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Title: Magnetic shielding

Abstract

A magnetically-conductive filler material bridges the gap between a multi-part magnetic shield structure which substantially encloses a predetermined volume so as to minimize the ingress or egress of magnetic fields with respect to that volume. The filler material includes a heavy concentration of single-magnetic-domain-sized particles of a magnetically conductive material (e.g. soft iron, carbon steel or the like) dispersed throughout a carrier material which is generally a non-magnetic material that is at least sometimes in a plastic or liquid state. The maximum cross-sectional particle dimension is substantially less than the nominal dimension of the gap to be filled. An epoxy base material (i.e. without any hardening additive) low volatility vacuum greases or the like may be used for the carrier material. The structure is preferably exposed to the expected ambient magnetic field while the carrier is in a plastic or liquid state so as to facilitate alignment of the single-magnetic-domain-sized particles with the expected magnetic field lines. 3 figs.

Inventors:
; ;
Publication Date:
OSTI Identifier:
7147608
Patent Number(s):
US 4698197; A
Application Number:
PPN: US 6-701010
Assignee:
Dept. of Energy, Washington, DC (United States) PTO; EDB-94-124978
DOE Contract Number:
W-7405-ENG-48
Resource Type:
Patent
Resource Relation:
Patent File Date: 12 Feb 1985
Country of Publication:
United States
Language:
English
Subject:
42 ENGINEERING; MAGNETIC SHIELDING; SHIELDS; DESIGN; EPOXIDES; SHIELDING MATERIALS; MATERIALS; ORGANIC COMPOUNDS; ORGANIC OXYGEN COMPOUNDS; SHIELDING; 420200* - Engineering- Facilities, Equipment, & Techniques

Citation Formats

Kerns, J.A., Stone, R.R., and Fabyan, J.. Magnetic shielding. United States: N. p., 1987. Web.
Kerns, J.A., Stone, R.R., & Fabyan, J.. Magnetic shielding. United States.
Kerns, J.A., Stone, R.R., and Fabyan, J.. 1987. "Magnetic shielding". United States. doi:.
@article{osti_7147608,
title = {Magnetic shielding},
author = {Kerns, J.A. and Stone, R.R. and Fabyan, J.},
abstractNote = {A magnetically-conductive filler material bridges the gap between a multi-part magnetic shield structure which substantially encloses a predetermined volume so as to minimize the ingress or egress of magnetic fields with respect to that volume. The filler material includes a heavy concentration of single-magnetic-domain-sized particles of a magnetically conductive material (e.g. soft iron, carbon steel or the like) dispersed throughout a carrier material which is generally a non-magnetic material that is at least sometimes in a plastic or liquid state. The maximum cross-sectional particle dimension is substantially less than the nominal dimension of the gap to be filled. An epoxy base material (i.e. without any hardening additive) low volatility vacuum greases or the like may be used for the carrier material. The structure is preferably exposed to the expected ambient magnetic field while the carrier is in a plastic or liquid state so as to facilitate alignment of the single-magnetic-domain-sized particles with the expected magnetic field lines. 3 figs.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = 1987,
month =
}
  • 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,more » 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.« less
  • A magnetically-conductive filler material bridges the gap between a multi-part magnetic shield structure which substantially encloses a predetermined volume so as to minimize the ingress or egress of magnetic fields with respect to that volume. The filler material includes a heavy concentration of single-magnetic-domain-sized particles of a magnetically conductive material (e.g. soft iron, carbon steel or the like) dispersed throughout a carrier material which is generally a non-magnetic material that is at least sometimes in a plastic or liquid state. The maximum cross-sectional particle dimension is substantially less than the nominal dimension of the gap to be filled. An epoxymore » base material (i.e. without any hardening additive) low volatility vacuum greases or the like may be used for the carrier material. The structure is preferably exposed to the expected ambient magnetic field while the carrier is in a plastic or liquid state so as to facilitate alignment of the single-magnetic-domain-sized particles with the expected magnetic field lines.« less
  • A neutron generator in which a target plate is bombarded by ions of a hydrogen isotope is described. The ions are formed in a discharge that takes place between two flat plates, one of which is provided with an aperture for the ions produced, serving as a cathode. The discharge is surrounded by a cylindrical anode. An axial magnetic field is provided, which is, in accordance with the invention, completely screened from the acceleration space, the space between the target electrode and the apertured plate. There is no magnetic field in the acceleration space, so that higher acceleration voltages aremore » permissible, since the reduction of the breakdown voltage by the apparent increase in pressure due to the presence of a magnetic field does not occur in this case. (M.C.G.)« less
  • A magnetically-conductive filler material bridges the gap between a multi-part magnetic shield structure which substantially encloses a predetermined volume so as to minimize the ingress or egress of magnetic fields with respect to that volume. The filler material includes a heavy concentration of single-magnetic-domain-sized particles of a magnetically conductive material (e.g. soft iron, carbon steel or the like) dispersed throughout a carrier material which is generally a non-magnetic material that is at least sometimes in a plastic or liquid state. The maximum cross-sectional particle dimension is substantially less than the nominal dimension of the gap to be filled. An epoxymore » base material (i.e. without any hardening additive) low volatility vacuum greases or the like may be used for the carrier material. The structure is preferably exposed to the expected ambient field while the carrier is in a plastic or liquid state so as to facilitate alignment of the single-magnetic-domain-sized particles with the expected magnetic field lines.« less
  • 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,more » 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.« less