Changes to the reflectance of Be mirrors due to deuterium plasmas contaminated with oxygen

Bardamid, A. F.; Bondarenko, V. N.; Davis, James W.; Konovalov, V. G.; Литвин, Оксана Степанівна; Ryzhkov, I. V.; Shapoval, A. N.; Shtan, A. F.; Solodovchenko, S. I.; Voitsenya, V.S.

doi:10.1016/j.jnucmat.2010.07.039

Cited by 8 publications

(20 citation statements)

References 19 publications

(49 reference statements)

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“…The second stage is characterized by a relatively slower increase in the thickness of the oxide-hydroxide (possibly, only hydroxide) layer due to the reactions of free Be atoms either with new oxygen molecules to produce oxide, or with water molecules to produce hydroxide. This stage is accompanied by a gradual saturation of the reflectance drop at ion fluences of ≈2·10 23 m -2 [43].…”

Section: Beryllium Mirrorsmentioning

confidence: 96%

“…9); ■ -reflectance recovery after exposure to D + ions, E i =60 eV, after the second reflectance drop (X3 in Fig. 9) [43].…”

Section: Fig (9)mentioning

confidence: 98%

“…In a detailed study on the behavior of Be mirrors exposed to deuterium plasma ions [42,43] it was found that their optical properties strongly depend on the ion energy: with keV energy-range ions a significant drop of reflectance occurs already at relatively low ion fluence (≥5·10 21 ion/m 2 ). After the drop, the reflectance can be fully restored during a much longer time (ion fluence ≥1·10 24 ion/m 2 ) by exposing the mirror to low energy ions (~50 eV) of the same plasma.…”

Section: Beryllium Mirrorsmentioning

confidence: 99%

“…This process mainly proceeds through the formation of the hydroxide Be(OD) 2 by the reaction: 2BeO + 2D → Be(OD) 2 + Be. The first stage of this process is characterized by a complete transformation of the existing oxide film (extinction coefficient k ≈ 0) into a hydroxide film (here k > 0 [43]) that leads to the reflectance drop after exposure to a very low ion fluence of keV energy range, to a level of ≥5x10 21 m -2 . The second stage is characterized by a relatively slower increase in the thickness of the oxide-hydroxide (possibly, only hydroxide) layer due to the reactions of free Be atoms either with new oxygen molecules to produce oxide, or with water molecules to produce hydroxide.…”

Section: Beryllium Mirrorsmentioning

confidence: 99%

“…1 -reflectance drop due to 1350 eV ion bombardment; 2-reflectance recovery after long-term exposures to 60 eV ions; 3 -partial reflectance recovery after vacuum annealing for 2 hours at 200°C [43]. X1, X2, and X3 indicate the states of experiment when XPS measurements were provided (see Fig.…”

Section: Fig (9)mentioning

confidence: 99%

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Experimental Simulation of the Behaviour of Diagnostic First Mirrors Fabricated of Different Metals for ITER Conditions

Voitsenya¹,

Bardamid²,

Donné³

2016

PHY

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In the experimental fusion reactor ITER, the plasma-facing component of each optical and/or laser diagnostic needs to be based on reflective optics with at least one mirror (first mirror) facing the thermonuclear plasma. The different kinds of radiation emanating from the burning plasma (neutrons, neutral atoms, electromagnetic radiation) create hostile operating conditions for the first mirrors. Therefore, a special program has been set up under the ITER framework aimed at solving the first mirror problem. This paper will review the main results in this field that have been obtained in the Institute of Plasma Physics, National Science Center “Kharkov Institute of Physics and Technology” (in many cases in cooperation with groups of other countries, as indicated in corresponding parts of the manuscript) during long-term investigations directed to find a solution of this problem,i.e., to find a material and accompanying precautions in order to satisfy the requirements for first mirrors. The main efforts were devoted to finding solutions to overcome the impact of the most severe deteriorating factors resulting in degradation of the optical properties of mirrors: sputtering by charge exchange atoms and deposition of contaminants. The obtained results are focused on: the effects of long term sputtering on mirror specimens fabricated from different metals with different structures (polycrystals, single crystals, metal film on metal substrates, amorphous), the effects of contaminating film and the possible protection to avoid of its appearance, the role of chemical processes for some metal mirrors, and the choice of material of laser mirrors.

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Section: Beryllium Mirrorsmentioning

confidence: 96%

“…9); ■ -reflectance recovery after exposure to D + ions, E i =60 eV, after the second reflectance drop (X3 in Fig. 9) [43].…”

Section: Fig (9)mentioning

confidence: 98%