US3916248A
Expired / Lapsed
US
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Superconductive gradiometric device
Assignee: United States Department of the Navy
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Filing: 1970-04-06
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Granted: 1975-10-28
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Expires: 1990-04-06
Abstract
Abstract A gradiometer in which two superconductive identical sensing coils are aligned with their axes parallel, the coils being spaced from one another along a common or another axis. The coils are series connected in opposition so that any net current flowing therein induced by a common field is proportional to a gradient in the field component parallel to the axes of the coils. This net current is detected by a superconductive sensor such as a Josephson Magnetometer tightly coupled to a drive coil connected as a load across the sensing coils, the superconductive sensor and the drive coil being magnetically shielded from the field to which the sensing coils are exposed. A ranging system is formed of two such gradiometers by aligning the latter along a field gradient from a magnetic field source, obtaining scaled sum and differences of the signals from the gradiometers and providing the ratio of the sum and difference. The resulting ratio is proportional to the distance from the gradiometer to the field source.
Inventors
- 👤 James Nicol
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 11:16
CPC Classifications
G; G01; G01R; G01R33/00; G01R33/02; G01R33/022; G01R33/035; G01R33/0354; G01R33/0358; Y; Y10; Y10S; Y10S505/00; Y10S505/825; Y10S505/842; Y10S505/843; Y10S505/845
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
177 words
A magnetometric system for determining the range to a source of magnetic field, and comprising in combination a first gradiometer having first and second sensing coils formed of superconductive material and spaced from one another, said coils being aligned so that their long axes are nonperpendicular to one another, said coils being series connected in opposed sense so as to form a continuous superconducting circuit, and superconductive means for detecting and producing first output signal proportional to the net current flowing through said coils; a second like gradiometer spaced from said first gradiometer, for producing a second output signal proportional to the net current flowing in its coils; means for adding the first and second signals and scaling the sum thereof to produce a sum signal; means for producing a difference signal proportional to the difference between said first and second signals and scaled relative to the spacing between said magnetometers; and means for providing a system outpuT signal proportional to the ration of said sum and difference signals, said output signal being proportional to said range.
Claim 2
Dependent Claim
177 words
A magnetometric system for determining the range to a source of magnetic field, and comprising in combination a first gradiometer having first and second sensing coils formed of superconductive material and spaced from one another, said coils being aligned so that their long axes are nonperpendicular to one another, said coils being series connected in opposed sense so as to form a continuous superconducting circuit, and superconductive means for detecting and producing first output signal proportional to the net current flowing through said coils; a second like gradiometer spaced from said first gradiometer, for producing a second output signal proportional to the net current flowing in its coils; means for adding the first and second signals and scaling the sum thereof to produce a sum signal; means for producing a difference signal proportional to the difference between said first and second signals and scaled relative to the spacing between said magnetometers; and means for providing a system outpuT signal proportional to the ration of said sum and difference signals, said output signal being proportional to said range.
Claim 3
Dependent Claim
174 words
A gradiometric system comprising, in combination first and second sensing coils formed of superconductive material, said coils be spaced from one another and aligned so that their long axes are non-perpendicular, said coils being connected in an electrical series relationship so as to form a continuous superconducting circuit such that the current induced in said coils by a common regular magnetic field oppose one another, superconductive means for detecting and for producing an output signal proportional to the net difference between said currents, said last mentioned means including a third coil formed of superconductive material and connected in series as a load across said first and second sensing coils so as to form a continuous closed superconducting current circuit and a superconductive sensor device responsive to magnetic field change and disposed adjacent said third coil so as to detect magnetic fields due to current flow through said third coil, and means for magnetically shielding said superconductive means for detecting and for producing said output signal from fields affecting said first and second sensing coils.
Claim 4
Dependent Claim
174 words
A gradiometric system comprising, in combination first and second sensing coils formed of superconductive material, said coils be spaced from one another and aligned so that their long axes are non-perpendicular, said coils being connected in an electrical series relationship so as to form a continuous superconducting circuit such that the current induced in said coils by a common regular magnetic field oppose one another, superconductive means for detecting and for producing an output signal proportional to the net difference between said currents, said last mentioned means including a third coil formed of superconductive material and connected in series as a load across said first and second sensing coils so as to form a continuous closed superconducting current circuit and a superconductive sensor device responsive to magnetic field change and disposed adjacent said third coil so as to detect magnetic fields due to current flow through said third coil, and means for magnetically shielding said superconductive means for detecting and for producing said output signal from fields affecting said first and second sensing coils.
Claim 5
Dependent Claim
18 words
In a system as defined in claim 2 wherein said superconductive sensor device is a Meissner superconductive magnetometer.
Claim 6
Dependent Claim
18 words
In a system as defined in claim 2 wherein said superconductive sensor device is a Josephson superconductive magnetometer.
Claim 7
Dependent Claim
17 words
In a system as defined in claim 2 wherein said superconductive sensor device is quantized-flux superconductive magnetometer.
Claim 8
Dependent Claim
18 words
In an arrangement as defined in claim 2 wherein said first and second sensing coils are substantially identical.
Claim 9
Dependent Claim
55 words
In a system as defined in claim 6 wherein the cross-section of each of said first and second sensing coils is larger than the cross-section of said third coil and wherein the number of turns of said third coil is greater than the number of turns of each of said first and second sensing coils.
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) | 1978-10-27 | 1979-04-28 | 1979-10-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-10-27 | 1983-04-28 | 1983-10-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-10-27 | 1987-04-28 | 1987-10-28 | $7700.00 | Window Closed / Lapsed |