Angular dependence of secondary electron yield from microporous gold surfaces
Jonathan Ludwick, Asif Iqbal, Daniel Gortat, John D. Cook, M. Cahay, Peng Zhang, Tyson C. Back, Steven B. Fairchild, Martin Sparkes, W O’Neill
Abstract
We report exhaustive measurements of the secondary electron yield (SEY) from a gold film containing an array of micropores as a function of the angle of incidence of the primary electrons. The SEY measurements are in good agreement with Monte-Carlo (MC) simulations. A highly accurate empirical fit to the SEY data as a function of the incident electron impact angle is also proposed. In this study, the micropores have aspect ratios (ratio of pore height over pore diameter) ranging from about 1.5 to 3.5. The effect of the pore array density (porosity) and pore aspect ratio is analyzed in greater detail. It is found that increasing the pore aspect ratio and porosity leads to a sharp reduction in the total SEY in agreement with MC simulations.