Magnetic Field Detection Using SQUID
Magnetic current imaging uses the magnetic fields produced by currents in electronic devices to obtain images of those currents. This is accomplished though the fundamental physics relationship between magnetic fields and current, the Biot-Savart Law:
- B is the magnetic induction, Idℓ is an element of the current, the constant µ0 is the permeability of free space, and r is the distance between the current and the sensor.
As a result, the current can be directly calculated from the magnetic field knowing only the separation between the current and the magnetic field sensor. The details of this mathematical calculation can be found elsewhere, but what is important to know here is that this is a direct calculation that is not influenced by other materials or effects, and that through the use of Fast Fourier Transforms these calculations can be performed very quickly. A magnetic field image can be converted to a current density image in about 1 or 2 seconds.
Read more about this topic: Scanning SQUID Microscope, High Temperature Scanning SQUID Microscope
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