Three axis SQUID magnetometer for low-frequency geophysical applications

Abstract

We have developed a compact low-Tc three axis superconducting quantum interference device magnetometer (SQUID magnetometer) for geophysical applications at low frequency from dc up to 1 kHz, such as for searching for magnetized metals buried under the ground or moving magnetized objects, and for measurements of the geomagnetic fields. Relaxation oscillation SQUIDs (ROSs) which have larger voltage outputs compared to that of standard SQUIDs have been used so that larger dynamic performance is obtained for stable operation in the field.