The SQUID magnetometer technology developed for cryoEDM has potential further applications in many other areas of physics. We have carried out geomagnetic measurements, in collaboration with the LSBB low noise underground laboratory.

We worked with the team at LSBB on a joint project to measure the magnetic signal from groundwater flow. During this investigation we established the principle of using two 3-axis SQUID magnetometers to subtract the dominant magnetic field fluctuations from ionospheric currents, and search for a weak local signal, as might be produced by water flow. We then conducted two long term measurements to search for such a signal.

We are now investigating industrial applications for geophysical exploration with support from the STFC Follow on Fund.

SQUIDs can track the three vector components of magnetic field fluctuations at a fast rate, however a ³He measurement is needed to provide an absolute calibration. A hybrid SQUID-³He probe may be the ultimate magnetometer for a future generation of geomagnetic observatories.

References

Tracking geomagnetic fluctuations to picotesla accuracy using two SQUID vector magnetometers, S. Henry, E. Pozzo di Borgo, A. Cavaillou, Rev. Sci. Instrum. 84 024501 (2013).