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The effect of gamma radiation from a 60Co source on the intensity of re-emitted luminescence at the output of WLS fibers of the Y-11M and O-2M types and the subsequent restoration of the characteristics of the irradiated fibers after holding them at room temperature are investigated. Irradiation, starting from a low dose rate (0.048 MRad/h) to a dose of 1 MRad, leads to an insignificant decrease in the intensity of re-emitted luminescence at the output of both types of fibers, and with a further increase in the dose, the course of the curve practically does not change. When irradiated with a dose rate of 0.158 MRad/h, the characteristics of both types of fibers deteriorate significantly. When the irradiated samples are kept at room temperature, the fiber characteristics are restored.

The effect of the dose rate from 0.00022 to 0.0032 MGy/h and the radiation dose of 0.043 and 0.2 MGy of the 60Co gamma source, as well as of oxidative conditions on the optical transmission and absorption spectra of plastic scintillators of the BC-408 (Bicron, USA), UPS-923A (Amcrys-H, Ukraine), and LHE (JINR, Russia) brands has been investigated at 300 K. It has been shown that the optical transmission of scintillators in the range of 400–850 nm decreases when increasing radiation dose. There was no noticeable effect of adsorbed oxygen on the induced optical losses under these conditions.

It is shown that the replacement of a part of sulfur atoms with selenium atoms in a TlInS2 single crystal stimulates the formation of a single-phase state with a monoclinic structure (space group [Formula: see text]/[Formula: see text] in TlInS[Formula: see text]Se[Formula: see text] ([Formula: see text]). Irradiation with 2 MeV electrons and a fluence of [Formula: see text] electron/cm2 of powder TlInS[Formula: see text]Se[Formula: see text] ([Formula: see text]) leads to an increase in the crystallite size from 56.5 nm to 65 nm, which is most likely associated with a decrease in the interface. The difference between the surface morphology of the synthesized TlInS[Formula: see text]Se[Formula: see text] ([Formula: see text]) single crystal and the surface morphology of the TlInS2 single crystal is established, which consists in a decrease in the height and width of the roughness in TlInS[Formula: see text]Se[Formula: see text] ([Formula: see text]). Irradiation of a TlInS[Formula: see text]Se[Formula: see text] ([Formula: see text]) single crystal with electrons with a fluence of [Formula: see text] electron/cm2 does not lead to a change in the height of the tubercle on its surface, and the average value of its width increases more than ten-fold. The identity of the peaks in the Raman spectra of the TlInS[Formula: see text]Se[Formula: see text] ([Formula: see text]) single crystal before and after its irradiation with electrons with an energy of 2 MeV and upto a fluence of [Formula: see text] electron/cm2, along with the absence of a shift of the peaks, indicates the radiation resistance of the TlInS[Formula: see text]Se[Formula: see text] ([Formula: see text]) single crystal.

In this research work, the effects on the structural and optical properties of e-beam irradiated Al nanoparticles (Al-NPs) by three field sizes, [Formula: see text], [Formula: see text] and [Formula: see text] fluence were studied. As a result of systematic observations, it has been possible to study the effect of electron beam on X-ray diffraction (XRD), infrared (IR) spectroscopy and Raman band modifications and, consequently, on the crystal structure and atomic dynamics of Al-NPs. The XRD method determined that Al-NPs are combined with water molecules in the air to form aluminum hydroxide (Al(OH)3) groups. The Al(OH)3 formation was not observed in any of the samples irradiated with three different fluences, [Formula: see text], [Formula: see text] and [Formula: see text], respectively. Confirmation of these results was also shown in the method of IR spectroscopy. While 12 vibrational modes were observed in the non-irradiated samples, only the vibrational modes corresponding to Al–Al bonds were observed in [Formula: see text], [Formula: see text], and [Formula: see text] fluence irradiated samples. It was determined by the Raman spectroscopy method that a low concentration of Al(OH)3 remains in the samples irradiated with [Formula: see text] fluence. Only [Formula: see text] and [Formula: see text] fluence irradiated samples were found to correspond to the XRD and IR spectra, and Raman vibrational modes corresponding to Al–Al bonds were observed. In addition, electron irradiation is a suitable technique to increase the optical properties of nanoparticles by controlling the size of the particles.

