US4931640A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Mass spectrometer with reduced static electric field
Assignee: Individual
•
Filing: 1989-05-19
•
Granted: 1990-06-05
•
Expires: 2009-05-19
Abstract
Abstract An ion cyclotron resonance cell (20) in which samples are analyzed has plates (21, 22) serving as excitation electrodes, top and bottom plates (25, 26) serving as detector electrodes and end trapping plates (23, 24). The cell (20) is maintained in a magnetic field of flux density B oriented longitudinally between the end trapping plates (23, 24). An ion generating source (30) causes ionization of the sample molecules within the cell (20). An electrostatic trapping potential is applied to the end trapping plates (23, 24) to prevent ions from escaping in the direction of the magnetic field B. Grounded screens (40, 41) are positioned within the cell (20) just inside the end trapping plates (23, 24) to reduce an electrostatic electric field in the cell (20) resulting from the application of a potential to the end trapping plates (23, 24).
Inventors
- 👤 Alan G. Marshall
- 👤 Mingda Wang
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 23:02
CPC Classifications
H; H01; H01J; H01J49/00; H01J49/26; H01J49/34; H01J49/36; H01J49/38
Claims Analysis
Total Claims: 41
Claim 1
Independent Claim
178 words
Mass spectrometry apparatus comprising: (a) an ion cell into which an ion sample may be introduced, the cell including a plurality of electrode plates that define the cell boundary, the electrode plates including trapping plates that produce a trapping potential by the application of a static voltage to the trapping plates, the trapping potential constraining movement of ions in the direction of a magnetic field to be applied to the cell; (b) an ion generating source that produces ions in the cell; (c) magnetic field means for creating a unidirectional magnetic field, the magnetic field means mounted so that the unidirectional magnetic field passes through the cell in a predetermined location; (d) at least one screen positioned within the cell proximate each of the trapping plates, the screen having a plurality of interstitial openings, and means for maintaining the screen at a selected potential to substantially shield the interior of the cell from the potential applied to the trapping plate; and (e) means for detecting motion of ions in the cell and providing an output signal indicative thereof.
Claim 2
Dependent Claim
178 words
Mass spectrometry apparatus comprising: (a) an ion cell into which an ion sample may be introduced, the cell including a plurality of electrode plates that define the cell boundary, the electrode plates including trapping plates that produce a trapping potential by the application of a static voltage to the trapping plates, the trapping potential constraining movement of ions in the direction of a magnetic field to be applied to the cell; (b) an ion generating source that produces ions in the cell; (c) magnetic field means for creating a unidirectional magnetic field, the magnetic field means mounted so that the unidirectional magnetic field passes through the cell in a predetermined location; (d) at least one screen positioned within the cell proximate each of the trapping plates, the screen having a plurality of interstitial openings, and means for maintaining the screen at a selected potential to substantially shield the interior of the cell from the potential applied to the trapping plate; and (e) means for detecting motion of ions in the cell and providing an output signal indicative thereof.
Claim 3
Dependent Claim
15 words
The mass spectrometry apparatus of claim 1 wherein the interstitial openings form a two-dimensional lattice.
Claim 4
Dependent Claim
17 words
The mass spectrometry apparatus of claim 1 wherein the screen is a mesh of interwoven wire strands.
Claim 5
Dependent Claim
18 words
The mass spectrometry apparatus of claim 1 wherein the screen is a planar array of parallel wire strands.
Claim 6
Dependent Claim
22 words
The mass spectrometry apparatus of claim 1 wherein the screen is attached to a frame to fixedly hold the screen in place.
Claim 7
Dependent Claim
20 words
The mass spectrometry apparatus of claim 1 wherein the screen is made of a non-magnetic or slightly magnetic conductive material.
Claim 8
Dependent Claim
20 words
The mass spectrometry apparatus of claim 6 wherein the frame is made of a non-magnetic or slightly magneti conductive material.
Claim 9
Dependent Claim
28 words
The mass spectrometry apparatus of claim 1 wherein the means for maintaining the screens at a selected potential is an electrical connection between the screens and a ground.
