Contribution of Backscattered Electrons to Secondary Electron Formation

Kanter, H.

doi:10.1103/physrev.121.681

Cited by 89 publications

(33 citation statements)

References 7 publications

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“…The increase in d after cleaning for our sample suggests that the sample was initially coated with a thick layer of carbon like material that initially lowered d. Ar cleaning was not able to remove the oxide, so d increased at this stage. Our estimates for d (after cleaning) as a function of PE energy agree with some other authors (e.g., Kanter 1961;Bruining and De Boer 1938;Shimizu 1974). However, it has been suggested that Kanter (1961) must have had a thin surface layer of Al 2 O 3 contamination that resulted in a much higher value of d (Bronshtein and Fraiman 1969, p 199).…”

Section: Aluminumsupporting

confidence: 89%

“…Our estimates for d (after cleaning) as a function of PE energy agree with some other authors (e.g., Kanter 1961;Bruining and De Boer 1938;Shimizu 1974). However, it has been suggested that Kanter (1961) must have had a thin surface layer of Al 2 O 3 contamination that resulted in a much higher value of d (Bronshtein and Fraiman 1969, p 199). Bronshtein and Brozdnichenko (1969) have studied SEE from aluminum oxide and found that the much higher values of d on the oxide as compared with the clean metal are owing to the much longer path length of SEs in the oxide.…”

Section: Aluminumsupporting

confidence: 89%

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The secondary electron emission yield for 24 solid elements excited by primary electrons in the range 250–5000 ev: a theory/experiment comparison

et al. 2008

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The secondary electron (SE) yield, delta, was measured from 24 different elements at low primary beam energy (250-5,000 eV). Surface contamination affects the intensity of delta but not its variation with primary electron energy. The experiments suggest that the mean free path of SEs varies across the d bands of transition metals in agreement with theory. Monte Carlo simulations suggest that surface plasmons may need to be included for improved agreement with experiment.

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Section: Aluminumsupporting

confidence: 89%

Section: Aluminumsupporting

confidence: 89%

The secondary electron emission yield for 24 solid elements excited by primary electrons in the range 250–5000 ev: a theory/experiment comparison

et al. 2008

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“…8.nnels is approximate and not sufficiently good for the present case in which I is obtained by the sum of two currents which p . may be large and of opposite signs. The -reason for the inaccuracy lies in the fact that the charge.…”

Section: B Calibration Of Electronic System and Evaluation Of Randommentioning

confidence: 71%

Transmission Secondary Emission from Thin Films of Alkali Halides

Llacer¹

1968

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“…[3] This is reasonable, because their penetration depth is smaller than the thickness of the arachidic acid monolayer (2.7 nm) separating the catalase monolayer from the gold surface, and the secondary electron yield from the intermediate layer itself is small compared to the yield from the bulk gold (21).…”

Section: Methodsmentioning

confidence: 99%

Inactivation of catalase monolayers by irradiation with 100 keV electrons.

Hahn¹,

Seredynski²,

Baumeister³

1976

Proc. Natl. Acad. Sci. U.S.A.

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A catalase monolayer adsorbed on a layer of arachidic acid deposited on a solid support was irradiated with 100 keV electrons simulating the conditions of electron microscopic imaging. Effective doses were calculated taking into account the angular and energy distribution of backscattered electrons. Enzymatic inactivation was chosen as the criterion for damage and was monitored by a rapid and quantifiable but nevertheless sensitive assay. Dose-response curves revealed that inactivation is a one-hit-multiple-target phenomenon, which is consistent with biochemical evidence for a cooperative function of subunits. The experimentally determined target size coincides fairly well with both calculated cross sections for inelastic interactions based on the atomic composition of catalase and with calculated cross sections for ionizing events based on the chemical bonds involved. This legitimates both types of calculations even for complex biomolecules. Macromolecules and supramolecular assemblies are subject to substantial structural alterations when exposed to the unfavorable conditions in the electron microscope. Theoretical considerations (1) as well as experimental investigations (for review see ref.2) led to the suspicion that radiation-induced deteriorations of the molecular structure might fundamentally limit the resolution to which reliable structural information can be obtained. The degree of structural alteration is a function of the radiation sensitivity of the specimen under investigation and of the electron dose deposited on it, which in turn is defined by the wanted resolution (3, 4). Subtle structural alterations which can be neglected at moderate resolution levels become increasingly important with increasing resolution.The complexity of the phenomena associated with radiation damage of proteins or biomolecules in general made it impossible to formulate inductively a universal theory of the damaging process (for reviews see refs. 5-7) which could define or even predict the kind and degree of structural alterations following the fairly well understood physical interaction between the beam electrons and the specimen atoms. For essentially the same reason it is impossible to trace back on a theoretical basis to the original undisturbed structure of a protein from micrographs with manifest deteriorations.To evaluate realistic perspectives for "molecular microscopy" it seems necessary to measure quantitatively the electron doses causing distinct structural deterioration in various molecular species of biological relevance and under experimental conditions simulating the hazards of electron microscopical imaging. Hitherto, radiation damage was often measured by determining the dose that caused fading of distinct spots of the electron diffraction pattern. Unfortunately, this method is confined to crystalline specimens and, moreover, the situation of a molecule in a crystal need not necessarily reflect its reaction to ionizing radiation in a noncrystalline state. Organized monolayer systems assembled in a ...

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Contribution of Backscattered Electrons to Secondary Electron Formation

Cited by 89 publications

References 7 publications

The secondary electron emission yield for 24 solid elements excited by primary electrons in the range 250–5000 ev: a theory/experiment comparison

The secondary electron emission yield for 24 solid elements excited by primary electrons in the range 250–5000 ev: a theory/experiment comparison

Transmission Secondary Emission from Thin Films of Alkali Halides

Inactivation of catalase monolayers by irradiation with 100 keV electrons.

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