A Four-channel Optically Pumped Magnetometer for a Magnetoencephalography Sensor Array

Joonas Iivanainen; Tony R. Carter; Jonathan E. Dhombridge; Timothy S. Read; Kaleb Campbell; Quinn Abate; David M. Ridley; Amir Borna; Peter D. D. Schwindt

arXiv · 2312.14623

A Four-channel Optically Pumped Magnetometer for a Magnetoencephalography Sensor Array

Joonas Iivanainen·Tony R. Carter·Jonathan E. Dhombridge·Timothy S. Read·Kaleb Campbell·Quinn Abate·David M. Ridley·Amir Borna·Peter D. D. Schwindt

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Abstract

We present a novel four-channel OPM sensor for magnetoencephalography that utilizes a two-color pump/probe scheme on a single optical axis. We characterize its performance across 18 built sensor modules. The new sensor implements several improvements over our previously developed sensor including lower vapor-cell operating temperature, improved probe-light detection optics, and reduced optical power requirements. The sensor also has new electromagnetic field coils on the sensor head which are designed using stream-function-based current optimization. We detail the coil design methodology and present experimental characterization of the coil performance. The magnetic sensitivity of the sensor is on average 12.3 fT/rt-Hz across the 18 modules while the average gradiometrically inferred sensitivity is about 6.0 fT/rt-Hz. The sensor 3-dB bandwidth is 100 Hz on average. The on-sensor coil performance is in good agreement with the simulations.

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Joonas Iivanainen, Tony R. Carter, Jonathan E. Dhombridge, Timothy S. Read, Kaleb Campbell, Quinn Abate, David M. Ridley, Amir Borna, Peter D. D. Schwindt. 2023-12-22. A Four-channel Optically Pumped Magnetometer for a Magnetoencephalography Sensor Array. https://arxiv.org/abs/2312.14623

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