Koss, PeterPeterKossVoigt, JensJensVoigtRasser, RonjaRonjaRasserSchnabel, AllardAllardSchnabel2025-01-072025-01-072024-11-30https://publica.fraunhofer.de/handle/publica/48108310.3390/ma17235877A demagnetization study was conducted on a magnetically shielded room (MSR) at Fraunhofer IPM, designed for applications such as magnetoencephalography (MEG) and material testing. With a composite of two layers of mu-metal and an intermediate aluminum layer, the MSR must provide a residual field under 5 nT for the successful operation of optically pumped magnetometers (OPMs). The degaussing process, employing six individual coils, reached the necessary residual magnetic field within the central 1 m3 volume in under four minutes. Due to the low-frequency shielding factor of 100, the obtained average residual field is shown to be limited by environmental residual field changes after degaussing and not by the degaussing procedure.enDegaussingResidual magnetic fieldShieldingOPMMEGMagnetically shielded roomMagnetoencephalographyOptically pumped magnetometersjournal article