US4461996A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Nuclear magnetic resonance cell having improved temperature sensitivity and method for manufacturing same
Assignee: Northrop Grumman Guidance and Electronics Co Inc
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Filing: 1982-08-06
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Granted: 1984-07-24
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Expires: 2002-08-06
Abstract
Abstract A nuclear magnetic resonance (NMR) cell for use in a gyro is shown which is maintained at a predetermined temperature, established by testing. Testing of each cell is conducted by heating the cell within a gyro to a series of temperatures and plotting the gyro bias (degrees/time) for each temperature within the series. At one temperature the magnitude of gyro bias will no longer increase but will start to decrease. This temperature turning point is the temperature at which the NMR cell should be maintained for zero temperature sensitivity of the gyro.
Inventors
- 👤 Tae M. Kwon
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 23:46
CPC Classifications
G; G01; G01R; G01R33/00; G01R33/20; G01R33/28; G01R33/30; G01R33/31; G01N; G01N24/00; G01N24/006
Claims Analysis
Total Claims: 21
Claim 1
Independent Claim
128 words
A method for reducing the temperature sensitivity of a cell used within an NMR magnetic alignment device, comprising the steps of: introducing into said cell a mixture of gases including at least two isotopes of at least one magnetic moment gas wherein at least one isotope has a nuclear quadrupole moment; varying the temperature of said cell to a predetermined series of temperature values; measuring the change of the bias of said cell with temperature at each of said series of predetermined temperature values to determine the established temperature at which said change of said bias with temperature of said cell reaches its minimum rate of change; and maintaining said cell at nearly said established temperature of minimum rate of change during operation of said magnetic alignment device.
Claim 2
Independent Claim
128 words
A method for reducing the temperature sensitivity of a cell used within an NMR magnetic alignment device, comprising the steps of: introducing into said cell a mixture of gases including at least two isotopes of at least one magnetic moment gas wherein at least one isotope has a nuclear quadrupole moment; varying the temperature of said cell to a predetermined series of temperature values; measuring the change of the bias of said cell with temperature at each of said series of predetermined temperature values to determine the established temperature at which said change of said bias with temperature of said cell reaches its minimum rate of change; and maintaining said cell at nearly said established temperature of minimum rate of change during operation of said magnetic alignment device.
Claim 3
Dependent Claim
16 words
A method, as claimed in claim 1, wherein said cell is a nuclear magnetic resonance cell.
Claim 4
Dependent Claim
37 words
A method, as claimed in claim 1, wherein at least one isotope of said at least one magnetic moment gas having a nuclear quadrupole moment is selected from the group consisting of krypton-83, krypton-85, xenon-131, and neon-21.
Claim 5
Dependent Claim
25 words
A method, as claimed in claim 1, wherein said at least one isotope of said at least one magnetic moment gas is xenon-129 and xenon-131.
Claim 6
Dependent Claim
22 words
A method, as claimed in claim 4, wherein said isotopes of xenon-129 and xenon-313 are present in a 1 to 4 ratio.
Claim 7
Dependent Claim
22 words
A method, as claimed in claim 5, wherein said cell is maintained at said established temperature within a range of ±0.1° C.
Claim 8
Dependent Claim
55 words
A method, as claimed in claim 1, additionally comprising the steps of: coating the inner walls of said cell with an alkali metal hydride to reduce the adsorption energy of said cell; measuring said adsorption energy of said cell; and selecting those cells with a low adsorption energy of between 0.1 eV to 0.25 eV.
Claim 9
Dependent Claim
32 words
A method, as claimed in claim 1, additionally comprising the steps of: measuring the temperature of said cell; maintaining said cell at said established temperature to within a determined temperature range; and
Claim 10
Dependent Claim
22 words
introducing a corrective factor to said alignment device to correct said change of said bias with change in temperature of said cell.
Claim 11
Dependent Claim
22 words
introducing a corrective factor to said alignment device to correct said change of said bias with change in temperature of said cell.
Claim 12
Dependent Claim
71 words
A cell for use in a magnetic alignment device, comprising: a container for gas; a magnetic moment gas retained within said container having a mixture of gases including at least two isotopes of at least one noble gas; an oven for heating said container; and means for retaining said oven at an established temperature at which the change of bias with temperature of said cell is maintained at its minimum value.
Claim 13
Dependent Claim
71 words
A cell for use in a magnetic alignment device, comprising: a container for gas; a magnetic moment gas retained within said container having a mixture of gases including at least two isotopes of at least one noble gas; an oven for heating said container; and means for retaining said oven at an established temperature at which the change of bias with temperature of said cell is maintained at its minimum value.
Claim 14
Dependent Claim
29 words
A cell, as claimed in claim 9, wherein said at least one isotope of said noble gas is selected from the group consisting of krypton-83, krypton-85, xenon-131, and neon-21.
Claim 15
Dependent Claim
22 words
A cell, as claimed in claim 9, wherein said at least one isotope of said noble gas consists of xenon-129 and xenon-131.
Claim 16
Dependent Claim
21 words
A cell, as claimed in claim 11, wherein said xenon-129 and xenon-131 is present in a ratio of 1 to 4.
Claim 17
Dependent Claim
52 words
A cell, as claimed in claim 9, additionally comprising: said container having an inner surface; a coating of alkali metal hydride upon said inner surface of said container; said alkali metal hydride selected from a group consisting of cesium, lithium, potassium, sodium and rubidium to reduce the wall energy of said cell.
Claim 18
Dependent Claim
28 words
A cell, as claimed in claim 9, additionally comprising: said contained having an inner surface; and a coating of rubidium hydride upon the inner surface of said container.
Claim 19
Dependent Claim
36 words
A cell, as claimed in claims 13 or 14, wherein said coating reduces the adsorption energy of said cell to between 0.1 and 0.25 eV; and said established temperature is between 75° C. and 85° C.
Claim 20
Dependent Claim
34 words
A cell, as claimed in claims 9 or 15, wherein said means for retaining said oven at a said established temperature maintains said temperature to within a determined temperature range of approximately ±0.1° C.
Claim 21
Dependent Claim
57 words
A cell, as claimed in claim 9, additionally comprising: means for measuring the temperature of said cell; means for maintaining said cell at said established temperature to within a determined temperature range; and means for introducing a corrective factor to said alignment device to correct said change of said bias with change in temperature of said cell.
References Cited (Backward Citations)
US3621378A
Cited
US4157495A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1987-07-24 | 1988-01-23 | 1988-07-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-07-24 | 1992-01-23 | 1992-07-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-07-24 | 1996-01-23 | 1996-07-24 | $7700.00 | Window Closed / Lapsed |