Proton stopping power in a group of bioorganic compounds over the energy range of 0.05–10 MeV

Abstract

The systematic calculations of the stopping powers (SPs) for 0.05–10 MeV protons in a group of 10 important bioorganic compounds, i.e. DNA, five bases, three fatty acids and cellulose, have been performed. The calculations are based on the dielectric model of Ashley and on an evaluation of optical energy loss function (OELF) for the bioorganic compounds considered, most of which have no available optical data. Higher-order corrections, Barkas-effect correction and Bloch correction, are included and a concise form of SP calculation corresponding to Barkas-effect is presented by incorporating the evaluated OELF. Especially, the dependences of SP calculations on the two choices of the minimum impact parameter a are analyzed in detail, and hence an appropriate parameter a is determined for organic media. For the tested organic compounds the proton SPs calculated by use of the determined a are in excellent agreement with the tabulated values based on experimental data. The presented data are the first results of the proton SPs for the 10 bioorganic compounds in the energy range from 0.05 to 10 MeV, and might be useful for studies of various radiation effects in these materials.