Персона: Пришвицын, Александр Сергеевич
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Институт лазерных и плазменных технологий
Стратегическая цель Института ЛаПлаз – стать ведущей научной школой и ядром развития инноваций по лазерным, плазменным, радиационным и ускорительным технологиям, с уникальными образовательными программами, востребованными на российском и мировом рынке образовательных услуг.
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Александр Сергеевич
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- ПубликацияОткрытый доступElastic backscattering as a method for the measurement of the integral lithium content in thin films on fusion-relevant substrates(2019) Mayer, M.; Krat, S.; Vasina, Y.; Prishvitsyn, A.; Gasparyan, Y.; Pisarev, A.; Крат, Степан Андреевич; Пришвицын, Александр Сергеевич; Гаспарян, Юрий Микаэлович; Писарев, Александр Александрович© 2019 Elsevier B.V.Different ion beam analysis techniques for the study of thin lithium-containing layers on top of fusion relevant materials are discussed and compared to each other. Elastic backscattering analysis (EBS) with protons is determined to be one of the most promising techniques and allows measurements of Li layers with thicknesses from ∼100 nm up to ∼600 μm, as shown by SIMNRA simulations. The best sensitivity for thin films (∼100 nm) can be achieved using 4 MeV protons with 170° scattering detection angle for layers on Mo and W substrates, and 2 MeV for C substrates. Experimentally EBS measurements were successfully tested for Li films with thicknesses from ∼50 nm up to ∼400 nm after air exposure. The Li films become strongly inhomogeneous and require averaging over multiple measurements in nearby areas. This necessitates averaging over multiple nearby measurement points, and limits the overall precision of the measurement.
- ПубликацияОткрытый доступAnalytical approach for description of deuterium content in deuterium-beryllium co-deposited layers(2021) De, Temmerman, G.; Krat, S.; Gasparyan, Y.; Vasina, Y.; Prishvitcyn, A. S.; Pisarev, A.; Крат, Степан Андреевич; Гаспарян, Юрий Микаэлович; Пришвицын, Александр Сергеевич; Писарев, Александр Александрович© 2021 The Author(s)Available literature data for beryllium content in D-Be co-deposited layers was modeled using newly developed model. It was shown that the model adequately describes the experimental results. An empirical scaling for the available trap concentrations as a function of deuteron energy was introduced in order to improve the agreement between the experimental data and model predictions. The limited recombination rate describes the co-deposition better than the unlimited one. Assuming two types of traps in the film with detrapping energies of 0.8–0.9 and 1.2–1.3 eV and trap concentrations of 10 at. % and 1 at. %, respectively, and the deuterium implantation energy of 15.6 eV, the average relative deviation between experimental and predicted D/Be values of 1.9 was observed, which is better than the empirical D/Be scalings.
- ПубликацияОткрытый доступModeling of COMPASS tokamak divertor liquid metal experiments(2020) Horacek, J.; Dejarnac, R.; Cecrdle, J.; Tskhakaya, D.; Van, Oost, G.; Prishvitsin, A. S.; Gasparyan, Y.; Vasina, Y.; Пришвицын, Александр Сергеевич; Гаспарян, Юрий Микаэлович© 2020 The Author(s)Two small liquid metal targets based on the capillary porous structure were exposed to the divertor plasma of the tokamak COMPASS. The first target was wetted by pure lithium and the second one by a lithium-tin alloy, both releasing mainly lithium atoms (sputtering and evaporation) when exposed to plasma. Due to poorly conductive target material and steep surface inclination (implying the surface-perpendicular plasma heat flux 12–17 MW/m2) for 0.1–0.2 s, the LiSn target has reached 900 °C under ELMy H-mode. A model of heat conduction is developed and serves to evaluate the lithium sputtering and evaporation and, thus, the surface cooling by the released lithium and consequent radiative shielding. In these conditions, cooling of the surface by the latent heat of vapor did not exceed 1 MW/m2. About 1019 lithium atoms were evaporated (comparable to the COMPASS 1 m3 plasma deuterium content), local Li pressure exceeded the deuterium plasma pressure. Since the radiating Li vapor cloud spreads over a sphere much larger than the hot spot, its cooling effect is negligible (0.2 MW/m2). We also predict zero lithium prompt redeposition, consistent with our observation.
