MicroSQUID: A Close-Spaced Four Channel Magnetometer

Typical SQUID-based magnetometers are currently constructed with 15 to 25 mm diameter coils that are spaced back from the room temperature measurement surface 12 to 20 mm. Both of these dimensions limit the spatial resolution of these systems. To understand the fundamental determinants of magnetic fields produced by bioelectric activity, better spatial resolution is needed (Wikswo, 1988). To address this need we have developed a close-spaced, four-channel magnetometer having 3mm diameter first-order assymetric gradiometer pick-up coils spaced on a 4.4mm grid and residing < 1.5 mm from the measurement surface which is at room temperature: μSQUID™.