Influence of plasma impurities on the deuterium retention in tungsten exposed in the linear plasma generator PSI-2

Reinhart, M.; Kreter, A.; Buzi, L.; Rasiński, M.; Pospieszczyk, A.; Unterberg, B.; Linsmeier, Ch.

doi:10.1016/j.jnucmat.2014.11.045

Cited by 35 publications

(25 citation statements)

References 14 publications

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“…In addition, a Thomson scattering system for n e , T e measurements is under construction, which has an advantage of no moving parts inside the vacuum chamber. Optical emission spectroscopy is used for the characterization of the main plasma, 5,6 impurity ion concentration [7][8][9] and in-situ characterization of the PMI processes such as erosion from the target. 10 An in-situ quartz microbalance system is used to measure the amount of the re-deposition of material sputtered from the sample surface.…”

Section: Layout Diagnostics and Plasma Parameters Of Psi-2mentioning

confidence: 99%

Linear Plasma Device PSI-2 for Plasma-Material Interaction Studies

Kreter

Brandt

Huber

et al. 2015

Fusion Science and Technology

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146

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The linear plasma device PSI-2 serves as a pilot experiment for the development of components, operational regimes and control systems for the linear plasma device JULE-PSI, which will be located in the nuclear environment allowing studies of radioactive and toxic samples. PSI-2 is also used for fusion reactor relevant plasma-material interaction studies. This contribution describes the PSI-2 layout and parameters and summarizes the recent scientific and technical progress in the project, including the installation of a target station for the sample manipulation and analyses.

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Section: Layout Diagnostics and Plasma Parameters Of Psi-2mentioning

confidence: 99%

Linear Plasma Device PSI-2 for Plasma-Material Interaction Studies

Kreter

Brandt

Huber

et al. 2015

Fusion Science and Technology

Self Cite

146

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“…The multiply charged ions can obtain a relatively high energy when they travel through the plasma sheath and reach the W surface. However, different impurity ions can also change the material microstructure and change retention 31 . In this study, Raman spectroscopy and energy disperse spectroscopy (EDS) have been used to detect the surface microstructures and compositions of polycrystalline tungsten irradiated, and no impurities, such as C and O were found to exist on the W surface.…”

Section: Resultsmentioning

confidence: 99%

Surface degeneration of W crystal irradiated with low-energy hydrogen ions

Fan

You

et al. 2016

Sci Rep

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The damage layer of a W (100) crystal irradiated with 120 eV hydrogen ions at a fluence of up to 1.5 × 1025/m2 was investigated by scanning electron microscopy and conductive atomic force microscopy (CAFM). The periodic surface degeneration of the W crystal at a surface temperature of 373 K was formed at increasing hydrogen fluence. Observations by CCD camera and CAFM indicate the existence of ultrathin surface layers due to low-energy H irradiation. The W surface layer can contain a high density of nanometer-sized defects, resulting in the thermal instability of W atoms in the surface layer. Our findings suggest that the periodic surface degeneration of the W crystal can be ascribed to the lateral erosion of W surface layers falling off during the low-energy hydrogen irradiation. Our density functional theory calculations confirm the thermal instability of W atoms in the top layer, especially if H atoms are adsorbed on the surface.

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“…For He the picture is more complex. According to [43,44,45] He pre-or co-implantation with HIs reduces the uptake and permeation of HIs for which two explanations are suggested in literature: Either the He containing surface layer that forms, reduces the solute diffusion coefficient, similar to what has been shown for nitrides or carbides, or He nano-bubbles form and result in connected porosity to the surface thus increasing out-gassing, similar to HI-induced blisters as described in section 3. In order to disentangle the two processes the He containing layer was moved into the bulk by high energy (MeV) He implantation in [46] .…”

Section: Influence Of Impurities On Transport and Trappingmentioning

confidence: 89%

Recent progress in the understanding of H transport and trapping in W

et al. 2017

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The retention of hydrogen isotopes (H, D and T) in the first, plasma exposed wall is one of the key concerns for the operation of future long pulse fusion devices. It affects the particle-, momentum-and energy balance in the scrape off layer as well as the retention of hydrogen isotopes (HIs) and their permeation into the coolant. The currently accepted picture that is used for interpreting current laboratory and tokamak experiments is that of diffusion hindered by trapping at lattice defects. This paper summarises recent results that show that this current picture of how HIs are transported and retained in W needs to be extended: The modification of the surface (e.g. blistering) can lead to the formation of fast loss channels for near surface HIs. Trapping at single occupancy traps with fixed de-trapping energy fails to explain isotope exchange experiments, instead a trapping model with multi occupancy traps and fill level dependent de-trapping energies is required. The presence of interstitial impurities like N or C may affect the transport of solute HI. The presence of HIs during damage creation by e.g. neutrons stabilises defects and reduces defect annealing at elevated temperatures.

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Influence of plasma impurities on the deuterium retention in tungsten exposed in the linear plasma generator PSI-2

Cited by 35 publications

References 14 publications

Linear Plasma Device PSI-2 for Plasma-Material Interaction Studies

Linear Plasma Device PSI-2 for Plasma-Material Interaction Studies

Surface degeneration of W crystal irradiated with low-energy hydrogen ions

Recent progress in the understanding of H transport and trapping in W

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