DocumentCode :
1539224
Title :
SQUID gradiometers for a fundamental study of underwater magnetic detection
Author :
Hirota, M. ; Nanaura, K. ; Teranishi, Yuuichi ; Kishigami, T.
Author_Institution :
Japan Defense Agency, Kawasaki, Japan
Volume :
7
Issue :
2
fYear :
1997
fDate :
6/1/1997 12:00:00 AM
Firstpage :
2327
Lastpage :
2330
Abstract :
An LTS SQUID gradiometer measuring six elements of first order magnetic gradient was produced for a fundamental study of magnetic detection and localization under water. It was installed at the sea bottom shallower than 30 m and we measured magnetic noise which might degrade its detecting performance. Noise caused by the imbalance of the gradiometer pickup coils was suppressed by using an auxiliary three-axis SQUID magnetometer output. The imbalance parameters were determined by measuring geomagnetic variations surrounding the sea bottom. A test for the trial detection of an iron boat was conducted with the use of this gradiometer. The results obtained showed a high signal-to-noise ratio for the gradiometer.
Keywords :
SQUID magnetometers; geomagnetic variations; magnetic field measurement; object detection; superconducting device noise; superconducting device testing; 23 m; LTS SQUID gradiometer; SQUID gradiometers; auxiliary three-axis SQUID magnetometer output; first order magnetic gradient; geomagnetic variations; gradiometer pickup coil imbalance; iron boat detection; magnetic dipole localization; magnetic noise; sea bottom; signal-to-noise ratio; target localization; underwater magnetic detection; Boats; Coils; Degradation; Geomagnetism; Iron; Magnetic noise; Noise measurement; SQUID magnetometers; Sea measurements; Testing;
fLanguage :
English
Journal_Title :
Applied Superconductivity, IEEE Transactions on
Publisher :
ieee
ISSN :
1051-8223
Type :
jour
DOI :
10.1109/77.621705
Filename :
621705
Link To Document :
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