Implantation of deuterium and helium ions into composite structure with tantalum coating

Processes of retention and thermal release of implanted deuterium and helium from tantalum coatings of multilayer composite structure by thermodesorption spectrometry were investigated. The dependences of amount of accumulated deuterium and helium, and the shape of thermal desorption spectra as func...

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Published in:Вопросы атомной науки и техники
Date:2018
Main Authors: Bobkov, V.V., Tishchenko, L.P., Kovtunenko, Yu.I., Tsapenko, O.B., Skrypnik, A.O., Logachev, Yu.E., Gamayunova, L.A.
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Language:English
Published: Національний науковий центр «Харківський фізико-технічний інститут» НАН України 2018
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Online Access:https://nasplib.isofts.kiev.ua/handle/123456789/148847
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Cite this:Implantation of deuterium and helium ions into composite structure with tantalum coating / V.V. Bobkov, L.P. Tishchenko, Yu.I. Kovtunenko, O.B. Tsapenko, A.O. Skrypnik, Yu.E. Logachev, L.A. Gamayunova // Вопросы атомной науки и техники. — 2018. — № 6. — С. 63-66. — Бібліогр.: 11 назв. — англ.

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Digital Library of Periodicals of National Academy of Sciences of Ukraine
id nasplib_isofts_kiev_ua-123456789-148847
record_format dspace
spelling Bobkov, V.V.
Tishchenko, L.P.
Kovtunenko, Yu.I.
Tsapenko, O.B.
Skrypnik, A.O.
Logachev, Yu.E.
Gamayunova, L.A.
2019-02-18T20:10:56Z
2019-02-18T20:10:56Z
2018
Implantation of deuterium and helium ions into composite structure with tantalum coating / V.V. Bobkov, L.P. Tishchenko, Yu.I. Kovtunenko, O.B. Tsapenko, A.O. Skrypnik, Yu.E. Logachev, L.A. Gamayunova // Вопросы атомной науки и техники. — 2018. — № 6. — С. 63-66. — Бібліогр.: 11 назв. — англ.
1562-6016
PACS: 61.80.-x, 61.80.Jh
https://nasplib.isofts.kiev.ua/handle/123456789/148847
Processes of retention and thermal release of implanted deuterium and helium from tantalum coatings of multilayer composite structure by thermodesorption spectrometry were investigated. The dependences of amount of accumulated deuterium and helium, and the shape of thermal desorption spectra as functions of the D⁺ and He⁺ ions fluencies and of the temperature of irradiation were shown. Possible mechanisms of these processes are proposed.
Методом термодесорбційної спектрометрії досліджено процеси накопичення і виділення дейтерію та гелію у вакуум із танталових покриттів композиційної структури. Кількість накопиченого дейтерію та гелію і вигляд спектрів термічної десорбції показано в залежності від дози опромінення іонами D⁺ або He⁺ та температури зразка при опроміненні. Запропоновано можливі механізми цих процесів.
Методом термодесорбционной спектрометрии исследованы процессы накопления и выделения дейтерия и гелия в вакуум из танталовых покрытий композиционной структуры. Количество накопленного дейтерия и гелия и вид спектров термической десорбции показаны в зависимости от дозы облучения ионами D⁺ или He⁺ и температуры образца при облучении. Предложены возможные механизмы этих процессов.
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Національний науковий центр «Харківський фізико-технічний інститут» НАН України
Вопросы атомной науки и техники
ИТЭР и приложения для термоядерного реактора
Implantation of deuterium and helium ions into composite structure with tantalum coating
Імплантація іонів дейтерію та гелію в композиційну структуру з танталовим покриттям
Имплантация ионов дейтерия и гелия в композиционную структуру с танталовым покрытием
Article
published earlier
institution Digital Library of Periodicals of National Academy of Sciences of Ukraine
collection DSpace DC
title Implantation of deuterium and helium ions into composite structure with tantalum coating
spellingShingle Implantation of deuterium and helium ions into composite structure with tantalum coating
Bobkov, V.V.
Tishchenko, L.P.
Kovtunenko, Yu.I.
Tsapenko, O.B.
Skrypnik, A.O.
Logachev, Yu.E.
Gamayunova, L.A.
