Faculty of Physics
M.V.Lomonosov Moscow State University

# Issue 2, 2018

Nuclear physics

## Spectroscopic technique of registration of 90Sr  in samples with a high specific activity

### M. V. Zheltonozhskaya$^1$, A. P. Chernyeav$^2$

Memoirs of the Faculty of Physics 2018. N 2.

The new technique is developed to measure 90Sr in samples with a high specific activity and based on using characteristic Kx-radiation. The probability of Kx-radiation during the radioactive decay with the emission of electrons of 90Sr and 90Y was measured. The method for determination of 90Sr in the fuel-containing materials was proposed from the data on the probability of ionization of atoms in β-decay. Measurements of 90Sr were executed in fuel fragments of various types. Obtained results was compared and verified with the radiochemical research of these samples. The proposed method allows to execute the measurement of 90Sr with an accuracy of 3-5% in the samples with high specific activity. These results open up new possibilities in the study of radioactive materials produced as a result of nuclear fission. Keywords: spectroscopy, strontium, autoionization, fuel-containing materials

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## Description of spectra of heavy and super-heavy nuclei in two center shell model

### M. L. Markova$^1$, N. V. Antonenko$^2$, T. Yu. Tretyakova$^3$, T. M. Shneydman$^4$

Memoirs of the Faculty of Physics 2018. N 2.

The present paper is devoted to the description of quasi-neutron structure of odd isotones in chain with N = 149 : 243Pu, 245Cm , 247Cf, 249Fm , 251No, and 253Rf. The minimization of potential surface with respect to collective parameters was carried out in order to define ground states and describe low lying quasi-neutron states in the frame of two center shell model. The blocking effect was taken into account as well, transition probabilities and corresponding lifetimes for low lying quasi-neutron states were estimated.

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## Excited states multiplets in nuclear spectra near 208Pb

### M. E. Stepanov$^1$, L. T. Imasheva$^1$, B. S. Ishkhanov$^{1,2}$, T. Yu. Tretyakova$^2$

Memoirs of the Faculty of Physics 2018. N 2.

Excited states in heavy even-even and odd-A isotopes near 208Pb are considered. To calculate ground state multiplets the delta-approximation for pairing between nucleons in j = 9/2 state is used. Multiplet splitting corresponds to pairing energy, which can be defined from nuclear masses. It allows one to calculate low-lying excitations without any fitting parameters. Excited states for isotopes with more than two valence nucleons are obtained using seniority model and coefficients of fractional parentage. Results of calculations are in a quite agreement with experimental data as for stable as for exotic nuclei

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## Influence of isospin effects on the structure of light Ξ hypernucleus

### M. S. Khirk, D. E. Lanskoy

Memoirs of the Faculty of Physics 2018. N 2.

This work is devoted to of the isospin structure and decays of Ξ hypernuclei. Since the Ξ hyperon has two charge states, the existence of Ξ hypernuclei with mixed charge of Ξ hyperons is possible. In the limit of strong mixing of charge states, pure isospin states can occur, however, generally isospin states are also mixed. The main purpose of this work is studying of charge and isospin mixing effects in p-shell Ξ hypernuclei and their implications in decay widths.

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## Studying of 14.1 MeV neutrons inelastic scattering on light nuclei

### N. A. Fedorov$^{1,2}$, T. Yu. Tretyakova$^3$, D. N. Grozdanov$^{1,4}$, V. M. Bystritskiy$^1$, Yu. N. Kopach$^1$, I. N. Ruskov$^{1,4}$, V. R. Skoy$^1$, N. I. Zamyatin$^1$, D. .. Wang$^{1,5}$, F. A. Aliev$^{1,6}$, C. .. Hramco$^{1,7}$, A. .. Gandhi$^8$, A. .. Kumar$^8$, M. G. Sapozhnikov$^1$, Yu. N. Rogov$^1$, E. A. Razinkov$^1$, S. .. Dabylova$^1$

Memoirs of the Faculty of Physics 2018. N 2.

The characteristic gamma radiation from the interaction of 14.1 MeV neutrons with a SiO2 and H2O sample is investigated with Tagged Neutron Method (TNM). The anisotropies of gamma-ray emission of 1.779 MeV from silicon and 6.13 MeV from oxygen were measured at 11 azimuth angles with a step of ∠15◦. The present results are in good agreement with some recent experimental data.

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## Optimization of parameters of target irradiated by bremsstrahlung photons

### S. S. Belyshev, A. V. Druzhinina

Memoirs of the Faculty of Physics 2018. N 2.

