Tracking geomagnetic fluctuations to picotesla accuracy using two superconducting quantum interference device vector magnetometers
- University of Oxford, Department of Physics, Denys Wilkinson Building, Keble Road, Oxford OX1 3RH (United Kingdom)
- UAPV, UMR1114 EMMAH, F-84914 Avignon, France and INRA, UMR1114 EMMAH, F-84914 Avignon (France)
- LSBB URL, UMS 3538 UNS/UAPV/CNRS La Grande Combe, F-84400 Rustrel (France)
SQUIDs can be used to monitor the three vector components of the geomagnetic field to a high precision at very low frequencies, yet as they are susceptible to external interference, the accuracy to which they can track changes in the dc field over long periods has been unclear. We have carried out simultaneous measurements of the geomagnetic field recorded using two independent 3-axis SQUID magnetometers at the Laboratoire Souterrain a Bas Bruit (LSBB). We demonstrate a technique to take the difference between a linear transform of the three signals from one magnetometer, and a reference signal from the other, in order to account for any difference in alignment and calibration, and track local signals at a sub-nT level. We confirmed that both systems tracked the same signal with an RMS difference as low as 56pT over a period of 72 h. To our knowledge this is the first such demonstration of the long term accuracy of SQUID magnetometers for monitoring geomagnetic fields.
- OSTI ID:
- 22105414
- Journal Information:
- Review of Scientific Instruments, Vol. 84, Issue 2; Other Information: (c) 2013 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); ISSN 0034-6748
- Country of Publication:
- United States
- Language:
- English
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