| 摘要 |
PROBLEM TO BE SOLVED: To precisely cancel interfering magnetic fields. SOLUTION: This device is provided with the first SQUID fluxmeters 9-a, b, c, d for detecting a normal-directional magnetic field component, the second and third SQUID fluxmeters 10-a, b for detecting the normal-directional interfering magnetic field, and a computer for collecting signals from the first-third SQUID fluxmeters 9-a, b, c, d, 10-a, b to processing the signals. The first-third SQUID fluxmeters 9-a, b, c, d, 10-a, b has respective differential type direction coils, and the computer conducts processing (a) for canceling the interfering magnetic field caused by a difference in canceling rates among the first SQUID fluxmeters 9-a, b, c, d from magnetic field waveforms by the first SQUID fluxmeters 9-a, b, c, d, processing (b) for canceling the interfering magnetic field caused by a difference between base lines of the second and third differential type detection coils from magnetic waveforms by the processing (a), and processing (c) for canceling the interfering magnetic field caused by a frequency characteristic of a magnetic shielding room from a magnetic field waveform by the processing (b). |
