Energy Loss of Protons Beam in Liquid Water and DNA

In the present work the dielectric formalism like Plasmon Pole Approximation (PPA) has been used to calculate the probability for an energetic proton and α-particle to produce electronic excitations in two targets of high biological interest, namely, liquid water and DNA . Also, the effects of ionization fraction calculate the Partial Stopping Power Effective Charge (PSPEC) of ( Au, C, Al, Cs) , liquid water and DNA has been studied taking in to consideration electronic excitation in the target. Bragg rule has been used in calculation, but there is a need to pay more attention to investigate the kind of bond on energy loss.