X-ray source on the basis of the piroelectric crystal Sr0.61Ba0.39Nb2O6

Abstract

The properties of X-ray source based on Sr0.61Ba0.39Nb2O6 crystals (SBN-61) having a large pyroelectric coefficient γ = 85 nC/(cm2K) was studied. When the crystal was heated to 60 ° C, X-rays from a tungsten target with energy of 8.4 keV were detected. The maximum energy of the electron beam was 52 keV. The visualization of the electron beam with a grid electrode and a fluorescent screen showed that the electron beam was inhomogeneous in the polar plane of the crystal and varied during heating.The radiation intensity was unstable in time. The work of the X-ray source was limited to electrical breakdowns between the polar faces of the crystal. When the crystal was cooled, there was no X-ray emission, which could be due to the depolarization of the crystal by the total electric field or as a result of electrical breakdowns. The crystals SBN-61 and LiNbO3 are compared.

X-ray Flashes and Pulsating Electron Flow in X-Ray Generators Based on SBN-61 Crystals

“…The spectrum has the form of a wide maximum at energy of ≈ 6 keV and extends to an energy of ≈ 25 keV. We note that the tungsten line L(W) ≈ 8.4 keV, which is characteristic of the heating mode [5], is not observed. The ultimate energy of 25 keV can correspond to the maximum voltage between the crystal and the target in this experiment.…”

“…As indicated in the Introduction, electron flow and X-ray radiation was observed when heated in a vacuum, there was no radiation when cooled in a vacuum [5]. This behavior differs from the properties of traditional crystals LiNbO 3 and LiTaO 3 , in which the direction of the electron flow changes upon cooling, but X-ray generation of is preserved [1,11].…”

“…In order to preserve the polarization of the SBN crystals, the samples were cooled at an increased pressure of about 2 • 10 −1 Torr [5], when the compensation of surface charges due to exchange with gas atoms occurred quickly enough, and the total electric field was close to zero. When the temperature of ≈ 10 • C was reached, the chamber was pumped back to a pressure of P ≈ 10 −3 Torr, after which the next heating-cooling cycle began.…”

“…In [5] we investigated crystals of solid solutions of barium-strontium niobate Sr 0.61 Ba 0.39 Nb 2 O 6 (SBN-61), which have a very high pyroelectric coefficient γ = 85 nC • cm −2 K −1 [6,7]. The properties of SBN crystals differ from the classical ones: these crystals belong to the class of ferroelectric relaxers, have a diffuse phase transition with a low Curie temperature, about 80 • C, and a small electric coercive field [8,9].…”

“…The properties of SBN crystals differ from the classical ones: these crystals belong to the class of ferroelectric relaxers, have a diffuse phase transition with a low Curie temperature, about 80 • C, and a small electric coercive field [8,9]. In [5] the electron flow and generation of X-ray radiation in SBN crystals were recorded in heating mode.…”