³He polarization and injection system for the nEDM@SNS SOS apparatus

The Systematic and Operations Studies (SOS) for the neutron electric dipole moment (nEDM) experiment at the Spallation Neutron Source (SNS) will measure the trajectory correlation functions of ³He and neutrons in order the determine the expected frequency shift from the geometric phase effect in the nEDM@SNS experiment. To this end the SOS apparatus will utilize Metastability Exchange Optical Pumping (MEOP) to polarize ³He to 80% polarization at room temperature. The ³He will then be injected into the measurement cell inside the cryovessel where the experiment will be performed with concentrations of ³He as low as 10^-10 and a temperature of 0.4 K. We will describe the polarization and injection system and report on results from tests of the MEOP system.