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Publication of BE447583ApublicationCriticalpatent/BE447583A/xx
H01J1/00—Details of electrodes, of magnetic control means, of screens, or of the mounting or spacing thereof, common to two or more basic types of discharge tubes or lamps
H01J1/02—Main electrodes
H01J1/13—Solid thermionic cathodes
H01J1/14—Solid thermionic cathodes characterised by the material
H01J1/142—Solid thermionic cathodes characterised by the material with alkaline-earth metal oxides, or such oxides used in conjunction with reducing agents, as an emissive material