Mass stopping power of alpha particles in liquid water and some gases

The interaction of charged particles with the chemical elements involved in the synthesis of human tissues is one of the modern techniques in radiation therapy. One of these charged particles are alpha particles, where recent studies have confirmed their ability to generate radiation in a highly toxic localized manner because of its high ionization and short its range. In this work, We focused our study on the interaction of alpha particles with liquid water; since the water represents over 80% of the most-soft tissues, as well as, hydrogen, oxygen, and nitrogen, because they are key chemical elements involved in the synthesis of most human tissues. The mass stopping powers of alpha particle with H2O, CO2, O2, H2 and N2have been calculated in energy range (0.001-1000) MeV, using four methods (Beth-Bloch equation, Zeigler formula and SRIM2013 software, ASTAR program).We have produced semi-empirical formulas for calculating the mass stopping power of alpha particles, for such targets by knowing alpha particle energy. Comparing our results of the calculated mass stopping power with ICRU-Report 49 we find very good agreement between them, this confirms the ability of our result to be used in such cancer treatment and other fields where this quantity is used.