Measurement of Neutron Polarization and Transmission for the nEDM@SNS Experiment.*

The neutron electric dipole moment experiment at the Spallation Neutron Source (nEDM@SNS) will implement a novel method, which utilizes polarized ultra-cold neutrons (UCN) and polarized ³He in a bath of superfluid ⁴He, to place a new limit on the nEDM down to 2-3×10⁻²⁸ e·cm. The experiment will employ a cryogenic magnet and magnetic shielding package to provide the required magnetic field environment to achieve the proposed sensitivity. This talk will describe the design and implementation of a ³He polarimetry setup at the SNS to measure the monochromatic neutron polarization and transmission losses resulting from passage through the magnetic shielding and cryogenic windows. Preliminary results from monochromatic neutron polarization measurements as well as polarimetry component optimization will be presented.