The work is devoted to solving the problem of optimization of parameters of the target irradiated by bremsstrahlung photons. In the course of the work, a program, which simulates irradiation of the target with bremsstrahlung photons, was developed using the GEANT4 package. The program simulates the passage of the particles through a substance and selects the optimal geometric parameters of the target for irradiation using the MCMC method. As a result, optimal geometric parameters were calculated for irradiation of the gallium target with the purpose of production of the radionuclide 69mZn

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The impact of ionizing radiation on space technology

## Simulation of absorbed dose distribution in objects with complex configuration

### N. P. Chirskaya, L. S. Novikov, V. V. Sinolits

Memoirs of the Faculty of Physics 2018. N 2.

This paper considers the possibilities of different mathematical methods application to the problem of the absorbed dose calculation in objects with a complex configuration. The simulation results of the absorbed dose distribution in a spherical water detector placed inside a spherical shield due to protons of galactic cosmic rays with energy in the range 101 − 105 MeV are presented.

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## Interaction of high-speed particles with a solid barrier

### N. P. Chirskaya, I. K. Ermolaev, L. S. Novikov

Memoirs of the Faculty of Physics 2018. N 2.

The paper presents calculated and experimental data on the diameter and depth of craters formed in an aluminum target during impacts of steel balls with velocities ∼ 0.1 - 3 km/s. There is a good agreement between the two groups of data in determining the depth of the craters, but also there is significant disagreement in the diameter values. The main reason for the discrepancy is the incompleteness of the used calculation model

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## Development and research of carbon plastics with shape memory effect, which have the required thermomechanical characteristics and inversion properties

### A. A. Slyusarev, P. G. Babaevskiy, G. M. Reznichenko

Memoirs of the Faculty of Physics 2018. N 2.

The purpose of the study is to develop and investigate polymeric composite materials (carbon plastics) with thermally stimulated shape memory effect (TS SME) for an ultralight controlled, reversibly transforming structural member of picosatellites solar cells. Research aims on the development of a polymer matrix with TS SME and high glass transition temperature in the cured state (Tg over 140°C) and reinforced laminated carbon plastics on its basis. A polyetherurethane-epoxy (PEU-E) composition cured by diaminodiphenylmethane was developed and kinetics of its curing was investigated by the dielectric analysis method (DEA) for selecting of carbon plastics compression modes. The effect of the composition curing conditions on its Tg was studied and the reversible temperature of the TS SME development by the dynamic mechanical analysis (DMA) method of was determined. The last stage of the work was the TS SME realization studies – force and deployment angle kinetics dependence on the number of carbon fabric layers and its volume content in reinforced laminated carbon plastics specimen.

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## Thermostimulated hinge for transformable space structures

### P. G. Babaevskiy, N. A. Kozlov, I. G. Agapov, O. A. Nevolko

Memoirs of the Faculty of Physics 2018. N 2.

The article describes the design and testing of a thermally stimulated hinge made from polymeric composite material with shape memory effect for transformable space structures. Simulation of the hinge heating process using the ANSYS Workbench program under various environmental and heating conditions was carried out to determine the power of the heat sources and the selection of the heaters. An experimental study of the hinge heating process under ordinary conditions using built-in heaters is carried out, and the degree, time and effort of restoring it to the shape are determined. The received results testify to high working capacity of the developed thermostimulated hinge and the possibility of its use in transformable space structures.

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High energy physics

## B-Physics Trigger of the ATLAS Experiment in Run 2

### V. V. Sinetckii$^{1,2}$, L. N. Smirnova$^1$

Memoirs of the Faculty of Physics 2018. N 2.

During the Run 2 of the LHC the ATLAS experiment recorded about 86 fb−1 of proton-proton collision data at a center-of-mass energy of ps = 13 TeV. The trigger system of the ATLAS detector is a important component for this experiment and is necessary to reduce the data stream from about 40 MHz to 1 kHz. This article is an overview of the changes that the trigger experienced during the first long stop (LS1) in 2013 — 2014.

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## Modeling the production of B mesons in pp collisions at LHC energies

### I. I. Ovcharov, L. N. Smirnova

Memoirs of the Faculty of Physics 2018. N 2.

The spectra of the transverse momentum for B mesons of various types in pp interactions at center-of-mass energies 7 and 13 TeV were simulated with PYTHIA 8 event generator. Spectrum ratios for B mesons of different nature and the energy dependence of these distributions in the interval 7-13 TeV were obtained. It is shown that the spectra become more hard with increase of the proton collision energy.

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## Neutrino telescope KM3Net: features of the acoustic system

### A. A. Brusnitcyn$^1$, E. V. Shirokov$^{1,2}$

Memoirs of the Faculty of Physics 2018. N 2.

