Chemical erosion of amorphous hydrogenated carbon films by atomic and energetic hydrogen

Vietzke, E.; Flaskamp, K.; Philipps, V.; Esser, G.; Wienhold, P.; Winter, J.

doi:10.1016/0022-3115(87)90378-3

Cited by 120 publications

(70 citation statements)

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“…We reemphasise that chemical erosion is a purely chemical, thermally activated reaction which requires no kinetic energy-beyond thermal levels-to enable the reaction. The experimental and, as a consequence, also the model results of Horn et al [27] show qualitative agreement with the experimental results of Vietzke et al [15,16]. But the absolute yields of Horn et al are about a factor of 10 lower than those of Vietzke et al The absolute chemical erosion yield at the maximum temperature (T max ) was also determined by Schwarz-Selinger et al [28].…”

Section: Introductionsupporting

confidence: 78%

“…2). It should be noted here that in earlier publications of Vietzke et al [15,16] 4 contribute about 35% to the total erosion yield. In fact, the yields in Refs.…”

Section: Resultsmentioning

confidence: 55%

“…They found that the erosion yield of ther-mal hydrogen atoms for a-C:H films is much higher than for graphite and comparable to the yield for energetic hydrogen ions on graphite [15][16][17][18]. The temperature dependence for the erosion of a-C:H films with atomic hydrogen is similar to that of the chemical sputtering of graphite using energetic hydrogen ions [16][17][18].…”

Section: Introductionmentioning

confidence: 89%

“…On the other hand, a-C:H films represent a model system for the chemical sputtering of graphite by hydrogen ions and the study of such films helps to better understand the involved basic processes. The bulk of the studies devoted to a-C:H films addressed the measurement of the production yield of certain hydrocarbon species by mass spectrometry [11][12][13][14][15][16][17][18][19][20]. Although such experiments deliver very valuable information on the erosion process and the produced species, they do not necessarily determine the total erosion yield.…”

Section: Introductionmentioning

confidence: 99%

“…Vietzke et al [15,16] investigated the chemical erosion of a-C:H films due to exposure to thermal atomic hydrogen and the chemical sputtering due to bombardment with hydrogen ions, measuring hydrocarbon (C x H y ) production yields by mass spectrometry. They found that the erosion yield of ther-mal hydrogen atoms for a-C:H films is much higher than for graphite and comparable to the yield for energetic hydrogen ions on graphite [15][16][17][18].…”

Section: Introductionmentioning

confidence: 99%

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Temperature dependence of the chemical sputtering of amorphous hydrogenated carbon films by hydrogen

Schlüter

Hopf

Schwarz-Selinger

et al. 2008

Journal of Nuclear Materials

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The temperature dependence of chemical erosion and chemical sputtering of amorphous hydrogenated carbon films due to exposure to hydrogen atoms (H 0 ) alone and combined exposure to argon ions and H 0 was measured in the temperature range from 110 to 950 K. The chemical erosion yield for H 0 alone is below the detection limit for temperatures below about 340 K. It increases strongly with increasing temperature, goes through a maximum around 650 to 700 K and decreases again for higher temperatures. Combined exposure to Ar + and H 0 results in substantial chemical sputtering yields in the temperature range below 340 K. In this range the yield does not depend on temperature, but it increases with energy from about 1 (eroded carbon atoms per impinging Ar + ion) to about 4 if the ion energy is increased from 50 to 800 eV. For temperatures above 340 K the measured erosion rates show the same temperature dependence as for the H 0 -only case, but they are higher than for H 0 -only. The difference between the Ar + and H 0 and the H 0 -only cases increases monotonically with increasing ion energy.

