Active Shielding in Measurements of DC Near Biomagnetic Fields.

摘要

Measurements of DC near biomagnetic fields are disturbed by low frequency noise, that are not reduced sufficiently by most of the magnetically shielded rooms or gradiometers. An effective SQUID based active shielding system has been developed and installed at the magnetically shielded rooms in the Biomagnetic Center of the University Jena to reduce external low frequency disturbances. A reduction of the magnetic noise of about 23 dB could be achieved at 50 mHz.