A lightweight magnetically shielded room with active shielding

Area of Science:

• Biophysics
• Neuroscience
• Materials Science

Background:

• Magnetically shielded rooms (MSRs) are crucial for high-precision magnetic field measurements like magnetoencephalography (MEG).
• Optically pumped magnetometers (OPMs) enable wearable MEG systems, promising high spatiotemporal resolution and motion tolerance.
• Current MSRs for OPM-MEG are bulky, costly, and have challenging siting requirements, limiting widespread adoption.

Purpose of the Study:

• To develop a lightweight and compact MSR design for OPM-MEG.
• To create an effective active shielding system to minimize remnant magnetic fields within the MSR.
• To reduce the cost and installation complexity of MSRs for broader OPM-MEG deployment.

Main Methods:

• Designed a novel lightweight MSR with reduced weight and dimensions.
• Developed a 'window coil' active shielding system using simple rectangular coils on MSR walls.
• Mapped remnant magnetic fields and coil-generated fields to determine optimal coil currents for field cancellation.

Main Results:

• Achieved a 30% weight reduction and 40-60% reduction in external dimensions for the MSR.
• Successfully canceled the remnant magnetic field within the central cubic meter to |B| = 670 ± 160 pT.
• Demonstrated a significant reduction in cost, installation time, and siting restrictions compared to existing MSRs.

Conclusions:

• The new MSR design and window coil system significantly address barriers to OPM-MEG deployment.
• These advancements facilitate the widespread adoption of wearable, high-resolution brain imaging technology.
• The developed MSR offers a more practical and accessible solution for advanced neuroimaging research and clinical applications.