Exposure of tungsten surface to high-flux of helium and argon ions
Present work investigates the erosion yields of tungsten exposed to intense beams of He and Ar ions using weight-loss measurements. The ion beams were generated by FALCON ion source, typical particle fluxes were in the range of (0.4…1.0)×10²²m⁻²•s⁻¹ and the heat fluxes were 0.3…0.8 MW∙m⁻². Investiga...
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| Опубліковано в: : | Вопросы атомной науки и техники |
|---|---|
| Дата: | 2014 |
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| Мова: | Англійська |
| Опубліковано: |
Національний науковий центр «Харківський фізико-технічний інститут» НАН України
2014
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| Цитувати: | Exposure of tungsten surface to high-flux of helium and argon ions / I.O. Bizyukov, O.I. Girka, R.I. Starovoitov, O.A. Bizyukov, V.V. Bobkov // Вопросы атомной науки и техники. — 2014. — № 6. — С. 80-82. — Бібліогр.: 13 назв. — англ. |
Репозитарії
Digital Library of Periodicals of National Academy of Sciences of Ukraine| _version_ | 1860128055041720320 |
|---|---|
| author | Bizyukov, I.O. Girka, O.I. Starovoitov, R.I. Bizyukov, O.A. Bobkov, V.V. |
| author_facet | Bizyukov, I.O. Girka, O.I. Starovoitov, R.I. Bizyukov, O.A. Bobkov, V.V. |
| citation_txt | Exposure of tungsten surface to high-flux of helium and argon ions / I.O. Bizyukov, O.I. Girka, R.I. Starovoitov, O.A. Bizyukov, V.V. Bobkov // Вопросы атомной науки и техники. — 2014. — № 6. — С. 80-82. — Бібліогр.: 13 назв. — англ. |
| collection | DSpace DC |
| container_title | Вопросы атомной науки и техники |
| description | Present work investigates the erosion yields of tungsten exposed to intense beams of He and Ar ions using weight-loss measurements. The ion beams were generated by FALCON ion source, typical particle fluxes were in the range of (0.4…1.0)×10²²m⁻²•s⁻¹ and the heat fluxes were 0.3…0.8 MW∙m⁻². Investigations show that the erosion yield for He ions is in line with simulations and experimental literature data on physical sputtering, while for Ar bombardment one has observed lower erosion yields. The morphology of the surface has also been studied with SEM.
Исследуются коэффициенты эрозии вольфрама, измеренные с помощью метода потери веса. Образцы облучались интенсивными пучками ионов Не и Ar. Ионные пучки генерировались ионным источником FALCON, при этом плотность потока ионов составляла (0,4…1,0)×10²² м⁻²•с⁻¹, а тепловой поток на поверхность составлял 0,3…0,8 MВт∙м⁻². Исследования показали, что эрозия вольфрама под воздействием ионов Не соответствует результатам экспериментов и литературным данным по физическому распылению, в то время как при бомбардировке ионами Ar коэффициенты эрозии ниже.
Досліджено коефіцієнти ерозії вольфраму, виміряні за допомогою методу втрати маси. Зразки опромінювались інтенсивними пучками іонів He та Ar. Іонні пучки з густиною потоку іонів (0,4…1,0)×10²² м⁻²•с⁻¹, та тепловими потоками 0,3…0,8 MВт∙м⁻² генерувались джерелом іонів FALCON. Дослідження показали, що ерозія вольфраму під дією іонів He узгоджується з результатами інших експериментів та літературними даними з фізичного розпилення. За умови бомбардування іонами Ar здобуті коефіцієнти ерозії виявились меншими за очікувані майже вдвічі. Морфологію опромінених поверхонь було досліджено за допомогою РЕМ.
|
| first_indexed | 2025-12-07T17:42:43Z |
| format | Article |
| fulltext |
ISSN 1562-6016. ВАНТ. 2014. №6(94)
80 PROBLEMS OF ATOMIC SCIENCE AND TECHNOLOGY. 2014, №6. Series: Plasma Physics (20), p. 80-82.
EXPOSURE OF TUNGSTEN SURFACE TO HIGH-FLUX OF HELIUM
AND ARGON IONS
I.O. Bizyukov, O.I. Girka, R.I. Starovoitov, O.A. Bizyukov, V.V. Bobkov
V.N. Karazin Kharkiv National University, Kharkiv, Ukraine
E-mail: ivan.bizyukov@karazin.ua
Present work investigates the erosion yields of tungsten exposed to intense beams of He and Ar ions using weight-
loss measurements. The ion beams were generated by FALCON ion source, typical particle fluxes were in the range of
(0.4…1.0)×10
22
m
2
·s
1
and the heat fluxes were 0.3…0.8 MW·m
2
. Investigations show that the erosion yield for He
ions is in line with simulations and experimental literature data on physical sputtering, while for Ar bombardment one
has observed lower erosion yields. The morphology of the surface has also been studied with SEM.
