Abstract: The triple differential cross sections (TDCS) in coplanar equal energy sharing and fixed relative angle geometry for electron impact ionization of He⁺ are calculated (by using a modified BBK model) at incident electron energies of 58.4,68,81.6,108.8 and 174.4 eV.Dominant ionization mechanisms are identified and the contributions of different scattering amplitudes are discussed.It concludes that Coulomb interaction in the initial channel,exchange effects,correlation and the coherence between electron electron and electron nucleus scattering are all important at these energies.

Key words: He⁺ target, (e,2e)reaction, triple differential cross sections