Chemical sputtering of graphite by H+ ions

Busharov, N.P.; Gorbatov, E.A.; Гусев, В. М.; Guseva, M. I.; Martynenko, Yu. V.

doi:10.1016/0022-3115(76)90331-7

Cited by 30 publications

(4 citation statements)

References 2 publications

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“…Consequently, it has become common to refer to these low energy processes as chemical sputtering. [55][56][57] In this lower energy regime the ion beam itself constitutes a chemical reagent; chemical sputtering 58 is defined as a process in which surface molecules are ionized by chemical reactions with a hyperthermal projectile ion. The reactions can involve electron or proton (or other ion) transfer and they are strongly dependent on the chemical nature of the projectile.…”

Section: Chemical Sputteringmentioning

confidence: 99%

Ion/surface reactions and ion soft-landing

Gologan

Green

Alvarez

et al. 2005

Phys. Chem. Chem. Phys.

130

123

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Ion/surface collision phenomena in the hyperthermal collision energy regime (1-100 eV) are reviewed, with emphasis on chemical processes associated with the impact of small organic and biological ions at functionalized self-assembled monolayer surfaces. Inelastic collisions can lead to excitation of the projectile ion and can result in fragmentation, a process known as surface-induced dissociation which is useful in chemical analysis using tandem mass spectrometry. Changes in charge can accompany ion/surface collisions and those associated with a change in polarity (positive to negative ions or vice versa) are an attractive method for ion structural characterization and isomer differentiation. The surface-induced charge inversion of nitrobenzene and other substituted aromatics is discussed. Reactive collisions occurring between gaseous ions and surfaces depend on the chemical nature of the collision partners. These reactions can be used for selected chemical modifications of surfaces as well as for surface analysis. Particular emphasis is given here to ion soft-landing, another type of ion/surface interaction, in which the projectile ion is landed intact at the surface, either as the corresponding neutral molecule or, interestingly but less commonly, in the form of the ion itself. The ion soft-landing experiment allows for preparative mass spectrometry; for example the preparation of pure biological compounds by using the mass spectrometer as a separation device. After separation, the mass-selected ions are collected by soft-landing, at different spatial points in an array. If the experiment is performed using a suitable liquid medium, in the case of some proteins at least, biological activity is retained.

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Section: Chemical Sputteringmentioning

confidence: 99%

Ion/surface reactions and ion soft-landing

Gologan

Green

Alvarez

et al. 2005

Phys. Chem. Chem. Phys.

130

123

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“…FIG. 4. Temperature dependence of the sp' carbon concentration at a thin a-C:H layer exposed to thermal hydrogen calculated with Eq.…”

Section: Fig 9 Schematic Diagram Of the Reaction Steps Of The Chemica...mentioning

confidence: 99%

Analytic description of the chemical erosion of graphite by hydrogen ions

1996

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One main concern about the use of graphite as a plasma facing material is the enhanced erosion under hydrogen bombardment due to hydrocarbon formation. In view of the lifetime evaluation of plasma exposed carbon components and of impurity production in present and future machines such as ITER, an analytical expression for the erosion yield by chemical sputtering for the relevant energies, temperatures and incident fluxes is of special importance. An extrapolation to fluxes and energies relevant for high density divertor plasmas has not been possible up to now on the basis of semiempirical fits to laboratory data. Starting from a short review of the existing empirical formulas, recent detailed investigations of the atomistic processes for the thermally activated hydrocarbon emission are described, which enable the formulation of an improved analytical description including the ion flux as a parameter. The chemical erosion of graphite by hydrogen bombardment results from two processes: the thermally activated hydrocarbon emission, K h e r m , and a surface process at low energies and low temperatures resulting from the kinetic ejection of surface hydrocarbon complexes from collisional energy transfer, Yaurf. The new analytic description can be fitted well to the existing data for ion beam erosion, and extrapolation to divertor relevant fluxes is possible. At high ion fluxes the maximum of chemical erosion is shifted to higher temperatures, where annealing of damaged structures leads to a stronger reduction of &erm than previously estimated. There are no data on a possible flux dependence of Ysurf, leaving still some uncertainty in extrapolation.

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“…graphite [132]; (b) 200-1100 eVH + and IP on reactorgrade graphite [134],-(c) 10 keVIT^ on graphite [133]. (B) For thermal hydrogen atoms: (d) [223], (e) [129], (f) [224],…”

Section: Fig41 Comparison [132] Of the Temperature Dependence Of The ...mentioning

confidence: 99%

Plasma-surface interactions in tokamaks

1979

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A summary is given of the present status of research on plasma-surface interactions in tokamaks. Three groups of important interactions are considered: recycling of the principal ion species, usually hydrogen or deuterium; the release and effect of low-Z contaminants; and the release and effect of high-Z contaminants. In each case the basic physical processes are reviewed and the relevant data from particlebeam measurements are summarized. Emphasis is given to discussing the effect of the various surface interactions in present-day tokamak discharges and in future fusion reactors. Surface studies in tokamaks are reviewed and methods of controlling the surface interactions and their effects are considered.

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Chemical sputtering of graphite by H+ ions

Cited by 30 publications

References 2 publications

Ion/surface reactions and ion soft-landing

Ion/surface reactions and ion soft-landing

Analytic description of the chemical erosion of graphite by hydrogen ions

Plasma-surface interactions in tokamaks

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