US3936634A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method and apparatus for improved focusing of ion currents in quadrupole mass filter
Assignee: Extrel CMS LLC
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Filing: 1974-12-10
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Granted: 1976-02-03
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Expires: 1994-12-10
Abstract
Abstract Application of dc potentials of values other than ground to materials which appear as conductors to dc and low frequency ac electric fields and as dielectrics to high frequency ac electric fields in order to compensate for changes of potential due to ion and electron currents reaching the material and/or to provide for improved focusing of the ions, particularly with large ion currents, into a quadrupole mass filter.
Inventors
- 👤 Wade L. Fite
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 02:49
CPC Classifications
H; H01; H01J; H01J49/00; H01J49/26; H01J49/34; H01J49/42; H01J49/4205; H01J49/421; H01J49/4215; H01J49/02; H01J49/06
Claims Analysis
Total Claims: 25
Claim 1
Independent Claim
165 words
In a method of mass analysis which utilizes a quadrupole mass filter and comprises the steps of producing positive ions with an initial kinetic energy E i from an ion source having an electrical potential U S , introducing said ions into the space between the poles of the quadrupole mass filter wherein the electric potential along the axis of said poles is U P , causing the transmission of only those ions of a selected mass-to-charge ratio through the space between said poles, providing a selective shielding at at least one end of said poles which functions substantially as a conductor to the substantially dc fields and substantially as a dielectric to ac fields, said shielding having an electric connection at a potential of U E , and maintaining said potential U E less than said potential U P , and said potential U P less than said potential of U S plus E i /e where e is the charge of the ion.
Claim 2
Dependent Claim
165 words
In a method of mass analysis which utilizes a quadrupole mass filter and comprises the steps of producing positive ions with an initial kinetic energy E i from an ion source having an electrical potential U S , introducing said ions into the space between the poles of the quadrupole mass filter wherein the electric potential along the axis of said poles is U P , causing the transmission of only those ions of a selected mass-to-charge ratio through the space between said poles, providing a selective shielding at at least one end of said poles which functions substantially as a conductor to the substantially dc fields and substantially as a dielectric to ac fields, said shielding having an electric connection at a potential of U E , and maintaining said potential U E less than said potential U P , and said potential U P less than said potential of U S plus E i /e where e is the charge of the ion.
Claim 3
Dependent Claim
38 words
A method in accordance with claim 1, wherein said potential U E is maintained at a ground potential and both said potentials U S + E i /e and U P are maintained positive with respect to ground.
Claim 4
Dependent Claim
47 words
A method in accordance with claim 1, wherein said potential of the mass filter axis U P is set to ground potential and said potential U E is maintained negative and said potential U S + E i /e is maintained positive with respect to ground potential.
Claim 5
Dependent Claim
20 words
A method in accordance with claim 1, wherein the ions are produced initially at rest whereby E i = 0.
Claim 6
Dependent Claim
16 words
A method in accordance with claim 4, wherein the ions are produced by electron impact ionization.
Claim 7
Dependent Claim
14 words
A method in accordance with claim 4, wherein the ions are produced by photo-ionization.
Claim 8
Dependent Claim
168 words
In a method of mass analysis which utilizes a quadrupole mass filter and comprises the steps of producing negative ions with an initial kinetic energy E i from an ion source having an electric potential U S , introducing said ions into the space between the poles of the quadrupole mass filter wherein the electric potential along the axis of said poles is U P , causing the transmission of only those ions of a selected mass-to-charge ratio through the space between said poles, providing a selective shielding of at least one end of said poles which functions substantially as a conductor to the substantially dc fields and substantially as a dielectric to the ac fields, said shielding having electric connection at a potential of a U E , and maintaining in the negative charge sense said potential U E less than said potential U P , and U P less than said potential U S + E i /e where e is the charge on the ion.
Claim 9
Dependent Claim
168 words
In a method of mass analysis which utilizes a quadrupole mass filter and comprises the steps of producing negative ions with an initial kinetic energy E i from an ion source having an electric potential U S , introducing said ions into the space between the poles of the quadrupole mass filter wherein the electric potential along the axis of said poles is U P , causing the transmission of only those ions of a selected mass-to-charge ratio through the space between said poles, providing a selective shielding of at least one end of said poles which functions substantially as a conductor to the substantially dc fields and substantially as a dielectric to the ac fields, said shielding having electric connection at a potential of a U E , and maintaining in the negative charge sense said potential U E less than said potential U P , and U P less than said potential U S + E i /e where e is the charge on the ion.
