Indirectly heated dispenser cathode - with external gold or gold plated molybdenum foil screen cylinder around tantalum foil cylinder

摘要

An indirectly heated dispenser cathode for electric discharge devices is fitted with an external screening cylinder made of gold foil or gold-plated molybdenum foil which reacts with the evaporated barium even at under 500 degrees C. This cylinder is fixed on its base to the support plate concentric to the conventional tantalum foil cylinder. This prevents blackening of the tantalium foil which worsens the radiation, cathode temp. and output, and reduces shrinkage of the coil cylinder which alters the cathode distance to the other electrodes.