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Papers by Tetiana Malykhina

Дисертаційну роботу присвячено розв’язанню актуальної науково-прикладної задачі – визначенню і оп... more Дисертаційну роботу присвячено розв’язанню актуальної науково-прикладної задачі – визначенню і оптимізації технічних характеристик пристроїв для пошуку та ідентифікації джерел випромінювання шляхом дослідження методом Монте-Карло фізичних процесів, що відбуваються у речовині приладів під дією електромагнітного випромінювання. Зокрема, проведено дослідження фізичних процесів, що відбуваються у речовині детекторів супутникового спектрометра-телескопа “СТЕП-Ф” наукового космічного експерименту “КОРОНАС-ФОТОН”. Показано, що прилад дозволяє реєструвати електрони в діапазоні енергій 0,2-20 МеВ; протони - в діапазоні енергій 3,5-77 МеВ; альфа-частинки – в діапазоні енергій 13,5-307 МеВ. Встановлено, що визначення напрямку приходу електронів можливо для частинок з енергією більше 4,5 МеВ. Досліджені фізичні процеси, що впливають на амплітуду імпульсів у детекторах приладу для визначення напрямку на джерело γ-випромінювання. За рахунок зміщення детекторів приладу відносно центрів порожнин, в...

The emergence of powerful sources of ionizing radiation, the needs of nuclear energy, technology ... more The emergence of powerful sources of ionizing radiation, the needs of nuclear energy, technology and medicine, as well as the need to develop reliable methods of protection against the harmful effects of penetrating radiation stimulated the development of such branches of science as radiation chemistry, radiation biology, radiation medicine. When an organic dye solution is exposed to ionizing radiation, it irreversibly changes color. As a result, the absorbed dose can be determined. The processes of interaction of neutron fluxes with an aqueous solution of an organic dye methyl orange (МО) – C14H14N3О3SNa, containing and not containing 4% boric acid, have been investigated. The work was carried out on a LINAC LUE-300 at NSC KIPT. A set of tungsten plates was used as a neutron-generating target. The electron energy was 15 MeV, the average current was 20 μA. The samples were located behind the lead shield and without it, with and without a moderator. Using the GEANT4 toolkit code for ...

The results of computer simulation of the high-energy electrons passage through thin layers of ti... more The results of computer simulation of the high-energy electrons passage through thin layers of titanium (Ti) and polyimide Kapton (C 22 H 10 N 2 O 5) in the energy range from 3 MeV to 20 MeV are presented. Simulation is carried out using the Geant4 toolkit. The number of primary electrons is 6.24×10 7 for each series of calculations. The thickness of the titanium foil in the model experiment is 50 µm, the thickness of the Kapton film is 110 µm. The energies of primary electrons are chosen as following: 3 MeV, 5 MeV, 10 MeV, 15 MeV, and 20 MeV. The purpose of the calculations is to reveal the possibility of using the Kapton film in the output devices of linear electron accelerators. It was necessary to calculate the probable values of the energy absorbed in a Kapton film and in a titanium foil for each value of primary electrons energy. Another important characteristic is the divergence radius of the electron beam at a predetermined distance from the film, or the electron scattering angle. As a result of calculations, the energy spectra of bremsstrahlung gamma-quanta, formed during the passage of electrons through the materials of the films, are obtained. The most probable values of the energy absorbed in the titanium foil and in the Kapton film are calculated. The scattering radii of an electron beam for the Kapton film and also for the titanium foil at a distance of 20 centimeters are estimated. These calculations are performed for electron energies of 3 MeV, 5 MeV, 10 MeV, 15 MeV, and 20 MeV. A comparative analysis of the obtained results of computational experiments is carried out. It is shown that the ratio of the total amount of bremsstrahlung gamma quanta in the case of use the Kapton film is approximately 0.56 of the total amount of bremsstrahlung gamma quanta when using the titanium foil. The coefficients of the ratio of the electrons scattering radius most probable value after passing through Kapton to the most probable value of the scattering radius after passing through titanium are from 0.62 at electrons energy of 3 MeV to 0.57 at electrons energy of 20 MeV. The analysis of the calculated data showed that the use of Kapton (C 22 H 10 N 2 O 5) as a material for the manufacture of output devices for high-energy electron beams is more preferable in comparison to titanium films, since the use of Kapton instead of titanium makes it possible to significantly reduce the background of the generated bremsstrahlung gamma quanta and reduce the scattering radius of the electron beam.

