US4267448A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Ion detector with bipolar accelerating electrode
Assignee: Thermo Finnigan LLC
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Filing: 1979-06-04
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Granted: 1981-05-12
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Expires: 1999-06-04
Abstract
Abstract The ion detector of a mass spectrometer includes an accelerating electrode 10, 34, 38 disposed between the spectrometer discharge shutter 6 and a secondary electron multiplier 18. The electrode 10 is selectively energized by a high positive or negative voltage opposite the initial polarity of the ions by a source 16. Thus, a positively energized electrode draws in and accelerates negative ions, and strips away their electrons to leave them positively charged for further acceleration into the first dynode of the secondary electron multiplier.
Inventors
- 👤 Karl Feser
- 👤 Curt Brunnee
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 19:19
CPC Classifications
G; G01; G01T; G01T1/00; G01T1/16; G01T1/28; H; H01; H01J; H01J49/00; H01J49/02; H01J49/025
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
127 words
An apparatus for detecting ions generated by mass spectrometers, comprising: a conversion element which the ions strike, a secondary electron multiplier disposed after the conversion element in the direction of ion travel, said electron multiplier having an output that approaches ground potential, a high voltage source for the secondary electron multiplier, said conversion element comprising an accelerating electrode (10, 34, 38) disposed before and adjacent to the input of the secondary electron multiplier (18), and a separate, selective bi-polarity high voltage source (16) connected to the accelerating electrode, said accelerating electrode being impressed with a potential more negative than a first dynode of the secondary electron multiplier when detecting positive ions, and being impressed with a potential more positive than said first dynode when detecting negative ions.
Claim 2
Independent Claim
127 words
An apparatus for detecting ions generated by mass spectrometers, comprising: a conversion element which the ions strike, a secondary electron multiplier disposed after the conversion element in the direction of ion travel, said electron multiplier having an output that approaches ground potential, a high voltage source for the secondary electron multiplier, said conversion element comprising an accelerating electrode (10, 34, 38) disposed before and adjacent to the input of the secondary electron multiplier (18), and a separate, selective bi-polarity high voltage source (16) connected to the accelerating electrode, said accelerating electrode being impressed with a potential more negative than a first dynode of the secondary electron multiplier when detecting positive ions, and being impressed with a potential more positive than said first dynode when detecting negative ions.
Claim 3
Dependent Claim
16 words
Apparatus according to claim 1, wherein the accelerating electrode (10) is formed as a permeable screen.
Claim 4
Dependent Claim
15 words
Apparatus according to claim 2, wherein the accelerating electrode is of the venetian blind type.
Claim 5
Dependent Claim
17 words
Apparatus according to claim 1, wherein the accelerating electrode (10) is formed as a diverting plate (34).
Claim 6
Dependent Claim
32 words
Apparatus according to any one of claims 1 through 4, wherein the accelerating electrode (10 or 34) is provided at least on its input side with a screen grid (14 or 36).
Claim 7
Dependent Claim
30 words
Apparatus according to any one of claims 1 through 4, wherein the accelerating electrode (38) and the secondary electron multiplier (40a through 40n, 52) comprise a modular jointly manipulable unit.
Claim 8
Dependent Claim
28 words
Apparatus according to claim 6, further comprising a joint plug connector (42 through 50) for the accelerating electrode (38) and the secondary electron multiplier (40a through 40n, 52).
Claim 9
Independent Claim
67 words
A method for operating an apparatus for detecting ions generated by mass spectrometers, comprising; supplying a first dynode of a secondary electron multiplier with a high negative potential with the last dynode thereof connected to a potential which approaches ground, and; connecting an accelerating electrode to a potential at least 500 V more negative than the first dynode of the secondary electron multiplier, when detecting positive ions.
Claim 10
Independent Claim
67 words
A method for operating an apparatus for detecting ions generated by mass spectrometers, comprising; supplying a first dynode of a secondary electron multiplier with a high negative potential with the last dynode thereof connected to a potential which approaches ground, and; connecting an accelerating electrode to a potential at least 500 V more negative than the first dynode of the secondary electron multiplier, when detecting positive ions.
Claim 11
Dependent Claim
31 words
A method according to claim 8, wherein the accelerating electrode is connected to a potential between 3 and 10 kV more negative than the first dynode of the secondary electron multiplier.
Claim 12
Independent Claim
58 words
A method for operating an apparatus for detecting ions generated by mass spectrometers, comprising: supplying a first dynode of a secondary electron multiplier with a high negative potential with the last dynode thereof connected to a potential which approaches ground, and; connecting an accelerating electrode to a positive potential between 1 and 10 kV when detecting negative ions.
Claim 13
Independent Claim
58 words
A method for operating an apparatus for detecting ions generated by mass spectrometers, comprising: supplying a first dynode of a secondary electron multiplier with a high negative potential with the last dynode thereof connected to a potential which approaches ground, and; connecting an accelerating electrode to a positive potential between 1 and 10 kV when detecting negative ions.
Claim 14
Dependent Claim
21 words
A method according to claim 10, wherein the accelerating electrode is connected to a positive potential between 3 to 4 kV.
References Cited (Backward Citations)
US3774028A
Cited
US3898456A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1984-05-11 | 1984-11-10 | 1985-05-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-05-11 | 1988-11-10 | 1989-05-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-05-11 | 1992-11-10 | 1993-05-12 | $7700.00 | Window Closed / Lapsed |