Secondary electron emission from thin foils under fast-ion bombardment

Abstract

The total secondary electron emission (SEE) coefficient \ensuremath{\gamma} 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 \ensuremath{\mu}g/${\mathrm{cm}}^{2}$) in the energy range 0.4\ensuremath{\le}${E}_{p}$\ensuremath{\le}22 MeV. The material paramter \ensuremath{\Lambda} deduced from our measurements is calculated to 0.031\ifmmode\pm\else\textpm\fi{}0.005 nm/eV for the different studied targets with 28\ensuremath{\le}Z\ensuremath{\le}83. For all projectiles and velocity regions studied the SEE coefficient \ensuremath{\gamma} and the stopping power have the same velocity dependence. However, for a given projectile velocity, the \ensuremath{\gamma} 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.