Proton inelastic mean free path in amino acids and protein over the energy range of 0.05–10 MeV

The inelastic mean free paths (MFP) of 0.05–10 MeV protons in a group of 15 amino acids and a protein have been systematically calculated. The calculations are based on the method newly derived from the Ashley’s optical-data model and from the higher-order correction terms in stopping power calculations. Especially, in this method the new and empirical Bloch correction for the inelastic MFP was given. An evaluation for the optical energy loss function is incorporated into the present calculations because of the lack of available experimental optical data for the bioorganic compounds under consideration. The proton inelastic MFPs for these 15 amino acids and the protein in the energy range from 0.05 to 10 MeV are presented here for the first time, and the combination of these inelastic MFP data and our previous data of the SP calculations for these bioorganic compounds may form a useful database for Monte Carlo track-structure studies of various radiation effects in these materials.