“…(w, /Eo ij. (4) In (4) 0' is the delta ray cross-section, Eo is the total energy of the incident charged particle, me is the electron mass, W, is the kinetic energy of the recoil electron (delta ray), 70 is the classical radius of the electron which is equal to e2/(m,c2), and 13 0 is the incident charged parti cle's velocity divided by c. The maximum kinematically allowed energy transfer to the electron, Wm, is given by the following expression,…”