A magnetically shielded room has been constructed for biomagnetic applications. The room has internal dimensions of 2 m(length)×2 m(width)×2.5 m(height) and it consists of high permeability Mumetal and high conductivity aluminum, utilizing ferromagn...
A magnetically shielded room has been constructed for biomagnetic applications. The room has internal dimensions of 2 m(length)×2 m(width)×2.5 m(height) and it consists of high permeability Mumetal and high conductivity aluminum, utilizing ferromagnetic shielding and eddy current shielding. The dc shielding factor around the center of the room is above 60 ㏈, and the ac shielding factors at 1 and 10 ㎐ are larger than 60 and 80 ㏈, respectively. The internal magnetic field noise at 1 ㎐ is 500 fT/√㎐ and at 10 ㎐ is 100 fT/√㎐, and the field gradient noise at 1 ㎐ is below 7 fT/㎝√㎐. Successful measurements of cardiomagnetic fields using SQUID magnetometer and neuromagnetic fields using SQUID gradiometer have been done.