US5030914A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Electron paramagnetic resonance instrument with superconductive cavity
Assignee: United States Department of the Army
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Filing: 1989-11-16
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Granted: 1991-07-09
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Expires: 2009-11-16
Abstract
Abstract The EPR instrument includes an X-band klystron used to generate microwave power that is transmitted to a superconductive waveguide cavity resonator. The cavity is placed between the pole pieces of a large d-c magnet and small a-c magnet coils energized by a modulation signal source. A microwave crystal detector detects RF energy outputted from the cavity. The detector output is amplified, rectified and filtered in a phase sensitive filter that uses the modulation signal source as a reference. The resultant signal is recorded by an amplitude vs. time recorder. The superconductive cavity includes an inner wall of high-temperature superconductive material, a liquid coolant and an insulating sleeve that passes through the cavity. The specimen to be analyzed is placed in the sleeve.
Inventors
- 👤 Louis J. Jasper, Jr.
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 04:18
CPC Classifications
G; G01; G01R; G01R33/00; G01R33/20; G01R33/28; G01R33/32; G01R33/34; G01R33/345; G01R33/60
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
53 words
An EPR instrument comprising: a microwave power source; a high-Q microwave resonant cavity having an inner surface of superconductive material coupled to said source and having an output; a magnetic means for applying a variable magnetic field to said cavity; and means for detecting RF power transmitted from the output of said cavity.
Claim 2
Dependent Claim
53 words
An EPR instrument comprising: a microwave power source; a high-Q microwave resonant cavity having an inner surface of superconductive material coupled to said source and having an output; a magnetic means for applying a variable magnetic field to said cavity; and means for detecting RF power transmitted from the output of said cavity.
Claim 3
Dependent Claim
20 words
The instrument of claim 1 wherein said cavity includes an opening passing through the section of high RF power concentration.
Claim 4
Dependent Claim
38 words
The instrument of claim 2 wherein said cavity has a hollow wall surrounding the superconductive material and further includes a liquid coolant contained in said hollow wall having a temperature below the critical temperature of said superconductive material.
Claim 5
Dependent Claim
15 words
The instrument of claim 3 further including a dielectric insulating sleeve mounted in said opening.
Claim 6
Dependent Claim
13 words
The instrument of claim 4 wherein said power source is an X-band klystron.
Claim 7
Dependent Claim
19 words
The instrument of claim 4 wherein the loaded Q-factor for said resonant cavity is greater than 10 6 .
Claim 8
Dependent Claim
55 words
An EPR instrument comprising: a microwave power source; a microwave resonant cavity having an unloaded Q-factor much greater than 10 6 wherein the inner surface of said cavity has substantially no resistance to electrical currents; means for applying a variable magnetic field to said cavity; and means for detecting RF power transmitted from the cavity.
Claim 9
Dependent Claim
55 words
An EPR instrument comprising: a microwave power source; a microwave resonant cavity having an unloaded Q-factor much greater than 10 6 wherein the inner surface of said cavity has substantially no resistance to electrical currents; means for applying a variable magnetic field to said cavity; and means for detecting RF power transmitted from the cavity.
Claim 10
Dependent Claim
25 words
The instrument of claim 7 wherein said cavity has means for placing a sample at the point of greatest RF power concentration in the cavity.
Claim 11
Dependent Claim
18 words
The instrument of claim 8 wherein said inner surface of said cavity is lined with a superconductive material.
Claim 12
Dependent Claim
22 words
The instrument of claim 9 wherein said cavity includes means for cooling said superconductive surface at least to the critical temperature thereof.
Claim 13
Dependent Claim
20 words
The instrument of claim 10 wherein said means for cooling includes a reservoir of liquid coolant surrounding said superconductive material.
References Cited (Backward Citations)
US4674513A
Cited
US4870052A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1994-07-08 | 1995-01-07 | 1995-07-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1998-07-08 | 1999-01-07 | 1999-07-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2002-07-08 | 2003-01-07 | 2003-07-09 | $7700.00 | Window Closed / Lapsed |