axis and the tendency for ions to be repelled back through the aperture is thereby reduced.
Claim 5
Dependent Claim
31 words
Apparatus as claimed in claim 3 wherein said first apertured electrode comprises an assymetrically located projecting portion which extends towards said first retarding electrode in order to provide said field component.
Claim 6
Dependent Claim
26 words
Apparaus as claimed in claim 4 wherein said assymetrical portion comprises a part-cylindrical portion having its axis substantially parallel to a slit which constitutes the aperture.
Claim 7
Dependent Claim
28 words
Apparatus as claimed in claim 5 wherein said projecting portion extends beyond the end of the slit to provide a sensibly uniform transverse field in the slit region.
Claim 8
Dependent Claim
58 words
Apparatus as claimed in claim 1 whErein said means for applying a variable potential and said means for applying a potential comprise means for applying to said first retarding electrode a variable positive potential relative to said apertured resolving electrode, and means for applying to said first apertured electrode a negative potential relative to said apertured resolving electrode.
References Cited (Backward Citations)
GB1171700A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-11-19 | 1977-05-21 | 1977-11-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-11-19 | 1981-05-21 | 1981-11-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-11-19 | 1985-05-21 | 1985-11-20 | $7700.00 | Window Closed / Lapsed |