[en] A possibility of intense accelerated electron beam extraction from vacuum into atmosphere through the window representing a flat thin-wall channel in which liquid flow removing absorbed energy moves perpendicularly to the direction of the extracted beam is considered. Correlation associating the limiting value of electron current density with parameters of the window is obtained. It is shown that utilization of the window representing a thin-wall plane channel with water permits to increase density of the extracted electron beam up to dozens mA per cm², that two orders higher than that obtained when using the window as air-cooled sinqle foil

[en] Described is the design and presented are test results of a device intended for water cooling of thin semiconducting or metallic samples with the area of several cm² irradiated by an intense beam of accelerated electrons. The device has an arc form. Its main elements are two metallic foils between which strong water flow passes. The foils and indium seal are by two pairs of metallic flanges. The size of the gap between the foils is controlled by solid gaskets of the corresponding thickness placed between the flanges. The temperature of the sample surface did not exceed 90 deg C during irradiation of 12x5x0.3 m² Si samples by 1.5 MeV electrons at average current density of 2 mA/cm² and up to 10⁹ cm^-2 dose. The maximal average density of the electron flux was attained using Ti foil with 0.05 mm thickness and 1 mm thick flow of water and it constituted 20 mA/cm² for 1.5 MeV electron beam with 1x1 cm² beam profile

[en] Two new paramagnetic centres, labeled Si-H5 and Si-H6 are found in silicon containing aluminium (6 x 10¹⁷ to 5 x 10¹⁸ cm^-3) and irradiated with high dose of 1 MeV electrons (up to 2 x 10²⁰ cm^-2). Spin-Hamiltonian constants of the Si-H5 spectrum are determined for EPR measurements. Analysis of these constants and the kinetics of the defect accumulation allows to propose a possible model of the Si-H5 centre as a complex in [110] plane of the divacancy and aluminium in interstitial position. EPR arises from the unpaired electron in the extended orbital of the divacancy. Annealing of Si-H5 centre occurs at 230 ⁰C. (author)

[en] In silicon containing aluminium in 6x10¹⁷-5x10¹⁸ cm^-3 concentrations and irradiated with 1 MeV electrons within the dose range of 1x10¹⁸-2x10²⁰ cm^-2, a new paramagnetic center defined as H5 is discovered. The ESR analysis of the H5 center structure has shown that the center has the 1/2 spin and (110) symm etry. The main values of the g-tensor and their orientations in respect to the crystallographic axes are determined to be: g₁=2.0063+ g₂=2.0005, g₃=2.0036(+-0.0001), THETA=13+-2 deg, where THETA is the angle between the [110] direction and g₁, situated along with g₂ in the (110) plane, and g₃ long [110]. A superfine structure resulting from the interaction of an unpaired electron with two non-equivalent nuclei of the ²⁹Si isotope with a ²⁷Al nucleus is discovered. The constant of the superfine interaction (SFI) with a ²⁷Al nucleus is equal to (4.0+-0.7)x10^-4 cm^-1. The SFI tensor with one of ²⁹Si nuclei is axi-symmetric and its main values are Asub(perpendicular)=41.6x10^-4 and Asub(long)=41.6x10^-4 and Asub(long)=62.5x10^-4 cm^-1. The wave function densities of an unpaired electron on each ²⁹Si atoms (approximately 24, 15% in the s-state and 85% in the p-state) and on ²⁷Al(0.3%) are determined. Based on the analysis of the results obtained a possible model is suggested. According to this model the H5 center consists of a divacancy and interstitial aluminium atom, being in the (110) plane. The impaired electron is situated on an extended divacancy orbital (about 50% of the wave function density)

[en] The possibility of extraction of an intense beam of accelerated electrons from vacuum to the atmosphere, through a window, in the form of a plane-parallel thin-walled channel in which a liquid that removes the absorbed energy flows perpendicular to the extracted beam is examined. A relation is obtained that links the maximum electron-current density and the parameters of the window. It is shown that a window in the form of a plane-parallel thin-walled channel with water increases the density of the extracted electron beam to tens of milliamperes per square centimeter, which is two orders greater than that obtained with a single-foil window with an air stream

[en] The ESR method was used to study heavily doped n-type silicon (dopant concentrations up to 2 x 10¹⁸ cm^-3) irradiated with large doses of 1 MeV electrons. The G16 spectrum dominated the results obtained. A superhyperfine structure (SHFS) was observed in the spectrum: it corresponded to the hyperfine interaction of a paramagnetic electron with nuclei of the ²⁹Si silicon isotope which were located in four shells. A numerical analysis of the spectra yielded the SHFS line intensities and the numbers of equivalent sites in the shells: three sites in the first shell, one in the second, two in the third, and five or six in the fourth. A study of the G16 spectrum under uniaxial compression conditions at temperatures 150-500 K revealed two activation energies (E_A¹ ∼ 0.25, E_A² ∼ 1.4 eV) representing the process of reorientation of the investigated defect. The results obtained were used to propose a model of the G16 center. This was a vacancy-impurity complex in which the vacancy was localized in the second coordination sphere relative to the impurity atom. The mechanism resulting in a spatial separation of the components in this defect was considered. It was assumed that the impurity atom occurring in the G16 center was carbon

[en] Silicon of the n-type with the increased level of doping (up to 2x10¹⁸ cm^-3) irradiated by large doses of electrons with 1 MeV energy was investigated by the ESR method. It is established that G16 spectrum dominates in such materials. The spectrum hyperfine structure (HFS) correlating to hyperfine interaction (HFI) of a paramagnetic electron with nuclei of ²⁹Si isotope located in four shells is detected. Intensities of HFS lines and the quantity of equivalent points in the proper shells: three points in the first shell, one - in the second, two - in the third, and five - six - in the fourth shell, are determined by numerical calculation of the spectrum. Investigation of change in G16 spectrum during uniaxial compression in the temperature range from 150-500 K permitted to detect the presence of two activation energies (E_A¹ ∼ 0.25, E_A² ∼ 1.4 eV) characterizing the process of defect reorientation. A model of G16 center is suggested on the basis of the data obtained. This is a complex vacancy - impurity (V-I), where the vacancy is localized in the second coordination sphere relatively to the impurity atom. A possible mechanism causing spatial selectivity of components in V-I defects is discussed. Carbon is supposed to be an impurity atom entering G16 center

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