ИТЭР и приложения для термоядерного реактора
title_short Implantation of deuterium and helium ions into composite structure with tantalum coating
title_full Implantation of deuterium and helium ions into composite structure with tantalum coating
title_fullStr Implantation of deuterium and helium ions into composite structure with tantalum coating
title_full_unstemmed Implantation of deuterium and helium ions into composite structure with tantalum coating
title_sort implantation of deuterium and helium ions into composite structure with tantalum coating
author Bobkov, V.V.
Tishchenko, L.P.
Kovtunenko, Yu.I.
Tsapenko, O.B.
Skrypnik, A.O.
Logachev, Yu.E.
Gamayunova, L.A.
author_facet Bobkov, V.V.
Tishchenko, L.P.
Kovtunenko, Yu.I.
Tsapenko, O.B.
Skrypnik, A.O.
Logachev, Yu.E.
Gamayunova, L.A.
topic ИТЭР и приложения для термоядерного реактора
topic_facet ИТЭР и приложения для термоядерного реактора
publishDate 2018
language English
container_title Вопросы атомной науки и техники
publisher Національний науковий центр «Харківський фізико-технічний інститут» НАН України
format Article
title_alt Імплантація іонів дейтерію та гелію в композиційну структуру з танталовим покриттям
Имплантация ионов дейтерия и гелия в композиционную структуру с танталовым покрытием
description Processes of retention and thermal release of implanted deuterium and helium from tantalum coatings of multilayer composite structure by thermodesorption spectrometry were investigated. The dependences of amount of accumulated deuterium and helium, and the shape of thermal desorption spectra as functions of the D⁺ and He⁺ ions fluencies and of the temperature of irradiation were shown. Possible mechanisms of these processes are proposed. Методом термодесорбційної спектрометрії досліджено процеси накопичення і виділення дейтерію та гелію у вакуум із танталових покриттів композиційної структури. Кількість накопиченого дейтерію та гелію і вигляд спектрів термічної десорбції показано в залежності від дози опромінення іонами D⁺ або He⁺ та температури зразка при опроміненні. Запропоновано можливі механізми цих процесів. Методом термодесорбционной спектрометрии исследованы процессы накопления и выделения дейтерия и гелия в вакуум из танталовых покрытий композиционной структуры. Количество накопленного дейтерия и гелия и вид спектров термической десорбции показаны в зависимости от дозы облучения ионами D⁺ или He⁺ и температуры образца при облучении. Предложены возможные механизмы этих процессов.
issn 1562-6016
url https://nasplib.isofts.kiev.ua/handle/123456789/148847
citation_txt Implantation of deuterium and helium ions into composite structure with tantalum coating / V.V. Bobkov, L.P. Tishchenko, Yu.I. Kovtunenko, O.B. Tsapenko, A.O. Skrypnik, Yu.E. Logachev, L.A. Gamayunova // Вопросы атомной науки и техники. — 2018. — № 6. — С. 63-66. — Бібліогр.: 11 назв. — англ.