- ПубликацияТолько метаданныеVertical stray field measurements using an electron beam in the MEPhIST-0 tokamak(2024) Vinitskiy, E. A.; Efimov, N. E.; Prishvitsyn, A. S.; Sorokin, I. A.; Krat, S. A.; Виницкий, Егор Александрович; Ефимов, Никита Евгеньевич; Пришвицын, Александр Сергеевич; Сорокин, Иван Александрович; Крат, Степан Андреевич
- ПубликацияОткрытый доступИЗОТОПНЫЙ ЭФФЕКТ В НАКОПЛЕНИИ ВОДОРОДА В ОСАЖДЁННЫХ ИЗ ПЛАЗМЫ ВОЛЬФРАМОВЫХ СЛОЯХ(НИЯУ МИФИ, 2024) КРАТ, С. А.; ПРИШВИЦЫН, А. С.; ГАСПАРЯН, Ю. М.; ПИСАРЕВ, А. А.; Писарев, Александр Александрович; Пришвицын, Александр Сергеевич; Крат, Степан Андреевич; Гаспарян, Юрий МикаэловичВажность изучения накопления водорода в соосаждённых из плазмы металлических слоях во многом обусловлена опасностью избыточного накопления радиоактивного изотопа трития в термоядерных установках, где со-осаждение материалов стенки с частицами работчего газа – один из основных каналов накопления водорода в установке. Так как эксперименты с использованием трития крайне затруднены технически, опасны и дороги, подавляющее большинство работ в данной области проводится с использованием дейтерия как симулятора трития. При этом предполагается, что накопление трития будет происходить идентично накоплению дейтерия. В связи со сложностью проведения экспериментов с тритием, возможно провести опыты по сравнению свойств протия и дейтерия и сделать некоторые оценки в части трития на основе полученных данных.
- ПубликацияОткрытый доступOverview of power exhaust experiments in the COMPASS divertor with liquid metals(2020) Dejarnac, R.; Horacek, J.; Hron, M.; Jerab, M.; Prishvitcyn, A.; Van, Oost, G.; Пришвицын, Александр Сергеевич© 2020 The AuthorsPower handling experiments with a special liquid metal divertor module based on the capillary porous system technology were performed in the tokamak COMPASS. The performance of two metals (Li and LiSn alloy) were tested for the first time in a divertor under ELMy H-mode conditions. No damage of the capillary mesh and a good exhaust capability were observed for both metals in two separate experiments with up to 12 MW/m2 of deposited perpendicular, inter-ELM steady-state heat flux and with ELMs of relative energy ~3% and a local peak energy fluence at the module ~15 kJ.m−2. No droplets were directly ejected from the mesh top surface and for the LiSn experiment, no contamination of the core and SOL plasmas by Sn was observed. The elemental depth profile analysis of 14 stainless-steel samples located around the vacuum vessel for each experiment provides information about the migration of evaporated/redeposited liquid elements.
- ПубликацияОткрытый доступModel for hydrogen accumulation in co-deposited layers(2020) Krat, S. A.; Prishvitsyn, A. S.; Vasina, Y. A.; Gasparyan, Y. M.; Pisarev, A. A.; Крат, Степан Андреевич; Пришвицын, Александр Сергеевич; Гаспарян, Юрий Микаэлович; Писарев, Александр Александрович© 2020 The Author(s)An improved diffusion based model for prediction of the hydrogen content in co-deposited layers depending on the deposition conditions (the properties of the material which is co-deposited with hydrogen, rate of deposition, hydrogen flux and particle energy, substrate temperature) is presented. The model is validated using experimental data for W, Mo and Al, and is compared to empirical scaling equations currently in use. It is shown that a good agreement is observed in regards to hydrogen content vs substrate temperature experimental data, and no disagreement with scaling equations can be seen in regards to the role of hydrogen flux and the rate of deposition. It is shown that the influence of hydrogen particle energy on the hydrogen content requires further investigation. In addition to hydrogen, models for other mobile impurities both in co-deposited layers and in layers under steady-state net erosion conditions are given.
