Deviations from Rutherford elastic scattering cross sections for Cu and Zn with He ions

The onset of non Rutherford cross section for medium heavy elements like Cu (Z = 29; A = 63, 65) and Zn (Z = 30; A = 64, 66, 67, 68, 70) for He as a projectile is studied by means of elastic backscattering measurements made on pure Cu and Zn material samples with He ions at energy ranges from 3 to 10 MeV. The scattering cross section relative to Rutherford value is extracted from the experimental values in an energy range from 7 to 10 MeV with the help of available computer codes for the simulation of elastic backscattering spectra. The measured energy value for the onset of the deviation of the Rutherford value is in agreement with the calculations of Bozoian et al. (1990) [14].