In this work cubic phase, silicon carbide nano-powders were irradiated at the high-flux pulsed reactor IBR–2 (Dubna, Russia). The 3C–SiC powder was irradiated with neutron doses up to 1015 n/cm2. The irradiated samples were then analyzed using X-ray diffraction, Raman spectroscopy, Positron annihilation spectroscopy, and Fourier Transform Infrared Spectroscopy. The XRD analysis showed a slight decrease in the lattice parameters with the increase in neutron fluences. The results obtained from positron annihilation measurements were compared to the theoretical calculations, to recognizing the type of structural defect in the samples. A positron lifetime component 355 ps associated with the calculated values for clusters containing of 13–21 vacancies was identified. The concentration of these defects was estimated to be in the region of 5 ppm, and was very similar to the one identified on the unirradiated sample. The results also indicate high irradiation resistivity of the 3C–SiC after irradiation.

The development of nanotechnology has led to the use of various nanostructures in order to modify and produce new materials. In this regard, there is an increasing interest in studying the properties of nanostructures, methods for their preparation, and mechanisms for their incorporation into various matrices.The diamond-like hydrogen-passivated ultra-small Si29H36, Si34H36, Si59H60, Si71H60 nanocrystals were studied by the first-principle method. In this ultra-small length scale, the dependence of properties with gradually increasing sizes does not practically investigate. A detailed analysis of the structural deformation and charge distribution has been conducted to understand how structures change occurs within this length scale, where quantum confinement effects become predominant.

The problem of preparing a compensated material is solved by the radiation technology method (by irradiating the silicon single-crystal with fast neutrons), which makes it possible to intentionally change the photoelectric parameters of silicon. The changes in the photoelectric parameters of the compensated samples are monitored by measuring the Rd/Rl ratio, and the possibility of creating photo and thermal sensors with identical characteristics, operating within the temperature range of 30 to 100°C, is shown.

The effect of electrons on the surface, Raman spectra, structure and phase transition in a TlInS2 single crystal was studied. Irradiation of TlInS2 with electrons with an energy of 2 MeV and a fluency of 2 × 1017 electron/cm2 leads to an increase in the height of the bump and its width on the sample surface. Radiation treatment of TlInS2 with electrons indicates the appearance of new peaks at 204 cm−1, 224 cm−1 in the Raman spectra and stimulates the formation of a single-phase state with a hexagonal structure (space group P63/mmc).

The molecular–topological structure of a copolymer of tetrafluoroethylene and perfluoro(propyl vinyl ether) before and after γ-irradiation has been studied for the first time. The pseudo-network structure of the copolymer contains an amorphous block and the crystalline segments of macromolecules serve as branching points. After γ-irradiation to a dose of 15 to 2380 kGy, polyassociative cluster-type entities have appeared in the initial copolymer in place of the crystalline branching points with simultaneous structure amorphization and a decrease in the onset temperature of molecular flow.

With the use of thermomechanical spectrometry in two modes, coaxial, when the load application vector is coplanar with the compacting pressure vector (semicrystalline copolymer) during the measurement of the deformation of a copolymer of tetrafluoroethylene with perfluoro(propyl vinyl ether), and mutually perpendicular (completely amorphous copolymer), it has been established that the axial compression of the copolymer brought its topological structure to an absolutely anisotropic state. After γ-irradiation, the semicrystalline structure of the copolymer was retained regardless of the radiation dose. The minimum values of the glass transition temperature of the amorphous block and the degree of crystallinity were observed in the copolymer irradiated to a dose of 150 kGy. The molecular weight distribution functions of interjunction chains in the networks of the amorphous blocks of the initial copolymer and its γ-irradiated analogs are bimodal.