The study of the processes occurring in a matter when ionizing radiation passes through is import... more The study of the processes occurring in a matter when ionizing radiation passes through is important for solving various problems. Examples of such problems are applied and fundamental problems in the field of radiation physics, chemistry, biology, medicine and dosimetry. This work is dedicated to computer modeling of the parameters of a tungsten converter for studying the processes of radiation damage during the interaction of ionizing radiation with solutions of organic dyes. Simulation was carried out in order to determine the optimal thickness of the converter under predetermined experimental conditions. Experimental conditions include: energies and type of primary particles, radiation intensity, target dimensions, relative position of the radiation source and target. Experimental studies of the processes of radiation damage occurring in solutions of organic dyes are planned to be carried out using the linear electron accelerator "LINAC-300" of the National Scientific Center "Kharkov Institute of Physics and Technology". Electrons with 15 MeV energy are chosen as primary particles. The interaction of electrons with the irradiated target substances is planned to be studied in the first series of experiments. Investigations of the interaction of gamma quanta with the target matter will be carried out in the second series of experiments. The tungsten converter is used to generate a flux of bremsstrahlung gamma rays. One modeling problem is determination of the converter thickness at which the flux of bremsstrahlung gamma will be maximal in front of the target. At the same time, the flow of electrons and positrons in front of the target should be as low as possible. Another important task of the work is to identify the possibility of determining the relative amount of radiation damage in the target material by the Geant4-modeling method. Radiation damage of the target substance can occur due to the effect of bremsstrahlung, as well as electrons and positrons. Computational experiments were carried out for various values of the converter thickness-from 0 mm (no converter) to 8 mm with a step of 1 mm. A detailed analysis of the obtained data has been performed. As a result of the data analysis, the optimal value of the tungsten converter thickness was obtained. The bremsstrahlung flux in front of the target is maximum at a converter thickness of 2 mm. But at the same time, the flux of electrons and positrons crossing the boundaries of the target does not significantly affect the target. The computational experiment was carried out by the Monte Carlo method. A computer program in C++ that uses the Geant4 toolkit was developed to perform calculations. The developed program operates in a multithreaded mode. The multithreaded mode is necessary to reduce the computation time when using a large number of primary electrons. The G4EmStandardPhysics_option3 model of the PhysicsList was used in the calculations. The calculations necessary for solving the problem were carried out using the educational computing cluster of the

Problems of Atomic Science and Technology, 2021

The Monte-Carlo calculations of the Moliere radius (RM) for some homogeneous and heterogeneous me... more The Monte-Carlo calculations of the Moliere radius (RM) for some homogeneous and heterogeneous media used in electromagnetic calorimetry in the energy range from 50 MeV to 10 GeV are presented in detail. The obtained results, the uncertainties in determining RM, estimations of the absorbed energy, methods for approximating the absorbed energy, and the accuracy of the results are discussed as well. Some RM are shown for calorimeter proto-types of the Spin Physics Detector experiment (SPD). A one-parameter function of the Moliere radius dependence on the absorber-scintillator thickness ratio is obtained.

3, 2020, 2020

The response simulation of an ideal KOPIO-type electromagnetic sampling calorimeter was carried o... more The response simulation of an ideal KOPIO-type electromagnetic sampling calorimeter was carried out in the energy range of 50 MeV – 16 GeV using Geant4-10.6.0 toolkit. In this work, we obtained energy resolution parameters for prototypes of Shashlyk calorimeter modules (ECAL SPD) of the NICA collider SPD setup for different thicknesses of a lead absorber with different numbers of layers. The NICA scientific experiment provides a unique opportunity to study parton distributions and correlations in hadron structure when working with high-intensity polarized relativistic ion beams. The ECAL electromagnetic calorimeter is one of the key detectors of the SPD device. There are some preliminary requirements for an electromagnetic calorimeter, in particular, for energy resolution in the energy range from 50 MeV to 16 GeV. It has been shown in detail that a more accurate obtaining of stochastic as well as permanent coefficients acting as parameters of the energy resolution parameterization f...

