Hot cathode periodic electron emission current increase - by using tungsten-scandium oxide outer layer on impregnated tungsten@ cathode, for microwave tube and television with energy redn.

摘要

Emission substance dispensing cathode is used as the hot cathode and is coated with pref. outer layer of tungsten and a Gp.IIIb oxide, the hot cathode is activated with a slow increase of 500 deg.C- operating temp. to maintain residual gas pressure in the tube or in a vacuum chamber below 10 power-6 hPa (below 10 power-7 hPa), on operating the cathode in a tube, all the parameters which affect the emission are kept constant, partic. the cathode temp., the anode-cathode distance, the DC diode voltage or the frequency in pulse emission operation, the pulse-width repetition rate, the amplitude, the pulse shape in the pulse emission region and the residual gas pressure (the latter in partic. in a range less than 10 power-8 hPa), and the length of cycle and the amplitude of the emission peak are determined by pref. selection of the operating parameters e.g. the temp., and are not controlled by an external oscillator. USE/ADVANTAGE - Improves hot cathode performance for a wide range of devices by periodically increasing electron emission current density.