Effect of 2 MeV electron beam at the current density 0.09 nA/cm2 on surface structure, nanocrystallite size of (ZrTi)CN nanocomposite coating on steel was investigated at Scanning Electron and Atomic Force microscopes, and also X-ray diffractometer. Using the Rietveld method, two structure phases were indentified in the pristine samples: (ZrTi)(CN)-cubic (space group Fm-3m) and TiC — trigonal (sp.gr.R-3m). Electron beam irradiation to the fluency of [Formula: see text] electron/cm2 resulted in the phase transition of TiC from trigonal (sp.gr.R-3m) to cubic structure (sp.gr.Fm-3m). Besides, nanocrystallite size and shape have changed after the fluency [Formula: see text] electron/cm2. The lattice parameters have increased up to [Formula: see text] electron/cm2 fluence and the nanorcrystallite size of nanocomposite was enlarged 26%, which was attributed to generation of defects.

The goal of this article is to describe the new neutron imaging facility constructed on the 5th radial beamline of the WWR-SM research reactor at the Institute of Nuclear Physics of the Academy of Sciences of the Republic of Uzbekistan (Tashkent, Republic of Uzbekistan). The neutron beam with the dimensions of 90 × 90 mm2 is formed by the collimator system, the characteristic parameter L/D is 600. The two mirror detector system is based on the 6LiF/Zn(Cd)S:Ag scintillation screen and the high-resolution ProLine PL-09000 CCD camera. The design of the experimental facility, the main parameters, and recently obtained results of the neutron radiography and tomography experiments are presented.

We report differential scanning calorimetry (DSC) studies of boron nitride and boron trioxide compounds under different irradiation conditions. In the present work, boron nitride (h-BN) (purity of 99.8% and density of 2.29 g/cm3) and boron trioxide (B2O3) (purity of 99.5% and density of 3.10 g/cm3) samples were irradiated by using high intense electron beam and swift heavy ions irradiation. Electron beam irradiation of the samples was carried out at the different electron fluence of 4.16 × 1016, 1.20 × 1017 and 1.03 × 1018 cm−2 with energy of 2.5 MeV. Whereas the swift heavy ion irradiation of the samples was carried out using 132Xe ions with energy of 167 MeV/u at the different fluence of 5 × 1012, 5 × 1013 and 3.83 × 1014 ion/cm2. The thermal parameter changes with a differential mechanism under different irradiation conditions were investigated. In the DSC curves at the low temperature for initial and irradiation samples do not undergo phase transitions. However, at the 100 ≤ T ≤ 300 K temperature range widely changed the mechanism of the heat flow rate, specific heat capacity and thermodynamic functions in the boron nitride and boron trioxide samples is a more completed. In addition, for each of irradiation fluences, the calculated thermodynamic functions and specific heat capacity was found to increase from 0.002 J/g‧K to 0.08 J/g‧K as the irradiation electron fluence increased. For swift heavy ion irradiation, the specific heat capacity was found to increase from 0.005 J/g‧K to 0.06 J/g‧K. The results have revealed that there was a thermodynamic change.

In the presented work, a boron carbide sample with a purity of 99.9%, particle size [Formula: see text]–[Formula: see text]m and a density of [Formula: see text] was used. Boron carbide samples were irradiated with linear electrons in the energy range of 2.5 MeV at the doses of [Formula: see text], [Formula: see text] and [Formula: see text] at room temperature. XRD results show that only in the crystal structure of [Formula: see text] compound, among boron carbide samples irradiated in the dose rate from [Formula: see text] to [Formula: see text] phase transition does not occur. The observed decrease in the lattice parameter values was explained as the strengthening of the bonds as a result of the recombination of defects in the crystal by influencing electron fluence. Dynamics of Raman spectra change and analytic analysis of intensive and duplex modes in various electron fluxes in ([Formula: see text]) CBC-structure were performed and the occurring disorder in Raman active has been identified.

