ANORDNING OCH FOERFARANDE FOER MAETNING AV SVAGA, ORTS- OCH TIDSBEROENDE MAGNETFAELT.

摘要

The invention relates to an apparatus for the measurement of weak magnetic fields dependent upon position and time, which emanate from a source (Q) located in the interior of an object (1) to be investigated. The apparatus has a sensor arrangement (7) comprising at least ten first-order gradiometers (59) accommodated in a cryostat (64) and in each case inductively coupled to a DC-SQUID (63), and a chamber (8), enclosing the sensor arrangement (7) and the object (1) to be investigated, for shielding against magnetic fields, which exhibits a shielding factor of at least 10 for alternating magnetic fields having a frequency of 0.5 Hz, which factor increases with increasing frequency. The invention also relates to a method for operating such an apparatus. ……