Issue 2 2020, 2020

The present work is dedicated to study of the possibilities of improving the production method of... more The present work is dedicated to study of the possibilities of improving the production method of 11 C and 18 F medical isotopes using a linear electron accelerator. Experimental studies of 11 C and 18 F isotopes production by the photonuclear technique were carried out in [1]. Various targets were irradiated by bremsstrahlung photons following by measurements targets' activities. This experimental research has been carried out in the energy range from 10 to 40 MeV. The current work studies an angular distribution of bremsstrahlung photons in order to estimate the possibilities of producing maximum achievable levels of medical isotopes 18 F and 11 С activities. The angular distribution of bremsstrahlung photons is an important property of the irradiation stand which contains an assembly of targets. This important property allows designing necessary changes in the target assembly setup used to produce medical isotopes. The research presented in the current work was done as a computer simulation. The computer software package 'KIPT' was developed in С++ programming language, using the Geant4 toolkit in order to obtain the angular distribution of bremsstrahlung photons. Experimental setup materials as well as structural elements positions were defined in the DetectorConstruction class of our program. The parameters of an electron beam were defined in the PrimaryGeneratorAction class. The electron beam diameter was defined as 8 mm, energy Е е =36.7 MeV, corresponding to the real experiment carried out at the "Accelerator" Science and Research Establishment of Kharkiv Institute of Physics and Technology [1]. Models of physical processes occurring while the electron beam crosses the target assembly were defined in the PhysicsList class. All classes and modules necessary for the analysis of simulation results were included to our program together with visualization modules. Visualization modules use the OpenGL graphics library and the Qt5 software to represent the relative position of experimental setup parts and to visualize particle trajectories. As a result of this work, the angular distributions were obtained for the beam of electrons and bremsstrahlung photons directly before the target. This result will allow target assembly parameter optimization for optimal production of medical isotopes by the photonuclear technique.

East European Journal of Physics, 2019

Big amount of works deals with solution of differential equations, associated with electron motio... more Big amount of works deals with solution of differential equations, associated with electron motion in electromagnetic field, using methods of classical electrodynamics. Solution of equation of an electron motion in TEM wave field is interesting task because this equation is mathematical model of big number of wave processes, which are used for researches of different physical processes. The proposed work dedicated to finding the solution for the equation of an electron motion in TEM wave field in laboratory system of coordinates using the theory of almost periodic functions. The work demonstrates that the projections of electron velocity on coordinate axis conform to the wave equation, and, consequently, could be expanded into generalized Fourier series at any value of the wave and electron parameters. In the present work, the formulas received before for electron velocity projection on coordinate axis, are transformed to a well-behaved form, and are broken down into non-perfect gen...

East European Journal of Physics, 2019

The proposed work demonstrates the results of creating and investigating the mathematical model o... more The proposed work demonstrates the results of creating and investigating the mathematical model of the source of fast neutrons. Computer modeling of the energy spectrum of fast neutrons was carried out for 239PuBe neutron source. The model of the source of fast neutrons has been developed. Neutrons in this model have an energy spectrum from 100 keV to 11 MeV with 100 keV step. Simulation is performed by the Monte-Carlo method. The model carrier is a computer program developed in the C++ programming language in the Linux operating system environment, using the Geant4 toolkit. All necessary classes describing low-energy models were used for the simulation of the passage of neutrons through materials of detectors. Those take into account the elastic scattering, inelastic scattering, radiative capture and fission. We consider these processes because models of processes implemented in our software will be also used for other problems of neutrons transport, for example, for passing neutro...