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last_indexed 2025-11-26T16:39:27Z
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fulltext ISSN 1562-6016. ВАНТ. 2018. №6(118) PROBLEMS OF ATOMIC SCIENCE AND TECHNOLOGY. 2018, № 6. Series: Plasma Physics (118), p. 63-66. 63 IMPLANTATION OF DEUTERIUM AND HELIUM IONS INTO COMPOSITE STRUCTURE WITH TANTALUM COATING V.V. Bobkov, L.P. Tishchenko, Yu.I. Kovtunenko, O.B. Tsapenko, A.O. Skrypnik, Yu.E. Logachev, L.A. Gamayunova V.N. Karazin Kharkiv National University, Kharkiv, Ukraine E-mail: bobkov@karazin.ua Processes of retention and thermal release of implanted deuterium and helium from tantalum coatings of multi- layer composite structure by thermodesorption spectrometry were investigated. The dependences of amount of ac- cumulated deuterium and helium, and the shape of thermal desorption spectra as functions of the D+ and He+ ions fluencies and of the temperature of irradiation were shown. Possible mechanisms of these processes are proposed. PACS: 61.80.-x, 61.80.Jh INTRODUCTION Tantalum and tungsten are considered [1-4] as the materials used for protective coatings of structures facing the plasma in CTF facilities. One of the ad- vantages of their application is the insignificant accu- mulation of hydrogen isotopes in them under the effect of plasma flows. Being actual, this problem is studied intensively [1-7] to increase the radiation resistance of CTF facilities and to obtain new materials with im- proved parameters while using the ion implantation technique. In [5-8] we carried out comprehensive anal- ysis of the radiation defects formation in matrix, of capture, retention, and thermal desorption of ion- implanted deuterium and helium in tungsten coatings of multilayer composite systems. In this paper the pro- cesses accompanying the implantation of deuterium and helium ions into the composite structures with tantalum coating: capture, retention and release of the implanted gases from the coating were studied. The effects of the irradiation dose of D+ and He+ ions and the temperature of the sample on the above processes under irradiation were shown. The processes of accu- mulation and retention of deuterium and helium under the ion irradiation and of the thermal desorption of these gases from Ta and W coatings at the subsequent heating were compared. The types of the matrix radia- tion damage were determined; their influence on the coatings structural features was shown. 1. EXPERIMENTS The studies were carried out on tantalum coatings obtained by magnetron sputtering of Ta target in the Ar atmosphere at the pressure of 1.0 Pa. The deposition was carried out at the rate of 0.6 nm/s at the tempera- ture T = 600 K on a 0.8 mm thick stainless steel sub- strate with a Ti interlayer of less than 10 nm thickness predeposited on it. The thickness of the tantalum coat- ings under study was 1.5 μm. The composite structure with a Ta coating was marked as (SSt + Ta). The sam- ples were irradiated by ion beams of 20 keV He+ or 20 keV D2 + (10 keV D+), at the current density of  5 μA/cm2 to the doses Ф within the interval of (0.1…1.1) × 1018 cm-2. Deuterium ions were implanted into the tantalum coatings at the sample temperatures To: 290, 370, 470, 570, and 670 K. According to the calculations in [9] for the ions D+ (10 keV) and He+ (20 keV) the mean projective ranges of the ion in the tantalum coatings were about 60 nm, and total ones were about 160 nm. They were comparable for the ions under study and much shorter than the coating thick- ness. In the studies, the method of thermodesorption spectrometry (TDS) was used. Thermodesorption spec- tra of helium and deuterium were obtained using PTI- 7A gas mass spectrometer calibrated with a helium leak valve GELIT-1, applying the data of [10] on the ionization cross section of helium and deuterium parti- cles in the ion source of this mass spectrometer. The spectra of thermal desorption of helium and deuterium were obtained, and the values of the concentration C and of the capture coefficient η = C/Ф of the implanted gases were determined. The studies of helium and deuterium thermal desorption were carried out by heat- ing the irradiated samples at the constant rate α = 0.8 K/s in the temperature range of 290…1800 K. The spectra represent the dependences of the number of S particles of the implanted gas released at the given heating temperature T on this temperature. The error of the temperature measuring is ± 25 K. The sensitivity of the technique used to determine S is not worse than 2 × 1012 cm-2. When the unirradiated samples were heated in the same temperature range, the maximum of background intensity for ions with m = 4 a.m.u. did not exceed S = 0.003 × 1016 cm-2. 