The paper considers the computer model of silicon clusters doped with boron and phosphorus, and the effect of hydrogen on their structure and energy parameters. While calculating nanostructure formation, the model assumes hydrogenated Si29 clusters with substitution of a matrice atom with B and P impurities and insertion of one or some hydrogen atoms. Nanostructured defect complexes of Si-P-H or Si-B-H are suggested to be formed under hudrogen insertion, with their stability depending on the hydrogen atom number and the dopant type. Computer modelling and optimization calculations were carried out in the frame of nonempyrical modelling methods for structure and properties of multiparticle systems - ORCA under the approximation of local electron state density.

The experimental data of neutron diffraction study of Ti0.8V0.2C0.62, Ti0.8V0.2C0.62H0.08 and Ti0.8V0.2C0.62H0.11 prepared by self-propagating high-temperature synthesis are presented and discussed. It is established that in Ti0.8V0.2C0.62 exist cubic (space group Fd3m) and trigonal (space group R 3 ¯ m ) ordered structures. Only cubic ordered structure (space group Fd3m) exists in the compound carbidehydrides. The long-range order parameter is higher in Ti0.8V0.2C0.62Hx than in Ti0.8V0.2C0.62.

Phase transformations in titanium oxycarbide TiC0.545O0.08 have been studied by the methods of neutron diffraction and X-ray structure analysis. It was established that the ordered cubic structure δ′ (sp. gr. Fd3m) of the oxycarbide sample is the low-temperature ordered phase existing up to 990 K. The order-disorder phase transition (990 K) results in the formation of an ordered trigonal structure (sp. gr. or R3m or P3121). The α-Ti-phase is separated at the temperature 1020 K. The order-disorder phase transition was found at T = 1040 K.

The ordered structures and phase transitions in TiC 0.62 and TiC 0.59 are investigated on the high resolution neutron diffractometer. It is established, that low-temperature trigonal δ″(sp.gr. R 3 m or sp.gr. P3 1 21) and high-temperature cubic δ′(sp.gr. Fd3m) ordered structures, according to the temperature, exist in the investigated carbide samples. Under heating, the sample TiC 0.62 experiences the order-order (δ″( R 3 m )→δ′(Fd3m)) phase transition at 770°C and then, the order-disorder ((δ′(Fd3m)→δ(Fm3m)) phase transition at 790°C.

It is shown that on the basis of the disordered δ-phase (space group Fm3m) two ordered equilibrium phases with cubic (δ′-phase, space group Fd3m) and trigonal (δ″-phase, space group R3m or P3121) unit cells can be formed in titanium carbide TiC0.62 and carbidenitrides TiCxNy (x+y ≈ 0.63), whereas only a cubic δ′-phase has been observed in TiC0.62Hy. With increasing temperature the low temperature trigonal δ″-phase transforms at about 1053 K to the cubic δ′-phase which experiences disordering. The formation of the cubic δ′-phase at temperatures lower than 1053 K is explained by the difference between the order of δ δ and δ δ″ phase transitions. [Russian Text Ignored].

X-ray and neutron diffraction were used to investigate the effect of oxygen and nitrogen atoms on the formation of the intermediate δ′-cubic (sp. gr. Fd3m) and δ″-tetragonal (sp. gr. P3121) ordered structures in titanium carbide. In TiC0.545O0.08, TiC0.545N0.09 samples that were investigated, the metal atoms were shifted from ideal positions in the direction from vacancies to metalloid atoms. In the intermediate cubic phase (δ′), the free-parameter values of titanium atoms in the two samples are the same, but are different from their analogous value in titanium carbide.

Sumy Institute for Surface Modification, P.O.Box 163, 40030 Sumy, Ukraine, E-mail: apogrebnjak@simp.sumy.ua Sumy State University, 40021 Sumy, Ukraine, E-mail: alexp@i.ua National Technical University, Kharkov, Ukraine Science Center for Physics and Technology, Kharkov, Ukraine Concern “UKRROSMETAL”, Sumy, Ukraine Samarkand Branch of Tashkent Information Technology University, Samarkand, Uzbekistan Institute of Nuclear Physics, UAS, Tashkent, Uzbekistan