Active Magnetic Shielding Using Symmetric Magnetic Field Sensor Method

• Published in: IEEE transactions on magnetics 2012-11, Vol.48 (11), p.4554-4557
• Main Authors: Kobayashi, K., Kon, A., Yoshizawa, M., Uchikawa, Y.
• Format: Article
• Language: English
• Subjects: Active magnetic shielding; Coils; cross-axial interference; Cross-disciplinary physics: materials science; rheology; Electromagnetism; Exact sciences and technology; Frequency measurement; Interference; Magnetic field measurement; magnetic field sensor position; Magnetic fields; Magnetic noise; Magnetic shielding; Magnetism; Materials science; Other topics in materials science; Physics; symmetric sensor method
• ISSN: 0018-9464; 1941-0069
• DOI: 10.1109/TMAG.2012.2197854

Active magnetic shielding is a cheap and effective method for shielding magnetic noise that allows shielding the very low frequencies. In active magnetic shielding, it is possible to shield magnetic field sensor positions. However, there is a problem in which the shielding factor decreases at other positions. Also, the problem of cross-axial interference occurs when the magnetic field sensor cannot be installed at the center of the compensation coils, since the measurement object is installed at the center. In this study, an arrangement of the magnetic field sensors which solves these problems is proposed. This method installs pairs of magnetic field sensors symmetrically offset from the center along each axis. An experimental demonstration was carried out in a small model in order to prove the effectiveness of the proposed method. Our results show that a high shielding factor is obtained, even if the magnetic field sensor is not installed at the center.