A multi-channel biomagnetometer system for operation in unshielded environments
Abstract
We have recently completed a 6-channel biomagnetometer system for operation in unshielded environments. In this system, directly coupled high-Tc DC SQUID magnetometers are used as magnetic sensors. Expanding on the principle of a three-squid gradiometer, the magnetometers are configured as electronic first-order gradiometers, while at each sensor a common magnetic field was applied, cancelling out the background field as measured by a common reference magnetometer. Additional magnetometers were used as references to measure the magnetic fields in directions orthogonal to the main direction of interest. Using this setup completely unshielded in a laboratory environment, a noise floor of a few pT/√Hz at 1 Hz was achieved, and we were able to resolve the magnetic signature of a human heartbeat.
- Publication:
-
APS March Meeting Abstracts
- Pub Date:
- March 1997
- Bibcode:
- 1997APS..MAR.A1006W