2. RESULTS AND DISCUSSION When a composite structure with the tantalum coat- ing irradiated by D+ or He+ ions is heated, thermal release of the gases implanted into the vacuum is ob- served. Fig. 1 shows the spectra of deuterium thermal desorption from the tantalum coating of the composi- tion (SSt + Ta) (curves 1-5). For comparison, the data on thermal desorption from the tungsten coating of the composition (SSt + W) (curves 1'-6') taken from [8] are given. The compared samples were irradiated at the room temperature by D+ ions with the same energy to different doses. mailto:bobkov@karazin.ua 64 ISSN 1562-6016. ВАНТ. 2018. №6(118) The spectra of the deuterium thermal desorption from the tantalum coating of the same composite struc- ture, irradiated by D+ ions with the same dose (ФD+ = 2.0 × 1017 cm-2) but at different temperatures of the samples during deuterium implantation, are shown in Fig. 2. 0 0.2 0.4 0.6 0.8 1 200 400 600 800 1000 1200 1400 1600 T , K S , 1 0 1 6 c m -2 5' 2' 1' 4' 3' 6' 1 2 3 4 5 Fig. 1. The spectra of the deuterium thermal desorption from the Ta coating irradiated with D+ ions (ФD+, 1017 m-2: 1 – 1.0; 2 – 2.0; 3 – 4.0; 4 – 8.0; 5 – 11.0) and, according to [8], from the W coating irradiated with D+ ions (ФD+, 1017 cm-2: 1' – 1.0; 2' – 2.0; 3' – 3.0; 4' – 4.0; 5' – 5.0; 6' – 7.0); α = 0.8 K/s 0 0.05 0.1 0.15 200 400 600 800 1000 1200 1400 1600 T , K S , 1 0 1 6 c m -2 1 2 3 4 5 Fig. 2. The spectra of the deuterium thermal desorption from the Ta coating irradiated with D+ ions (ФD+, 2.0 × 1017 cm-2) at different temperatures of irradiation To, K: 1 – 290; 2 – 370; 3 – 470; 4 – 570; 5 – 670; α = 0.8 K/s Figs. 1 and 2 show, that a noticeable release of deu- terium from the tantalum coating starts at temperatures T ≥ 620 K and finished at T ≈ 1200 K (curves 1-5). The maximal thermal desorption of deuterium is observed at the temperature Tm ≈ 770 K. According to [8], a noticeable deuterium release from the tungsten coating starts at temperatures T ≥ 320 K and finished at T ≈ 1000 K (see Fig. 1, curves 1′-6'). The peak of ther- mal desorption of deuterium from the W coating has its maximum at Tm ≈ 640 K. The thermal desorption spectra of the deuterium, whose ions are implanted into Ta or W coatings at the irradiation doses not exceeding 11.0 × 1017 cm-2 for Ta and 7.0 × 1017 cm-2 for W, have the form of a single- peak dependence. For the peak of deuterium release from the Ta coating Tm shifts to a higher temperature, and the peak intensity is about a half of the thermal desorption peak from tungsten. Fig. 3 shows the spectra of helium thermal desorp- tion from the tantalum coating of the composition (SSt + Ta) (curves 1-4) and, for comparison, the analo- gous results of thermal desorption from the tungsten coating of the composition (SSt + W) (curves 1'-4'), taken from [8]. The compared samples were irradiated at the room temperature by He+ ions of the same ener- gy to different similar doses. 