Life Test Studies on Dispenser Cathode With Dual-Layer Porous Tungsten

This paper introduces a newly developed dual-layer porous tungsten dispenser cathode, which can meet the growing requirements on both life and current density. In comparison with the conventional dispenser cathodes, the new-type dispenser cathodes have higher emission current density, lower evaporation rate and longer lifetime. According to the results of the life tests and the related analysis, their longest lifetime at a 1.5 A/cm
²
current density under 974 °C
_br
is estimated to be over 1.9 ×10
⁵
h.