Claim 10
Dependent Claim
29 words
The mass spectrometry apparatus of claim 1 wherein the means for maintaining the screen at a selected potential is a electrical connection between the screens and a voltage supply.
Claim 11
Dependent Claim
20 words
The mass spectrometry apparatus of claim 1 wherein the interstitial openings are large enough to allow passage of ions therethrough.
Claim 12
Dependent Claim
24 words
The mass spectrometry apparatus of claim 1 wherein the interstitial openings are small enough to substantially shield the cell from the static electric field.
Claim 13
Dependent Claim
43 words
The mass spectrometry apparatus of claim 1 wherein the cell has a first section and a second section separated by a trapping plate, and there are two screens, each of the screens positioned proximate to the trapping plates in one of the sections.
Claim 14
Dependent Claim
113 words
An ion cell for use in a mass spectrometer, the cell comprising: (a) a plurality of electrode plates that define the cell boundary, the electrode plates including two trapping plates that produce a trapping potential by the application of a static voltage to the trapping plates, the trapping potential constraining movement of ions in the direction of a magnetic field to be applied to the cell; and (b) screens positioned within the cell proximate each of the trapping plates, the screens having a plurality of interstitial openings, and means for maintaining the screens at a selected potential to substantially shield the interior of the cell from the potential applied to the trapping plates.
Claim 15
Dependent Claim
113 words
An ion cell for use in a mass spectrometer, the cell comprising: (a) a plurality of electrode plates that define the cell boundary, the electrode plates including two trapping plates that produce a trapping potential by the application of a static voltage to the trapping plates, the trapping potential constraining movement of ions in the direction of a magnetic field to be applied to the cell; and (b) screens positioned within the cell proximate each of the trapping plates, the screens having a plurality of interstitial openings, and means for maintaining the screens at a selected potential to substantially shield the interior of the cell from the potential applied to the trapping plates.
Claim 16
Dependent Claim
14 words
The ion cell of claim 13 wherein the interstitial openings form a two-dimensional lattice.
Claim 17
Dependent Claim
18 words
The ion cell of claim 13 wherein one of the screens is a mesh of interwoven wire strands.
Claim 18
Dependent Claim
19 words
The ion cell of claim 13 wherein one of the screens is a planar array of parallel wire strands.
Claim 19
Dependent Claim
23 words
The ion cell of claim 13 wherein one of the screens is attached to a frame to fixedly hold the screen in place.
Claim 20
Dependent Claim
21 words
The ion cell of claim 13 wherein one of the screens is made of a non-magnetic or slightly magnetic conductive material.
Claim 21
Dependent Claim
19 words
The ion cell of claim 17 wherein the frame is made of a non-magnetic or slightly magnetic conductive material.
Claim 22
Dependent Claim
27 words
The ion cell of claim 13 wherein the means for maintaining the screens at a selected potential is an electrical connection between the screens and a ground.
Claim 23
Dependent Claim
28 words
The ion cell of claim 13 wherein the means for maintaining the screens at a selected potential is an electrical connection between the screens and a voltage supply.
Claim 24
Dependent Claim
19 words
The ion cell of claim 13 wherein the interstitial openings are large enough to allow passage of ions therethrough.
Claim 25
Dependent Claim
23 words
The ion cell of claim 13 wherein the interstitial openings are small enough to substantially shield the cell from the static electric field.
Claim 26
Dependent Claim
42 words
The ion cell of claim 13 wherein the cell has a first section and a second section separated by a trapping plate, and there are two screens, each of the screens positioned proximate to the trapping plates in one of the sections.
Claim 27
Independent Claim
135 words
A method of mass spectrometry comprising the step of: (a) introducing a sample into a cell, the cell boundary being defined by a plurality of electrode plates, the electrode plates including a trapping plate; (b) providing a unidirectional magnetic field that passes through the cell in a predetermined location; (c) producing ions in the cell; (d) producing a trapping potential proximate the trapping plate to constrain movement of ions in the direction of the magnetic field by the application of static voltage to the plate; (e) placing a screen having a plurality of interstitial openings within the cell proximate one of the trapping plates and controlling the potential applied to the screen to reduce the electric field within the cell; (f) detecting motion of ions in the cell and providing an output signal indicative thereof.
