DEVELOPMENT OF A HEART MONITORING-SYSTEM WITH HIGH-T-C DC-SQUID GRADIOMETERS

We investigated different types of high-T-C DC-SQUID gradiometers with the aim to develop an one-channel heart monitoring system for non-inv asive measurements in unshielded environment. This system could be use d to obtain information about the patients condition in serial examina tions and in Emergency cases fast and stable. Step-edge and bicrystal Josephson junctions were used to prepare planar galvanically coupled t hin film gradiometers and magnetometers. These sensors were used to ca rry out measurements in well-shielded and non-shielded environment and we compared the different noise properties and field gradient resolut ions. With different types and sizes of high-T-c DC-SQUID sensors magn etocardiograms were measured in a magnetically shielded room. The infl uence of antenna configurations, SQUID parameters, and cooling conditi ons on the measurement of magnetocardiograms will be discussed. We inv estigated possibilities to suppress the earth magnetic field (with pai rs of Helmholtz coils) and for noise field compensation in unshielded environment.