Dynamic shielding in biomagnetism

Abstract

The paper presents an installation for biomagnetic studies and measurements in ambiental electromagnetic environment of the biomagnetic signals produced by the electrophysiological activities. The installation consists of a shielded room made from nonferromagnetic materials and introduced in the centre of a Helmholtz rectangular triaxial system. The triaxial Helmholtz coil system realizes the dynamic control and compensation of the natural geomagnetic perturbations and the fields produced by human activity. The shielded room accomplishes the shielding of medium and high frequency electromagnetic fields. For very low frequencies, the the dynamic compensation method is used, which provides the field control near zero values. The system can work in both manual and automatic mode. For the detection of the biomagnetic signals a HTS SQUID magnetometer with three orthogonal channels is used. The technical solutions and the performances of the installation are presented. © 2009 Springer.