Developing and Testing the Helium-3 Polarization System and SQUID Magnetometers for nEDM@SNS SOS Apparatus*

The neutron electric dipole moment (nEDM) is a parameter that can probe the charge-parity and time-reversal symmetries of nature and could have profound implications for the origin of the baryon asymmetry in the Universe. The current best measured limit of the nEDM has a precision of 1.1 x 10^-26 e cm, and the goal of the nEDM@SNS collaboration is to improve this sensitivity by two orders of magnitude at the Spallation Neutron Source (SNS) at Oak Ridge National Laboratory. The experiment will use polarized Helium-3 and ultra-cold neutrons for the spin-dependent neutron capture reaction in uniform magnetic and strong electric fields. In this project, we aim to develop and test a Metastability Exchange Optical Pumping (MEOP) Helium-3 polarization apparatus and the Superconducting Quantum Interference Device (SQUID) magnetometers for the Systematic Operations Studies (SOS) at the NC State PULSTAR, which will serve as a test run to the larger scale experiment at Oak Ridge. In this talk, we report our progress and challenges in constructing the MEOP gas handling system and testing a SQUID magnetometer. We also outline our future plans for improving the performance of these devices.