A modular, extendible and field-tolerant multichannel vector magnetometer based on current sensor SQUIDs
A modular, extendible and field-tolerant multichannel vector magnetometer based on current sensor SQUIDs
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基于电流传感器 SQUID 的模块化、可扩展、耐磁场多通道矢量磁力计
DOI：
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发表时间：
2016
期刊：
影响因子：
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通讯作者：
Rainer Korber
中科院分区：
文献类型：
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作者：
J. Storm;D. Drung;M. Burghoff;Rainer Korber
给出了可扩展的、健壮的多通道SQUID磁强计系统的原型模块。最多使用7个模块即可实现大型多模块布置。该系统用于生物磁性和自旋进动的高精度测量。更苛刻的应用是磁弛豫法和超低场核磁共振(ULF核磁共振)，通常应用高达100 mT的脉冲磁场。该系统在柏林磁屏蔽室(BMSR-2)内运行，配备了18个由Nb(Nb)线绕拾取线圈组成的磁力计。共有16个直径为17.1 mm的小拾取线圈形成了规则的栅格，每个通道都有排列，以确保系统灵敏度覆盖所有三个垂直的空间方向。两个等效直径为74.5 mm、z向敏感的大型六角形拾取线圈以两种不同的高度环绕栅格，适用于深源探测。每个拾取线圈通过可拆卸的超导触点连接到薄膜NB SQUID电流传感器的输入。SQUID配备了集成的输入电流限制器。对拾取线圈的反馈被用来最小化通道之间的串扰。电流传感器芯片封装包括Nb的超导屏蔽。通过数值模拟分析了样机和多模块布局的场形变特性。小型磁强计的测量噪声在0.6~1.5FT Hz−1/2之间，而大型磁强计的噪声远低于1 FT Hz−1/2。使用软件梯度计，我们实现了0.54FT HZ−1/2的最低噪声水平。我们进行了超低频核磁共振实验，验证了系统对脉冲场的稳健性，并进行了体感诱发神经元活动的脑磁图(MEG)测试。我们的18通道原型的低噪声性能使MEG能够检测到1 kHz左右的高频分量。
We present the prototype module of our extendible and robust multichannel SQUID magnetometer system. A large multi-module arrangement can be implemented by using up to 7 modules. The system is intended for high-precision measurements of biomagnetism and spin precession. Further demanding applications are magnetorelaxometry and ultra-low-field nuclear magnetic resonance (ULF NMR), where pulsed magnetic fields of up to 100 mT are typically applied. The system is operated inside the Berlin magnetically shielded room (BMSR-2) and equipped with 18 magnetometers consisting of niobium (Nb) wire-wound pick-up coils. A total of 16 small pick-up coils with 17.1 mm diameter form a regular grid with individual channels arranged to ensure system sensitivity covers all three orthogonal spatial directions. Two large hexagonal pick-up coils with an equivalent diameter of 74.5 mm sensitive in z-direction surround the grid at two different heights and are suitable for the detection of deep sources. Each pick-up coil is connected to the input of a thin-film Nb SQUID current sensor via a detachable superconducting contact. The SQUIDs are equipped with integrated input current limiters. Feedback into the pick-up coils is employed to minimise crosstalk between channels. The current sensor chip package includes a superconducting shield of Nb. The field distortion of the prototype and a multi-module arrangement was analysed by numerical simulation. The measured noise of the small magnetometers was between 0.6 and 1.5 fT Hz − 1 / 2 , and well below 1 fT Hz − 1 / 2 for the large ones. Using a software gradiometer, we achieved a minimum noise level of 0.54 fT Hz − 1 / 2 . We performed ULF NMR experiments, verifying the system’s robustness against pulsed fields, and magnetoencephalographgy (MEG) on somatosensory evoked neuronal activity. The low noise performance of our 18-channel prototype enabled the detection of high-frequency components at around 1 kHz by MEG.
DOI：
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发表时间：
2018
期刊：
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影响因子：
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作者：
Kiwoong Kim
通讯作者：
Kiwoong Kim