Polarized $^{3}$He in the Neutron Electric Dipole Moment Experiment

In the neutron electric dipole moment (nEDM) experiment to be performed using the Fundamental Neutron Physics Beamline at the Spallation Neutron Source, ultra-cold neutrons (UCN) are produced by interaction with superfluid $^{4}$He. The precession frequency of polarized UCN in the presence of a strong electric field is measured using a spin-dependent capture reaction on polarized $^{3}$He; the protons and tritons produced in the reaction are detected via the scintillation light they produce in the superfluid $^{4}$He. In this talk, the production of polarized $^{3}$He, its introduction into the superfluid $^{4}$He, its relaxation in interactions with the materials of the experiment, its transport to the measurement cells and eventual removal from the system will be discussed.