A 7-Channel High-T-c SQUID-Based On-Scalp MEG System
Journal article, 2020

Objective: To present the technical design and demonstrate the feasibility of a multi-channel on-scalp magnetoencephalography (MEG) system based on high critical temperature (high-Tc) superconducting quantum interference devices (SQUIDs).
Methods: We built a liquid nitrogen-cooled cryostat that houses seven YBCO SQUID magnetometers arranged in a dense, head-aligned array with minimal distance to the room-temperature environment for all sensors. We characterize the performance of this 7-channel system in terms of on-scalp MEG utilization and present recordings of spontaneous and evoked brain activity.
Results: The center-to-center spacing between adjacent SQUIDs is 12.0 and 13.4 mm and all SQUIDs are in the range of 1-3 mm of the head surface. The cryostat reaches a base temperature of 70 K and stays cold for >16hwith a single 0.9 L filling. The white noise levels of the magnetometers is 50-130 fT/Hz1/2 at 10 Hz and they show low sensor-tosensor feedback flux crosstalk (<0.6%). We demonstrate evoked fields fromauditory stimuli and single-shot sensitivity to alpha modulation from the visual cortex.
Conclusion: All seven channels in the system sensitively sample neuromagnetic fields with mm-scale scalp standoff distances. The hold time of the cryostat furthermore is sufficient for a day of recordings. As such, our multi-channel high-Tc SQUID-based system meets the demands of on-scalp MEG. Significance: The system presented here marks the first high-Tc SQUID-based on-scalp MEG system with more than two channels. It enables us to further explore the benefits of on-scalp MEG in future recordings.

high-T-c SQUID

Magnetoencephalography (MEG)

on-scalp MEG

multichannel system

Author

[Person 7d43e8b7-d2b2-4951-8b51-703c1379b849 not found]

Chalmers, Microtechnology and Nanoscience (MC2), Quantum Device Physics

[Person 7fc198bc-b313-49e5-b08c-12a182d3baf9 not found]

Chalmers, Microtechnology and Nanoscience (MC2), Quantum Device Physics

[Person 5a47d0c1-be43-4d8b-9e81-2ec4be398c97 not found]

Chalmers, Microtechnology and Nanoscience (MC2), Quantum Device Physics

[Person 6d68c491-4e01-4f57-b866-855cbac0428d not found]

Stiftelsen Chalmers Industriteknik

[Person d58d8188-5be0-423a-8abf-551f1a971a8e not found]

Chalmers, Microtechnology and Nanoscience (MC2), Quantum Device Physics

[Person f9ca652f-fff4-4071-a932-040d047fac9a not found]

Chalmers, Microtechnology and Nanoscience (MC2), Quantum Device Physics

[Person 4793483f-f217-4862-aec9-9f08bdb5ba9f not found]

Chalmers, Microtechnology and Nanoscience (MC2), Quantum Device Physics

[Person 6621a8fb-1eb9-46e2-9559-9a2328f7cbaa not found]

University of Gothenburg

IEEE Transactions on Biomedical Engineering

0018-9294 (ISSN)

Vol. 67 5 1483-1489

Subject Categories

Computer Engineering

Medical Laboratory and Measurements Technologies

Other Electrical Engineering, Electronic Engineering, Information Engineering

DOI

10.1109/TBME.2019.2938688

PubMed

31484107

More information

Latest update

9/9/2020 1