Integrated LTS gradiometer SQUID systems for measuring of magnetic field distributions in an unshielded environment

摘要

Planar dc SQUID gradiometers with integrated antenna were designed for measurement of field distributions with gradients much smaller than 1 pT/cmHz/sup 1/2/ in an unshielded environment. Four types of first-order-gradiometer SQUIDs were fabricated in Nb-Pb technology and investigated. Their layouts are highly symmetrical and they can be made also with HTS materials. Further reduction of the effect of disturbances was achieved with a second order gradiometer realized electronically. The stable function of the systems under unshielded conditions is shown.