Drung D, Zimmermann R, Cantor R, Erné S N, Koch H, Matthies K P, Peters M, Scheer H J, Stollfuss D
Physikalisch-Technische Bundesanstalt, Institut Berlin, Federal Republic of Germany.
Clin Phys Physiol Meas. 1991;12 Suppl B:21-9. doi: 10.1088/0143-0815/12/b/003.
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 highly simplified read-out 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 electronic noise reduction technique the system white and 1 Hz flux density noise values are typically 5 and 10 fT Hz-1/2, respectively, including the noise contribution of the in-house fabricated dewar and the magnetically shielded room. The two parts of the data-processing system allow independent handling of the acquisition and analysing task. Two example measurements demonstrate the advantage of the electronic noise reduction method.
已搭建了一个用于生物磁学研究的37通道直流超导量子干涉仪（DC SQUID）磁力计系统。每个磁力计的SQUID环路用作有源传感元件，从而无需磁通耦合电路。磁力计位于外杜瓦瓶底部上方约3厘米处。SQUID通过每通道仅使用五根导线直接耦合到高度简化的读出电子设备；不需要氦温阻抗匹配电路。每个通道可以独立地插入杜瓦瓶或从杜瓦瓶中取出。使用一种新颖的电子降噪技术，该系统的白噪声和1赫兹磁通密度噪声值通常分别为5和10飞特斯拉·赫兹-1/2，包括内部制造的杜瓦瓶和磁屏蔽室的噪声贡献。数据处理系统的两个部分允许独立处理采集和分析任务。两个示例测量展示了电子降噪方法的优势。
