CONICET | Buscador de Institutos y Recursos Humanos

There are many fields in physics (medical, radiation and high energy physics among others) requiring a suitable knowledge of the range of charged particles traversing a material. To this aim, different theories of the stopping power of materials and the corresponding energy straggling are available in literature[1,2]. Most of the proposed frameworks, rely on a parameter called the mean excitation potential, which is always represented by a geometric average of the excitation levels of the atom or molecule present in the material. This parameter must depend of the atomic number Z, and several approximations for specific materials are also available in literature, most of them empirical or numerical in nature[3,4,5].This work proposes a theoretical framework for the calculation of the mean excitation potential, derived from first principles, but using inelastic cross section parameters obtained from experimental measurements. Also, comparisons of experimental Bragg curves for protons in water are performed with Monte Carlo simulations using the FLUKA code, leading to a value of (77+/-1) eV for the mean excitation potential of liquid water, differing from first international protocols, but in agreement with modern proposals[4,5].[1] Fano, U. Annual Review of Nuclear Science, 13(1), 1963[2] Ahlen, S.P. Rev. Mod. Phys., 52(1), 1980[3] Dalton, P. and Turner, J.E. Health Physics, 15(3), 1968[4] Emfietzoglou, D. et.al. Physics in Medicine and Biology, 5 4(11), 2009[5] Dingfelder, M. Applied Radiation and Isotopes, 83(B), 2014