Measurements of the total cross section for the scattering of polarized neutrons from polarized 3He

Measurements of polarized-neutron endash polarized-3He scattering are reported. The target consisted of cryogenically polarized solid 3He, with thickness 0.04 atom/b and polarization ∼0.4. Polarized neutrons were produced via the 3H(p searrow,n searrow)3He or 2H(d searrow,n searrow)3He polarization-transfer reactions. The longitudinal and transverse total cross-section differences ΔσL and ΔσT were measured for incident neutron energies 2 endash 8 MeV. The results are compared to phase-shift predictions based on four different analyses of n-3He scattering. The best agreement is obtained with a recent R-matrix analysis of A=4 scattering and reaction data, lending strong support to the 4He level scheme obtained in that analysis. Discrepancies with other phase-shift parametrizations of n-3He scattering exist, attributable in most instances to one or two particular partial waves. copyright 1996 The American Physical Society