The Spatial and Temporal Distortion of Magnetic Fields Applied Inside a Magnetically Shielded Room

摘要: In the context of biomagnetism, a magnetically shielded room (MSR) is designed for shielding against external magnetic fields. Recently, several applications, such as combined structural resonance imaging (MRI) and functional magnetoencephalography (MEG), have emerged that require applying relatively strong fields inside MSR. These induce eddy currents magnetize MSR walls are made materials with high permeability conductivity. magnetization generate secondary disturb, e.g., MEG-MRI by affecting sample spins exceeding available dynamic range field sensors. this work, static applied an studied both theoretically experimentally. Using spherical model, analytical expressions derived amplitudes time constants various modes. predictions validated comparison experimental measurements in rectangular The results study facilitate, design coils compatible MSR; self-shielded coil presented decreases to small fraction.