A 37 channel DC SQUID magnetometer system
A 37 channel DC SQUID magnetometer system
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37 通道 DC SQUID 磁力计系统
DOI：
10.1109/20.133788
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发表时间：
1991
影响因子：
2.1
通讯作者：
H. Hahlbohm
中科院分区：
文献类型：
--
作者：
H. Koch;R. Cantor;D. Drung;S. Erne;K. Matthies;M. Peters;T. Ryhänen;H. Scheer;H. Hahlbohm
建立了用于生物磁学研究的37通道直流SQUID磁强计系统。每个磁强计的SQUID回路作为有源传感元件，从而消除了磁通耦合电路的需要。磁强计位于杜瓦瓶外底上方约3厘米处。squid直接耦合到高度简化的读出电子设备，每个通道仅使用五根电线；不需要氦气温度阻抗匹配电路。每个通道都可以独立地插入或从杜瓦瓶中取出。采用一种新颖的补偿技术，系统的白噪声和1 Hz的磁通密度噪声值分别为5 fT/平方根Hz和10 fT/平方根Hz，其中包括内部制造杜瓦瓶（在100 Hz时约2 fT/平方根Hz）和磁屏蔽室（在100 Hz时约1 fT/平方根Hz）的噪声贡献。此外，还表明，由于传感器的大动态范围和高摆率，可以通过电子方式形成梯度配置，可以利用该配置来提高信噪比。
A 37-channel DC SQUID magnetometer system has been built for biomagnetic studies. The SQUID loop of each magnetometer serves as the active sensing element, thereby eliminating the need for flux coupling circuits. The magnetometers are located approximately=3 cm above the outer dewar bottom. The SQUIDs are directly coupled to a highly simplified readout electronics using only five wires per channel; no helium temperature impedance matching circuits are required. Each channel can be independently inserted into or removed from the dewar. Using a novel compensation technique, the system white and 1-Hz flux density noise values are typically 5 fT/ square root Hz and 10 fT/ square root Hz, respectively, including the noise contribution of the in-house fabricated dewar (about 2 fT/ square root Hz at 100 Hz) and the magnetically shielded room (about 1 fT/ square root Hz at 100 Hz). In addition, it is shown that due to the large dynamic range and high slew rate of the sensors it is possible to electronically form a gradiometric configuration that can be exploited in order to improve the signal-to-noise ratio.