The Polarization and Transmission Test of the nEDM@SNS's Cryogenic Apparatus

The nEDM@SNS experiment's aim to measure the neutron's electric dipole moment (nEDM) to the order of 10^-28 e cm requires novel cryogenic-based techniques, such as loading its two measurement cells in situ with ultracold neutrons produced by the downscattering of 9 A neutrons in superfluid 4He and shielding magnetic field variation with a superconducting lead shield. The cryogenic apparatus consists of nested layers, including an inner magnet vessel containing a magnet package for spin manipulation and its flux return layer inside of the superconducting lead shield. A polarization and transmission test was constructed at the Spallation Neutron Source at Oak Ridge National Lab to characterize a 9 A neutron beam passing through the layers of the cryogenic apparatus. This will inform and troubleshoot the sensitivity for the final nEDM@SNS experiment. The construction efforts and measurement status will be presented.