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.

In this paper, we focus on simulating a pyroelectric accelerator using COMSOL Multiphysics. We utilize the static surface charge distribution obtained from an experiment conducted on a LiTaO3 3 single crystal surface. We analyze the characteristics of the electron flow generated by the accelerator and determine the emittance and Twiss parameters. Our findings reveal that the normalized RMS emittance remains relatively constant in the space behind the target.

A comparison of the induction current and the emission current during the pyroelectric effect in 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 does not allow one to observe the effect of the optimal frequency with the maximum amplitude, as for the induction current. The conformity of both current forms is shown, except for the region of 2 mHz or 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.

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.

The solid solution Ce0.8Y0.2O2-? was obtained by three methods: sol gel, glycine nitrate and solid-state reaction. The synthesis temperature was 1350 ?C for the sample obtained by the sol gel method and 1500 ?C for the remaining samples. It’s shown by the X-Ray method that all samples have a cubic lattice with a fluorite structure. The microstructure, density, electrical conductivity, microhardness and crack resistance of the synthesized ceramics were investigated. By the impedance spectroscopy method, a system Ce0.8Y0.2O2-? obtained by the sol gel method was found to have the highest electrical conductivity reaching 5.37 mS/cm at a temperature of 550 ?С and the lowest activation energy equal to 0.83 eV in the temperature range of 300 – 550 ?C. The contribution to the conductivity of the grains and the grain boundaries is defined. A common conductivity is shown to be decreased because of the resistance of the grain boundaries for all samples.

Deflection of a relativistic electron beam by means of the pyroelectric deflector is demonstrated experimentally for the first time. The operating principle of the pyroelectric deflector is based on the generation of a strong transverse electric field in a vacuum in the gap between a pair of pyroelectric crystals due to the pyroelectric effect. The experiments on observation of deflection of 7 MeV electron beam for 26 mrad in the transverse electric field with a strength of about 100 kV/cm arising at a variation of the temperature of a pair of pyroelectric crystals in vacuum are described. The possibility for application of the installed sequentially pyroelectric deflectors in pyroelectric undulator for production of undulator radiation by relativistic electron beam without any external high voltage power supply is discussed.

A pyroelectric X-ray source is proposed, in which a lithium tantalate crystal is heated by an infrared laser with a wavelength of 10.6 μm. X-ray spectra measured during irradiation of the crystal with infrared radiation and during natural cooling of the crystal include characteristic X-ray radiation of atoms contained in the structural parts of the source, as well as bremsstrahlung of electrons with energies above 50 keV. An 8 mm sodium chloride window was used to inject 64 W infrared radiation into a vacuum chamber with the pyroelectric crystal installed.

The solid solution Ce 0.8 Y 0.2 O 2–δ was obtained by three methods: sol-gel, glycine-nitrate, and solid-phase reactions. The synthesis temperature was 1350°C for the sol-gel method and 1500°C for the remaining samples. The x-ray method showed that all samples have a cubic lattice with fluorite structure. The microstructure, density, electrical conductivity, microhardness, and crack resistance of the resulting ceramics were studied. It was found by means of impedance spectroscopy that the Ce 0.8 Y 0.2 O 2–δ system obtained by the sol-gel method has the highest electrical conductivity, 5.37 mS/cm at 550°C, and the lowest activation energy, equal to 0.83 eV in the temperature range of 300 – 550°C. The contribution made to the conductivity by grains and grain boundaries is determined. It is shown that the total conductivity for all samples decreases due to the resistance along the grain boundaries.

Results of first experiments with piezoelectric accelerator built on quartz crystals as piezoelectric elements are presented. Accelerating voltage in such quartz accelerator is produced at compression in vacuum of quartz crystals along polar axis. The construction of the quartz accelerator and results of measurements the spectra of X-ray radiation which is produced by electrons accelerated in such accelerator are described. Accelerating voltage in quartz accelerator observed in the experiment is discussed.

