An active method to reduce magnetic noise for measurements of human magnetic fields

Levels of artificial and geomagnetic fields are one million times higher than the levels of human magnetic fields. Therefore, the measurement of weak magnetic fields often requires shields which reduce external magnetic noise. Today, as opposed to expensive magnetically shielded rooms (MSRs), active shielding is a less expensive method of suppressing magnetic noise. Active suppression of magnetic noise is realized by a method of negative feedback. Based on this principle, we develop a device for the reduction of magnetic noise in three orthogonal planes. In this paper, we present the design and realization as well as first test measurements with this active magnetic shielding. We have obtained a reduction of 25 dB for external noise interferences. In the future, this device will allow to carry out magnetic measurements of biological objects without expensive antimagnetic rooms.