Multichannel flux measuring apparatus having function for compensating interference due to crosstalk

A flux measuring apparatus comprising:

• a plurality of measuring means, each of the measuring means having a pick-up coil and detection means which is formed of a superconductor quantum interference device, SOUID, and for measuring a magnetic flux linked with said pick-up coil;
• and
• compensation means for compensating an interference due to a crosstalk between said pick-up coils of said plurality of measuring means included in a measured value from said plurality of measuring means, said compensation means comprises means for calculating a product A.PHI.', where the A is a compensation matrix and the .PHI.' is the measured value, to obtain a flux vector .PHI. which is free of the crosstalk interference, said compensation matrix A is based on a self inductance of each pick-up coil and a mutual inductance between pick-up coils of said plurality of measuring means, wherein said detection means includes an input coil connected to said pick-up coil, and said compensation means, when flux detected by said plurality of magnetic detection means is .PHI..sub.i ', compensates the flux .PHI..sub.i ' on the basis of the following equation:
• ##EQU7## and obtains flux .PHI..sub.i which is free from an interference due to crosstalk, where N represents the number of said plurality of measuring means, i and j each are an arbitrary numeral from 1 to N, .PHI..sub.i ' represents flux detected by the i-number-th detection means, M.sub.ij represents a mutual inductance between the i-number-th pick-up coil and the j-number-th pick-up coil, L.sub.pi is a self inductance of the i-number-th pick-up coil, L.sub.si represents a self inductance of the i-number-th input coil, and L.sub.li represents a self inductance of wiring of the i-number-th measuring means.