Binary encounter electron production at relativistic velocities

Relativistic binary-encounter electrons produced in very fast collisions of bare and H-like Ar with carbon foils are studied as a function of laboratory frame emission angle. It is found that the velocity of the binary-encounter peak is consistent with a relativistic billiard ball model. The cross section for binary-encounter electron production is not in good agreement with a simple Rutherford scattering model. It is also found that the ratio of H-like to bare projectile cross sections is 1 at 0 degrees and becomes less than 1 at large emission angles.