Elastic neutron-proton differential cross section at 647 MeV

The differential cross section for n-p elastic scattering in the angular range 510 less than theta/sub cm/ less than 1800 was measured with high statistical accuracy using the 647 MeV monoenergetic neutron beam of the Los Alamos Meson Physics Facility. A proton recoil magnetic spectrometer was used for momentum analysis of the charge exchange protons from the reaction n + p → p + n. Absolute normalization of the cross section was established to within 7 percent using existing cross section data for the reaction p + p → π+ + d. The results differ significantly from previous Dubna and PPA cross sections but agree well with recent Saclay data except at extreme backward angles