Electron Capture and Loss Processes in Heavy Ion and Molecular Ion Collisions with Solids

Angular (θ) and velocity (ve) distributions of convoy electrons have been measured with monoatomic and molecular projectile ions (H+, D+, H+2, D+2, H+2, He+, He++ at 1.7 MeV/U and U+44, Ti+14 at 1.4 MeV/U) as a function of the projectile dwell time tD in carbon foils (2 to 50 μg/cm2). The spectra with light projectiles from carbon foils are compared with those of gaseous CH4 targets. For the light and molecular projectiles the shapes and yield of convoy electrons depend strongly on the dwell time. A narrow, strongly θ-dependent contribution at Ve = vp can be distinguished from a θ-independent part at Ve < vp indicating different production mechanisms. A relation is presented which connects the yield of loss electrons from projectiles with the transmission of projectiles and electrons through solids. The yield of electrons in the spectrum for H+2 at ve = vp and under zero degrees is found to be more than about 20 times as large as is expected from the contribution of loss electrons in last layer collisions.