PACS: 79.20 Rf
INTRODUCTION
The long-term solution of the energy problem is
tightly connected to International Thermonuclear
Experimental Reactor (ITER) which is currently under
construction at its site in Cadarache, France. ITER
operation and discharge regimes are under investigation
still. Stability of the plasma-facing materials exposed to
high particle fluxes and fluence is one of the problems
which need to be addressed by ITER. It has been agreed
that tungsten surface will be used at least in the divertor
region [1] where particle and heat loads are rather
intense. Preliminary estimations show that these
components will be exposed to particle fluxes in the
range of 10
20
…10
23
m
2
·s
1
, while heat fluxes will be up
to 3 MW·m
2
[2]. The total number of discharges should
be about 10
4
with the average duration of the each pulse
up to 400 s according to currently existing specifications
of ITER. This results in total particle fluence of
10
27
…10
30
m
2
·s
1
.
The given fluence range for the divertor component
could be used to evaluate its lifetime based on physical
sputtering. Unfortunately, this range has not been
investigated with laboratory devices, which may
provide suitable accuracy for measurement of the
erosion yields. The ion beam setups like HiFIT could
provide particle fluxes up to 3.6×10
21
m
2
·s
1
at the
energy of kilo electron volt range [3]. Various plasma
devices can provide much lower energies for the particle
fluxes of ≈10
22
m
2
·s
11
and above [4-6]. As an
intermediate solution, FALCON ion source has been
developed to provide the fluxes typical for plasma
devices, however, at kilo electron volt range [7, 8]. It is
based on design of closed drift thrusters (also known as
Hall thrusters), which are typically used as space
propulsions [9]. In contrast to plasma devices, its
simplicity and compactness allow it to be installed
virtually on any vacuum system and provide the setup
for the fusion oriented plasma-material research.
Present work continues our previous studies with the
bombardment of tungsten surface with hydrogen ions in
the high-flux range [10]. It is supposed that this range
can contain new effects, which influence the material
erosion and, therefore, the long-term lifetime of the
plasma facing components. In this work the
investigation is further extended to helium and argon
ion fluxes, and the erosion of the surface is studied by
both weight-loss method and ex-situ post bombardment
scanning electron microscopy. The obtained results are
further compared to experimental data from literature as
well as to the results of the computer simulations based
on binary-collision approximations. This allows
identifying the deviations from pure physical sputtering,
which can be the indication of new mechanisms
influencing the surface erosion.
1. METHODS
The tungsten samples were exposed to the ion beam
generated by FALCON ion source. The discharge gap
was filled with He or Ar working gas. The acceleration
voltage was 5.4 keV and the average energy of the ion
beam was 2.2 keV. The ion flux for He was in the range
of (0.4…0.5)×10
22
m
2
·s
1
and the heat flux was
0.3…0.4 MW·m
2
. This led to the increase of the
sample temperature up to 770°K. The particle flux for
Ar ion beam was 10
22
m
2
s
1
and the heat flux was
about 0.8 MW·m
2
. Therefore, the sample exposed to Ar
ion beam heats up to a temperature of 970 K. Both ion
beams had irradiated the samples up to the fluence
above 10
26
m
2
·s
1
.
The samples were made of polycrystalline tungsten
manufactured by Plansee with a purity of 99.999 % wt.
This material was proposed for ITER. The dimensions
of the samples were 12×15×0.8 mm. The grain sizes
were estimated to be in the range of 5…20 µm. All
specimens were mechanically polished to the mirror-
like surface. The temperature of the sample was
evaluated basing on Stephan-Boltzmann law and
preliminary measurements with thermocouple, see
details in [10].
The erosion yield has been measured by using ex-
situ weight-loss measurements before and after the
exposure. The absolute accuracy of the weight
measurements was ±5 µg, while typical weigh-change
of the sample before and after the exposure was well
above 1 mg. The charge collection measurements are
assumed being a good representative of total number of
incident particles. Details of ion beam characterization
could be found in [8]. Therefore, weight-loss
measurements of erosion introduce negligible errors
under given conditions.
