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DRIFT AND DIFFUSION OF ACTIVATION IN OXIDE COATED CATHODES
MISSOURI UNIV COLUMBIA AGRICULTURAL EXPERIMENT STATION
Two experiments pertaining to oxide coated cathodes are described. One of these involves the drift of activators in oxide coated cathodes under the influence of an electric field and the other involves the diffusion of these activators in the absence of an electric field. On the bases of these results, a mobile acceptor model for oxide coated cathodes is presented which suggests that activation is achieved by the removal of the highly mobile acceptors barium vacancies which compensate the relatively immobile donors oxygen vacancies and not by an increase in the density of the donors as has usually been assumed. Nergaards theory explaining the millisecond decay of thermionic emission from oxide coated cathodes is modified in terms of the mobile acceptor model, and the kinetic processes involved in the activation of oxide coated cathodes are discussed. Author