Secondary electron emission from thin foils under fast-ion bombardment

The total secondary electron emission (SEE) coefficient γ was measured from sputter-cleaned self-supporting C, Al, Ni, Cu, Pd, Ag, Sm, Gd, Au, and Bi targets under bombardment of fast protons, as well of incident ${\mathrm{H}}^{+}$, ${\mathrm{Li}}^{2+}$, ${\mathrm{Li}}^{3+}$, ${\mathrm{C}}^{3+}$, ${\mathrm{C}}^{4+}$, ${\mathrm{O}}^{3+}$, ${\mathrm{O}}^{4+}$, and ${\mathrm{O}}^{5+}$ ions from thin carbon foils (20 μg/${\mathrm{cm}}^2$) in the energy range 0.4≤$E_p$≤22 MeV. The material paramter Λ deduced from our measurements is calculated to 0.031±0.005 nm/eV for the different studied targets with 28≤Z≤83. For all projectiles and velocity regions studied the SEE coefficient γ and the stopping power have the same velocity dependence. However, for a given projectile velocity, the γ coefficient and the stopping power do not have the same projectile $Z_p$ dependence. The data are discussed in the frame of an extended Sternglass model.