Changes in the surface structure of K-208 glass under medium-energy proton irradiation
Changes in the surface structure of K-208 glass under medium-energy proton irradiation
I. P. Malashin
The effect of proton irradiation on the process of changes in the surface structure of K-208 glass caused by the formation of microcracks and gas-filled bubbles was studied using atomic force microscopy methods. The K-208 glass plates, which are used to protect solar cells of spacecrafts, were chosen as experimental samples. As a result of the analysis of experimental data obtained by atomic force microscopy, it was found that on the surface of K-208 glass irradiated in vacuum ($10^{-4}$ Pa) by protons with an energy of 20 and 30 keV at a flux density of $\varphi_p =6{,}0 \cdot 10^{10}$ cm$^{-2}$s$^{-1}$ and fluences $\Phi_p = (10^{15} \div 6{,}6\cdot 10^{16})$ cm$^{-2}$ gas-filled bubbles and microcracks are formed, the characteristic sizes of which grow with increasing fluence. It was shown that for the same values of $\varphi_p$ and $\Phi_p$ irradiation of K-208 glass with protons with energy of 20 keV does not lead to the formation of microcracks.
Show AbstractТopical issues of development of combined radiation methods of bone implant sterilization
Тopical issues of development of combined radiation methods of bone implant sterilization
A. O. Khutsistova$^1$, A. A. Nikolaeva$^3$, V. V. Rozanov$^{1,2}$, I. V. Matveychuk$^2$, A. P. Chernyaev$^{1,4}$
Topical issues of improving the technologies of bone implant sterilization for solving the problems of modern bioimplantology and creating innovative combined methods based on the combined effect of sterilizing factors of various physical and chemical nature are considered. The results of experimental developments of the authors, as well as data from other researchers, are presented, indicating the prospects of combined radiation technologies, the effectiveness of their use in comparison with currently used methods in medical practice. The importance of continuing further complex structural and functional studies of bone tissue for optimizing the parameters of sterilization modes under one-stage ozone and radiation exposure, as well as when using them in combined technologies, is noted. Priority tasks are formulated and methodological approaches to the practical implementation of one of the main conditions of radiation treatment - the maximum permissible, objectively controlled reduction of the dose load on tissues with ensuring their necessary sterility are proposed. Particular attention is paid to the importance of finding alternative (above) methods of sterilization, the use of which will expand the possibilities of single-stage methods and combined radiation technologies.
Show AbstractPhotoneutron reactions on $^{51}$V: systematic uncertainties of experiments and new evaluated data
Photoneutron reactions on $^{51}$V: systematic uncertainties of experiments and new evaluated data
V. V. Varlamov$^1$, A. I. Davydov$^2$, V. N. Orlin$^1$
Using the objective physical data reliability criteria it was shown that partial photoneutron reaction cross sections for $^{51}$V obtained at Livermore (USA) and Saclay (France) using the method of neu-tron multiplicity-sorting are not reliable because significant systematic uncertainties. In the frame of experimental-theoretical method the new cross sections of such reactions satisfying reliability criteria were evaluated. The disagreements between evaluated and experimental cross sections were analyzed in detail. It was found that in the case relatively light nucleus 5$^{51}$V the main reason of significant sys-tematic uncertainties of the procedure of identification of neutrons from the reactions $(\gamma, 1n)$, $(\gamma, 1n1p)$ and $(\gamma, 2n)$ used in Livermore is the that the part of the reaction $(\gamma, 1n1p)$ was not taken into account.
Show AbstractSystematical uncertainties of photonuclear experiments for Pb isotopes and As, I, and Ta nuclei
Systematical uncertainties of photonuclear experiments for Pb isotopes and As, I, and Ta nuclei
A. I. Davydov$^1$, V. V. Varlamov$^2$, V. N. Orlin$^2$
It was found before that experimental $(\gamma, 1n)$, $(\gamma, 2n)$ and $(\gamma, 3n)$ reactions cross sections obtained for many nuclei using the beams of quasimonoenergetic annihilation photons and the method for photoneutron multiplicity sorting do not satisfy to objective physical criteria of data reliability. Using the experimental-theoretical method of evaluation the new data on partial and total photoneutron reaction cross sections satisfying the mentioned criteria were obtained. It was shown that in the majority of cases significant disagreements between evaluated and experimental cross sections are because presence of noticeable systematical uncertainties of the processes of identification of multiplicities of detected neutrons. The new kind uncertainties from the loss of many neutrons from $(\gamma, 1n)$ reaction were found out for several nuclei ($^{75}$As, $^{127}$I, $^{181}$Ta). The evaluation of reliable cross sections $\sigma(\gamma, 1n)$, $\sigma(\gamma, 2n)$, $\sigma(\gamma, 3n)$, $\sigma(\gamma, sn) = \sigma(\gamma, 1n) + \sigma (\gamma, 2n) + \sigma (\gamma, 3n)$ and $\sigma(\gamma, xn) = \sigma(\gamma, 1n) + 2\sigma (\gamma, 2n) + 3\sigma (\gamma, 3n)$ was done for $^{206,207}$Pb. It was shown that for both isotopes $^{206,207}$Pb as well as for $^{208}$Pb investigated before similar to $^{75}$As, $^{127}$I, $^{181}$Ta the competitions between various reactions cross sections testify to unreliability of experimental data.
