US4409579A
Expired / Lapsed
US
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Superconducting magnetic shielding apparatus and method
Assignee: United States Department of Energy
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Filing: 1982-07-09
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Granted: 1983-10-11
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Expires: 2002-07-09
Abstract
Abstract Disclosed is a method and apparatus for providing magnetic shielding around a working volume. The apparatus includes a hollow elongated superconducting shell or cylinder having an elongated low magnetic pinning central portion, and two high magnetic pinning end regions. Transition portions of varying magnetic pinning properties are interposed between the central and end portions. The apparatus further includes a solenoid substantially coextensive with and overlying the superconducting cylinder, so as to be magnetically coupled therewith. The method includes the steps passing a longitudinally directed current through the superconducting cylinder so as to depin magnetic reservoirs trapped in the cylinder. Next, a circumferentially directed current is passed through the cylinder, while a longitudinally directed current is maintained. Depinned magnetic reservoirs are moved to the end portions of the cylinder, where they are trapped.
Inventors
- 👤 John R. Clem
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 06:44
CPC Classifications
G; G01; G01R; G01R33/00; G01R33/20; G01R33/28; G01R33/42; G01R33/421; G01R33/38; G01R33/381; G01R33/3815; Y; Y10; Y10S; Y10S505/00; Y10S505/825; Y10S505/872
Claims Analysis
Total Claims: 21
Claim 1
Independent Claim
102 words
An apparatus for providing a magnetic shield around a working volume, comprising: (a) first cylinder of superconducting material surrounding said working volume, said first cylinder having an axis, a circumference, a central portion of predetermined magnetic pinning properties, end portions of higher magnetic pinning properties, and transition regions interposed between said central and said end portions, said transition regions having a predetermined length and magnetic pinning properties which vary monotonically along the length of said transition regions: (b) first current means for generating circumferentially-directed currents in said first cylinder; and (c) second current means for generating axially-directed currents in said first cylinder.
Claim 2
Independent Claim
102 words
An apparatus for providing a magnetic shield around a working volume, comprising: (a) first cylinder of superconducting material surrounding said working volume, said first cylinder having an axis, a circumference, a central portion of predetermined magnetic pinning properties, end portions of higher magnetic pinning properties, and transition regions interposed between said central and said end portions, said transition regions having a predetermined length and magnetic pinning properties which vary monotonically along the length of said transition regions: (b) first current means for generating circumferentially-directed currents in said first cylinder; and (c) second current means for generating axially-directed currents in said first cylinder.
Claim 3
Dependent Claim
24 words
The apparatus of claim 1 wherein said first current means comprise electrical solenoid means magnetically coupled to said transition regions of said first cylinder.
Claim 4
Dependent Claim
26 words
The apparatus of claim 1 wherein said second current means comprise means for connecting end portions of said first cylinder to a first external electrical circuit.
Claim 5
Dependent Claim
25 words
The apparatus of claim 1 wherein said second current means comprise a second electrically conductive cylinder disposed within said first cylinder in electrical connection therewith.
Claim 6
Dependent Claim
34 words
The apparatus of claim 4 wherein said second current means comprise means for electrically connecting a first and a second end portion of said second electrically conductive cylinder to a first external electrical circuit.
Claim 7
Dependent Claim
34 words
The apparatus of claim 1 wherein said central portion of said first cylinder has a predetermined critical magnetic depinning current, and said first curremt means generates a current exceeding said critical magnetic depinning current.
Claim 8
Dependent Claim
21 words
The apparatus of claim 6 wherein said second current means generates a current which exceeds said predetermined critical magnetic depinning current.
Claim 9
Dependent Claim
20 words
The apparatus of claim 1 further including means for reversing the direction of current flow of said first current means.
Claim 10
Dependent Claim
20 words
The apparatus of claim 1 further including means for reversing the direction of current flow of said second current means.
Claim 11
Dependent Claim
28 words
The apparatus of claim 1 wherein said transition regions comprise overlapping first and second layers of varying thickness magnetic pinning materials, said materials having different magnetic pinning properties.
