Electron Yield Analysis of Different Surface Morphologies

Surface morphologies can affect electron yield by modifying the probability of electrons emitted from a surface from escaping the material. Electron yield (EY) is a material attribute defined as the the ratio of emitted electrons to incident electrons for a surface irradiated with an electron beam. EY is incident energy dependent and is characterized for each material by intrinsic properties including its chemical composition, crystal structure, electronic configurations. It can be potentially modified by extrinsic factors such as surface roughness, contamination, oxidation, and charging. The surface morphology can reduce EY by recapturing a portion of escaping electrons through interactions with the extended surface features. EY versus incident energy curves were measured for Al, Cu, and stainless steel. Each conducting surface was studied for four distinct surface morphologies: polished, scratched, grit blasted, and granular. Observed changes in EY for the different surface morphologies will be presented and discussed in terms of proposed simple EY models.