A study on the thermionic emission and anti-electron-bombing characteristics of the Y2O3-Gd2O3-HfO2 doping W base direct-heated cathode

Abstract:

In order to improve the anti-electron-bombing performance of the cathode applied in high-power magnetron tube. A method of Y2O3-Gd2O3-HfO2(Y-Gd-Hf-O) doping metallic W powders was used to prepare direct-heated cathode. The thermionic emission and anti-electron-bombing characteristics of different mass percent Y-Gd-Hf-O doping cathode were researched. Experimental results show that the 50 wt% Y-Gd-Hf-O doping cathode has large thermionic emission, which can provide 1.0 A/cm2 knee-point emitted current at 1500 ℃. The 10 wt% Y-Gd-Hf-O doping cathode has good anti-electron-bombing capability, whose thermionic emission current density has merely fell by 0.1 A/cm2 after 200 h continuous 14 W/cm2 electron bombing. At last, the thermionic emission and anti-electron-bombing mechanisms of the Y-Gd-Hf-O doping cathode were discussed reasonably.