Magnetic Shielding Studies for the nEDM Experiment at the SNS

The nEDM Experiment at the SNS requires an overall magnetic shielding factor of order $10^5$ to attenuate external background magnetic fields. At present, the shielding design includes an external (room-temperature) multi-layer $\mu$-metal magnetic shield, a cryogenic (4 Kelvin) Pb superconducting shield, and a cryogenic (4 Kelvin) ferromagnetic shield composed of a Metglas winding. This presentation will discuss results from a number of R\&D prototyping studies on the magnetic shielding design we have completed, including the formation of $\mu$-metal to $\mu$-metal magnetic seals across shielding gaps, optimized winding patterns for Metglas shields, studies of degaussing cycles, and methods for external background-field stabilization.