2023, Sinelnikov, D. N., Gasparyan, Y. M., Grishaev, M. V., Efimov, N. E., Krat, S. A., Nikitin, I. A., Крат, Степан Андреевич, Гаспарян, Юрий Микаэлович, Синельников, Дмитрий Николаевич, Никитин, Иван Андреевич, Ефимов, Никита Евгеньевич, Гришаев, Максим Валерьевич

Hydrogen isotopes retention in thermonuclear fusion reactors is limited due to safety regulations and should be well controlled. Surface conditions can strongly affect accumulation rates of hydrogen isotopes in the bulk of plasma facing materials. Therefore, in vacuo methods of surface composition control may help to investigate mechanisms of this effects.

2021, Efimov, N. E., Sinelnikov, D. N., Bulgadaryan, D. G., Gasparyan, Y. M., Vovchenko, E. D., Marenkov, E. D., Маренков, Евгений Дмитриевич, Ефимов, Никита Евгеньевич, Вовченко, Евгений Дмитриевич, Синельников, Дмитрий Николаевич, Гаспарян, Юрий Микаэлович

One of the critical issues on the way to controlled nuclear fusion is related to plasma wall interaction. Such interaction leads to co-deposition of hydrogen isotopes together with eroded first wall materials. It is known that the deuterium-tritium (DT) mixture will be used in ITER and future fusion devices as a fuel. So as the accumulation of radioactive tritium in the machines is limited by the nuclear license, there is a need for some remote fuel retention monitoring system. In current devices, the total fuel amount is determined from the gas balance (difference between input and output flows) measurements and from a post mortem analysis of plasmafacing components. One of the most promising techniques which can be applied in situ in tokamaks is based on laser irradiation of the surface of interest followed by mass- or optical spectroscopy. Such a technique was already applied in TEXTOR tokamak to the hydrogenic carbon layers [1], and it is included in the task list of ITER with a high priority.

2019, Bulgadaryan, D. G., Sinelnikov, D. N., Sorokin, I. A., Kurnaev, V. A., Efimov, N. E., Синельников, Дмитрий Николаевич, Сорокин, Иван Александрович, Ефимов, Никита Евгеньевич

© 2019, Pleiades Publishing, Ltd.The erosion and redeposition processes of plasma-facing materials in fusion devices are the most important factors affecting near-wall and core plasma parameters and device lifetime. To determine the possibility of in situ analyzing these processes, we developed an experimental model of a built-in surface analyzer utilizing low-energy proton scattering spectroscopy. The results of experimental approbation of the method are presented.

2019, Mamedo, N. V., Kurnaev, V. A., Sinelnikov, D. N., Mamedov, I. M., Синельников, Дмитрий Николаевич, Мамедов, Никита Вадимович

Low-energy (1-20 keV) ion scattering spectroscopy is the widespread method of surface analysis [1,2]. The surface layer composition can be reconstructed from narrow peaks in the energy spectra of the scattered inert gas ions and recoil ions [3]. The main advantage of the surface analysis using inert gas ions is the high sensitivity to the first layer of surface atoms. This is due to the low initial energy of the ions (and therefore small ion penetration depth) and the high neutralization probability of the reflected ions, which increases with the penetration depth of the incident particle into the solid [3]. However, for quantitative surface analysis, it is extremely important to determine the neutralization probability (or the probability of ion survival), since this method usually detects reflected ions only.

2023, Efimov, N. E., Sinelnikov, D. N., Wang, Y., Harutyunyan, Z. R., Gasparyan, Y. M., Grishaev, M. V., Nikitin, I. A., Tan, X., Синельников, Дмитрий Николаевич, Ефимов, Никита Евгеньевич, Арутюнян, Зорий Робертович, Никитин, Иван Андреевич, Гаспарян, Юрий Микаэлович, Гришаев, Максим Валерьевич

One of the challenging problems which arise in the controlled nuclear fusion is related to the design and material choice of plasma facing components for the future reactors. Tungsten is considered to be one of the most suitable candidates due to its high melting point, thermal conductivity and relatively low erosion rate, and, therefore, it is planned to be used in nextgen facilities like ITER and DEMO. However, under high neutron fluxes its stable isotopes may form radioactive ones. Being not so hazardous while it is inside the reactor, in case of a loss of coolant accident (LOCA) a volatile oxide of W and of its transmutation products may appear, which is undesirable. A possible solution to avoid the release of the radioactive oxides is the use of self-passivating W-Cr-Y alloys [1], which under LOCA scenarios forms on the surface a chromium oxide, preventing the formation of tungsten oxide. Such alloys are of the great interest now, especially when it comes to analyzing the dynamics of the chromium release to the outermost layers [2,3]. In this work, capabilities of low energy ion scattering spectroscopy (LEIS) with small angle scattering to the characterization the surface morphology of W-11,4Cr-0,6Y after pre-annealing at different temperatures are revealed.

2023, Grishaev, M. V., Efimov, N. E., Sinelnikov, D. N., Nikitin, I. A., Gasparyan, Y. M., Vovchenko, E. D., Вовченко, Евгений Дмитриевич, Синельников, Дмитрий Николаевич, Ефимов, Никита Евгеньевич, Гришаев, Максим Валерьевич, Гаспарян, Юрий Микаэлович, Никитин, Иван Андреевич

One of the most detrimental phenomena in fusion research is the interaction of plasma with a surface of a first wall and in-chamber elements. It causes erosion of the plasma-facing components (PFC), which in turn results in a degradation of plasma parameters due to transport of erosion products into the hot plasma. On the other hand, these processes cause re-deposition of the eroded material together with fuel components (deuterium and tritium). This is the dominant mechanism for fuel retention in PFC.

2017, Mamedov, N. V., Kurnaev, V. A., Sinelnikov, D. N., Kolodko, D. V., Sorokin, I. A., Мамедов, Никита Вадимович, Колодко, Добрыня Вячеславич, Синельников, Дмитрий Николаевич, Сорокин, Иван Александрович

The adsorption of water on the surface is one of the main problems in vacuum technology. Since water is a good adsorbent, its adsorption is the reason that prevents the fast pumping of vacuum systems up to ultra-high vacuum. In addition, water vapor adsorption on metal surfaces during plasma surface interaction is a problem [1]. Singly scattered and recoil ions could form narrow peaks in energy spectra and provide information about atomic composition of the first atomic layer giving information about structure and composition of the surface and very sensitivity to the first layer of atoms [2 -5]. It was also shown [6] that the thickness of light element thin layers on the heavy substrate can be analyzed with good depth resolution (~0,3nm) due to scattering of hydrogen ions with keV energies. Application of ion scattering spectroscopy at pressures up to several mTorr is presented in [7, 8]. In this work experimental results of low energy ion spectroscopy (LEIS) of W samples during water vapor adsorption are presented.