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How MuMetal Magnetic Shielding Works

Product Announcement from MuShield Company, Inc. (The)


When learning how magnetic fields work, think of the expanding rings on the surface of a pond caused by a single drop of water.  Magnetic flux actually looks like this. It will dissipate with distance, but unlike a drop of water on a pond, it will not move constantly outward like the wave on the surface of the water. Instead, magnetic flux travels around and around as if a pellet were dropped into a circular rim that tipped it around, allowing it to continually return to its place of origin.

When a magnetic field encounters high permeability magnetic shielding material (such as MuMetal or HyMu 80), the lines of flux are absorbed into the material like a sponge. A better analogy for this phenomenon is a beaver dam. When water hits a beaver dam, the water is keeping them safe. When we shield a sensitive instrument using high permeability magnetic shielding materials, the magnetic flux is absorbed and re-routed around the shield, keeping the instrument safe and operational.

If the high flux density field is too strong for the high permeability MuMetal magnetic shield, the shield will saturate. In this scenario, we would use a two-stage design with an outside layer of medium permeability/high saturation Alloy 49 magnetic shielding material (depending on the magnetic field strength) to dilute the burst of dense magnetic interference. The second layer of high permeability MuMetal magnetic shielding would absorb the residual magnetic flux. This double shield allows us to protect from sudden and dense magnetic shields, as well as shield from strong residual magnetic shields.

Do you have any applications that may require MuShield's MuMetal Magnetic Shielding? Contact us today and let us to go to work for you!