Electron emission and plasma generation in a modulator electron gun using ferroelectric cathode

Strong electron emission and dense plasma generation have been observed in a modulator electron gun with a Ba0.67Sr0.33TiO3 ferroelectric cathode. Parameter of the modulator electron gun and lifetime of the ferroelectric cathode were investigated. It was shown that electron emission from Ba0.67Sr0.33TiO3 cathode with a positive triggering pulse is a sort of plasma emission. Electrons were emitted by the co-effect of surface plasma and non-compensated negative polarization charges at the surface of the ferroelectric. The element analyses of the graphite collector after emission process was performed to show the ingredient of the plasma consist of Ba, Ti and Cu heavy cations of the ceramic compound and electrode. It was demonstrated the validity of the Child–Langmuir law by introducing the decrease of vacuum gap and increase of emission area caused by the expansion of the surface plasma.