Персона: Писарев, Александр Александрович
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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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- ПубликацияОткрытый доступINTERACTION OF LITHUM-DEUTERIUM FILMS WITH ATMOSPHERIC GASES(НИЯУ МИФИ, 2015) Popkov,A. S.; Krat, S. A.; Gasparyan, Yu. M.; Pisarev, A. A.; Гаспарян, Юрий Микаэлович; Писарев, Александр Александрович; Крат, Степан АндреевичA choice of plasma-facing materials is one of the key issues in thermonuclear fusion reactor design. Lithium as an element with the low atomic number is a promising material for plasma-facing components (PFC) in fusion installations and a number of experiments at tokamaks already demonstrated many positive effects on plasma operation [1,2]. Lithium can be used for conditioning, PFC on the base of of capillary porous system with liquid lithium are also considered. In any way, one can expect lithium co-deposition with hydrogen isotopes at the surface of PFC and at remote areas. Lithium as a good getter can accumulate high amount of hydrogen isotopes (deuterium, tritium) that can be a problem from the safety reason. Deuterium retention and thermal desorption from lithium films formed in plasma discharge were investigated in this work.
- 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.
- 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 метаданныеSubstitution of heavy hydrogen isotopes in tungsten layers during gas exposure ЗАМЕЩЕНИЕ ТЯЖЕЛЫХ ИЗОТОПОВ ВОДОРОДА В ВОЛЬФРАМОВЫХ СЛОЯХ ПРИ ВЫДЕРЖКЕ В ГАЗЕ(2020) Krat, S. A.; Vasina, Ya. A.; Prishvitcyn, A. S.; Fefelova, E. A.; Popova, M. A.; Gasparyan, Yu. M.; Pisarev, A. A.; Крат, Степан Андреевич; Пришвицын, Александр Сергеевич; Гаспарян, Юрий Микаэлович; Писарев, Александр Александрович© 2020 National Research Center Kurchatov Institute. All rights reserved.Efficiency of deuterium removal from tungsten co-deposited layers was studied by means of thermal desorption spectroscopy in the 30 to 200 °С temperature range in vacuum and hydrogen atmosphere (8 104 Pa). Tungsten layers 100 nm and 500 nm thick were deposited in magnetron discharge in argon-deuterium environment and contained ~2% at. of deuterium. Presence of hydrogen (protium) during sample degassing increases the rate of deuterium removal. Simultaneously, an additional amount of protium is captured in the co-deposited layers. The rate of deuterium removal increases with temperature. Exposure at a temperature of 473 K in a hydrogen atmosphere for 18 hours allowed 99% of the captured deuterium to be removed.
- ПубликацияОткрытый доступDeuterium trapping in co-deposited layers of ITER-relevant materials(НИЯУ МИФИ, 2021) Krat, S. A.; Prishvitsyn, A. S.; Vasina, Ya. A.; Fefelova, E. A.; Gasparyan, Yu. M.; Pisarev, A. A.; Писарев, Александр Александрович; Гаспарян, Юрий Микаэлович; Крат, Степан Андреевич; Пришвицын, Александр СергеевичHydrogen isotope accumulation in fusion devices is a serious problem. Because deuterium-tritium mixture will be a working gas in future fusion devices, including ITER tokamak, tritium accumulation is an issue from the perspective of radiation safety. In total, only 700 grams of tritium are allowed to be present in ITER vessel at any time, with additional 120 in the cryopumps, and 180 grams allocated to measurement error, to the total of 1000 grams.
- ПубликацияОткрытый доступHYDROGEN CO-DEPOSITION WITH METALS IN PLASMA DISCHARGE(НИЯУ МИФИ, 2017) Krat, S. A.; Gasparyan, Yu. M.; Vasina, Ya. A.; Pisarev, A. A.; Писарев, Александр Александрович; Крат, Степан Андреевич; Гаспарян, Юрий МикаэловичDeposition of a single element film is always accompanied by co-deposition of a certain amount of other elements. This can be done properly to improve properties of the coating or due to contamination by impurities. In the field of thermonuclear fusion research, where hydrogen isotopes are used as a fuel, co-deposition with sputtered material from the wall is one of major mechanisms of hydrogen isotopes accumulation in the installation. Since D-T fuel will be used in ITER and future fusion reactors, accumulation of radioactive tritium will limit the lifespan of the installations due to safety concerns. For example, tritium accumulation in ITER is limited by 1 kg. This is why carbon materials were not accepted for the use in ITER. Basing on experiments, it was predicted that the safety limit could be reached after 100 of shots with tritium. Recent experiments in JET [1] demonstrated in the case of “ITER-like” wall (first wall – Be, divertor area - tungsten) accumulation of deuterium fuel in the co-deposits was 20 times lower than in the full-carbon wall campaign. This is both due to smaller amount of co-deposits and smaller concentration of deuterium in them.
- ПубликацияТолько метаданныеAccumulation of Deuterium and Helium in Co-Deposited W Layers Formed in He-Seeded Deuterium Plasma(2022) Krat, S. A.; Fefelova, E. A.; Prishvitcyn, A. S.; Khomyakov, A. K.; Gasparyan, Y. M.; Pisarev, A. A.; Крат, Степан Андреевич; Пришвицын, Александр Сергеевич; Гаспарян, Юрий Микаэлович; Писарев, Александр Александрович© 2022, Allerton Press, Inc.Abstract: The effect He in plasma has on the co-deposition of D–W films is investigated for the room–800 K range of substrate temperatures and two He/D2 ratios of 5 and 20%. He can both raise and lower the content of D in a film, and a mechanism is proposed for this effect. The ratio of He/D in the film is higher than in gas, due to the stronger diffusivity and bonding energy of He. A similarity is observed between the dependences of D and He content on temperature, and it is suggested that the low temperature release of D and He during TDS could be due to annealing-induced relaxation of stresses in the film structure. It is expected that the desorption of He above 1300 K could lead to underestimates of the He content.
- ПубликацияТолько метаданныеLithium-deuterium co-deposition(2023) Krat, S. A.; Popkov, A. S.; Vasina, Y. A.; Gasparyan, Y. M.; Pisarev, A. A.; Крат, Степан Андреевич; Гаспарян, Юрий Микаэлович; Писарев, Александр Александрович