Optimization Theory for Induction-Coil Magnetometers at Higher Frequencies

An optimization theory for iron-cored induction-coil magnetometers in the audiofrequency range and above is described. The article shows, in a closed mathematical form, that for a given sensor weight a limited length of the ferromagnetic core and a chosen high-end cutoff frequency in combination with an available preamplifier there exists one particular magnetometer configuration, exhibiting minimum equivalent magnetic-field noise. The optimum parameters can be determined for any set of boundary conditions with only a few calculations.