A high performance static magnetic shielded room for detecting biomagnetic nanoparticles

A three-layer magnetic shielded room (MSR) has been built to house biomagnetic nanoparticles detecting system based on a low temperature Superconducting Quantum Interference Device (SQUID). The MSR with an open type door was designed to match the noise levels of SQUID coupled with one-order gradiometers while minimizing the overall facility cost. The room measures 2 × 2 × 2 m
³
internally and consists of three-layer silicon-steel plate shell instead of the permalloy. The static shielding factor in the room is 25000 at which point the eminent magnetization is 2 nT. This valve matches the measurement of isothermal remanent magnetizations (IRM). We conclude that using cheap materials of silicon-steel plate with relative low permeability can also produce a high performance MSR.