Claim 28
Independent Claim
135 words
A method of mass spectrometry comprising the step of: (a) introducing a sample into a cell, the cell boundary being defined by a plurality of electrode plates, the electrode plates including a trapping plate; (b) providing a unidirectional magnetic field that passes through the cell in a predetermined location; (c) producing ions in the cell; (d) producing a trapping potential proximate the trapping plate to constrain movement of ions in the direction of the magnetic field by the application of static voltage to the plate; (e) placing a screen having a plurality of interstitial openings within the cell proximate one of the trapping plates and controlling the potential applied to the screen to reduce the electric field within the cell; (f) detecting motion of ions in the cell and providing an output signal indicative thereof.
Claim 29
Dependent Claim
12 words
The method of claim 25 wherein the interstitial openings form a lattice.
Claim 30
Dependent Claim
17 words
The method of claim 25 wherein one of the screens is a mesh of interwoven wire strands.
Claim 31
Dependent Claim
18 words
The method of claim 26 wherein one of the screens is a planar array of parallel wire strands.
Claim 32
Dependent Claim
20 words
The method of claim 25 wherein the screen is attached to a frame to fixedly hold the screen in place.
Claim 33
Dependent Claim
20 words
The method of claim 25 wherein one of the screens is made of a non-magnetic or slightly magnetic conductive material.
Claim 34
Dependent Claim
18 words
The method of claim 29 wherein the frame is made of a non-magnetic or slightly magnetic conductive material.
Claim 35
Dependent Claim
10 words
The method of claim 25 wherein the screen is grounded.
Claim 36
Dependent Claim
14 words
The method of claim 25 wherein the screen is maintained at a selected potential.
Claim 37
Dependent Claim
18 words
The method of claim 25 wherein the interstitial openings are large enough to allow passage of ions therethrough.
Claim 38
Dependent Claim
22 words
The method of claim 25 wherein the interstitial openings are small enough to substantially shield the cell from the static electric field.
Claim 39
Dependent Claim
41 words
The method of claim 25 wherein the cell has a first section and a second section separated by a trapping plate, and there are two screens, each of the screens positioned proximate to the trapping plates in one of the sections.
Claim 40
Independent Claim
122 words
A method of mass spectrometry comprising the steps of: (a) introducing a sample into a cell, the cell boundary being defined by a plurality of electrode plates, the electrode plates including a trapping plate; (b) providing a unidirectional magnetic field that passes through the cell in a predetermined location; (c) producing ions in the cell; (d) producing a trapping potential proximate the trapping plate to constrain movement of ions in the direction of the magnetic field by the application of static voltage to the plate; (e) shielding the cell from a static electric field resulting from the application of the static voltage to the trapping plate; and (f) detecting motion of ions in the cell and providing an output signal indicative thereof.
Claim 41
Independent Claim
122 words
A method of mass spectrometry comprising the steps of: (a) introducing a sample into a cell, the cell boundary being defined by a plurality of electrode plates, the electrode plates including a trapping plate; (b) providing a unidirectional magnetic field that passes through the cell in a predetermined location; (c) producing ions in the cell; (d) producing a trapping potential proximate the trapping plate to constrain movement of ions in the direction of the magnetic field by the application of static voltage to the plate; (e) shielding the cell from a static electric field resulting from the application of the static voltage to the trapping plate; and (f) detecting motion of ions in the cell and providing an output signal indicative thereof.
References Cited (Backward Citations)
US2939952A
Cited
US3475605A
Cited
US3511986A
Cited
US3461381A
Cited
US3527939A
Cited
US4090075A
Cited
US3742212A
Cited
US4034191A
Cited
US3984681A
Cited
US3937955A
Cited
US4315149A
Cited
US4540884A
Cited
US4535235A
Cited
US4581533A
Cited
US4686365A
Cited
US4588888A
Cited
US4739165A
Cited
US4761545A
Cited
US4818864A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1993-06-04 | 1993-12-04 | 1994-06-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-06-04 | 1997-12-04 | 1998-06-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-06-04 | 2001-12-04 | 2002-06-05 | $7700.00 | Window Closed / Lapsed |