Asymmetry in the (p,n) Reaction on Deuterium and Carbon at 215 MeV

A double-scattering experiment was performed on targets of deuterium and carbon, using 215-MeV, 85% polarized protons as incident particles. The asymmetry of recoil neutrons was measured at laboratory angles between 10° and 35°, using a neutron counter consisting of a polyethylene converter and multi-element scintillation telescope. The deuterium measurements are related to the free $n-p$ polarization parameter by an impulse-approximation calculation. The deuterium results are in good agreement with the predictions of Yale phase-shift solutions 3, 3M, and 4M and the new Livermore solution, and are incompatible with Yale solutions 0, 1, 2, 2M. The asymmetries from carbon agree with free-$n-p$ scattering except at laboratory angles of 10° and 35°, where they are greater in absolute value. The asymmetry from carbon showed the greatest dependence on neutron energy at these angles.