High-Tc SQUID gradiometer system for magnetocardiography in an unshielded environment
High-Tc SQUID gradiometer system for magnetocardiography in an unshielded environment
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用于非屏蔽环境中心磁图的高温 SQUID 梯度计系统
DOI：
10.1088/0953-2048/16/12/023
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发表时间：
2003
影响因子：
3.6
通讯作者：
Hong
中科院分区：
文献类型：
--
作者：
S. Liao;S. C. Hsu;C. C. Lin;H. Horng;J. C. Chen;M. J. Chen;C. H. Wu;Hong
我们设计了一个心磁图（MCG）系统，能够在无屏蔽环境中测量心磁图。为了进行这样的测量，必须应对各种环境噪声源。这些包括电源线和射频干扰，颤噪拾音，地球磁场波动和静电拾音。为克服这些问题而设计的早期解决方案需要在深井或磁屏蔽外壳内使用二阶梯度仪[1]。除了上述低Tc和高Tc SQUID共有的问题外，高Tc SQUID还表现出额外的1/f噪声[2]。这种噪声是磁通涡旋跳跃的结果，磁通涡旋被捕获在场冷却的高Tc SQUID的主体中，并且只能通过零场冷却SQUID来消除。
We have designed a magnetocardiography (MCG) system that is capable of measuring magnetocardiograms in an unshielded environment. In order to carry out such a measurement, one has to contend with various ambient noise sources. These include power line and RF interference, microphonics pickup, fluctuations in the earth’s magnetic field, and electrostatic pickup. Earlier solutions devised to overcome these problems have entailed the use of a second-order gradiometer inside a deep mine or inside a magnetically shielded enclosure [1]. Apart from the above problems which are common to both low-Tc and high-Tc SQUIDs, high-Tc SQUIDs exhibit additional 1/f noise [2]. This noise is the result of hopping of flux vortices that are trapped in the body of the field cooled high-Tc SQUID, and can only be eliminated by zero-field cooling the SQUID.