Practical range and energy loss of 0.1-3-keV electrons in thin films ofN2,O2, Ar, Kr, and Xe

Abstract

Thin solid films of ${\mathrm{N}}_2$, ${\mathrm{O}}_2$, Ar, Kr, and Xe were condensed on a cooled (11 K) sapphire substrate and then bombarded by monoenergetic electrons. The fluorescence intensity of the ${\mathrm{Cr}}^{3+}$ color center in sapphire ($\lambda =693\mathrm{}$ nm) was measured as a function of film thickness and electron energy to determine the electron practical range and effective energy loss ($\frac{\mathrm{dE}}{\mathrm{dz}}$). The ${\mathrm{Cr}}^{3+}$ intensity versus primary-electron-energy and film-thickness curves also yield information on the production of secondary electrons. The results are compared to an extrapolation of Bethe-Bloch theory to low energies for total range and energy loss ($\frac{\mathrm{dE}}{\mathrm{ds}}$) and to the electron-gas statistical model of Tung, Ashley, and Ritchie for low-energy electrons.