EP0481211A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Gradiometer having a magnetometer which cancels background magnetic field from other magnetometers
Assignee: International Business Machines Corp
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Filing: 1991-09-10
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Granted: —
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Expires: 2011-09-10
Abstract
Abstract A gradiometer utilizing at least three vector magnetometers (11, 12, 13) (preferably SQUIDs) to measure a magnetic field gradient. An average magnetometer (13) (SQUID) is used to cancel background magnetic fields from outputs of the difference magnetometers (11, 12) via a feedback loop (21, 22, 23) provided with a signal from the average magnetometer (13). Similarly, higher order gradiometers can be built using an average magnetometer cube and a plurality of difference magnetometer cubes. The gradiometer would find application in a wide range of fields, such as geology and medecine.
Inventors
- 👤 Roger H. Koch
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-06 18:09
CPC Classifications
G; G01; G01R; G01R33/00; G01R33/02; G01R33/022; Y; Y10; Y10S; Y10S505/00; Y10S505/825; Y10S505/842; Y10S505/843; Y10S505/845; Y10S505/846
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
83 words
A gradiometer for measuring a magnetic field gradient, comprising: a plurality of difference magnetometers (11, 12) each producing an output; an average magnetometer (13) rigidly mounted to said plurality of difference magnetometers (11, 12), said average magnetometer (13) cancelling a background magnetic field from respective outputs of said plurality of difference magnetometers (11, 12) to produce a plurality of cancelled different magnetometer outputs; and means for providing said magnetic field gradient by performing magnetic subtraction on said plurality of cancelled difference magnetometer outputs.
Claim 2
Dependent Claim
19 words
A gradiometer as claimed in claim 1, wherein said difference magnetometers (11, 12) are Superconducting Quantum Interference Devices (SQUIDs).
Claim 3
Dependent Claim
21 words
A gradiometer as claimed in claim 1 or 2, wherein said average magnetometer (13) is a Superconducting Quantum Interference Device (SQUID).
Claim 4
Dependent Claim
25 words
A gradiometer as claimed in any of the above claims, wherein said average magnetometer (13) provides a feedback signal to cancel said background magnetic field.
Claim 5
Dependent Claim
19 words
A gradiometer as claimed in any of the above claims, wherein said SQUIDs include Josephson elements having weak links.
Claim 6
Dependent Claim
19 words
A gradiometer as claimed in claims 2-5, wherein high T c superconductive materials are used for fabricating said SQUIDs.
Claim 7
Dependent Claim
21 words
A gradiometer as claimed in any of the above claims, wherein a number of said difference magnetometers (11, 12) is two.
Claim 8
Dependent Claim
26 words
A gradiometer as claimed in any of the above claims, wherein superconducting loops of each of said magnetometers (11, 12, 13) are parallel to each other.
Claim 9
Dependent Claim
44 words
A gradiometer as claimed in claim 1, further comprising a feedback coil (21, 22, 23) associated with each of said difference magnetometers (11, 12) and said average magnetometer (13) wherein said feedback coils (21, 22, 23) are used to cancel said background magnetic field.
Claim 10
Dependent Claim
44 words
A gradiometer as claimed in claim 1, wherein each of said difference magnetometers (11, 12) and said average magnetometer (13) is a magnetometer cube provided with a first magnetometer, a second magnetometer and a third magnetometer on respective non-parallel sides of said magnetometer cube.
Claim 11
Dependent Claim
17 words
A gradiometer as claimed in claim 10, wherein a number of said difference magnetometer cubes is three.
Claim 12
Dependent Claim
25 words
A gradiometer as claimed in claim 11, wherein said three difference magnetometer cubes and said average magnetometer cube are all situated in a common plane.
Claim 13
Dependent Claim
17 words
A gradiometer as claimed in claim 10, wherein a number of said difference magnetometer cubes is two.
Claim 14
Dependent Claim
25 words
A gradiometer as claimed in claim 13, wherein said two difference magnetometer cubes and said average magnetometer cube are all situated in a common line.
Claim 15
Dependent Claim
25 words
A gradiometer as claimed in any of the above claims, wherein said gradiometer makes at least a five axis measurement of said magnetic field gradient.
References Cited (Backward Citations)
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