0 2 4 6 8 10 200 400 600 800 1000 1200 1400 1600 1800 T , K S , 1 0 1 6 c m -2 1' 1 2 2' 4 3 3' 4' Fig. 3. The spectra of helium thermal desorption from the Ta coating irradiated with He+ ions (ФHe+, 1017 cm-2: 1 – 1.0; 2 – 1.9; 3 – 4.2; 4 – 6.0) and, according to [8], from the W coating irradiated with He+ ions (ФHe+, 1017 cm-2: 1' – 1.0; 2' – 2.0; 3' – 3.1; 4' – 4.0); α = 0.8 K/s Fig. 3 (curves 1-4) shows, that helium released from the tantalum coating within the temperature range of 1000  ∆T  1800 K. A single peak of helium ther- mal desorption with maximum temperature Tm ≈ 1650 K is observed. A noticeable release of heli- um from the tungsten coating, according to [8], starts at temperatures T ≥ 800 K and finished at T ≈ 1800 K (see Fig. 3, curves 1'-4'). The maximum helium thermal desorption from the W coating occurs at Tm ≈ 1500 K. The comparison of the spectra of He thermal desorp- tion from Ta and W coatings shows, that at the irradia- tion doses, not exceeding 6.0 × 1017 cm-2 for Ta and 4.0 × 1017 cm-2 for W, the spectra of helium thermal desorption have the form of a single-peak dependence. In this case, Tm of the peak of the helium release from the Ta coating shifts to the higher temperatures, as compared with the W coating. Any significant decrease in the peak height is not observed. It was also deter- mined that the deuterium release from the coatings of both types occurs at lower temperatures, as compared to that of helium, (see Figs. 1, 3). Fig. 4 shows the dependences of the concentrations C for deuterium (1, 1') and helium (2, 2'), implanted at the room temperature, on the irradiation dose of D+ and He+ ions for the tantalum coating (curves 1, 2), and for the tungsten coating data taken from [8] (curves 1', 2'). Fig. 5 shows the dependences of the capture coeffi- cient for deuterium ηD (1, 1') and helium ηHe (2, 2') on the dose of irradiation by D+ and He+ ions for Ta coat- ing (curves 1, 2) and, according to [8], for the W coat- ing (curves 1', 2'). As Figs. 4 and 5 show, the values of the concentration C and the helium capture coefficient ηHe are much higher for both tantalum and tungsten coatings than the analogous values of C and ηD for deuterium. As compared to helium, deuterium accumu- ISSN 1562-6016. ВАНТ. 2018. №6(118) 65 lates in the coatings of both materials to a lower con- centration with the capture coefficient of about an order of magnitude lower. With increase of the dose Ф of irradiation by He+ ions, the value of ηHe decreases for both tantalum and tungsten coatings (see Fig. 5, curves 2 and 2'). Some decrease in ηD with an increase in Φ of D+ ions is observed only for the tungsten coat- ing (see Fig. 5, curve 1'). 0 2 4 6 8 0 2 4 6 8 10 12 14 Ф, 10 17 cm -2 C , 10 17 cm -2 2' 2 1 × 5 1' × 5 Fig. 4. Dependences of the concentrations of the implanted deuterium (1, 1') and helium (2, 2') on the dose of irradiation by D+ and He+ ions for the Ta coat- ing – curves 1, 2, and, according to [8], for the W coating – curves 1', 2'; To = 290 K 0 0.2 0.4 0.6 0.8 1 0 2 4 6 8 10 12 14 Ф, 10 17 cm -2 η He, η D 2 1' ×5 1 ×5 2' Fig. 5. The dependences of the capture coefficient of deuterium (1, 1') and helium (2, 2') on the dose of irradiation by D+ and He+ ions for the Ta – curves 1, 2 and, according to [8], for the W coating – curves 1', 2'; To = 290 K The dependences of the capture coefficient of deu- terium ηD on the temperature To of the sample irradiat- ed by D+ ions for the Ta coating are shown in Fig. 6 by curve 1, and for the W coating by curve 2. With in- crease of To some decrease in ηD is observed for both Ta and W coatings. In the analyzed interval ΔTo some more significant (approximately tenfold) decrease in the ηD value for the tungsten coating is observed. 0 0.02 0.04 0.06 200 300 400 500 600 700 T o , K ηD 2 1 Fig. 6. The dependence of the capture coefficient of deuterium on the temperature To of the sample irradi- ated by D+ ions for the Ta coating – curve 1, and for the W coating – curve 2; ФD+ = 2.0 × 1017 cm-2 From the results (see Figs. 4 and 5, curves 2 and 2') it follows, that at To = 290 K for Ta and W coatings, the process of He+ ions implantation into them to various doses in the interval of 1.0 × 1017 ≤ Φ ≤ 1.1 × 1018 cm-2 can be described by the same dependences C = ƒ(Φ) or ηHe = ƒ(Φ) within the measurement error. But D+ ions implantation into the same coatings and at the same temperature To up to different doses in the interval of 1.0 × 1017 ≤ Ф ≤ 1.3 × 1018 cm-2 is not described by the same dependences C = ƒ(Φ) or ηD = ƒ(Φ ). A particu- larly large difference is observed in the dependence ηD = ƒ(Φ). If for the W coating the coefficient of deu- terium capture decreases with the increase of the irra- diation dose of D+ ions, then for the Ta coating it does