Magnetic Shielding in the nEDM Experiment at Los Alamos National Laboratory*

The search for the neutron electric dipole moment (nEDM) is an ongoing project at Los Alamos National Laboratory (LANL) with the intention to improve measurement precision using techniques of room-temperature Nuclear Magnetic Resonance (NMR). The current accepted upper limit of the nEDM is |d_n| < 1.1 · 10⁻²⁶ e·cm recently published by the Paul Scherrer Institut group (2020). The nEDM@LANL effort looks to improve the measurement uncertainty to 3 · 10⁻²⁷ e·cm. A non-zero nEDM result of this sensitivity will suggest CP-violating physics beyond the Standard Model that will further our understanding of the matter-antimatter asymmetry of the universe. In order to reach this sensitivity, a magnetically shielded room (MSR) is necessary. The MSR is currently under construction at LANL; it consists of five independent layers: one layer of copper and four layers of MuMetal, an alloy with a high magnetic susceptibility. The MSR is expected to produce a shielding factor of 100,000 at 0.01Hz. In this poster, I will discuss the design principle and report on the construction of the MSR.