Cusp shape studies in H+ → He collision in the energy range 75–1400 keV: experiment and theory

Abstract The aim of the present study was to measure the double differential cross section (DDCS) for the electron ejection as a function of electron energy at 0° observation angle in H + → He collisions. Having in mind that the experimental and theoretical shape parameters of the DDCS known in the literature are rather scattered, we made a systematic study in the projectile energy range 75–1400 keV. The total electron yield and the shape parameters of the DDCS were determined and compared with the corresponding values from 2nd order OBK, CDW and CDW-EIS theories. A further aim of this work was to check whether the velocity of the projectile and that of the electrons at the maximum of the cusp peak are indeed equal.