Облучение ионами аргона Cr/4H-SiC-фотоприемников

The results of the effect of irradiation with Ar ions on the structural, electrophysical and optical characteristics of the ultraviolet Cr/4H-SiC photodetectors in the spectral range of 200−400 nm are presented. After a single irradiation with 53MeV Ar ions with a fluence of 1 · 1010 cm−2, the quantum efficiency of the photodetectors practically remained at the level of the initial samples due to the "gettering effect“ of simple radiation defects by cluster formations. The observed effect promoted a decrease in the number of simple radiation defects of the vacancy type, an increase in the lifetime of current carriers, and, as a consequence, unchanged values of the photoconductivity of Cr/4H-SiC photodetectors. After repeated irradiation of the photodetectors with Ar ions with a total fluence of 2 · 1010 cm−2, the decay of clusters was observed, the formation of a significant number of simple defect centers, which led to a decrease in the lifetime of current carriers and, as a consequence, to a decrease in photoconductivity of Cr/4H-SiC photodetectors.

The features of deformation-stimulated RbI luminescence

This paper studies deformation-stimulated features of radiative relaxation of self-trapped excitons and recombination assembly of exciton-like luminescence in RbI crystal. Methods of research were luminescence and thermal activation spectroscopy. The identity of the mechanism of manifestation of the X-ray luminescence, tunnel luminescence and thermally stimulated luminescence spectra were found in the elastically deformed RbI crystal, interpreted by the luminescence of self-trapped exciton, tunnel recharge of F′, VK -pairs and thermally stimulated recombination of e−, VK -centres, respectively.The temperatures of the maximum destruction peaks of thermally stimulated luminescence, their spectral composition and activation energies were determined experimentally, on the basis of which the mechanisms of recombination assembly of exciton-like luminescences in a RbI crystal were interpreted. Uniaxial elastic deformation leads to the effective formation of point radiation defects ( F′, HA, VK -centers) in comparison with an unbroken lattice, where the predominant mechanism is the association of interstitial atoms ( H -centres) with the formation of I3−-centres.

Study of the Effect of Y2O3 Doping on the Resistance to Radiation Damage of CeO2 Microparticles under Irradiation with Heavy Xe22+ Ions

This paper presents the results of a study on the influence of Y2O3 doping on the resistance to radiation damage and an assessment of structural changes associated with the accumulation of radiation defects in CeO2 microparticles under irradiation with heavy Xe22+ ions. The relevance of this study consists of the prospects for the use of CeO2 microparticles as materials and candidates of inert matrices of nuclear fuel. A method of solid-phase synthesis was applied to obtain microparticles with different concentrations of dopant. It included grinding of CeO2 and Y2O3 microparticles followed by thermal sintering at 1100 °C in an oxygen-containing medium to produce highly ordered microparticles. During the study of the structural characteristics of the synthesized microparticles, it was found that increasing the dopant concentration from 0.05 mol.% to 0.15 mol.% leads to an increase in the crystallinity degree as well as a decrease in dislocation density. According to the results of the assessment of the resistance of microparticles to radiation damage, it was found that an increase in the dopant concentration leads to a decrease in swelling and structural distortion by more than 2.5–3 times, which indicates an increase in the radiation resistance.

On Optimization of Manufacturing of a Comparator in Track State to Increase Integration Rate of Elements

In this paper, an approach to increase integration rate of elements of a comparator in track state was introduced. Framework the approach a het-erostructure with special configuration was consider. Several specific are-as of the heterostructure should be doped by diffusion or ion implantation. Annealing of dopant and/or radiation defects should be optimized.

Study of Resistance to Helium Swelling of Lithium-Containing Ceramics under High-Temperature Irradiation

The aim of this work was to study resistance to helium accumulation processes in the structure of the surface layer of lithium-containing ceramics and the subsequent destruction and embrittlement processes, depending on radiation fluence. The objects of study were Li2TiO3-type ceramics obtained by thermal sintering. The fluence dependency of changes in the structural and strength properties of ceramics was determined to be in the range from 1018 to 1022 ion/m2, which corresponded to the concentration of implanted helium from 0.01% to 0.8–1 at.%. Irradiation was carried out at a temperature of 700 °C, which made it possible to simulate the processes of radiation damage that were closest to the real conditions in the reactor core. During the studies carried out, it was found that, at irradiation fluences of 1018–1020 ion/m2, the formation of point radiation defects was equaled by the process of thermal annealing of defects, as a result of which the concentration of defects and their effect on the change in the structural and strength properties of ceramics were insignificant. An increase in the concentration of implanted helium in the structure of the surface layer to above 0.5 at.% led to the dominance of radiation damage processes over the annealing of defects and the formation of gas-filled cavities, which negatively affects the strength of ceramics.

Kinetic Interaction of Hexan Conversion and Oxidation on the Surface of an Al2O3 Nanocatalyzer at Room Temperature under the Effect of Gamma Radiation

The kinetic and temperature dependencies of the conversion of hexane to gas and liquid oxide products on the surface of the nano-Al2O3 catalyst in the homo and hetero phase were investigated and compared. The rate of hexane conversion in air in different phases at temperature ∆T = 180–2000 C was determined ((a) 10–15% from the homo phase in the hetero phase; (b) thermal 12–17%; (c) radiation-thermal 14–22%). It is shown that the excess electron density formed in radiation defects migrates from the surface to the adsorbents, thereby weakening the intramolecular chemical bonds of the adsorbent and accelerating the decomposition processes investigated.

Single-walled carbon nanotube structure and radiation defects under the high energy electron beam

The effect of electron irradiation up to fluence of 1.54×1017 electron/cm2 on the structural parameters, sizes of nanocrystallites, microstrains, and Raman spectra of a single-walled carbon nanotube (SWCNT) was studied. Electron irradiation leads to an increase in the lattice parameters in the a and b directions from 4.7623 Å to 4.9378 Å and a decrease along the c axis from 3.9491 Å to 3.9469 Å. Electron irradiation stimulates the growth of the nanocrystallite size from 4.06 nm to 5.03 nm, leads to a shift of the Raman spectra towards higher frequencies, and indicates the appearance of a spectrum at 805 cm–1, which is caused by the formation of defects in a SWCNT.

Influence of penetrating radiations on electrical low frequency noise of semiconductors

The influence of penetrating radiations on the electrical low-frequency noise of semiconductors is studied. Expression is calculated that determines the number of structural defects in semiconductors arising from exposure to penetrating radia-tion. General form expression is calculated for the spectrum of electrical low-frequency noise in semiconductors when exposed to penetrating radiation. Quanti-tative relationship was established between the spectrum of electrical low-frequency noise and the development of disturbances in the structure of semicon-ductors caused by penetrating radiations. The results obtained can be used to de-termine the spectra of electrical noise in semiconductors of various types and in numerous semiconductor devices. The results of the article have practical applica-tions. Calculated expressions allow to make estimates of the intensity of electrical low-frequency noise, from which conclusions can be drawn about possibility of functioning and reliability of semiconductor devices. Established relationship be-tween electrical noise and radiation defects can be used to estimate, based on spec-tral characteristics of the noise, the defectiveness of structure of semiconductors subjected to radiation damage.