The generation of electrons and X-rays using a pyroelectric accelerator is highly appealing from a practical point of view due to the potential for compact and energy-efficient devices. This study focuses on investigating the influence of accelerator geometry, particularly the position and area of the target. We have determined that a smaller target area enhances X-ray intensity and monoenergetic electron flux, while the balance between positive and negative polarity exhibits weak dependence on geometry. Altering the position of the target-collimator enables regulation of the energy of the collimated electron flow. The focal spot of the electron flow in a pyroelectric accelerator exhibits a complex longitudinal structure, as demonstrated by both experimentation and computer modelling. Furthermore, increasing the distance between the crystal and the target enhances the stability of the pyroelectric accelerator. Consequently, the combined effect of target area and its position relative to the crystal significantly influences the observed particle flux, and we propose approaches for their regulation in practical devices.
Recently, it was established that the X-ray generation intensity increases in a certain range of temperature variation rates (6–8°C/min) of lithium tantalate single crystal (LiTaO3). In this work, the pyroelectric current generation is studied as a function of the temperature variation rate. Four stages of the pyroelectric current generation dynamics are determined. In the same rate range (6–8°C/min), an anomalously long stage of current saturation is observed, which is most likely the cause of the observed effect of an increase in the X-ray intensity. The observed anomaly is described, as well as systematic features in the pyroelectric current dynamics with varying the pyroelectric material temperature with a constant rate.
Realization of a pyroelectric effect in vacuum provides the possibility to develop a compact and relatively inexpensive electron source. In this paper we observe and analyze the I-V curve of electron flow generated during the pyroelectric effect in a lithium tantalate single crystal. The region of the monoenergetic electron flow with a slow change in the peak energy is determined. This phenomenon is accompanied by a current avalanche process. The analysis of the electron spectra and the I-V curve shows that the observed avalanche process and the stabilization of the peak energy occurs due to a sharp increase of secondary electrons in the total electron flow.
A comparison of the induction current and the emission current during the pyroelectric effect under vacuum conditions with periodic variation in the temperature of a single crystal of lithium tantalate is presented. An increase in the variation frequency leads to suppression of the emission current, which prevents observing the effect of the optimal frequency with the maximum amplitude as in the case of the induction current. The conformity of both current forms is shown, except for the region of 2 mHz and less where an additional current wave is observed. It is established that this additional wave is initiated above a certain threshold of potential difference and leads to its stabilization. Keywords: pyroelectric effect, ferroelectric electron emission, pyroelectric accelerator, lithium tantalate.
Description of modern pyroelectric technologies is presented in this article. Various schemes for generating X-ray radiation are presented. The possibility of controlling charged particle beams by means of a pyroelectric deflector is demonstrated. The prospects for the development of pyroelectric technologies and their application are discussed.
This paper presents the results of the study of the dependence of the endpoint energy of X-ray radiation on the preliminary change in the temperature of the lithium tantalate (LiTaO3) single crystal, which is a source of a strong electric field of the pyroelectric effect under vacuum conditions. Measurements were performed in a pulsed mode of X-ray generation, consisting in a preliminary change in the pyroelectric sample temperature in high vacuum and the use of an additional electron source for complete pyroelectric discharge. The obtained dependence suggests that the maximum capacity of X-ray generation by a pyroelectric source manifests itself when using the pulsed mode.