Quantum sensing provides advanced technologies which significantly improve sensitivity and accuracy for sensing changes of motion, gravity, electric and magnetic field. Therein, sensors for magnetic field detection, so-called quantum magnetometers, are one of the most promising technological realizations useful for mineral exploration.
In this work, we present our advanced 3D vector magnetometer based on LTS Superconducting QUantum Interference Devices (SQUIDs) which enables to measure the full vector of the Earth’s magnetic field in mobile operation for passive electromagnetic exploration. The SQUIDs are multi-loop structures using sub-µm sized niobium Josephson junctions and have thus large voltage swings of >130µV and a low intrinsic white noise floor of about 2 fT(rms)/sqrt(Hz). Three orthogonally oriented magnetometers are read out by a flux counting electronics which provides a large dynamic range of >32bit, a slew rate exceeding 1MPhi0/s or equivalently 0.54 mT/s, and a bandwidth ranging from DC to 32kHz.
We will provide insights about the instruments performance in exploration e.g. in Namibia. By data post-processing, transfer functions are calculated and later inverted for deriving electrical conductivity anomalies for exploration depths exceeding 1km.
Acknowledgement: We gratefully acknowledge the DESMEX team. This work was partly supported by the Eurostars program in QMAG (no. 01QE1710) and by BMBF in the DESMEX (no. 033R130) and DESMEX-Real project (no. 033R385).