DocumentCode :
1498932
Title :
Experimental Study of the Active Compensation to a Full-Size Separate-Shell Magnetic Shield
Author :
Nakashima, Yoshihiro ; Suzuki, Yusuke ; Sasada, Ichiro ; Shimada, Masaki ; Takeda, Toshikazu
Author_Institution :
Dept. of Appl. Sci. for Electron. & Mater., Kyushu Univ., Fukuoka, Japan
Volume :
46
Issue :
6
fYear :
2010
fDate :
6/1/2010 12:00:00 AM
Firstpage :
2318
Lastpage :
2321
Abstract :
Shielding efficiency of a full-size separate-shell magnetic shield equipped with active compensation coils is presented. Its size is 135 cm in height, 100 cm in width, and 240 cm in depth. With respect to active compensation two control schemes, i.e., feedback and feedforward, are compared. The shielding efficiency is estimated from the measurements of the attenuation of environmental magnetic fields in two axial directions (horizontal and vertical). In the case of feedback, a reference sensor that measures the incoming magnetic fields is positioned inside the shield, whereas in the case of feedforward the reference sensor is positioned outside the shell. In both axial directions, the environmental magnetic noise can be reduced to less than 500 pT: the noise floor measured by a fluxgate magnetometer is approximately 10 pT/¿Hz in the frequency range from 10 to 100 Hz.
Keywords :
coils; compensation; feedback; feedforward; magnetic sensors; magnetic shielding; magnetic variables control; active compensation coils; depth 240 cm; environmental magnetic field attenuation; environmental magnetic noise; feedback; feedforward; fluxgate magnetometer; frequency 10 Hz to 100 Hz; full-size separate-shell magnetic shield; reference sensor; shielding efficiency; size 100 cm; size 135 cm; Attenuation measurement; Coils; Feedback; Magnetic field measurement; Magnetic noise; Magnetic sensors; Magnetic separation; Magnetic shielding; Noise reduction; Position measurement; Active compensation; magnetic shielding; magnetocardiography; separate-shell structure;
fLanguage :
English
Journal_Title :
Magnetics, IEEE Transactions on
Publisher :
ieee
ISSN :
0018-9464
Type :
jour
DOI :
10.1109/TMAG.2010.2040469
Filename :
5467524
Link To Document :
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