DC-SQUID magnetometer system for detecting vector value of magnetic field

A vector magnetometer system for biomagnetic applications is described. The system consists of two vector magnetometers, each comprising three integrated SQUID (superconducting quantum interference device) magnetometers located perpendicularly to each other to detect three orthogonal components of the magnetic field simultaneously. The resolution of each orthogonal component is 11 fT/ square root Hz in the write noise region. This system has been used in magneto-cardiography and for measuring the spontaneous magnetic field from the human brain.>