Дисертаційну роботу присвячено розв’язанню актуальної науково-прикладної задачі – визначенню і оп... more Дисертаційну роботу присвячено розв’язанню актуальної науково-прикладної задачі – визначенню і оптимізації технічних характеристик пристроїв для пошуку та ідентифікації джерел випромінювання шляхом дослідження методом Монте-Карло фізичних процесів, що відбуваються у речовині приладів під дією електромагнітного випромінювання. Зокрема, проведено дослідження фізичних процесів, що відбуваються у речовині детекторів супутникового спектрометра-телескопа “СТЕП-Ф” наукового космічного експерименту “КОРОНАС-ФОТОН”. Показано, що прилад дозволяє реєструвати електрони в діапазоні енергій 0,2-20 МеВ; протони - в діапазоні енергій 3,5-77 МеВ; альфа-частинки – в діапазоні енергій 13,5-307 МеВ. Встановлено, що визначення напрямку приходу електронів можливо для частинок з енергією більше 4,5 МеВ. Досліджені фізичні процеси, що впливають на амплітуду імпульсів у детекторах приладу для визначення напрямку на джерело γ-випромінювання. За рахунок зміщення детекторів приладу відносно центрів порожнин, в...

The emergence of powerful sources of ionizing radiation, the needs of nuclear energy, technology ... more The emergence of powerful sources of ionizing radiation, the needs of nuclear energy, technology and medicine, as well as the need to develop reliable methods of protection against the harmful effects of penetrating radiation stimulated the development of such branches of science as radiation chemistry, radiation biology, radiation medicine. When an organic dye solution is exposed to ionizing radiation, it irreversibly changes color. As a result, the absorbed dose can be determined. The processes of interaction of neutron fluxes with an aqueous solution of an organic dye methyl orange (МО) – C14H14N3О3SNa, containing and not containing 4% boric acid, have been investigated. The work was carried out on a LINAC LUE-300 at NSC KIPT. A set of tungsten plates was used as a neutron-generating target. The electron energy was 15 MeV, the average current was 20 μA. The samples were located behind the lead shield and without it, with and without a moderator. Using the GEANT4 toolkit code for ...

The results of computer simulation of the high-energy electrons passage through thin layers of ti... more The results of computer simulation of the high-energy electrons passage through thin layers of titanium (Ti) and polyimide Kapton (C 22 H 10 N 2 O 5) in the energy range from 3 MeV to 20 MeV are presented. Simulation is carried out using the Geant4 toolkit. The number of primary electrons is 6.24×10 7 for each series of calculations. The thickness of the titanium foil in the model experiment is 50 µm, the thickness of the Kapton film is 110 µm. The energies of primary electrons are chosen as following: 3 MeV, 5 MeV, 10 MeV, 15 MeV, and 20 MeV. The purpose of the calculations is to reveal the possibility of using the Kapton film in the output devices of linear electron accelerators. It was necessary to calculate the probable values of the energy absorbed in a Kapton film and in a titanium foil for each value of primary electrons energy. Another important characteristic is the divergence radius of the electron beam at a predetermined distance from the film, or the electron scattering angle. As a result of calculations, the energy spectra of bremsstrahlung gamma-quanta, formed during the passage of electrons through the materials of the films, are obtained. The most probable values of the energy absorbed in the titanium foil and in the Kapton film are calculated. The scattering radii of an electron beam for the Kapton film and also for the titanium foil at a distance of 20 centimeters are estimated. These calculations are performed for electron energies of 3 MeV, 5 MeV, 10 MeV, 15 MeV, and 20 MeV. A comparative analysis of the obtained results of computational experiments is carried out. It is shown that the ratio of the total amount of bremsstrahlung gamma quanta in the case of use the Kapton film is approximately 0.56 of the total amount of bremsstrahlung gamma quanta when using the titanium foil. The coefficients of the ratio of the electrons scattering radius most probable value after passing through Kapton to the most probable value of the scattering radius after passing through titanium are from 0.62 at electrons energy of 3 MeV to 0.57 at electrons energy of 20 MeV. The analysis of the calculated data showed that the use of Kapton (C 22 H 10 N 2 O 5) as a material for the manufacture of output devices for high-energy electron beams is more preferable in comparison to titanium films, since the use of Kapton instead of titanium makes it possible to significantly reduce the background of the generated bremsstrahlung gamma quanta and reduce the scattering radius of the electron beam.

