Avoiding non-linearity of optically pumped magnetometer MEG within an actively shielded two-layer mu-metal room

Some optically pumped magnetometer (OPM) sensors available for biomagnetic investigations have a linear range limited to +- 1 nT due to the specific properties of their open loop operation. In a two-layer magnetically shielded room of type Ak3b/Vacoshield Advanced with an external active compensatio...

Full description

Saved in:
Bibliographic Details
Published inCurrent directions in biomedical engineering Vol. 7; no. 2; pp. 543 - 546
Main Authors Sander, Tilmann H., Marhl, Urban, Jazbinšek, Vojko
Format Journal Article
LanguageEnglish
Published De Gruyter 01.10.2021
Subjects
heartbeat artifact
Magnetoencephalography
movement artifact
non-linearity
optically pumped magnetometer
Online AccessGet full text

Cover

More Information
Summary:Some optically pumped magnetometer (OPM) sensors available for biomagnetic investigations have a linear range limited to +- 1 nT due to the specific properties of their open loop operation. In a two-layer magnetically shielded room of type Ak3b/Vacoshield Advanced with an external active compensation we studied how much sensor movement is allowed until amplitudes exceed the linearity range. Intentional movements were performed by a subject wearing an OPM-MEG sensor array. It was found that movements of 8 cm did yield non-linear amplitudes, but a reduction of the movement in half already preserves linearity. Despite movements, the heartbeat was found to generate a periodic signal, although the generating mechanism could not be identified so far.
ISSN:2364-5504
2364-5504
DOI:10.1515/cdbme-2021-2138