Statistical Model of Non-Uniform Emission/rom Polycrystalline Tungsten Cathodes

We have constructed a model capturing the statistical nature of non-uniform thermionic electron emission from polycrystalline W cathodes. This model incorporates the proportion of different crystallographic emitting surfaces from commercial cathode samples via electron backscatter diffraction (EBSD), the effects of surface roughness from optical interferometry measurements, and surface-specific work function values calculated using density functional theory (DFT). Using this model, we aim to calculate 2D emission maps and the corresponding Miram curves for real cathodes. This model provides a pathway to understanding the complex physics of emission from inhomogeneous cathode surfaces, which is a key issue for the commercial production and use of impregnated cathodes in vacuum electronic devices.