Show AbstractSelecting the events of $ep\rightarrow e\pi ^{+}\pi ^{-}p$ exclusive electroproduction from the CLAS12 detector experimental data
Selecting the events of $ep\rightarrow e\pi ^{+}\pi ^{-}p$ exclusive electroproduction from the CLAS12 detector experimental data
A. S. Frolova$^1$, A. A. Golubenko$^2$, E. L. Isupov$^2$
The first results on the selection of events of $ep\rightarrow e\pi ^{+}\pi ^{-}p$ exclusive electroproduction from the CLAS12 detector experimental data in the resonance area for the beam energy $E_e = 6.5$GeV are presented in this report. For the $ep\rightarrow e\pi ^{+}\pi ^{-}p$ reaction the missing mass distributions were obtained for four topologies corresponding to different sets of detected particles. The primary selection criteria were worked out and the invariant mass for the various pairs of particles were obtained. The obtained distributions demonstrate the reliability of the algorithms reconstructing the final particles in exclusive electroproduction reactions.
Show AbstractCalculation of the exclusive structural functions of the channel of one-pion electroproduction on a proton
Calculation of the exclusive structural functions of the channel of one-pion electroproduction on a proton
A. G. Nasrtdinov$^1$, M. M. Davydov$^1$, A. D. Bulgakov$^1$, A. A. Golubenko$^2$, E. L. Isupov$^2$, V. I. Mokeev$^3$, V. V. Chesnokov$^3$
This article presents an approach for extracting unpolarized transverse, longitudinal, transverse-transverse, longitudinal-transverse structural functions. The extraction of structure functions is performed from experimental data on the differential cross sections of one-pion production obtained with the CLAS detector (Jefferson Laboratory, USA). The available data cover a wide kinematic range for the invariant mass of the final hadronic system W < 1.7 GeV and the virtuality of the photon $Q^2$ < 5.0 $GeV^2$. The extracted $N\pi$ exclusive structure functions play a significant role in the study of the structure of the excited states of the nucleon. In the course of the work, new methods for calculating structure functions were developed. The results obtained by various methods are in good agreement with each other.
Show AbstractDevelopment of an equivalent circuit of a ring resonator with a working mode of oscillation E020, for use in one-dimensional programs for calculating a multibeam klystron with non-identical electron beams
Development of an equivalent circuit of a ring resonator with a working mode of oscillation E020, for use in one-dimensional programs for calculating a multibeam klystron with non-identical electron beams
R. A. Kosarev$^1$, I. A. Freydovich$^2$
Annotation. The article presents an equivalent circuit of a ring resonator operating on the E020 vibration mode. A comparison of the results of modeling resonators using three-dimensional programs of electrodynamic modeling (CST Studio Suite) and using an equivalent circuit is carried out. The equivalent circuit is based on the idea of a ring resonator as a waveguide rolled into a ring. The electromagnetic field in a waveguide is described using an equivalent long line. The equivalent circuit is intended for use in programs for calculating the parameters of a klystron with non-identical conditions for the interaction of electron beams.
Show AbstractStudy of the albedo of marble and sand
Study of the albedo of marble and sand
B. M. Ibrahim$^1$, Yu. P. Pyt'ev$^2$, A. A. Samah$^1$, O. V. Falomkina$^2$
In this paper, the intensity of solar radiation incident and reflected from the surfaces of marble and sand is studied in detail. The albedo values of these surfaces are calculated on the basis of radiation intensity measurements performed using a luxmeter. The measurements were carried out for marble and sand surfaces during two days of the summer months at two points in the vicinity of Baniyas on the Mediterranean coast in the province of Tartus, in Syria: in the town of Alqurdiye and at the station "Baniyas". The albedo values are calculated based on the measurement results. The results are compared, graphical curves are constructed that reflect the changes in albedo depending on time.
Show AbstractCentrality dependence of particle emission in nucleus-nucleus collisions at the nucleon and quark levels
Centrality dependence of particle emission in nucleus-nucleus collisions at the nucleon and quark levels
G. O. Ambaryan$^3$, V. L. Korotkikh$^1$, G. H. Eyyubova$^2$
A theoretical analysis of the particle multiplicity as a function of centrality is made with respect to particle emission sources (wounded nucleons, quarks) in a wide energy range from RHIC to LHC. The Monte Carlo Glauber model is used for heavy ion collisions. It is shown that scaling in terms of the number of wounded quarks is fulfilled at all energies. This effect is associated with an increase of the wounded quarks pairs in the transverse plane with a decrease of the colliding nuclei impact parameter. A wounded quark emits the same number of particles regardless of the colliding nuclei impact parameter.
Show AbstractAcoustic field of a source moving perpendicular and along the interface with a sharp impedance drop
Acoustic field of a source moving perpendicular and along the interface with a sharp impedance drop
Yu. M. Zaslavsky$^1$, V. Yu. Zaslavsky$^{1,2}$
The acoustic field generated by a pulsating source moving in the atmosphere along and perpendicular to the water-atmosphere interface at a subsonic speed is investigated. Calculated relationships are derived for the amplitude, frequency, and duration of a sound pulse recorded in both media in the vicinity of the interface. The spatial distribution of the amplitude of the acoustic field in the atmosphere and in the liquid is presented in the form of a two-dimensional relief to demonstrate its features and dependence on the speed and direction of motion of the sound source. The relationship between the characteristics of acoustic radiation and the average depth in the water area is analyzed.
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