Secondary standards for 7Li beam polarimetry

Primary standards for 7Li polarimetry requiring a measurement of the reaction p(7Li→,α) at 0° to the beamline impose excessive radiation damage on the detectors. Eliminating this damage requires the establishment of secondary standards for the online measurement of beam polarization. A complete set of analyzing powers has been obtained for the scattering of polarized 7Li by 4He to the 4.63 MeV excited state of 7Li at a bombarding energy of 31.5 MeV. Certain angles at which both the differential cross-sections and analyzing powers are large are tabulated as secondary polarization standards.