The paper focuses on the surfaces electrization of Z-cut single-crystal lithium niobate during the pyroelectric effect. It is shown that the properties of the electric current passing through the surfaces of single-crystal lithium niobate depend on the ground circuit, the rate of temperature change, and orientation of polar axes. Experiments show that grounding of lithium niobate surfaces has an effect on the X-ray radiation during the pyroelectric effect.

In the coming years, the compact monoenergetic neutron generators (CNG) producing up to 104 n/s may become an alternative to the standard neutron sources based on radioactive isotopes for the calibrations of neutrino and dark matter detectors. Such neutron generators have a typical size of about several centimetres, they may be manufactured using low-background materials and may require only low voltage power supply for operation. We discuss the advantages and disadvantages of two main types of the compact neutron generators, namely a pyroelectric neutron source and a high voltage neutron generator. Also the results of the technical analysis of the possibilities to apply such sources for the calibration of low-background experiments are given, the variant of the internal device design is shown and the full-size compact neutron generator prototype are presented.

The main goal of the MultiPurpose Detector (MPD) at NICA facility in Dubna is to study hot and dense baryonic matter in ion-ion collisions at energies root sNN = 4 - 11 GeV. It is necessary to identify particles produced in interactions with high efficiency for a detailed study of the processes and registration of the slightest fluctuations occurring under these conditions. The time-of-flight identification system (TOF) of the MPD based on the MRPC has characteristics that make it possible to cope with this task as efficiently as possible. The TOF system performance and results of a realistic simulation of hadrons identification are presented in this paper.

The pyroelectric neutron generator is a compact source of fast neutrons with an energy of 2.45 MeV and a yield up to ∼104 neutrons/s. The device is designed for calibration of low-background neutrino and dark matter detectors and may also serve as an alternative to traditional radioactive sources of fast neutrons in physical research and practical work. Numerical simulation of the angular distribution of neutrons emitted by the pyroelectric generator with the D(d, n)3He reaction proceeding within it was performed in order to calculate the neutron yield in the full solid angle and in a given direction correctly. The angular distribution was found to be anisotropic: the neutron yield increased in the direction of motion of incident deuterium ions. This anisotropy was as large as ∼25% at a maximum energy of 28 keV of incident particles. The anisotropy increased nonlinearly with the ion energy: it reached ∼70% at 50 keV and a monoenergetic flux, but was virtually zero below 10 keV. The obtained angular distribution is similar to that of neutrons in the case of a 15-keV monoenergetic flux of deuterium ions.

In this work we present the results of the experimental studies of the dependence of the X-ray radiation on the temperature change speed of the lithium tantalate monocrystal in the pyroelectric source of the X-ray radiation. We have found an optimized linear temperature speed change pattern for the pyroelectric crystal designed for generation of the X-ray radiation with enhanced capabilities. The studies that were made open an opportunity to determine the most convenient conditions for generation of X-ray radiation with pyroelectric effect and for development of high-capacity pyroelectric X-ray radiation sources.

Here we propose the conception of small-size piezoelectric accelerator of charged particles that operates due to the piezoelectric effect at varying mechanical force applied to piezoelectrics in vacuum. The accelerating voltage and the energy of accelerated particles are estimated. In the proof-of-principle experiment we demonstrate the effect of the emission of X-ray radiation at the mechanical compression of piezoelectric ceramics in vacuum. The compression leads to the appearance of charges and potentials on the surfaces of the piezoelectrics and also to the arising of the electric field in vacuum. Electrons are accelerated in the electric field, strike the matter and produce the X-ray radiation. In the experiment, we have observed emission of the characteristic and bremsstrahlung X-ray radiation of energy up to 60 keV due to the compression of piezoelectric ceramics in vacuum. This means that electrons are accelerated in the piezoelectric accelerator up to the energy at least of 60 keV. The agreement of calculated and experimental data confirms the conception. Advantages of the piezoelectric accelerator and possibilities of its development and applications are discussed.