Magnetic full tensor SQUID gradiometer system for geophysical applications

Institute for Physical High‐Technology, P.O.B. 100239, D‐07702 Jena, Germany Superconducting Quantum Interference Devices (SQUIDs) are known to be one of the most sensitive detectors of magnetic flux. The actual sensor technology has reached a stage where reliable systems for geophysical purposes can now be built and have become a reality. As a result, it opens a wide range of different applications in geophysics. In this paper we describe a program started in 1997 at the Institute for Physical High‐Technology (IPHT) in Jena with the aim of developing an airborne full tensor magnetic gradiometer superconducting quantum interference device (SQUID) using liquid‐helium‐based thin‐film technology. Since that time, the sensor, system electronics, data acquisition system, and cryogenics have been developed and extensively tested. We report on successful tests of the intrinsic planar LTS (Low Temperature Superconductor) SQUID gradiometers which were conducted by towing the system from a helicopter as well as for a stinger mounted configuration in a Cessna 208 aircraft. This paper gives an introduction to the SQUID technology and the system setup, provides some preliminary results from the trials, and describes upcoming improvements.