High-Tc second-order gradiometer for magnetocardiography in an unshielded environment
High-Tc second-order gradiometer for magnetocardiography in an unshielded environment
复制标题
用于非屏蔽环境中心磁图的高温二阶梯度计
DOI：
10.1063/1.124891
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发表时间：
1999
影响因子：
4
通讯作者：
J. Clarke
中科院分区：
文献类型：
--
作者：
K. Kouznetsov;J. Borgmann;J. Clarke
我们制作了平面一阶导数梯度仪，其中在单层YBa2Cu3O7−x膜中图案化的非对称磁通Transformer永久地结合到基于直流超导量子干涉器件（SQUID）的直接耦合磁强计。梯度计基线为48 mm。均匀磁场的共模抑制通常为几百分之一。两个这样的梯度仪的输出以数字方式相减以形成二阶导数梯度仪。此外，三个正交的SQUID磁力计用于减少对均匀磁场的剩余响应，使其优于100 ppm。该系统能够在无屏蔽环境中检测来自人类心脏的磁信号。
We have fabricated planar first-derivative gradiometers in which an asymmetric flux transformer patterned in a single-layer YBa2Cu3O7−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.