Biplanar Nulling Coil System for OPM-MEG Using Printed Circuit Boards
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A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
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en
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18
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Sensors, Volume 25, issue 9, pp. 1-18
Abstract
Optically pumped magnetometers (OPMs) are a promising magnetoencephalography (MEG) technology for the non-invasive measurement of human electrophysiological signals. Prior work developed biplanar background field-nulling coils necessary for OPM operation, but these were expensive to produce and required tedious error-prone manual winding of >1 km of copper wire. Here, we developed a precise and reproducible manufacturing process by fabricating these coils on two-layer printed circuit boards (PCBs). Building on open-source software (bfieldtools), we developed a pipeline to determine the optimal current loops of 1.5 × 1.5 m2 biplanar nulling coils, connected these loops into a continuous conducting path across PCB layers, and printed them as pairs of 1.5 × 0.75 m2 PCBs, which were soldered and mounted on an aluminum frame. Our coils achieved efficiencies of 1.3–7.1 nT/mA, similar to or higher than previous designs. We reduced the largest background field component from 21 to 2 nT, enabling OPMs in a lightly shielded room to record somatosensory evoked fields (SEFs) comparable to SQUID-MEG. Our coil system is cheaper than commercial alternatives and is available as an open-source package opmcoils, thus enabling more affordable background field nulling for OPM-MEG and realizing its potential as an accessible sensor technology for human neuroscience.Description
Publisher Copyright: © 2025 by the authors.
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Jas, M, Kamataris, J, Matsubara, T, Dong, C, Motta, G, Sohrabpour, A, Ahlfors, S P, Hämäläinen, M, Okada, Y & Sundaram, P 2025, 'Biplanar Nulling Coil System for OPM-MEG Using Printed Circuit Boards', Sensors, vol. 25, no. 9, 2759, pp. 1-18. https://doi.org/10.3390/s25092759