not change. This may be due to different types of the deuterium solubility: endothermic (W) or exothermic (Ta), and due to the ability to form hydrides in tanta- lum. The authors of this work early carried out electron microscopic studies of changes in the microstructure of W coatings containing deuterium or helium implanted at room temperature (see [11]). The studies showed the formation of interstitial dislocation loops and disloca- tion nets with a mean diameter d ≥ 5 nm and the densi- ty exceeding 3.2 × 1012 cm-2 in the coatings irradiated by D+ ions (ФD+ ≤ 6 × 1018 cm-2) or He+ (ФHe+ < 7.0 × 1017 cm-2) while the formation of deuteri- um and helium bubbles was not observed. The helium bubbles were observed at ФHe+ ≥ 7 × 1017 cm-2; their mean diameter and density were 2.5 nm and 5 × 1012 cm-2, respectively, at ФHe+ = 7 × 1017 cm-2. On the bases of the obtained results, it can be as- sumed that in both Ta and W coatings [8, 11], irradiat- ed by D+ or He+ ions, some radiation defects are formed such as vacancy-type defects and gas-vacancy complexes, which are traps for the implanted gases, as well as the dislocation interstitial loops. CONCLUSIONS The radiation resistance of tantalum coatings of the composite structure (SSt + Ta) to the irradiation by He+ and D+ ions of medium energies at the doses of 1.0 × 1017  Ф  1.1 × 1018 cm-2 and at different temper- atures of the sample under bombardment was studied. The spectra of thermal desorption of deuterium and helium from Ta coatings into the vacuum 66 ISSN 1562-6016. ВАНТ. 2018. №6(118) were studied, and the capture coefficients of these gases in the coating were determined. When implanting D+ and He+ ions into the tantalum coatings it was found, that deuterium accumulates in the coating with the capture coefficient of approximately an order of magnitude lower than helium, and its release from the samples into the vacuum as compared to helium occurs at lower temperatures. It is shown that at Tо= 290 K, the accumulation of He+ ions (1.0 × 1017 ≤ Ф ≤ 1.1 × 1018 cm-2) in the tanta- lum and tungsten coatings is described by the same dependences C = ƒ(Φ) and ηHe = ƒ(Φ) within the meas- urement error. The thermal desorption spectra of heli- um implanted at doses not exceeding 6.0 × 1017 cm-2 (Ta) or 4.0 × 1017 cm-2 (W) are described by single- peak dependences. D+ ion implantation into the same coatings and at the same temperature To up to different doses 1.0 × 1017 ≤ Ф ≤ 1.3 × 1018 cm-2 is not described by the same dependences C = ƒ(Φ) and ηD = ƒ(Φ). In the tantalum coatings irradiated by D+ or He+ ions is supposed the formation of the following radia- tion defects: vacancy-type defects, dislocation intersti- tial loops, gas-vacancy complexes. REFERENCES 1. M. Dias, R. Mateus, et al. Synergistic helium and deuterium blistering in tungsten–tantalum composites // J. Nucl. Mater. 2013, v. 442, issues 1-3, p. 69-74. 2. T.J. Novakowski, J.K. Tripathi, A. 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Article received 11.10.2018 ИМПЛАНТАЦИЯ ИОНОВ ДЕЙТЕРИЯ И ГЕЛИЯ В КОМПОЗИЦИОННУЮ СТРУКТУРУ С ТАНТАЛОВЫМ ПОКРЫТИЕМ В.В. Бобков, Л.П. Тищенко, Ю.И. Ковтуненко, А.Б. Цапенко, А.А. Скрипник, Ю.Е. Логачев, Л.А. Гамаюнова Методом термодесорбционной спектрометрии исследованы процессы накопления и выделения дейтерия и гелия в вакуум из танталовых покрытий композиционной структуры. Количество накопленного дейтерия и гелия и вид спектров термической десорбции показаны в зависимости от дозы облучения ионами D+ или He+ и температуры образца при облучении. Предложены возможные механизмы этих процессов. ІМПЛАНТАЦІЯ ІОНІВ ДЕЙТЕРІЮ ТА ГЕЛІЮ В КОМПОЗИЦІЙНУ СТРУКТУРУ З ТАНТАЛОВИМ ПОКРИТТЯМ В.В. Бобков, Л.П. Тищенко, Ю.І. Ковтуненко, О.Б. Цапенко, А.О. Скрипник, Ю.Є. Логачов, Л.О. Гамаюнова Методом термодесорбційної спектрометрії досліджено процеси накопичення і виділення дейтерію та ге- лію у вакуум із танталових покриттів композиційної структури. Кількість накопиченого дейтерію та гелію і вигляд спектрів термічної десорбції показано в залежності від дози опромінення іонами D+ або He+ та тем- ператури зразка при опроміненні. Запропоновано можливі механізми цих процесів.