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Title: High-T{sub c} second-order gradiometer for magnetocardiography in an unshielded environment

Abstract

We have fabricated planar first-derivative gradiometers in which an asymmetric flux transformer patterned in a single-layer YBa{sub 2}Cu{sub 3}O{sub 7{minus}x} film is permanently bonded to a directly coupled magnetometer based on a dc superconducting quantum interference device (SQUID). The gradiometer base line is 48 mm. The common mode rejection of uniform magnetic fields is typically one part in a few hundred. The outputs of two such gradiometers are subtracted digitally to form a second-derivative gradiometer. Additionally, three orthogonal SQUID magnetometers are used to reduce the residual response to uniform magnetic fields to better than 100 ppm. The system is able to detect magnetic signals from a human heart in an unshielded environment. {copyright} {ital 1999 American Institute of Physics.}

Authors:
; ;  [1]
  1. Department of Physics, University of California, Berkeley and Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States)
Publication Date:
OSTI Identifier:
686434
Resource Type:
Journal Article
Journal Name:
Applied Physics Letters
Additional Journal Information:
Journal Volume: 75; Journal Issue: 13; Other Information: PBD: Sep 1999
Country of Publication:
United States
Language:
English
Subject:
66 PHYSICS; 36 MATERIALS SCIENCE; YTTRIUM COMPOUNDS; BARIUM COMPOUNDS; HIGH-TC SUPERCONDUCTORS; CARDIOGRAPHY; YTTRIUM OXIDES; BARIUM OXIDES; COPPER OXIDES; SUPERCONDUCTING FILMS; MAGNETOMETERS; HEART

Citation Formats

Kouznetsov, K.A., Borgmann, J., and Clarke, J. High-T{sub c} second-order gradiometer for magnetocardiography in an unshielded environment. United States: N. p., 1999. Web. doi:10.1063/1.124891.
Kouznetsov, K.A., Borgmann, J., & Clarke, J. High-T{sub c} second-order gradiometer for magnetocardiography in an unshielded environment. United States. doi:10.1063/1.124891.
Kouznetsov, K.A., Borgmann, J., and Clarke, J. Wed . "High-T{sub c} second-order gradiometer for magnetocardiography in an unshielded environment". United States. doi:10.1063/1.124891.
@article{osti_686434,
title = {High-T{sub c} second-order gradiometer for magnetocardiography in an unshielded environment},
author = {Kouznetsov, K.A. and Borgmann, J. and Clarke, J.},
abstractNote = {We have fabricated planar first-derivative gradiometers in which an asymmetric flux transformer patterned in a single-layer YBa{sub 2}Cu{sub 3}O{sub 7{minus}x} film is permanently bonded to a directly coupled magnetometer based on a dc superconducting quantum interference device (SQUID). The gradiometer base line is 48 mm. The common mode rejection of uniform magnetic fields is typically one part in a few hundred. The outputs of two such gradiometers are subtracted digitally to form a second-derivative gradiometer. Additionally, three orthogonal SQUID magnetometers are used to reduce the residual response to uniform magnetic fields to better than 100 ppm. The system is able to detect magnetic signals from a human heart in an unshielded environment. {copyright} {ital 1999 American Institute of Physics.}},
doi = {10.1063/1.124891},
journal = {Applied Physics Letters},
number = 13,
volume = 75,
place = {United States},
year = {1999},
month = {9}
}