ISSN 1562-6016. ВАНТ. 2014. №6(94) 81
After the exposure, the surface of the samples has
been examined with scanning electron microscopy
(SEM).
2. RESULTS AND DISCUSSION
Results of erosion yield measurement are shown in
Fig. 1. Bombardment of W samples with He ion beam
has been performed in a few steps to evaluate the
fluence dependent erosion yield. The data are compared
to TRIDYN simulations [11] and experimental data
taken from [12].
Fig. 1,a shows the fluence dependent erosion yield
of W sample exposed to He ion beam. Experimentally
measured erosion yield is stable in the fluence range up
to 10
26
m
2
, and it is in a good agreement with the
results of simulation. Fig. 1,b shows the experimentally
measured data against the energy dependent sputtering
yield as obtained by simulations and experimental data
[12]. One can see that the measured erosion yields are in
a good agreement with data for physical sputtering and
could be well explained by this phenomenon.
Fig. 1. Sputtering yields: (a) as a function of fluence for
W sample exposed to He ions; (b) comparison of data
for He ions bombarding W; (c) comparison of data for
Ar ions bombarding W
At the same time erosion of W sample with Ar ion
beam shows the yield which is somewhat lower than
results of simulations and literature data [12]. Generally,
erosion of W with heavy noble gases is well reproduced
by the simulations with programs based on binary-
collision approximation. Therefore, the observed
difference could not be explained by the experimental
errors and the possible low amount of light impurities,
which potentially decrease the measured erosion yield.
Most probable explanation of the observed lower sputter
yield is the high particle and heat fluxes. At the same
time, the temperature of the surface has possibly not
contributed to observed decrease, because similar
surface temperature has been reached during exposure
with He and with H ion beams [10].
Fig. 2 shows the morphology of the surface after the
exposure as obtained by SEM. The morphology of the
sample exposed to He ions is shown in Fig. 2,a. This
surface is typical for sputter erosion mechanism. Similar
morphology has been observed in [10], where W
surface has been exposed to high-flux H ion beam.
Surface shows no blisters or other features which can be
found on the surface exposed to He ion flux.
On the other hand, recently carried out experiments
on bombardment of the W surface with high heat and
particle fluxes of H-He mixture [13] have shown that
the measured erosion yield exceeds the yield for
physical sputtering only by factor of two. This might be
explained by origination of the features on the surface
and consequent increase of the local angle of incidence.
Fig. 2. The SEM images of W surface exposed to:
(a) He ion beam; (b) Ar ion beam
The morphology of W surface exposed to Ar ion
beam is shown see in Fig. 2,b. One can observe small
pores and cracks with typical dimension of ≈1 µm.
Similar defects had not been observed in case of
irradiation of W surface either with H ions [10] or with
He ions. Therefore, factors like surface temperature or
high flux have not resulted in production of such
features. Origination of the features might be explained
by factors like mass of the incident ions and/or amount
of the sputtered atoms from the surface.
CONCLUSIONS
The tungsten samples were irradiated with keV ion
beams featuring He or Ar species. The beam has been
generated by FALCON ion source with typical particle
fluxes of (0.4…1.0)×10
22
m
2
s
1
and the heat fluxes of
0.3…0.8 MW·m
2
. The heat fluxes elevate the
temperature of the samples up to 770…970 K. The long
exposure with intense particle flux allowed reaching
fluence above 10
26
m
2
.
The weight-loss measurements have shown nearly
constant erosion yield for He ion beam as fluence
82 ISSN 1562-6016. ВАНТ. 2014. №6(94)
increases. The measured erosion yields have been
compared to experimental data taken from literature and
to the results of the simulation. Erosion yield of
tungsten with He ion beam is in a good agreement with
data for physical sputtering. At the same time erosion
yields produced by Ar ion beam are below yields for
physical sputtering by factor of two. The morphology of
the surface exposed to He ion beam has been found to
be typical for erosion produced by physical sputtering.
In contrast, bombardment of the W surface with Ar ion
beam produces pores and cracks with typical dimension
of 1 µm.
Therefore, high-flux and high-fluence exposure of
the tungsten with Ar ions can involve the effects, which
decrease the erosion while He ion flux does not
demonstrate this kind of effects limiting its influence
within the physical sputtering.
