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Optimal Faraday cage

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Foil is not much good for large shields. With larger shield cans and rooms the thickness needs to be greater to do much. It basically scales with size.

Doors are the biggest problem because there is always a clearance for it to be able to move. A large flap around the door helps a lot.

Pound for pound aluminum is better. For large shields, copper becomes impractical. Aluminum is far easier to support. The welding of the joints requires someone with skill to do. With copper, you can solder the joints.

Reply to
MooseFET
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Skin depth is the smaller of the two effects governing low frequency shielding. The bigger one is that the continuous conductor suppresses the B field in its neighbourhood. The leakage due to finite skin depth has to be calculated _after_ the field suppression.

Also it's hard to get the full effect of mu metal in a large fabrication, because it's so delicate--the mu drops like a rock if you bang it or bend it, and it has to be re-annealed. It's tough to anneal a shield room!

Cheers

Phil Hobbs

--
Dr Philip C D Hobbs
Principal
ElectroOptical Innovations
55 Orchard Rd
Briarcliff Manor NY 10510
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email: hobbs (atsign) electrooptical (period) net
http://electrooptical.net
Reply to
Phil Hobbs

Reminds me of a l-o-o-o-n-g time ago when we at Philips had the only large kiln around capable of holding a mu-metal shield about 1.5 m diameter and 1 m high, wanted for some scientific experiment by a defence department. They provided the shield, and told us the temperature profile they wanted for annealing, in pure nitrogen. No problem, it got done on night shift, when we were not using that kiln for production. Only problem was that someone got the instructions mixed up, and fired in pure oxygen. Was a bit of a surprise when they opened the kiln, and found a small pile of powder.

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Regards,

Adrian Jansen           adrianjansen at internode dot on dot net
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Reply to
Adrian Jansen

Wow, I hope that person got...fired (use your imagination as to how)!

Tim

--
Deep Friar: a very philosophical monk.
Website: http://webpages.charter.net/dawill/tmoranwms
Reply to
Tim Williams

Ouch. The mere thought of it, makes my oyes glaze.

--
Dave Platt                                    AE6EO
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Reply to
Dave Platt

Pobably cost them the price of the item plus a penalty as well.

Several tens of $ks sounds likely.

Reply to
I AM THAT I AM

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