US4423324A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Apparatus for detecting negative ions
Assignee: Thermo Finnigan LLC
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Filing: 1979-07-23
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Granted: 1983-12-27
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Expires: 1999-07-23
Abstract
Abstract A negative ion detector converts negative ions to positive ions by means of a conversion anode which is maintained at a relatively high positive voltage. The resultant positive ions are detected by a standard continuous dynode electron multiplier which has its detection signal output at ground potential.
Inventors
- 👤 George C. Stafford
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 08:49
CPC Classifications
H; H01; H01J; H01J49/00; H01J49/02; H01J49/025; G; G01; G01T; G01T1/00; G01T1/16; G01T1/28; G21; G21K; G21K1/00; G21K1/14; H01J43/00; H01J43/02; H01J49/0095
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
84 words
Apparatus for detecting the abundance of negative ions from a source of such ions comprising: conversion means maintained at a high positive voltage for attracting and accelerating only said negative ions whereby the negative ions impact the conversion means with sufficient kinetic energy to produce a proportional amount of secondary positive ions, and electron multiplier means having an input operated at a negative potential to attract said secondary positive ions and for providing an output signal indicative of the abundance of said negative ions.
Claim 2
Dependent Claim
84 words
Apparatus for detecting the abundance of negative ions from a source of such ions comprising: conversion means maintained at a high positive voltage for attracting and accelerating only said negative ions whereby the negative ions impact the conversion means with sufficient kinetic energy to produce a proportional amount of secondary positive ions, and electron multiplier means having an input operated at a negative potential to attract said secondary positive ions and for providing an output signal indicative of the abundance of said negative ions.
Claim 3
Dependent Claim
18 words
Apparatus as in claim 1 wherein said positive voltage is in the order of magnitude of 3000 volts.
Claim 4
Dependent Claim
14 words
Apparatus as in claim 1 where said output signal is referenced to ground potential.
Claim 5
Dependent Claim
128 words
In a mass spectrometer of the type in which both positive and negative ions are produced, mass analyzed and applied to detection means to provide output detection signals indicative of the composition of a chemical compound, the improvement comprising a signal electron multiplier means including a first stage operated at negative potential to attract positive ions and provide an output signal indicative of the abundance of said positive ions and means for receiving the negative ions and converting them to secondary positive ions and whereby said secondary positive ions are attracted to said electron multiplier means to provide an output signal indicative of the abundance of said negative ions whereby a single detection means serves to provide output signals indicative of the abundance of negative or positive ions.
Claim 6
Dependent Claim
128 words
In a mass spectrometer of the type in which both positive and negative ions are produced, mass analyzed and applied to detection means to provide output detection signals indicative of the composition of a chemical compound, the improvement comprising a signal electron multiplier means including a first stage operated at negative potential to attract positive ions and provide an output signal indicative of the abundance of said positive ions and means for receiving the negative ions and converting them to secondary positive ions and whereby said secondary positive ions are attracted to said electron multiplier means to provide an output signal indicative of the abundance of said negative ions whereby a single detection means serves to provide output signals indicative of the abundance of negative or positive ions.
Claim 7
Dependent Claim
19 words
A mass spectrometer as in claim 4 wherein said electron multiplier means provides output signals referenced to ground potential.
Claim 8
Dependent Claim
89 words
A mass spectrometer system comprising: an ionizing region where a chemical composition to be analyzed is ionized to form positive and negative ions, a mass analyzer disposed to receive and analyze at least said negative ions; means for converting said negative ions from said analyzer to secondary positive ions, and electron multiplier means having an input operated at a negative potential to attract said secondary positive ions from said conversion means and provide an output signal with respect to ground potential indicative of the abundance of said negative ions.
Claim 9
Dependent Claim
89 words
A mass spectrometer system comprising: an ionizing region where a chemical composition to be analyzed is ionized to form positive and negative ions, a mass analyzer disposed to receive and analyze at least said negative ions; means for converting said negative ions from said analyzer to secondary positive ions, and electron multiplier means having an input operated at a negative potential to attract said secondary positive ions from said conversion means and provide an output signal with respect to ground potential indicative of the abundance of said negative ions.
Claim 10
Dependent Claim
28 words
Apparatus as in claim 6 where said negative ions are polyatomic and said amount of secondary positive ions for polyatomic ions is substantially 100% of said negative ions.
References Cited (Backward Citations)
US2213140A
Cited
US3136908A
Cited
US3660655A
Cited
US3898456A
Cited
US4066894A
Cited
US4267448A
Cited
US4267448B1
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1986-12-26 | 1987-06-27 | 1987-12-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1990-12-26 | 1991-06-27 | 1991-12-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1994-12-26 | 1995-06-27 | 1995-12-27 | $7700.00 | Window Closed / Lapsed |