Abstract: A magnetic field shielding system includes a first stage superconducting coil and a second stage superconducting coil. The first stage superconducting coil and the second stage superconducting coil are coaxial, coplanar and electrically connected in series to form a closed loop; the first stage superconducting coil has a first radius R1, the second stage superconducting coil has a second radius R2, and R1>R2; a radius ratio ? between the first radius R1 and the second radius R2 is: ?=R1/R2; the first stage superconducting coil has N1 turns; the second stage superconducting coil has N2 turns; a turns ratio ? between N1 and N2 is: ?=N1/N2; and the radius ratio ? satisfies: ??2; the turns ratio ? satisfies: 0.01???20.

Abstract: A magnetic field shielding system includes a first stage superconducting coil and a second stage superconducting coil. The first stage superconducting coil and the second stage superconducting coil are coaxial, coplanar and electrically connected in series to form a closed loop; the first stage superconducting coil has a first radius R1, the second stage superconducting coil has a second radius R2, and R1>R2; a radius ratio ? between the first radius R1 and the second radius R2 is: ?=R1/R2; the first stage superconducting coil has N1 turns; the second stage superconducting coil has N2 turns; a turns ratio ? between N1 and N2 is: ?=N1/N2; and the radius ratio ? satisfies: ??2; the turns ratio ? satisfies: 0.01???20.