An improved dispenser cathode

Electron emissivity of tungsten dispenser cathode has been remarkably increased only by improving the process technology. Improved process includes firing impregnants in an oxidizing atmosphere which contains CO2and finishing the emitting area clean by new \´physical and chemical\´ treantemts. The application of this process to the Ir coated dispenser cathode leads to electron emissivity of 39A/cm²(pulsed FSCL) at cathode temperature 1050°CB. Measured Richardson parameters are 1 .06 eV and 0.155 A/cm²deg², respectively. At the same time, the short acivation time and low evaporation are given by this process. Cathodes of this type are most suitable for high resolution camera tubes and microwave tubes.