Emission Characteristics of Nanosized Scandia-Doped Dispenser Cathodes in Open Electron-Gun Structures

The emission properties of nanosized scandia-doped dispenser cathodes tested in open-structure Pierce electron guns are reported in this paper. Over 100 A/cm
²
and over 80 A/cm
²
space-charge-limited current densities have been obtained at the operating temperatures of 950 °C
_b
and 1025°C
_b
for cathodes with planar emitting surfaces and cathodes with concave emitting surfaces, respectively, at rated anode voltages.