Investigation of Terahertz Cathode Heated by Electron Beam

An electron beam heating model capable of heating terahertz (THz) cathode has been developed. The cathode temperature field was simulated, which showed that both the heat radiation of the THz heater and the electron beam bombardment made contribution to heating the THz cathode. Experimentally, the emission capacity of the THz heater made of tungsten-thorium filament was investigated at different temperatures. The dependences of the cathode temperature on the bombardment power
$P$
or the THz heater temperature
$T_{h}$
were studied, respectively. The cathode temperature can reach 1098 °C at
$P$
of 3.98 W and
$T_{h}$
of 1725 °C. The warm-up time of the THz cathode was investigated, and the cathode temperature became stable at 1100 °C in 27 s.