K-shell ionisation cross-sections of Cu,Ge, Mo,Ag and Sn by protons of energy 0.3 to 1.8 MeV

K-shell ionisation cross secions of Cu, Ge, Mo, Ag and Sn in proton impact have been measured systematically in the energy range 0.3 to 1.8 MeV. Thin targets have been used in transmission geometry. Data are compared with the predictions of the PWBA and the PWBA modified to include corrections due to Coulomb retardation of the projectile, increased binding of the target electron during collision and the relativistic nature of theK-shell electrons. The intensity ratiosK _α /K _β have also been obtained as a function of proton energy for all the five elements.