Cross sections, stopping power and Bragg peak range calculation of proton collisions with the DNA base adenine

Abstract

Passage of ionizing radiation into the biological medium plays an important role in a variety of chemical modifications, directly or indirectly of the four DNA bases. However, up to now proton collisions on DNA bases remain experimentally approached and a theoretical model for total cross section, stopping cross section and Bragg peak calculation are poorly characterized. In this current work, we restricted our study on the interaction of energetic ion proton beams with DNA base adenine (C5H5N5). The total cross section produced by high energy impact of protons are here analytically investigated via a novel model combining two methods - the Rudd semi-empirical formulas to calculate the ionization and the analytic method based on the similitude between the electron energy loss in adenine and liquid water to calculate the excitation and charge-transfer - these cross sections used to describe the total stopping cross section of adenine molecule by protons including the nuclear stopping powers. We give in this work an estimation of the Bragg peak profile and position with impact energies ranging from 1 to 20 MeV/amu. The results are compared to the available experimental, theoretical and Monte-Carlo results, and reasonable agreements are generally observed especially for the ionization. The proposed method is useful as an alternative to traditional approaches, and is useful for studies of various radiation effects in other biological material.