Claim 12
Dependent Claim
26 words
The arrangement of claim 1 wherein said transition regions comprise a transition material having substantially uniform magnetic pinning properties and a varying thickness throughout its length.
Claim 13
Dependent Claim
25 words
The arrangement of claim 4 wherein said first and said second cylinders each have first and second ends of reduced and enlarged circumferential dimensions, respectively.
Claim 14
Independent Claim
155 words
A method for providing an ultra-low magnetic field in a superconducting shield apparatus which comprises a first cylinder of superconducting material having an axis, a circumference, a central portion of predetermined magnetic pinning properties, end portions of higher magnetic pinning properties, and transition regions interposed between said central and said end portions, said transition regions having a predetermined length and magnetic pinning properties which vary monotonically along the length of said transition regions, the method comprising the steps of: (a) passing an axially-directed current through said first cylinder so as to depin and mutually annihilate magnetic vortices and antivortices trapped in said central portion of said first cylinder; (b) passing circumferentially-directed current through said central region of said first cylinder so as to depin magnetic vortices and antivortices trapped in said cylinder; and (c) moving said depinned vortices and antivortices in opposing axial directions so as to cause mutual annihilation of said vortices and antivortices.
Claim 15
Independent Claim
155 words
A method for providing an ultra-low magnetic field in a superconducting shield apparatus which comprises a first cylinder of superconducting material having an axis, a circumference, a central portion of predetermined magnetic pinning properties, end portions of higher magnetic pinning properties, and transition regions interposed between said central and said end portions, said transition regions having a predetermined length and magnetic pinning properties which vary monotonically along the length of said transition regions, the method comprising the steps of: (a) passing an axially-directed current through said first cylinder so as to depin and mutually annihilate magnetic vortices and antivortices trapped in said central portion of said first cylinder; (b) passing circumferentially-directed current through said central region of said first cylinder so as to depin magnetic vortices and antivortices trapped in said cylinder; and (c) moving said depinned vortices and antivortices in opposing axial directions so as to cause mutual annihilation of said vortices and antivortices.
Claim 16
Dependent Claim
49 words
The method of claim 13 wherein said step of passing an axially-directed current in said first cylinder comprises the step of passing an electrical current through a second electrically conductive cylinder which is disposed within and coextensive with said first cylinder, so as to be in electrical connection therewith.
Claim 17
Dependent Claim
45 words
The method of claim 13 wherein the steps of passing circumferentially-directing currents through said first cylinder comprises the step of energizing a coaxial solenoid which is substantially coextensive with and surrounds said first cylinder, so as to be set up an axially-directed magnetic field therethrough.
Claim 18
Dependent Claim
27 words
The method of claim 13 further including the step of altering the first current means so as to reverse the direction of flow of said circumferentially-directed currents.
Claim 19
Dependent Claim
31 words
The method of claim 16 further including the step of altering said second current means so as to reverse the direction of flow of said axially-directed currents in said first cylinder.
Claim 20
Dependent Claim
91 words
The method of claim 17 further including a repetition of the steps of reversing the direction of flow of longitudinal and circumferentially-directed currents so as to depin vortices and antivortices in said transition regions of said cylinder, and so as to depin any remaining vortices and antivortices trapped in said central portion of said first cylinder, until the number of longitudinal flux quanta threading through the interior of the first cylinder is reduced to zero and said central portion of said first cylinder is rendered free of trapped vortices and antivortices.
Claim 21
Dependent Claim
59 words
The method of claim 13 further including the step of cooling said first cylinder in the presence of an external axially-directed magnetic field so as to cancel axially-directed magnetic flux threading through ends of said central region of said first cylinder, and so as to create reservoirs of vortices and antivortices in said transition regions of said first cylinder.
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) | 1986-10-10 | 1987-04-11 | 1987-10-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1990-10-10 | 1991-04-11 | 1991-10-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1994-10-10 | 1995-04-11 | 1995-10-11 | $7700.00 | Window Closed / Lapsed |