Claim 10
Dependent Claim
37 words
A method in accordance with claim 7, wherein said potential U E is maintained at ground potential and both said potentials U S + E i /e and U P are maintained negative with respect to ground.
Claim 11
Dependent Claim
47 words
A method in accordance with claim 7, wherein the potential of the mass filter axis U P is set to ground potential and said potential U E is maintained positive and said potential U S + E i /e is maintained negative with respect to ground potential.
Claim 12
Dependent Claim
20 words
A method in accordance with claim 7, wherein the ions are produced initially at rest whereby E i = 0.
Claim 13
Dependent Claim
16 words
A method in accordance with claim 10, wherein the ions are produced by electron impact ionization.
Claim 14
Dependent Claim
14 words
A method in accordance with claim 10, wherein the ions are produced by photo-ionization.
Claim 15
Independent Claim
179 words
A device for improving the efficienty of injection and/or transmission of ions passing through a quadrupole mass filter, said device comprising an ion source having an electric potential U S , means for producing ions from said ion source having an initial kinetic energy of E i , a selective shielding at at least one end of the poles of the quadrupole mass filter adapted to receive said ions therethrough, said shielding functioning substantially as a conductor to the substantially dc fields and substantially as a dielectric to the ac fields produced by said poles, said shielding having electric connection to a potential of U E , means for causing the transmission of said ions through said quadrupole mass filter, means for maintaining an electric potential along the axis of said poles of U P , and biasing means in said quadrupole mass filter for maintaining said potential U E less than said potential U P and said potential U P less than said potential U S + E i /e wherein e is the charge on the ion.
Claim 16
Independent Claim
179 words
A device for improving the efficienty of injection and/or transmission of ions passing through a quadrupole mass filter, said device comprising an ion source having an electric potential U S , means for producing ions from said ion source having an initial kinetic energy of E i , a selective shielding at at least one end of the poles of the quadrupole mass filter adapted to receive said ions therethrough, said shielding functioning substantially as a conductor to the substantially dc fields and substantially as a dielectric to the ac fields produced by said poles, said shielding having electric connection to a potential of U E , means for causing the transmission of said ions through said quadrupole mass filter, means for maintaining an electric potential along the axis of said poles of U P , and biasing means in said quadrupole mass filter for maintaining said potential U E less than said potential U P and said potential U P less than said potential U S + E i /e wherein e is the charge on the ion.
Claim 17
Dependent Claim
48 words
A device in accordance with claim 13, wherein said ion source produces positive ions and said potential U E is maintained less than said potential U P and said potential U P is maintained less than said potential U S + E i /e in the positive sense.
Claim 18
Dependent Claim
43 words
A device in accordance with claim 14, wherein said biasing means is adapted to maintain said potential U E at ground potential and both said potentials U S + E i /e and U P at positive potential with respect to the ground.
Claim 19
Dependent Claim
46 words
A device in accordance with claim 14, wherein said means for establishing said potential U P is set to ground potential and said biasing means maintains said potential U E negative and said potential U S + E i /e positive with respect to ground potential.
Claim 20
Dependent Claim
23 words
A method in accordance with claim 13, wherein said means for producing ions produces said ions at rest whereby E i = 0.
Claim 21
Dependent Claim
17 words
A device in accordance with claim 17, which includes electron impact ionization means for producing said ions.
Claim 22
Dependent Claim
17 words
A device in accordance with claim 17, including photo-ionization means wherein said ions are produced by photo-ionization.
Claim 23
Dependent Claim
48 words
A device in accordance with claim 13, wherein said ions source produces negative ions and said biasing means maintains said potential U E less than said potential U P and said potential U P less than said potential U S + E i /e in the negative sense.
Claim 24
Dependent Claim
40 words
A device in accordance with claim 20, wherein said biasing means maintains said potential U E at ground potential and both said potentials U S + E i /e and U P are maintained negative with respect to the ground.
Claim 25
Dependent Claim
52 words
A device in accordance with claim 20, wherein said means for establishing the potential for the mass filter axis U P maintains such potential at ground potential and said biasing means is adapted to maintain said potentials U E and U S + E i /e negative with respect to ground potential.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1979-02-02 | 1979-08-04 | 1980-02-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-02-02 | 1983-08-04 | 1984-02-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-02-02 | 1987-08-04 | 1988-02-03 | $7700.00 | Window Closed / Lapsed |