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

The existence and size of a neutron electric dipole moment (nEDM) remains an important question in particle and cosmological physics. The nEDM@SNS experiment proposes a new limit for nEDM search by using ultra-cold neutrons (UCN) in a bath of superfluid helium. The experiment uses polarized 8.9Å neutrons to create polarized UCN in situ in superfluid helium via superthermal downscattering. The experiment will measure the change in precession frequency of UCN and ³He via the scintillation light produced from the spin-dependent n-³He absorption. This process requires 8.9Å neutrons to retain their polarization as they pass through magnetic shielding and nEDM cryostat windows. This talk will describe a setup that will allow us to measure neutron polarization loss from the magnetic shielding and cryostat windows.