Interactions of diamond surfaces with fusion relevant plasmas

Temmerman, G. De; Doerner, R.; Lisgo, S.; Litnovsky, A.; Marot, L.; Porro, Samuele; Petersson, P.; Rubel, M.; Rudakov, D. L.; Rooij, G.J. van; Westerhout, J.; Wilson, J. I. B.

doi:10.1088/0031-8949/2009/t138/014013

Cited by 29 publications

(26 citation statements)

References 18 publications

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“…In previous experiments on Pilot-PSI the nano-crystalline and microcrystalline diamond CVD films were exposed to high flux hydrogen plasma: electron density ne = 2×10 19 m −3 , electron temperature Te = 0.31.4 eV (giving energy below 10 eV), ion flux of 2×10 23 m −2 s −1 . CH emission produced by erosion of diamond films was found to be reduced by a factor 2 compared to graphite if Te was less than 1 eV [3]; unfortunately, Tsurf could not be measured at that time. Partial amorphization of the diamond structure within the penetration depth of ions (appearance of sp 2 carbon in XPS) occurred at Te = 1.5 eV [3].…”

Section: Chemical Sputtering Of Carbon and Diamondmentioning

confidence: 94%

“…CH emission produced by erosion of diamond films was found to be reduced by a factor 2 compared to graphite if Te was less than 1 eV [3]; unfortunately, Tsurf could not be measured at that time. Partial amorphization of the diamond structure within the penetration depth of ions (appearance of sp 2 carbon in XPS) occurred at Te = 1.5 eV [3]. When dealing with higher ion energy, above ~10 eV, more studies devoted to erosion of diamond and defect creation on diamond can be found.…”

Section: Chemical Sputtering Of Carbon and Diamondmentioning

confidence: 94%

“…[12] as a function of the surface temperature for different fluxes of incident ions. Ychem is thermally activated chemical erosion yield and Ysurf is the yield of near-surface sputtering of weakly bound sp 3 CHn groups.…”

Section: Chemical Sputtering Of Carbon and Diamondmentioning

confidence: 99%

“…It has outstanding thermal properties; the chemical erosion rate of diamond by thermal hydrogen atoms is 2-4 orders of magnitude lower than that of graphite depending on the surface temperature [7], although in case of 200800 eV hydrogen ions the physical sputtering yields of diamond and graphite are comparable [8]. The previous studies in the linear plasma device Pilot-PSI have shown that diamond could be a suitable PFM for a fusion reactor [3]. Unfortunately, these measurements have lacked the control of the surface temperature during the exposure and only polycrystalline diamond samples have been investigated.…”

Section: Introductionmentioning

confidence: 99%

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Single-crystal and polycrystalline diamond erosion studies in Pilot-PSI

Kogut

Aussems

Ning

et al. 2018

Journal of Nuclear Materials

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Diamond is a promising candidate for enhancing the negative-ion surface production in the ion sources for neutral injection in fusion reactors; hence evaluation of its reactivity towards hydrogen plasma is of high importance. High quality PECVD single crystal and polycrystalline diamond samples were exposed in Pilot-PSI with the D + flux of (4-7)·10 24 m -2 s -1 and the impact energy of 7-9 eV per deuteron at different surface temperatures; under such conditions physical sputtering is negligible, however chemical sputtering is important. Net chemical sputtering yield Y = 9.7·10 -3 at/ion at 800°C was precisely measured ex-situ using a protective platinum mask (5x10x2 µm) deposited beforehand on a single crystal followed by the post-mortem analysis using Transmission Electron Microscopy (TEM). The structural properties of the exposed diamond surface were analyzed by Raman spectroscopy and X-ray Photoelectron Spectroscopy (XPS). Gross chemical sputtering yields were determined in-situ by means of optical emission spectroscopy of the molecular CH A-X band for several surface temperatures. We observed a bell shape dependence of the erosion yield versus temperature between 400°C and 1200°C, with a maximum yield of ~1.5·10 -2 at/ion attained at 900°C. The yields obtained for diamond are relatively high (0.51.5)·10 -2 at/ion, comparable with those of graphite. XPS analyses show amorphization of diamond surface within 1 nm depth, in good agreement with molecular dynamics (MD) simulation. MD was also applied to study the hydrogen impact energy threshold for erosion of [100] diamond surface at different temperatures.

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Section: Chemical Sputtering Of Carbon and Diamondmentioning

confidence: 94%

Section: Chemical Sputtering Of Carbon and Diamondmentioning

confidence: 94%

Section: Chemical Sputtering Of Carbon and Diamondmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Single-crystal and polycrystalline diamond erosion studies in Pilot-PSI

Kogut

Aussems

Ning

et al. 2018

Journal of Nuclear Materials

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“…Diamond has excellent thermal properties and its etching rate by thermal hydrogen is 2 orders of magnitude smaller than that of graphite [10]. Preliminary experiments with diamond coatings deposited by chemical vapour deposition (CVD) on molybdenum substrates have confirmed the lower erosion rate of diamond (factor 3-5) and the good resistance of the material to fusion-relevant conditions [11,12]. Micrometrethick coatings are of limited relevance to a fusion reactor however.…”

mentioning

confidence: 99%

Growth of InP nanowires on graphene-covered Fe

Tateno¹,

Zhang²,

Gotoh³

2013

Jpn. J. Appl. Phys.

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Thick free-standing boron-doped diamonds were prepared by microwave plasma assisted chemical vapour deposition. Samples with a final thickness close to 5 mm and with lateral dimensions 25 × 25 mm were produced. The thermal shock resistance of the material was tested by exposure in the JUDITH electron gun to reproduce the conditions expected in a fusion reactor during plasma instabilities. Boron-doped diamond is shown to exhibit thermal shock resistance far better than current material of choice for a fusion reactor like tungsten, with no surface damage after exposure to 100 cycles at 2.5 GW m −2 for 5 ms.

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Composite Materials for Plasma‐Facing Applications in Nuclear Fusion

Temmerman

2012

Wiley Encyclopedia of Composites

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On the road to the development of nuclear fusion, the interaction of the hot plasma with the surrounding solid walls in a fusion reactor presents stringent requirements to be successfully met by the plasma‐facing materials. Indeed, the plasma‐facing materials are continuously submitted to extreme heat and particle fluxes, and their bombardment by energetic particles such as ions and neutrons greatly affects the materials properties. As fusion devices gets bigger and move toward long‐pulse operations, the severity of the problem quickly increases. While the first fusion devices were operating with glass or stainless steel wall, high performance solutions are now developed based on different principles such as composite materials and structures. This article gives a brief review of the basic structures of plasma‐facing materials and composites and discusses their response to the fusion environment.

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Interactions of diamond surfaces with fusion relevant plasmas

Cited by 29 publications

References 18 publications

Single-crystal and polycrystalline diamond erosion studies in Pilot-PSI

Single-crystal and polycrystalline diamond erosion studies in Pilot-PSI

Growth of InP nanowires on graphene-covered Fe

Composite Materials for Plasma‐Facing Applications in Nuclear Fusion

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