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US4804838A
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Inductively-coupled radio frequency plasma mass spectrometer
Assignee: Shimadzu Corp
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Filing: 1987-07-07
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Granted: 1989-02-14
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Expires: 2007-07-07
Abstract
Abstract An inductively-coupled radio frequency plasma mass spectrometer comprises an induction coil for generating a high frequency magnetic field, a plasma torch for causing a plasma by introducing an aerosol therein, and an electrostatic shield, interposed between the induction coil and the plasma torch, for shielding off the plasma from the electric field by the induction coil.
Inventors
- 👤 Kozo Miseki
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 04:18
CPC Classifications
H; H01; H01J; H01J49/00; H01J49/02; H01J49/10; H01J49/105
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
63 words
An inductively-coupled radio frequency plasma mass spectrometer comprising: induction coil means for generating a high frequency magnetic field: plasma torch means for introducing aerosol therein and generating a plasma; and electrostatic shield means comprised of an open loop structure, interposed between said induction coil means and said plasma torch means, for shielding the plasma from the electric field of said induction coil means.
Claim 2
Dependent Claim
63 words
An inductively-coupled radio frequency plasma mass spectrometer comprising: induction coil means for generating a high frequency magnetic field: plasma torch means for introducing aerosol therein and generating a plasma; and electrostatic shield means comprised of an open loop structure, interposed between said induction coil means and said plasma torch means, for shielding the plasma from the electric field of said induction coil means.
Claim 3
Dependent Claim
26 words
The mass spectrometer as set forth in claim 1, wherein said electrostatic shield means is attached to the outside of said plasma torch means and grounded.
Claim 4
Dependent Claim
67 words
The mass spectrometer as set forth in claim 1, wherein said plasma torch means is operated to cause a plasma therein with the aid of said induction coil means and said electrostatic shield means is maintained substantially at ground level so as to electrically isolate the plasma from the electric field caused by said induction coil means, so that the voltage variations of ions caused are restricted.
Claim 5
Dependent Claim
37 words
The mass spectrometer as set forth in claim 1, wherein said electrostatic shield means comprises a plurality of ring portions each having an open end, and an elongated support member for connecting the plurality of ring portions.
Claim 6
Dependent Claim
45 words
The mass spectrometer as set forth in claim 2, wherein said electrostatic shield means is coupled to a wall of a vacuum compartment means, said compartment means having orifice means through which ions are taken out of the plasma generated within said plasma torch means.
References Cited (Backward Citations)
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1992-02-14 | 1992-08-15 | 1993-02-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-02-14 | 1996-08-15 | 1997-02-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-02-14 | 2000-08-15 | 2001-02-14 | $7700.00 | Window Closed / Lapsed |