A polarization standard for protons between 6 and 8 MeV

Arguments based on the continuity of the scattering phase-shifts predict that the analyzing-power A in proton scattering from spin-zero targets reaches exactly +-1 at certain proton energies E0 and scattering angles theta0. A polarized proton beam was used to determine precise values of E0, theta0 for the A = -1 point in p + 12C scattering near 7.3 MeV proton energy. A polarimeter based on p + α scattering is calibrated at this energy E0. The polarimeter calibration was extended to different bombarding energies by calculating its energy dependence from p + α phase shifts. This procedure is tested by the investigation of an A = 1 point in p + α scattering near 6.3 MeV proton energy. (Auth.)