H01J9/00—Apparatus or processes specially adapted for the manufacture, installation, removal, maintenance of electric discharge tubes, discharge lamps, or parts thereof; Recovery of material from discharge tubes or lamps
H01J9/02—Manufacture of electrodes or electrode systems
H01J9/04—Manufacture of electrodes or electrode systems of thermionic cathodes
H01J9/042—Manufacture, activation of the emissive part