The sources of electron-induced contamination in kinetic vacuum systems

Ennos, A. E.

doi:10.1088/0508-3443/5/1/307

Cited by 152 publications

(43 citation statements)

References 2 publications

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“…6 Similar observations were reported by other researchers, and the sources of specimen contamination were investigated. [7][8][9][10][11][12] The contamination was believed to be the result of interaction between the electron beam and organic molecules adsorbed on the bombarded surface. Several models were proposed for the arrival of hydrocarbon molecules at the irradiated region.…”

Section: Mechanics Of Hydrogenated Amorphous Carbon Deposits From Elementioning

confidence: 99%

Mechanics of hydrogenated amorphous carbon deposits from electron-beam-induced deposition of a paraffin precursor

Ding

Dikin

Chen

et al. 2005

Journal of Applied Physics

142

162

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Many experiments on the mechanics of nanostructures require the creation of rigid clamps at specific locations. In this work, electron-beam-induced deposition ͑EBID͒ has been used to deposit carbon films that are similar to those that have recently been used for clamping nanostructures. The film deposition rate was accelerated by placing a paraffin source of hydrocarbon near the area where the EBID deposits were made. High-resolution transmission electron microscopy, electron-energy-loss spectroscopy, Raman spectroscopy, secondary-ion-mass spectrometry, and nanoindentation were used to characterize the chemical composition and the mechanics of the carbonaceous deposits. The typical EBID deposit was found to be hydrogenated amorphous carbon ͑a-C:H͒ having more sp 2 -than sp 3 -bonded carbon. Nanoindentation tests revealed a hardness of ϳ4 GPa and an elastic modulus of 30-60 GPa, depending on the accelerating voltage. This reflects a relatively soft film, which is built out of precursor molecular ions impacting the growing surface layer with low energies. The use of such deposits as clamps for tensile tests of poly͑acrylonitrile͒-based carbon nanofibers loaded between opposing atomic force microscope cantilevers is presented as an example application

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Section: Mechanics Of Hydrogenated Amorphous Carbon Deposits From Elementioning

confidence: 99%

Mechanics of hydrogenated amorphous carbon deposits from electron-beam-induced deposition of a paraffin precursor

Ding

Dikin

Chen

et al. 2005

Journal of Applied Physics

142

162

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“…The linear fall in each case is caused by the deposition of carbon from residual organic vapours when bombarded by the electron beam (Ennos 1953(Ennos , 1954Fisher, Orisp, and Williams 1958). After 35 or 40 min bombardment a brownish film is clearly visible on the target surfaces.…”

Section: Experimental Methods and Resultsmentioning

confidence: 99%

The Soft X-Ray L23 Emission Spectrum of Magnesium from Solid and Evaporated Targets

Crisp¹

1958

Aust. J. Phys.

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Spectroscopic studies in the soft X-ray region of 50-1000 A have used both photographic and photomultiplier detection of the radiation diffracted in the grating spectrograph (see, for example, Tomboulian 1957). The photomultiplier method offers the advantage that it is possible to record the time variation in the intensity of radiation emitted at a particular wavelength as changes proceed in the condition of the target.Using aIm grazing-incidence spectrograph with photomultiplier detector (Fisher, Orisp, and Williams 1958) a detailed study has been made of the magnesium L 23 emission band at 250 A. Experimental Method and ResultsThe targets, which were water cooled, consisted either of a solid magnesium specimen scraped clean in vaouo, or a layer of magnesium evaporated onto a solid copper backing. The variation with time of the peak intensity of the band at 250 A is illustrated in Figure 1, in which curve (a) is for solid magnesium and (b) and (0) are for thick and thin films of magnesium evaporated onto copper. The zero of the time scale corresponds to switching the electron beam onto the freshly prepared surface. The initial small drop in (a) is attributed to a rapid oxidation of the freshly cut metal surface. This effect has also been observed for solid targets of the alkali metals where there is a much greater fall to about 30 per cent. of the initial intensity in some 60 sec. The decrease is approximately exponential, in agreement with the findings of Kingston (1951) for potassium and calcium.The initial fall is not observed in (b) because there is about 15 sec delay between ceasing evaporation and turning on the electron beam and presumably there is a more rapid oxidation of evaporated magnesium. The initial rise in (0) is attributed to homogenization of the thin film under the action of the electron beam.The linear fall in each case is caused by the deposition of carbon from residual organic vapours when bombarded by the electron beam (Ennos 1953(Ennos , 1954 Fisher, Orisp, and Williams 1958). After 35 or 40 min bombardment a brownish film is clearly visible on the target surfaces. Oontamination curves of the above kind were recorded at the peak, dip, and hump at 250, 253, and 263 A respectively * Manuscript

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“…The main impurities in the metal were C, N, O, Al, Si and Fe. C, N and O impurities were considered as over-estimated owing to (a) carbon deposition from residual hydrocarbon disintegration by the action of the electron beam and (b) the ubiquitous presence of a surface oxide film, and (c) amplification of the signal coming from the low mass elements (over the heavy elements), for low accelerating voltages [33][34][35]. Preliminary scanning electron microscopy (SEM) inspection of the surface revealed carbides and carbo-nitrides of varied morphology.…”

Section: Sample Characterisationmentioning

confidence: 99%

The effect of work-hardening and thermal annealing on the early stages of the uranium-hydrogen corrosion reaction

2018

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A B S T R A C TThe characteristics of hydride formation on metallic U at the early stages were investigated for three differently treated samples. The first sample reacted in its as-received state, the second was thermally annealed and the third sample underwent cold work-hardening prior to reaction with deuterium. From the analysis, the vacuum heat-treated sample was found to be more resilient to hydriding at the nucleation and growth stage, exhibiting a reduced number of nucleation points when compared to the as-cast uranium. The work-hardened sample was observed to be more susceptible to H 2 corrosion, displaying very dissimilar hydriding behaviour when compared to the other.

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The sources of electron-induced contamination in kinetic vacuum systems

Cited by 152 publications

References 2 publications

Mechanics of hydrogenated amorphous carbon deposits from electron-beam-induced deposition of a paraffin precursor

Mechanics of hydrogenated amorphous carbon deposits from electron-beam-induced deposition of a paraffin precursor

The Soft X-Ray L23 Emission Spectrum of Magnesium from Solid and Evaporated Targets

The effect of work-hardening and thermal annealing on the early stages of the uranium-hydrogen corrosion reaction

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