L-subshell ionisation studies of Ta, W and Pt with protons

L-subshell ionisation cross-sections for Ta, W and Pt by proton impact in the energy range of 2–5.2 MeV have been determined from the experimental data on X-ray production cross-section and the currently available radiative transition probabilities, fluorescence and Coster–Kronig factors of Krause, Werner and Jitschin and Xu. The measured ionisation cross-sections and their ratios are compared with the results of ECPSSR and RPWBA-BC theoretical calculations and previously reported experimental results. The deviations in the various L subshell ionisation cross-sections with three sets of decay yield parameters are found to be less than 20%. Our results of absolute L-subshell ionisation cross-sections and their ratios are in better agreement with the theoretical calculations as compared to previously reported experimental results. The L-subshell coupling effects are found to be weak for the elements of Ta, W and Pt in the energy region 2–5.2 MeV by proton impact.