New measurements of spin-dependent n-p cross sections

Abstract

We report on new measurements of the spin-dependent neutron-proton total cross-section differences in longitudinal and transverse geometries (ΔσL and ΔσT respectively) and between 5 and 20 MeV. These transmission experiments involve a polarized neutron beam and polarized proton target. The polarized neutron beam was produced as a secondary beam via charged-particle induced neutron-production reactions. The proton target was cryogenically cooled and dynamically polarized. These data will be used to extract e1, the phase-shift parameter which characterizes the strength of the tensor interaction at low energy.