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Section: Introductionsupporting

confidence: 78%

“…2). It should be noted here that in earlier publications of Vietzke et al [15,16] 4 contribute about 35% to the total erosion yield. In fact, the yields in Refs.…”

Section: Resultsmentioning

confidence: 55%

Section: Introductionmentioning

confidence: 89%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Temperature dependence of the chemical sputtering of amorphous hydrogenated carbon films by hydrogen

Schlüter

Hopf

Schwarz-Selinger

et al. 2008

Journal of Nuclear Materials

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Chemische Aspekte der Fusionstechnologie

Ache

1989

Angewandte Chemie

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Die Beherrschung der thermisch kontrollierten Kernfusion wird sicherlich einmal als einer der groRten Erfolge der Kernphysik betrachtet werden. Sie wird aber auch zugleich eine technologische Leistung ohne Parallele in der Geschichte der Natur-und Ingenieurwissenschaften sein. Das bedeutet wiederum, daR entscheidende Beitrage aus einer Reihe von Disziplinen, angefangen von den Material-und Ingenieurwissenschaften bis hin zur Chemie, erforderlich waren und auch in Zukunft sein werden, um das angestrebte Ziel zu erreichen, d. h. einen Reaktor zu bauen, der aus nahezu unerschopflichen Ausgangsmaterialien (Brennstoffen) wie Deuterium und Lithium Energie zu erzeugen imstande ist. Was ist nun die Rolle des Chemikers bei dieser Entwicklung? Ahnlich wie bei Spaltreaktoren, d. h. bei den derzeitigen Kernkraftwerken, wird es auch bei Fusionsreaktoren seine Aufgabe sein, einen sicheren Brennstoffkreislauf zu gewahrleistenangefangen von der Bereitstellung, der geeigneten Aufbewahrung und der Wiederaufarbeitung des Brennstoffs bis hin zur sicheren Lagerung der Abfalle. In diesem Beitrag sol1 gezeigt werden, welche Probleme dabei auftreten und welche Wege der Chemiker beschreiten muR, um sie zu losen.

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Chemical Aspects of Fusion Technology

Ache¹

1989

Angew. Chem. Int. Ed. Engl.

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Managing thermally controlled nuclear fusion will certainly be regarded one day as one of the most successful accomplishments in nuclear physics. At the same time, however, it will represent a technical achievement unparalleled in the history of science and engineering. This in turn would mean, in retrospect, that decisive contributions had to come from a number of disciplines as diverse as materials and engineering sciences and classical chemistry, and that the same collaboration will have to continue in the future in order to reach the ultimate goal, to construct a reactor capable of producing energy from almost inexhaustible source materials (fuels), such as deuterium and lithium. What is the chemist's role in this development? Similarly as in the development of fission reactors, i.e., the nuclear power plants currently in operation, chemists will have to ensure the existence of a reliable fuel cycle-starting from the availability, storage and reprocessing of the fuel through to the provision for safe storage of the waste. In this review article an attempt will be made to outline the problems associated with these tasks and the approaches to be made by the chemist in solving them. How Does a Fusion Reactor Work?The underlying principle of nuclear fusion is that atomic nuclei are brought together close enough to fuse despite the repelling electric forces of their two identical charges. In D-T fusion, i.e., the fusion reaction at present standing the best chance of technical realization, this process requires deuterons and tritons with a mean thermal energy of about 10 keV. Consequently, a temperature of ca. I00 million K must be produced in the fuel mixture (plasma) of such a fusion reactor. Fusion of a deuterium nucleus and a tritium nucleus leads to the production of a He-4 nucleus (a-particle) and a high-energy neutron (14.1 MeV).The neutron, which carries some 80% of the energy released in the reaction, leaves the plasma without undergoing any major interactions, penetrates the first wall of the reactor, transfers its energy by collisions in the blanket, and produces the tritium necessary to maintain the fuel cycle (Fig. '1) in nuclear reactions with the Li-bearing breeding material in the blanket. This means that 80% of the energy produced in the fusion process is no longer available to maintain the temperature required in the plasma. Consequently, it is imperative that the remaining 20% available

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Chemical erosion of amorphous hydrogenated carbon films by atomic and energetic hydrogen

Cited by 120 publications

References 1 publication

Temperature dependence of the chemical sputtering of amorphous hydrogenated carbon films by hydrogen

Temperature dependence of the chemical sputtering of amorphous hydrogenated carbon films by hydrogen

Chemische Aspekte der Fusionstechnologie

Chemical Aspects of Fusion Technology

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