The study of the processes occurring in a matter when ionizing radiation passes through is import... more The study of the processes occurring in a matter when ionizing radiation passes through is important for solving various problems. Examples of such problems are applied and fundamental problems in the field of radiation physics, chemistry, biology, medicine and dosimetry. This work is dedicated to computer modeling of the parameters of a tungsten converter for studying the processes of radiation damage during the interaction of ionizing radiation with solutions of organic dyes. Simulation was carried out in order to determine the optimal thickness of the converter under predetermined experimental conditions. Experimental conditions include: energies and type of primary particles, radiation intensity, target dimensions, relative position of the radiation source and target. Experimental studies of the processes of radiation damage occurring in solutions of organic dyes are planned to be carried out using the linear electron accelerator "LINAC-300" of the National Scientific Center "Kharkov Institute of Physics and Technology". Electrons with 15 MeV energy are chosen as primary particles. The interaction of electrons with the irradiated target substances is planned to be studied in the first series of experiments. Investigations of the interaction of gamma quanta with the target matter will be carried out in the second series of experiments. The tungsten converter is used to generate a flux of bremsstrahlung gamma rays. One modeling problem is determination of the converter thickness at which the flux of bremsstrahlung gamma will be maximal in front of the target. At the same time, the flow of electrons and positrons in front of the target should be as low as possible. Another important task of the work is to identify the possibility of determining the relative amount of radiation damage in the target material by the Geant4-modeling method. Radiation damage of the target substance can occur due to the effect of bremsstrahlung, as well as electrons and positrons. Computational experiments were carried out for various values of the converter thickness-from 0 mm (no converter) to 8 mm with a step of 1 mm. A detailed analysis of the obtained data has been performed. As a result of the data analysis, the optimal value of the tungsten converter thickness was obtained. The bremsstrahlung flux in front of the target is maximum at a converter thickness of 2 mm. But at the same time, the flux of electrons and positrons crossing the boundaries of the target does not significantly affect the target. The computational experiment was carried out by the Monte Carlo method. A computer program in C++ that uses the Geant4 toolkit was developed to perform calculations. The developed program operates in a multithreaded mode. The multithreaded mode is necessary to reduce the computation time when using a large number of primary electrons. The G4EmStandardPhysics_option3 model of the PhysicsList was used in the calculations. The calculations necessary for solving the problem were carried out using the educational computing cluster of the

Problems of Atomic Science and Technology, 2021

The Monte-Carlo calculations of the Moliere radius (RM) for some homogeneous and heterogeneous me... more The Monte-Carlo calculations of the Moliere radius (RM) for some homogeneous and heterogeneous media used in electromagnetic calorimetry in the energy range from 50 MeV to 10 GeV are presented in detail. The obtained results, the uncertainties in determining RM, estimations of the absorbed energy, methods for approximating the absorbed energy, and the accuracy of the results are discussed as well. Some RM are shown for calorimeter proto-types of the Spin Physics Detector experiment (SPD). A one-parameter function of the Moliere radius dependence on the absorber-scintillator thickness ratio is obtained.

3, 2020, 2020

The response simulation of an ideal KOPIO-type electromagnetic sampling calorimeter was carried o... more The response simulation of an ideal KOPIO-type electromagnetic sampling calorimeter was carried out in the energy range of 50 MeV – 16 GeV using Geant4-10.6.0 toolkit. In this work, we obtained energy resolution parameters for prototypes of Shashlyk calorimeter modules (ECAL SPD) of the NICA collider SPD setup for different thicknesses of a lead absorber with different numbers of layers. The NICA scientific experiment provides a unique opportunity to study parton distributions and correlations in hadron structure when working with high-intensity polarized relativistic ion beams. The ECAL electromagnetic calorimeter is one of the key detectors of the SPD device. There are some preliminary requirements for an electromagnetic calorimeter, in particular, for energy resolution in the energy range from 50 MeV to 16 GeV. It has been shown in detail that a more accurate obtaining of stochastic as well as permanent coefficients acting as parameters of the energy resolution parameterization f...

