INTEGRATED SQUID GRADIOMETERS FOR MEASUREMENT IN DISTURBED ENVIRONMENTS

Planar de SQUID gradiometers with integrated antenna were designed and investigated. With low-T-c superconductors they were realized as wash er type and as transformer type SQUID gradiometers. With high-T-c supe rconductors we tested galvanometer SQUIDs. Field gradient sensitivitie s of 32 fT/(cm root Hz) could be achieved with low-T-c SQUIDs and of 5 20 fT(cm root Hz) with high-T-c SQUIDs, respectively. All types of gra diometers could work stable in disturbed environments. The influence o f the SQUID gradiometer layout and the construction of the sample hold er on the degree of disturbance suppression is shown.