MULTICHANNEL HEART SCANNER BASED ON HIGH-TC SQUIDS

A 7-channel magnetometer for magnetocardiography based on high-T-c SQU IDs has been realized, This magnetometer is used for test experiments in the development of a multichannel high-T-c SQUID based heart-scanne r for clinical applications, The intrinsic noise level of the channels in the 7-channel system is typically 120 fT/root Hz down to 1 Hz. Mag netocardiograms were recorded inside a magnetically shielded room, Int roductory experiments were performed on the suppression of noise by co mbining magnetometers to form planar gradiometers. The noise suppressi on that can be established appeared to be limited by the imbalance of the gradiometric configuration, which is roughly 2%. This relatively p oor balance of the system is caused by inaccuracies in the transfer fu nctions of the individual SQUID magnetometers, and by deviations from the planar geometry.