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The problem of nonuniform distribution of atom packing density and work function values over the field electron metal cathode microsurface is discussed. Different crystallographic faces on the tip of cathode are considered and the method of ones positions determination is proposed. As a result computer model of current density and field emission images is presented. Crystal surface is assumed to be ideal. Lattice geometry for given emitter shape is calculated in "thin shell" and "broken bonds" models. The model "sphere on cone" is used for cathode shape and macroelectric field distribution. Local field enhancement factor is the fitting parameter of a model.
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