Quantitative depth profiling of deuterium up to very large depths

Mayer, M.; Gauthier, E.; Sugiyama, K.; Toussaint, U. von

doi:10.1016/j.nimb.2008.11.033

Cited by 135 publications

(85 citation statements)

References 21 publications

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“…NRA was performed at IPP-Garching. Multiple 3 He ion energies were used to further refine the depth profiling [10]; energies of 1.0, 1.4, 1.8, and 2.5 MeV were used to give a depth profile with ~0.5 µm resolution to a depth of 4 µm. The D concentrations are then integrated over the depth to give the total retention in the first 4 µm of the surface.…”

Section: D( 3 Hep)α Nuclear Reaction Analysismentioning

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: D( 3 Hep)α Nuclear Reaction Analysismentioning

confidence: 99%

Hydrogenic retention in irradiated tungsten exposed to high-flux plasma

et al. 2010

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“…Most importantly such microstructure leads to reduced D retention [2,3,5,6]. The formation of nano-bubbles by few eV to keV He ion irradiation is fluence and temperature dependent, having a formation threshold around a fluence of 3×10 20 He/m 2 at 290 K that is decreasing with the increase of temperature [4]. Similar nanobubble formation but in larger depth was observed by MeV He ion irradiation where a fluence threshold of 10 21 He/m 2 was obtained [7].…”

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confidence: 99%

“…After each step the sample was cooled down and the NRA analysis was performed on the no-He and He-irradiated half of the sample in-situ by detecting protons from the D( 3 He,p)α nuclear reaction. In order to determine the D depth profile [20] We used the same collected charge of 7.45 µC for all five energies, corresponding to an ion dose of 4.65×10 13 He + for the four lower energies and 2.3×10 13 He 2+ for the highest energy. The maximum 3 He concentration accumulated for each depth profile ranges between 0.08 at.…”

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Hydrogen isotope accumulation in the helium implantation zone in tungsten

2017

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The influence of helium (He) on deuterium (D) transport and retention was studied experimentally in tungsten (W). Helium was implanted 1 μm deep into W to a maximum calculated concentration of 3.4 at.%. To minimize the influence of displacement damage created during the He implantation on D retention so-called self-damaged W was used. W was damaged by 20 MeV W ion bombardment and defects were populated by low-temperature D plasma at room temperature before He implantation.Deuterium depth profiling was performed in-situ during isochronal annealing in the temperature range from 300 K to 800 K. It is shown for the first time unambiguously that He attracts D and locally increases D trapping. Deuterium retention increased by a factor of two as compared to a non-He implanted W reference after sample annealing at 450 K. Rate equation modelling can explain the measured D depth profiles quantitatively when keeping the de-trapping parameters unchanged but only increasing the number of traps in the He zone. This bolsters the confidence in the theoretical calculations predicting that more hydrogen isotopes can be stored around a He cluster zone.

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“…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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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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Quantitative depth profiling of deuterium up to very large depths

Cited by 135 publications

References 21 publications

Hydrogenic retention in irradiated tungsten exposed to high-flux plasma

Hydrogenic retention in irradiated tungsten exposed to high-flux plasma

Hydrogen isotope accumulation in the helium implantation zone in tungsten

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

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