P. Weber et al., INTEGRATED LTS GRADIOMETER SQUID SYSTEMS FOR MEASURING OF MAGNETIC-FIELD DISTRIBUTIONS IN AN UNSHIELDED ENVIRONMENT, IEEE transactions on applied superconductivity, 5(2), 1995, pp. 2493-2496
Planar dc SQUID gradiometers with integrated antenna were designed for
measurement of field distributions with gradients much smaller than 1
pT/cmHz(1/2) in an unshielded environment. Four types of first-order-
gradiometer SQUIDs were fabricated in Pb-Pb technology and investigate
d. Their layouts are highly symmetrical and they can be made also with
HTS materials. Further reduction of the effect of disturbances was ac
hieved with a second order gradiometer realized electronically. The st
able function of the systems under unshielded conditions is shown.