The high energy astronomy studies fundamental questions and also allows to explore galactic and extragalactic objects. KM3NeT is the largest neutrino telescope in the Northern hemisphere being construction. Its intended volume will be 5 km3, with final construction date deemed to be in 2020. The detector is placed in 3500 m depth, 100 km from Capo Passero’s coast and consists of two types of structures: strings and towers. Acoustic positioning of detector structure will be provided by detection of the acoustic signals developed on LongBaseLine, by five fixed acoustic beacons being placed on a seabed. System of the acoustic sensors is used as receivers moving together with a mechanical design of the block of detection. Exact knowledge of speed of distribution of an acoustic wave is required to find the exact position of each detector. Modules finding conductivity, temperature and depth, as well as module for definition salinity of water areinstalled for this purpose. The analysis of data will be carried out in real time. The program for calibration of location of all elements of the detector has been created and tested by this time.

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## Observation of the Moon shadow in the muon flux and its application for the calibration of the ANTARES neutrino telescope

### E. S. Davydova, A. N. Romanov

Memoirs of the Faculty of Physics 2018. N 2.

The Sun and the Moon are expected to be obstacles for the primary cosmic rays on their way to the Earth. As a result of absorption, the effect of their deficiency and, consequently, the deficiency in the flow of atmospheric muons, measured on the Earth in the direction of the Sun and the Moon, should also arise. Detection of such a lack of events («shadow») and the determination of its position in the sky provide the ability to measure the resolving power of the particle detector and determine its orientation. The data of these measurements can be applied for its calibration. This article presents the results of analysis of data from the ANTARES detector collected during the period from 2013 to 2015.

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## Extrapolation of the structural functions F1 and F2 for virtualities of the photon Q^2 from 2 to 7 GeV^2

### A. A. Golubenko

Memoirs of the Faculty of Physics 2018. N 2.

An estimation of the inclusive structural functions of the proton in the excitation energy region of nucleon resonances for virtualities of the photon Q^2 from 2 to 7 GeV^2 is performed. Extrapolation of the inclusive structural functions F1 and F2 was carried out on the basis of experimental data in the region Q^2 < 4.5 GeV^2 and data obtained from the Bosted’s fit for Q^2 > 4.5 GeV^2. This evaluation is important in the development of the CLAS12 detector program of experiments to study the structure of the ground and excited states of the nucleon, which opens access to the dynamics of strong interactions in the nonperturbative regime.

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## A new mechanism for the action of continuous and pulsed UV-C radiation on water

### I. M. Piskarev$^1$, K. A. Astaf'eva$^2$, I. P. Ivanova$^2$

Memoirs of the Faculty of Physics 2018. N 2.

The formation of hydrogen peroxide in bidistilled water under the influence of UV-C radiation from a low-pressure mercury lamp DKB-9 was studied. The yield of hydrogen peroxide was (1 ± 0.2) · 10−7 mol (ls) −1. The wavelengths of radiation are estimated, under the influence of which the formation of H2O2 is possible. It was assumed that the intermediate product of the reaction formed directly under the action of radiation is the radical HO2•/O2•−. Oxidation-reduction reactions in aqueous solutions containing F e2+, F e3+ and I− ions at pH values from 0.8 to 8.1 were studied for its identification. The quantum yield of the HO2• radicals in an acidic medium under the action of mercury lamp radiation is 0.015 ± 0.005

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## Ion irradiation influence on living systems by dielectric matrices

### B. '. Merzuk$^1$, D. K. Minnebaev$^1$, A. V. Kozemyako$^1$, E. N. Muratova$^2$, V. S. Chernysh$^3$

Memoirs of the Faculty of Physics 2018. N 2.

This work studies passing of an helium ion beam with an energy of 1.5-2 MeV. It is shown that even a slight deviation of the membrane from the normal (1.5 ... 3 degrees) leads to a decrease in the yield of backscattered ions from the target HfO2 and, consequently, to a decrease in the measured current. Thus, the created and studied template membranes ensure the channeling functions of the high-energy ion flux. It is established that the coefficient of passing accelerated ions through the membrane can exceed 60%. It has been shown that it is possible to apply por − Al2O3 membranes as a medium for growth and reproduction of living organisms, in particular bacterial colonies. A solution based on fluorescein was chosen to perform a primary visual study of membrane properties, without extra diagnostic methods. The calculation of the capillary flow was carried out according to the Poiseuille law. As a result, it was determined that for membranes with a small (≈ 20nm) and large (≈ 200nm) pore diameter obtained in the electrolyte based on sulfuric and orthophosphoric acids, the liquid flow through the membrane is Q1 = 0, 0023 and Q2 = 0.03 mm3/s, respectively. It has been proposed to use the technique of focused high-energy ion beams that allows a local effect on under study biological micro-objects, and it has been revealed that membranes are a good platform for their life and growth.

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