Doubly differential cross sections (DDCSs) for electron emission have been measured for collisions of 3.6 MeV/u ${\mathrm{Ne}}^{10+}$, ${\mathrm{Xe}}^{40+}$ and 5.9 MeV/u ${\mathrm{U}}^{29+}$ on neon, xenon, water, ethanol, methanol, propanol, ${\mathrm{C}}_2{\mathrm{F}}_6$, ${\mathrm{SF}}_6$, and ${\mathrm{C}}_3$${\mathrm{F}}_8$. Electrons ejected with emission angles between $0°$ and $180°$ with respect to the ion beam axis have been recorded simultaneously using a toroidal electron spectrometer. We analyze the singly differential cross section (SDCS) for binary encounter electron (BEe) production as a function of target electron number and laboratory emission angle. We find that there exists a linear scaling of the BEe SDCS with the number of electrons bound in the target with an energy lower than the reduced projectile energy. The enhancement of BEe production in the forward direction in collisions with partially stripped ions is studied for the different projectiles and targets and compared to theoretical calculations.

• Received 4 December 1997

DOI:https://doi.org/10.1103/PhysRevA.58.1971