- ПубликацияОткрытый доступHelium accumulation in tungsten layers deposited in Ar-He magnetron discharge(2020) Krat, S.; Fefelova, E.; Prishvitsyn, A. S.; Vasina, Y.; Harutyunyan, Z.; Gasparyan, Y. u.; Pisarev, A.; Крат, Степан Андреевич; Пришвицын, Александр Сергеевич; Арутюнян, Зорий Робертович; Гаспарян, Юрий Микаэлович; Писарев, Александр Александрович© Published under licence by IOP Publishing Ltd.W-He co-deposition was studied by means of in-vacuo thermal desorption spectroscopy. W-He co-deposited layers were produced at substrate temperatures varied from 400 K to 800 K with a 50 K temperature step. It was found that the He content decreases from ~1.7 at. % at 400 K to ~0.17 at. % at 750 K. At 800 K, an increase in the He content was observed, that should be caused by significant changes in the film structure. Helium TDS spectra had two main peaks with maxima in the 500-600 K range and at ~960 K; the peaks observed are similar to those previously seen for He ion implantation in W. Several scaling expressions are proposed for He/W vs. T.
- ПубликацияТолько метаданныеA setup for study of co-deposited films(2020) Krat, S. A.; Popkov, A. S.; Gasparyan, Y. M.; Vasina, Y. A.; Prishvitsyn, A. S.; Pisarev, A. A.; Крат, Степан Андреевич; Гаспарян, Юрий Микаэлович; Пришвицын, Александр Сергеевич; Писарев, Александр Александрович© 2020 IOP Publishing Ltd and Sissa Medialab.A setup for investigation of thermal desorption spectra of gases accumulated in thin films deposited by plasma sputtering of solid targets is described. Deposition and thermal desorption spectroscopy (TDS) are performed in two different vacuum chambers separated by a gate valve with the sample transferred between the chambers in-vacuo. The temperature of the substrate for deposited films can be varied in the range of 300-800 K; and the deposition rate is controlled by a quartz microbalance. Thermal desorption of co-deposited gases is analyzed by a quadrupole mass spectrometer. Sputtering rate and evaporation of the film during TDS are measured by quartz microbalances. Three experiments are described 1) trapping of deuterium by the growing chemically active Li film with subsequent decomposition and evaporation of the film, 2) temperature dependent deuterium trapping in the growing W film resulting in trapping with several binding energies, and 3) chemical interaction of D-Li layer with water vapor leading to isotopic H-D exchange and chemical transformation of the deposited film.
- ПубликацияТолько метаданныеIsotope exchange in Li-D co-deposited layers at temperatures below 200 °C(2020) Krat, S.; Vasina, Y.; Prishvitsyn, A.; Gasparyan, Y.; Pisarev, A.; Крат, Степан Андреевич; Пришвицын, Александр Сергеевич; Гаспарян, Юрий Микаэлович; Писарев, Александр Александрович© 2020 Elsevier B.V.Hydrogen-deuterium isotope exchange in Li-D co-deposited films was studied as a method of removal of heavy hydrogen isotopes from Li films deposited in fusion devices. The total H and D retention was measured using in-vacuo thermal desorption spectroscopy. Co-deposited Li-D films were kept in H2 gas at 1 Pa and 105 Pa at room temperature, 100 °C, and 200 °C. Some reduction of the D content was observed even at RT, while nearly full isotope substitution was achieved at 200 °C after 1 day at 105 Pa in H2 gas.