Neutron polarimetry using a polarized 3He cell for the aCORN experiment

The neutron polarization of the NG-C beamline at NIST Center for Neutron Research was measured as part aCORN beta decay experiment. transmission through a polarized 3He spin filter cell recorded while adiabatic fast passage (AFP) nuclear magnetic resonance (NMR) reversed direction in an eight-step sequence to account drifts. dependence on used calculate polarization. time dependent fit model which included spectrum, and losses from relaxation AFP-NMR. found be ${\mid}P_\mathrm{n}{\mid} \leq 4\times 10^{-4}$ with 90 % confidence.