Ion-driven deuterium permeation through tungsten at high temperatures

Gasparyan, Yu. M.; Голубева, А. В.; Mayer, M.; Писарев, А. А.; Roth, J.

doi:10.1016/j.jnucmat.2009.01.172

Cited by 22 publications

(10 citation statements)

References 17 publications

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“…Literature states that desorption peaks near 900 K correspond to trap energies of ~2.1 eV [21]. These traps are typically voids [23] and the D is trapped at the inner surface of the internal void. These voids are often formed from vacancies clustering together to form small microvoids.…”

Section: Deuterium Trapping In Irradiated Wmentioning

confidence: 99%

Hydrogenic retention in irradiated tungsten exposed to high-flux plasma

et al. 2010

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Two sets of identical tungsten (W) targets are irradiated at 300 K with 12.3 MeV W 4+ ions to peak damage levels ranging from 0.5-10 displacements per atom (dpa). This results in a damage profile that is peaked at ~0.8 µm and extends to a depth of ~1.5 µm. Both sets of targets are exposed to high-density (n e,center = 3 x 10 20 m -3 ), lowtemperature (T e,center = 1.6 eV) deuterium (D) plasma in Pilot-PSI. One set of irradiated targets is exposed at high surface temperatures (T W = 950 -680 K) and the other at low surface temperatures (T W = 480 K -340 K). The surface temperature is determined by the local plasma conditions. Nuclear reaction analysis (NRA) is used to determine the D depth profiles at specific radial locations, thus giving a surface temperature scan of the D retention in the damaged W. Global retention is determined by thermal desorption spectroscopy, which yields total D retained in the target and also gives information of the different types of lattice defects that are trapping the D in the W lattice. The main results are that there is no measurable difference between the different dpa levels, implying a saturation of the retention enhancement at a level ≤0.5 dpa. For both irradiated and unirradiated tungsten, a peak in the retention is seen at T W = 480 K, however the W 4+ irradiation clearly enhances the retention. This enhancement is also temperature dependent and increases with increasing surface temperature up to an enhancement by a factor of 15-23 at T W = 950 K. At the lowest surface temperatures, a fluence dependence appears since the implanted deuterium is diffusion limited to only a small fraction of the irradiated zone. TDS spectra show an enhancement of both low energy trap sites and high energy trap sites. For these conditions, diffusion-limited, low fill fraction trapping determines the hydrogenic retention of the W.

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Section: Deuterium Trapping In Irradiated Wmentioning

confidence: 99%

Hydrogenic retention in irradiated tungsten exposed to high-flux plasma

et al. 2010

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“…14 The sample temperature in all permeation experiments was 873 K. There were several reasons for this choice. One of the main factors was the lag time for permeation through the tungsten substrate: Our previous experiments with bare tungsten 9 showed that the lag time was about 20 mins at 873 K and strongly increased with decrease of the temperature. Therefore, experiments became too long at lower temperatures.…”

Section: B Sample Preparation and Characterizationmentioning

confidence: 99%

Deuterium permeation through carbon-coated tungsten during ion bombardment

Gasparyan

Mayer

Писарев

et al. 2011

Journal of Applied Physics

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Deuterium permeation during ion bombardment through tungsten membranes coated by amorphous carbon films was investigated and compared with the permeation through bare tungsten. The membrane was bombarded by D3+ ions with energies of 200 and 1200 eV/D at a temperature of 873 K. The thickness of the amorphous carbon film was 120–170 nm. Detailed characterization of the carbon films were performed using AFM, NRA, RBS, FIB/SEM and XPS. The influence of the carbon films on permeation were strong for both ion energies, but different for each energy. In the case of 200 eV/D ions, the film was completely removed by the end of permeation due to intensive chemical sputtering, the lag time of permeation was much longer than for the bare membrane, and the permeation rate rose to a maximum value close to the bare membrane and then decreased to lower values. In the case of 1200 eV/D, the films were sputtered only very slowly, the lag time was much longer than in the case of the bare membrane but shorter than at 200 eV/D, and the permeation rate increased steadily up to several percents of the incident flux.

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“…Due to such considerations, we have performed ion or plasma driven permeation experiments to determine how changes in plasma and material parameters impact the diffusion behavior of H transport in W. Earlier works on hydrogen ion or plasma driven permeation have focused on pure hydrogen irradiation [12][13][14][15][16][17]. We have also performed experiments with pure D irradiation for comparative data as well as to determine microstructure dependence [18].…”

Section: Introductionmentioning

confidence: 99%