US3924176A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Magnetometer using superconducting rotating body
Assignee: National Aeronautics and Space Administration
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Filing: 1974-11-11
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Granted: 1975-12-02
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Expires: 1994-11-11
Abstract
Abstract A method and apparatus for measuring the strength and direction of an unknown magnetic field are disclosed. A freely rotatable suspended superconducting body, such as a sphere, is maintained at a superconducting temperature. A magnetic field to be measured induces super current flow on the sphere''s surface. The induced current causes the sphere to rotate at a rate that is proportional to the strength of the field, and the axis of rotation of the sphere aligns with the direction of the magnetic field to be measured. An operator applies current to orthogonal electro-magnetic coils arranged relative to the sphere so as to apply variable magnetic fields to the sphere. Varying the current and the resulting fields nulls out the effect of the magnetic field to be measured. As the field is nulled out, the angular momentum generated by the superconducting current flow is reduced to zero and the sphere stops rotating. An operator or an optical monitoring system determines the amount of current required by the electro-magnetic coils to achieve nulling. The measurement of the nulling currents thus can indicate the direction and strength of the unknown magnetic field.
Inventors
- 👤 James C Administrator Fletcher
- 👤 Melvin M Saffren
- 👤 Daniel D Elleman
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 19:40
CPC Classifications
G; G01; G01R; G01R33/00; G01R33/02; G01R33/035; Y; Y10; Y10S; Y10S505/00; Y10S505/825; Y10S505/842; Y10S505/843; Y10S505/845
Claims Analysis
Total Claims: 25
Claim 1
Independent Claim
86 words
A magnetometer for measuring the strength of a magnetic field comprising: a body capable of becoming superconducting at a critical temperature; means for maintaining the body at a temperature below the critical temperature; means for supporting the body to permit free rotation of the body in response to the induced flow of superconducting current on the body by the magnetic field; and sensing means for determining the strength of the magnetic field as a function of the rate of rotation of the mass of the body.
Claim 2
Dependent Claim
86 words
A magnetometer for measuring the strength of a magnetic field comprising: a body capable of becoming superconducting at a critical temperature; means for maintaining the body at a temperature below the critical temperature; means for supporting the body to permit free rotation of the body in response to the induced flow of superconducting current on the body by the magnetic field; and sensing means for determining the strength of the magnetic field as a function of the rate of rotation of the mass of the body.
Claim 3
Dependent Claim
36 words
The invention of claim 1 wherein the means for supporting the body includes at least a pair of levitation magnetic coils to counterbalance the forces of gravity whereby the body is suspended between the levitation coils.
Claim 4
Dependent Claim
44 words
The invention of claim 1 wherein the means for supporting the body includes at least a pair of closed loop superconducting coils carrying an electrical current which generates a combined uniform magnetic field and suspending field to suspend the body between the superconducting coils.
Claim 5
Dependent Claim
34 words
The invention of claim 1 wherein the means for suspending the body includes an acoustical transducer means for establishing a standing wave pressure pattern capable of holding the body at a minimum pressure position.
Claim 6
Dependent Claim
30 words
The invention of claim 1 wherein the sensing means includes at least one coil receiving electrical current for generating a uniform magnetic component to null the ortation of the body.
Claim 7
Dependent Claim
30 words
The invention of claim 5 wherein the amount of current flow to the coil to null the rotation of the body is representative of the strength of the magnetic field.
Claim 8
Dependent Claim
34 words
The invention of claim 6 further including feedback means for determining the relative rotation of the body and varying the current flow in response to the rotation to stop the rotation of the body.
Claim 9
Dependent Claim
29 words
The invention of claim 6 wherein the sensing means further includes a photodetector assembly means for producing an output signal representative of the rate of rotation of the body.
Claim 10
Dependent Claim
28 words
The invention of claim 8 wherein the body is a hollow sphere having exterior indicia to permit the determination of the body rotation by the photodetector assembly means.