REFERENCES
1. R.E.H. Clark, D.H. Reiter. Nuclear Fusion Research:
Understanding plasma surface interactions. Springer,
2005.
2. G. Federici et.al. Plasma-material interactions in
current tokamaks and their implications for next step
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2002, v. 73, p. 1741-1745.
4. G.M. Wright, D.G. Whyte, B. Lipschultz, R.P. Doerner,
and J. G. Kulpin. Dynamics of hydrogenic retention in
molybdenum: First results from DIONISOS // J. Nucl.
Mat. 2007, v. 363-365, p. 977-983.
5. D.M. Goebel, G.A. Campbell, R.W. Conn. Plasma
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6. D. Nishijima, M.Y. Ye, N. Ohno, and S. Takamura.
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333, p. 1029-1033.
7. M. Gutkin, A. Bizyukov, V. Sleptsov, I. Bizyukov,
K. Sereda. Focused anode layer ion source with
converging and charge compensated beam (FALCON).
U.S. Patent № US 7622721 B2, 2009.
8. O. Girka, I. Bizyukov, K. Sereda, A. Bizyukov,
M. Gutkin, V. Sleptsov. Compact steady-state and high-
flux FALCON ion source for tests of plasma-facing
materials // Rev. Sci. Instrum. 2012, v. 83, p. 083501.
9. V.V. Zhurin, H.R. Kaufman, R.S. Robinson. Physics
of closed drift thrusters // Plasma Sources Sci. Technol.
1999, v. 8, p. R1-R20.
10. I. Bizyukov. Sputtering of tungsten exposed to high-
flux and high-fluence hydrogen ion beam // Problems of
Atomic Science and Technology. Ser. ''Plasma Physics''
2013, v. 86. p. 304-307.
11. W. Moeller, W. Eckstein, J.P. Biersack. TRIDYN –
binary collision simulation of atomic collisions and
dynamic composition changes in solids // Comput. Phys.
Commun. 1988, v. 51, p. 355.
12. W. Eckstein, C. Garcia-Rosales, J. Roth,
W. Ottenberg. Sputtering data. IPP Report 9/82
Garching, Max-Planck-Institute for Plasmaphysics,
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13. H. Greuner, H. Maier, M. Balden, B. Boeswirth,
Ch. Linsmeier. Investigation of W components exposed
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Article received 25.09.2014
ОБЛУЧЕНИЕ ПОВЕРХНОСТИ ВОЛЬФРАМА БОЛЬШИМ ПОТОКОМ ИОНОВ АРГОНА И ГЕЛИЯ
И.O. Бизюков, А.И. Гирка, Р.И. Старовойтов, А.А. Бизюков, В.В. Бобков
Исследуются коэффициенты эрозии вольфрама, измеренные с помощью метода потери веса. Образцы
облучались интенсивными пучками ионов Не и Ar. Ионные пучки генерировались ионным источником
FALCON, при этом плотность потока ионов составляла (0,4…1,0)×10
22
м
-2
·с
-1
, а тепловой поток на
поверхность составлял 0,3…0,8 MВт·м
2
. Исследования показали, что эрозия вольфрама под воздействием
ионов Не соответствует результатам экспериментов и литературным данным по физическому распылению, в
то время как при бомбардировке ионами Ar коэффициенты эрозии ниже ожидаемых приблизительно в два
раза. Морфология поверхности была исследована с помощью РЭМ.
ОПРОМІНЕННЯ ПОВЕРХНІ ВОЛЬФРАМУ ВЕЛИКИМ ПОТОКОМ ІОНІВ АРГОНУ ТА ГЕЛІЮ
І.О. Бізюков, О.І. Гірка, Р.І. Старовойтов, О.О. Бізюков, В.В. Бобков
Досліджено коефіцієнти ерозії вольфраму, виміряні за допомогою методу втрати маси. Зразки
опромінювались інтенсивними пучками іонів He та Ar. Іонні пучки з густиною потоку іонів
(0,4…1,0)×10
22
м
2
·с
1
та тепловими потоками 0,3…0,8 MВт·м
2
генерувались джерелом іонів FALCON.
