Ion-induced deuterium retention in tungsten coatings on carbon substrate

Огородникова, О. В.; Sugiyama, K.; Schwarz-Selinger, T.; Dürbeck, T.; Balden, M.

doi:10.1016/j.jnucmat.2011.07.023

Cited by 30 publications

(41 citation statements)

References 16 publications

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“…In addition to the main release peak around 510 K, all spectra of W films show a shoulder at about 690 K. For the sample W-12 we find a further release peak at about 800 K. The appearance of three desorption peaks suggests the presence of at least three trap energies. These two desorption peaks at 500 and 690 K are typical D 2 release peaks reported for polycrystalline W [12,17,21,[29][30] or W [19][20]31] films. They are assigned to deuterium trapped in intrinsic defects such as grain boundaries and dislocations.…”

Section: Deuterium Retention Measured By Tpdsupporting

confidence: 54%

“…Consequently, the total D amount in bulk W measured by NRA should always be equal to or lower than the value measured by TPD. This assumption has been widely confirmed by different research groups [12,[29][30][31]. But in some cases opposite results were reported [23,[32][33].…”

mentioning

confidence: 77%

“…integrating the D profile over depth [27][28][29][30][31][32]. A drawback of NRA is the limitation of measurable depth.…”

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confidence: 99%

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Comparing deuterium retention in tungsten films measured by temperature programmed desorption and nuclear reaction analysis

Wang

Jacob

Gao

et al. 2013

Nuclear Instruments and Methods in Physics Research Section B:

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Abstract:Tungsten (W) films with thicknesses ranging between 1 and 12 m deposited by magnetron sputtering on silicon substrates were used as a model system for comparing the deuterium (D) retention measured by both temperature programmed desorption (TPD) and nuclear reaction analysis (NRA). Samples were loaded with deuterium ex-situ with an ECR plasma at 370 and 600 K with an energy of 38 eV per deuteron. To avoid diffusion of D into the silicon substrate and to increase adhesion a copper interlayer was applied. The results show that all implanted D atoms were retained exclusively in the W films. The distribution of D is homogenous throughout the W layer with an atomic fraction of 3±0.4×10 -3 . With increasing W thickness the D profile extends to correspondingly larger depths with practically identical D concentration. For W films with a thickness lower than the NRA information depth of about 8 μm the total retained D amount measured by TPD and NRA is in excellent agreement. As expected, for films thicker than the NRA information depth, TPD deviates from NRA.

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Section: Deuterium Retention Measured By Tpdsupporting

confidence: 54%

mentioning

confidence: 77%

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Comparing deuterium retention in tungsten films measured by temperature programmed desorption and nuclear reaction analysis

Wang

Jacob

Gao

et al. 2013

Nuclear Instruments and Methods in Physics Research Section B:

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“…Some results for D retention in W films used in ASDEX Upgrade were published by Ogorodnikova et al [8]. We used W films deposited by magnetron sputtering as a model system to investigate the influence of film structure on the deuterium retention.…”

Section: Introductionmentioning

confidence: 99%

“…However, up to now mostly tungsten coatings were used as first-wall material for the so-called full-metal fusion devices, predominantly due to design limitations and cost concerns. Consequently, the influence of coating structure on the D retention should be taken into account.Some results for D retention in W films used in ASDEX Upgrade were published by Ogorodnikova et al [8]. We used W films deposited by magnetron sputtering as a model system to investigate the influence of film structure on the deuterium retention.…”

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confidence: 99%

Deuterium retention in tungsten films deposited by magnetron sputtering

et al. 2014

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Abstract:Deuterium retention in tungsten films deposited on polycrystalline bulk tungsten substrates was investigated and compared with deuterium retention in W films deposited on silicon and in polycrystalline bulk W alone. The structure of the deposited films was investigated by X-ray diffraction and scanning electron microscopy combined with focused ion beam cutting. D retention after implantation was measured by nuclear reaction analysis and temperature programmed desorption (TPD). The W films deposited on bulk W show a typical columnar epitaxial growth. After D implantation, high densities of blisters with diameters of about hundred µm were formed. Interestingly, the blisters are located within the W substrate well below the interface of deposited film and substrate. TPD spectroscopy reveals two D 2 release peaks at 510 and 700 K, indicating at least two different trap energies. Keywords IntroductionBecause retention of large quantities of tritium in the first-wall materials increases the fuel costs of a reactor and presents a safety concern, understanding of the fuel-retention properties of first-wall materials is important for ITER and next step fusion reactors such as DEMO [1][2][3]. Due to its favourable physical properties, such as low erosion yield and high melting temperature, tungsten is under consideration for use as plasma-facing material in the ITER divertor. Actually, a full tungsten inner wall and a full tungsten divertor have already been successfully developed and tested in ASDEX Upgrade and JET, respectively [4][5][6][7]. However, up to now mostly tungsten coatings were used as first-wall material for the so-called full-metal fusion devices, predominantly due to design limitations and cost concerns. Consequently, the influence of coating structure on the D retention should be taken into account.Some results for D retention in W films used in ASDEX Upgrade were published by Ogorodnikova et al. [8]. We used W films deposited by magnetron sputtering as a model system to investigate the influence of film structure on the deuterium retention. Different film structures were achieved by using different deposition parameters or annealing treatments. Deuterium loading was performed in well-quantified deuterium plasma. In this work, D retention in W films deposited on polycrystalline bulk W was studied and compared with deuterium retention in W films deposited on silicon and in polycrystalline bulk W alone. D retention and release and blistering after D implantation were investigated and are discussed in this article.

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