Shielding from External Magnetic Fields
From a HS physics teacher: A conducting enclosure provides shielding
from external electric fields. Is there any way to shield something
from external MAGNETIC fields?
Yes - a superconducting enclosure! There is also
something called mu-metal but I am not sure how
it works. You might want to look up the literature
on magnetic monopole searches to see what kind of
equipment they used.
In particle physics we often use mu-metal (mentioned
in the first reply) to shield our detectors from magnetic
fields. This is a big problem because the beams of particles
used in particle physics are always directed and focussed
by magnets, but the detectors used to detect particles
are sensitive to the magnetic fields, and kidisrupt things.
We wrap or surround the detectors with this special metal.
I think the helpful property of the material is that the
magnetic permeability of the metal, mu (as it is called in
most textbooks), is greater than that of the detector you
want to shield. So, in a sense, it "absorbs" the em field
This is a sketchy anwswer, and if you want to really find out
how mu metal works I can detail it for you. You can also
find it for yourself in any books on detectors or detection
robin d erbacher
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Update: June 2012