Дослідження показали, що ерозія вольфраму під дією іонів He узгоджується з результатами інших
експериментів та літературними даними з фізичного розпилення. За умови бомбардування іонами Ar здобуті
коефіцієнти ерозії виявились меншими за очікувані майже вдвічі. Морфологію опромінених поверхонь було
досліджено за допомогою РЕМ.
|
| id | nasplib_isofts_kiev_ua-123456789-81202 |
| institution | Digital Library of Periodicals of National Academy of Sciences of Ukraine |
| issn | 1562-6016 |
| language | English |
| last_indexed | 2025-12-07T17:42:43Z |
| publishDate | 2014 |
| publisher | Національний науковий центр «Харківський фізико-технічний інститут» НАН України |
| record_format | dspace |
| spelling | Bizyukov, I.O. Girka, O.I. Starovoitov, R.I. Bizyukov, O.A. Bobkov, V.V. 2015-05-13T15:56:00Z 2015-05-13T15:56:00Z 2014 Exposure of tungsten surface to high-flux of helium and argon ions / I.O. Bizyukov, O.I. Girka, R.I. Starovoitov, O.A. Bizyukov, V.V. Bobkov // Вопросы атомной науки и техники. — 2014. — № 6. — С. 80-82. — Бібліогр.: 13 назв. — англ. 1562-6016 PACS: 79.20 Rf https://nasplib.isofts.kiev.ua/handle/123456789/81202 Present work investigates the erosion yields of tungsten exposed to intense beams of He and Ar ions using weight-loss measurements. The ion beams were generated by FALCON ion source, typical particle fluxes were in the range of (0.4…1.0)×10²²m⁻²•s⁻¹ and the heat fluxes were 0.3…0.8 MW∙m⁻². Investigations show that the erosion yield for He ions is in line with simulations and experimental literature data on physical sputtering, while for Ar bombardment one has observed lower erosion yields. The morphology of the surface has also been studied with SEM. Исследуются коэффициенты эрозии вольфрама, измеренные с помощью метода потери веса. Образцы облучались интенсивными пучками ионов Не и Ar. Ионные пучки генерировались ионным источником FALCON, при этом плотность потока ионов составляла (0,4…1,0)×10²² м⁻²•с⁻¹, а тепловой поток на поверхность составлял 0,3…0,8 MВт∙м⁻². Исследования показали, что эрозия вольфрама под воздействием ионов Не соответствует результатам экспериментов и литературным данным по физическому распылению, в то время как при бомбардировке ионами Ar коэффициенты эрозии ниже. Досліджено коефіцієнти ерозії вольфраму, виміряні за допомогою методу втрати маси. Зразки опромінювались інтенсивними пучками іонів He та Ar. Іонні пучки з густиною потоку іонів (0,4…1,0)×10²² м⁻²•с⁻¹, та тепловими потоками 0,3…0,8 MВт∙м⁻² генерувались джерелом іонів FALCON. Дослідження показали, що ерозія вольфраму під дією іонів He узгоджується з результатами інших експериментів та літературними даними з фізичного розпилення. За умови бомбардування іонами Ar здобуті коефіцієнти ерозії виявились меншими за очікувані майже вдвічі. Морфологію опромінених поверхонь було досліджено за допомогою РЕМ. en Національний науковий центр «Харківський фізико-технічний інститут» НАН України Вопросы атомной науки и техники Динамика плазмы и взаимодействие плазма-стенка Exposure of tungsten surface to high-flux of helium and argon ions Облучение поверхности вольфрама большим потоком ионов аргона и гелия Опромінення поверхні вольфраму великим потоком іонів аргону та гелію Article published earlier |
| spellingShingle | Exposure of tungsten surface to high-flux of helium and argon ions Bizyukov, I.O. Girka, O.I. Starovoitov, R.I. Bizyukov, O.A. Bobkov, V.V. Динамика плазмы и взаимодействие плазма-стенка |
| title | Exposure of tungsten surface to high-flux of helium and argon ions |
| title_alt | Облучение поверхности вольфрама большим потоком ионов аргона и гелия Опромінення поверхні вольфраму великим потоком іонів аргону та гелію |
| title_full | Exposure of tungsten surface to high-flux of helium and argon ions |
| title_fullStr | Exposure of tungsten surface to high-flux of helium and argon ions |
| title_full_unstemmed | Exposure of tungsten surface to high-flux of helium and argon ions |
| title_short | Exposure of tungsten surface to high-flux of helium and argon ions |
| title_sort | exposure of tungsten surface to high-flux of helium and argon ions |
| topic | Динамика плазмы и взаимодействие плазма-стенка |
| topic_facet | Динамика плазмы и взаимодействие плазма-стенка |
| url | https://nasplib.isofts.kiev.ua/handle/123456789/81202 |
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