Measurements of the Total Cross Section for the Scattering of Polarized   Neutrons from Polarized $^3$He
  Measurements of polarized neutron--polarized $^3$He scattering are reported. The target consisted of cryogenically-polarized solid $^3$He, thickness 0.04 atom/b and polarization 40%. The longitudinal and transverse total cross-section differences $\Delta\sigma_L$ and $\Delta\sigma_T$ were measured for incident neutron energies 2-8 MeV. The results are compared to phase-shift predictions based on four different analyses of n-$^3$He scattering. The best agreement is obtained with a recent R-matrix analysis of A=4 scattering and reaction data, lending strong suport to the $^4$He level scheme obtained in that analysis. 
C. D. Keith, C. R. Gould, D. G. Haase, M. L. Seely (North Carolina   State University, Triangle Universities Nuclear Laborat...