Toward a statistical model of electron emission from tungsten cathode surfaces

摘要

In this work, we have begun to construct a statistical model of electron emission for polycrystalline W cathode surfaces. Construction of such a model requires knowledge of which surfaces are present, the area fractions of each surface, and the work function values of each surface. We have used Density Functional Theory to explore the effect of O, Ba and Ba-O adsorbates on W surfaces to assess the impact of these adsorbates on the work function and surface stability for several different W surface orientations. A discussion of the impact of different surface adsorbates on the surface stability and work function is presented, together with newly discovered stable Ba-O arrangements on W(011) and W(111) surfaces. Finally, a plan is presented to further develop our statistical model of electron emission and the potential impact of the model for the improved design of high power microwave electronics.