Total Yield and Escape Depth of Electrons from Heavy Ion Solid Interactions

Abstract
At high projectile energies (~MeV/U) several mechanisms for electron production are discussed as e.g. direct ionization collisions, recoil particle cascades, collective electron emission. Results are presented of total electron yield (γ) measurements over a wide projectile energy Ep range (40 keV/U<Ep/M <12 MeV/U) and a wide projectile Zp range (1<Zpγ92) of both monoionic and molecular projectiles and of different target thicknesses. From the target thickness dependence of γ the mean free path λ of electrons in carbon can be calculated. The data are discussed in the frame of current theories. Significant deviations from calculated values and predicted dependencies are found, in particular for projectile velocities vp close to the Fermi velocity VF of target electrons Rnd for molecular projectile ions.