Improved Shielding Method for Reducing Magnetic Field Leakage Through Magnetically Shielded Room Openings

2019 ◽  
pp. 23-31
Author(s):  
H. Sugiyama ◽  
T. Tokuda ◽  
K. Kamata ◽  
T. Nakayama ◽  
T. Suzuki ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Magnetically Shielded Room

scholarly journals Magnetic Field Compensation Coil Design for Magnetoencephalography

2021 ◽  
Author(s):  
Hermann Sonntag ◽  
Christian F. Doeller ◽  
Jens Haueisen ◽  
Burkhard Maess
Keyword(s):  
Magnetic Field ◽  
Head Movements ◽  
Side Length ◽  
Coil Design ◽  
Optically Pumped ◽  
Active Suppression ◽  
Highly Sensitive ◽  
Movement Artifacts ◽  
Operational Range ◽  
Magnetically Shielded Room

Abstract While optically pumped magnetometers (OPMs) can be attached to the head of a person and allow for highly sensitive recordings of the human magnetoencephalogram (MEG), they are mostly limited to an operational range of approximately ±5 nT. Consequently, even inside a magnetically shielded room (MSR), movements in the remnant magnetic field disable the OPMs. Active suppression of the remnant field utilizing compensation coils is therefore essential. We propose 8 compensation coils on 5 sides of a cube with a side length of approximately 2 m which were optimized for operation inside an MSR. Compared to previously built bi-planar compensation coils, the coils proposed in this report are more complex in geometry and achieved 10 times smaller errors for simulated compensation fields. The proposed coils will allow for larger head movements or smaller movement artifacts in future MEG experiments compared to existing coils.

scholarly journals Compensation System for Biomagnetic Measurements with Optically Pumped Magnetometers inside a Magnetically Shielded Room

Sensors ◽  
2020 ◽  
Vol 20 (16) ◽  
pp. 4563 ◽  
Author(s):  
Anna Jodko-Władzińska ◽  
Krzysztof Wildner ◽  
Tadeusz Pałko ◽  
Michał Władziński
Keyword(s):  
Magnetic Field ◽  
Quantum Interference ◽  
Spin Exchange ◽  
Initial Conditions ◽  
Sensor Arrays ◽  
Compensation System ◽  
Zero Field ◽  
Optically Pumped ◽  
Ambient Magnetic Field ◽  
Magnetically Shielded Room

Magnetography with superconducting quantum interference device (SQUID) sensor arrays is a well-established technique for measuring subtle magnetic fields generated by physiological phenomena in the human body. Unfortunately, the SQUID-based systems have some limitations related to the need to cool them down with liquid helium. The room-temperature alternatives for SQUIDs are optically pumped magnetometers (OPM) operating in spin exchange relaxation-free (SERF) regime, which require a very low ambient magnetic field. The most common two-layer magnetically shielded rooms (MSR) with residual magnetic field of 50 nT may not be sufficiently magnetically attenuated and additional compensation of external magnetic field is required. A cost-efficient compensation system based on square Helmholtz coils was designed and successfully used for preliminary measurements with commercially available zero-field OPM. The presented setup can reduce the static ambient magnetic field inside a magnetically shielded room, which improves the usability of OPMs by providing a proper environment for them to operate, independent of initial conditions in MSR.

Modeling of Leakage Magnetic Field of Electric Machines Using Blocks With Magnetizations for Design of Magnetically Shielded Room

2017 ◽  
Vol 53 (6) ◽  
pp. 1-4
Author(s):  
Kazuhiro Muramatsu ◽  
Yanhui Gao ◽  
Yusuke Moriyama ◽  
Hiroshi Dozono ◽  
Takaaki Nishino ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Electric Machines ◽  
Leakage Magnetic Field ◽  
Magnetically Shielded Room

scholarly journals Magnetic field compensation coil design for magnetoencephalography

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Hermann Kutschka ◽  
Christian F. Doeller ◽  
Jens Haueisen ◽  
Burkhard Maess
Keyword(s):  
Magnetic Field ◽  
Head Movements ◽  
Side Length ◽  
Coil Design ◽  
Optically Pumped ◽  
Active Suppression ◽  
Highly Sensitive ◽  
Movement Artifacts ◽  
Operational Range ◽  
Magnetically Shielded Room

AbstractWhile optically pumped magnetometers (OPMs) can be attached to the head of a person and allow for highly sensitive recordings of the human magnetoencephalogram (MEG), they are mostly limited to an operational range of approximately 5 nT. Consequently, even inside a magnetically shielded room (MSR), movements in the remnant magnetic field disable the OPMs. Active suppression of the remnant field utilizing compensation coils is therefore essential. We propose 8 compensation coils on 5 sides of a cube with a side length of approximately 2 m which were optimized for operation inside an MSR. Compared to previously built bi-planar compensation coils, the coils proposed in this report are more complex in geometry and achieved smaller errors for simulated compensation fields. The proposed coils will allow for larger head movements or smaller movement artifacts in future MEG experiments compared to existing coils.

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