Issue 2 2020, 2020

The present work is dedicated to study of the possibilities of improving the production method of... more The present work is dedicated to study of the possibilities of improving the production method of 11 C and 18 F medical isotopes using a linear electron accelerator. Experimental studies of 11 C and 18 F isotopes production by the photonuclear technique were carried out in [1]. Various targets were irradiated by bremsstrahlung photons following by measurements targets' activities. This experimental research has been carried out in the energy range from 10 to 40 MeV. The current work studies an angular distribution of bremsstrahlung photons in order to estimate the possibilities of producing maximum achievable levels of medical isotopes 18 F and 11 С activities. The angular distribution of bremsstrahlung photons is an important property of the irradiation stand which contains an assembly of targets. This important property allows designing necessary changes in the target assembly setup used to produce medical isotopes. The research presented in the current work was done as a computer simulation. The computer software package 'KIPT' was developed in С++ programming language, using the Geant4 toolkit in order to obtain the angular distribution of bremsstrahlung photons. Experimental setup materials as well as structural elements positions were defined in the DetectorConstruction class of our program. The parameters of an electron beam were defined in the PrimaryGeneratorAction class. The electron beam diameter was defined as 8 mm, energy Е е =36.7 MeV, corresponding to the real experiment carried out at the "Accelerator" Science and Research Establishment of Kharkiv Institute of Physics and Technology [1]. Models of physical processes occurring while the electron beam crosses the target assembly were defined in the PhysicsList class. All classes and modules necessary for the analysis of simulation results were included to our program together with visualization modules. Visualization modules use the OpenGL graphics library and the Qt5 software to represent the relative position of experimental setup parts and to visualize particle trajectories. As a result of this work, the angular distributions were obtained for the beam of electrons and bremsstrahlung photons directly before the target. This result will allow target assembly parameter optimization for optimal production of medical isotopes by the photonuclear technique.

East European Journal of Physics, 2019

Big amount of works deals with solution of differential equations, associated with electron motio... more Big amount of works deals with solution of differential equations, associated with electron motion in electromagnetic field, using methods of classical electrodynamics. Solution of equation of an electron motion in TEM wave field is interesting task because this equation is mathematical model of big number of wave processes, which are used for researches of different physical processes. The proposed work dedicated to finding the solution for the equation of an electron motion in TEM wave field in laboratory system of coordinates using the theory of almost periodic functions. The work demonstrates that the projections of electron velocity on coordinate axis conform to the wave equation, and, consequently, could be expanded into generalized Fourier series at any value of the wave and electron parameters. In the present work, the formulas received before for electron velocity projection on coordinate axis, are transformed to a well-behaved form, and are broken down into non-perfect gen...

East European Journal of Physics, 2019

The proposed work demonstrates the results of creating and investigating the mathematical model o... more The proposed work demonstrates the results of creating and investigating the mathematical model of the source of fast neutrons. Computer modeling of the energy spectrum of fast neutrons was carried out for 239PuBe neutron source. The model of the source of fast neutrons has been developed. Neutrons in this model have an energy spectrum from 100 keV to 11 MeV with 100 keV step. Simulation is performed by the Monte-Carlo method. The model carrier is a computer program developed in the C++ programming language in the Linux operating system environment, using the Geant4 toolkit. All necessary classes describing low-energy models were used for the simulation of the passage of neutrons through materials of detectors. Those take into account the elastic scattering, inelastic scattering, radiative capture and fission. We consider these processes because models of processes implemented in our software will be also used for other problems of neutrons transport, for example, for passing neutro...