Claim 11
Independent Claim
106 words
A method of measuring the strength and direction of an ambient magnetic field with a body capable of becoming superconducting at a critical temperature, comprising the steps of: maintaining the body at a temperature below the critical temperature; suspending the body, within the magnetic field, to permit free rotation of the body about an axis in response to the induced flow of superconducting current on the body by the magnetic field; and sensing the rate of rotation of the mass of the body and the direction of the axis of rotation wherein the strength and direction of the magnetic field can be determined as functions thereof.
Claim 12
Independent Claim
106 words
A method of measuring the strength and direction of an ambient magnetic field with a body capable of becoming superconducting at a critical temperature, comprising the steps of: maintaining the body at a temperature below the critical temperature; suspending the body, within the magnetic field, to permit free rotation of the body about an axis in response to the induced flow of superconducting current on the body by the magnetic field; and sensing the rate of rotation of the mass of the body and the direction of the axis of rotation wherein the strength and direction of the magnetic field can be determined as functions thereof.
Claim 13
Dependent Claim
45 words
The invention of claim 10 further including the step of applying a torque to the body to null the magnetic field induced rotation wherein the amount of torque and the direction of the torque are representative of respectively strength and direction of the magnetic field.
Claim 14
Dependent Claim
17 words
The invention of claim 10 wherein the body is suspended by the application of a magnetic field.
Claim 15
Dependent Claim
18 words
The invention of claim 10 wherein the rate of rotation and the direction of rotation is sensed optically.
Claim 16
Dependent Claim
16 words
The invention of claim 10 wherein the body is suspended by the application of acoustical pressure.
Claim 17
Dependent Claim
34 words
The invention of claim 11 wherein the torque applied to the body to nullify its rotation is a magnetic field having a uniform component that opposes the directional component of the ambient magnetic field.
Claim 18
Dependent Claim
113 words
A magnetometer for measuring the strength and direction of a magnetic field comprising: a body capable of becoming superconducting at a critical temperature; means for maintaining the body at a temperature below the critical temperature; suspension means for suspending the body to permit free rotation of the body about an axis in response to the angular momentum torque generated by the induced flow of superconducting current on the body by the magnetic field; and sensing means for determining the strength and direction of the magnetic field as a function respectively of the rate of rotational angular momentum force imposed on the mass of the body and the direction of the axis of rotation.
Claim 19
Dependent Claim
113 words
A magnetometer for measuring the strength and direction of a magnetic field comprising: a body capable of becoming superconducting at a critical temperature; means for maintaining the body at a temperature below the critical temperature; suspension means for suspending the body to permit free rotation of the body about an axis in response to the angular momentum torque generated by the induced flow of superconducting current on the body by the magnetic field; and sensing means for determining the strength and direction of the magnetic field as a function respectively of the rate of rotational angular momentum force imposed on the mass of the body and the direction of the axis of rotation.
Claim 20
Dependent Claim
42 words
The invention of claim 16 wherein the means for supporting the body includes at least a pair of electrically isolated closed loop superconducting coils carrying a current flow for generating a gradient magnetic field to suspend the body between the superconducting coils.
Claim 21
Dependent Claim
34 words
The invention of claim 16 wherein the means for suspending the body includes an acoustical transducer means for establishing a standing wave pressure pattern capable of suspending the body at a minimum pressure position.
Claim 22
Dependent Claim
30 words
The invention of claim 16 wherein the sensing means includes at least three coils receiving current flow and generating a uniform magnetic component to null the rotation of the body.
Claim 23
Dependent Claim
16 words
The invention of claim 19 wherein the three coils also suspend the body for free rotation.
Claim 24
Dependent Claim
34 words
The invention of claim 16 further including feedback means for determining the relative rotation of the body and varying the current flow in response to the rotation to stop the rotation of the body.
Claim 25
Dependent Claim
29 words
The invention of claim 21 wherein the sensing means further includes a photodetector assembly means for producing an output signal representative of the rate of rotation of the body.
References Cited (Backward Citations)
US3454875A
Cited
US3667033A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-12-01 | 1979-06-02 | 1979-12-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-12-01 | 1983-06-02 | 1983-12-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-12-01 | 1987-06-02 | 1987-12-02 | $7700.00 | Window Closed / Lapsed |