Magnetic background noise cancellation in a biomagnetometer system for unshielded environments
Abstract
We are presently building a 7-channel high-Tc SQUID-based biomagnetometer system to measure magnetocardiograms in an unshielded environment. The main challenge in such a system is to resolve the very small magnetic signals originating from the human heart in the noisy magnetic background of a real-world environment. In this biomagnetometer setup, the SQUID sensors are being used in a three-SQUID gradiometer arrangement. The sensors are configured as first-order gradiometers, and at each sensor a common magnetic field is applied to cancel out the background field as measured by a reference sensor. To investigate the limits of magnetic background noise cancellation, the frequency dependence of the correlation between the magnetic backgrounds at two positions was measured as a function of distance between these positions. Furthermore, a study was made of how eddy currents induced in nearby metallic objects affect these correlations and the background noise cancellation.
- Publication:
-
APS March Meeting Abstracts
- Pub Date:
- March 1996
- Bibcode:
- 1996APS..MAR.G2103W