Elastic Scattering of 40-Mev Protons from Isotopes of Fe, Ni, and Cu

39.8-Mev protons were scattered from thin targets of Fe⁵⁴, Fe⁵⁶, Ni⁵⁸, Ni⁶⁰, and Cu⁶⁵. Absolute differential cross sections obtained with a statistical accuracy of {} 3% have been determined for the elastically scattered protons. The range of the angular distributions, 7.5^∘{} to 110^∘{}, encompassed three minima and three maxima in the measured cross sections. The energy resolution of the detection equipment, utilizing a NaI(Tl) crystal, was 1.2-2%. This enabled a separation to be made of elastic from nonelastic events. A detector telescope allowed angular resolutions of ±1/8^∘ to be used in determining the shape of the features in the angular distributions. The general variation of the cross sections with the nuclear mass is noted. In addition, the data suggest that the nucleon shell closing about nucleon number 28 introduces fine structure differences in the shape and magnitude of features of the scattering pattern.