ZERO-DEGREE BINARY ENCOUNTER ELECTRONS IN FAST COLLISIONS OF HIGHLY-CHARGED F AND O IONS WITH H2 TARGETS

Doubly differential cross sections (DDCS) for binary encounter electro ns (BEe) produced by 0.5-2 MeV/u highly-charged F and O ions in collis ions with H-2 gas targets have been studied at 0-degrees with respect to the ion beam direction. The measured DDCS of the broad binary encou nter peak was well described by a simple impulse approximation (IA) tr eatment for bare ions, and was demonstrated to provide in situ detecti on efficiency of the electron spectrometer. The projectile energy depe ndence of the BEe production for nonbare (clothed) projectiles is foun d to follow a scaled IA prediction, in which a BEe enhancement is cons istently exhibited for the collision energy range studied.