Intra-atomic double scattering of Binary Encounter electrons in heavy ion collisions with gas targets

Experimental evidence for intra-atomic double scattering of fast Binary Encounter (BE) electrons produced in collisions of 5.9 MeV/u U29+with various gas targets is presented. A broad distribution of electrons displaying the shape of the (BE) peak at twice of the velocity of the ion beam at angles up to 135° is observed in the double differential electron emission spectra. This emission is attributed to target electrons ejected in a knock-on collision that are subsequently elastically scattered at their own target nuclear potential.