X-ray flashes and pulsating electron flow in X-ray generators based on SBN-61 crystals

In an X-ray generator based on a ferroelectric crystal of barium-strontium niobate Sr$_{0.61}$Ba$_{0.39}$Nb$_2$O$_6$ (SBN-61) at a temperature of about 50$^\circ$C, pulsations of the electron flux and X-ray radiation were detected with an increase in gas pressure in the range 2 $\cdot$ 10$^{-2}$–10$^{-1}$ Torr. The electron flux had the shape of a cross in the crystal plane. The flash duration did not exceed 0.04 seconds. The pulsation period varied from 0.2 seconds at the beginning and up to 5–10 s at the end at a pressure of $\approx$ 0.1 Torr. The observed effect is explained by the movement of domain boundaries on the depolarized crystal face in vacuum conditions, resulting in a large surface charge and, accordingly, an electric potential, leading to the formation of a pulsed electron flux.