Shielding effect of superconducting magnetically shielded room

A Superconducting Magnetically Shielded Room (SMSR) has been developed. Superconducting panels are soldered to form a shielding wall of which the soldered connections have normal conduction. Therefore, the Shielding Factor (SF) of the SMSR degrades especially at low frequency, which is different from a superconducting shielded room without a normal conductive connection. A permalloy box is combined inside the SMSR to improve the SF. The combination (CMSR) shows a SF of 2,000 at 0.3 Hz and 100,000 at 10 Hz. The SF of the CMSR exceeds the product of the SF of the SMSR with the SF of the permalloy box. This peculiar tendency of the CMSR is validated by a 3-D magnetic field analysis. The maximum SF is obtained with zero distance between the walls.