Electron energy loss studies of polymers during radiation damage

Ditchfield, R.; Grubb, D. T.; Whelan, M. J.

doi:10.1080/14786437308226885

Cited by 46 publications

(20 citation statements)

References 22 publications

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“…Electron energy-loss spectroscopy provides an in situ method whereby the inelastic scattering of electrons (which is itself the primary cause of radiation damage) is measured directly from its effect on the transmitted beam. Various types of information can be obtained from the energy loss spectrum; changes in density and composition can be observed from the position of 'plasmon' peaks (Ditchfield et al, 1973), the destruction of chemical bonds can be followed from changes in the fine structure of valence-electron peaks or inner-shell edges (Johnson, 1972;Isaacson et al, 1973;Lin, 1974) and the hydrogen content of hydrocarbons can be 0 1980 The Royal Microscopical Society measured as a function of dose from the inelastic/elastic scattering ratio (Egerton, 1976).…”

Section: Introductionmentioning

confidence: 99%

Measurement of radiation damage by electron energy‐loss spectroscopy

Egerton

1980

Journal of Microscopy

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SUMMARY Inner shell ionization edges in the energy‐loss spectrum were used to measure the loss of gaseous elements from thin samples of nitrocellulose, polyvinyl formal, copper phthalocyanine, graphite bisulphate and sodium chloride during exposure to 80 keV electrons. The irradiation kinetics were measured for electron doses up to 104 C m−2 and for dose rates up to 10 mA m−2. The energy‐loss technique is discussed in relation to other methods for assessing radiation damage.

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Section: Introductionmentioning

confidence: 99%

Measurement of radiation damage by electron energy‐loss spectroscopy

Egerton

1980

Journal of Microscopy

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“…In recent years EELS has also found favour among chemists and biologists (Ditchfield et al, 1972;Isaacson, 1972a,b;Bell & Liang, 1976;Costa et al, 1978;Hainfield & Isaacson, 1978;Ritzko et al, 1978;Briber & Khoury, 1988;Leapman & Ornberg, 1988;Wolf & Schwinde, 1988). The Zeiss EM 902 was the first commercial transmission electron microscope (TEM) with an integrated Castaing filter by which energy-filtered images could be obtained (Olins et al, 1988;Ottensmeyer, 1988;Rattner & Bazett-Jones, 1988;Heinrich et al, 1990).…”

Section: Introductionmentioning

confidence: 99%

EELS data acquisition, processing and display for the Zeiss CEM 902 based on lotus 1–2‐3®: application examples from a biological system and inorganic transition metal compounds

Drechsler

Cantow

1991

Journal of Microscopy

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SUMMARY A personal computer combined with lotus 1‐2‐3® software, including the RS232 module of lotus measure® and a 12‐bit ADC, has been used for data acquisition of electron energy‐loss spectroscopy (EELS) spectra with the Zeiss CEM 902. The internal macro language of lotus 1‐2‐3 allows a menu‐driven procedure. Macro‐programs partly combined with external FORTRAN programs can be chosen from the menu for background subtraction, removal of multiple scattering effects by deconvolution, elemental quantification and several utilities. For special applications or conditions the macro programs can easily be modified. Spectra from crystals of two inorganic transition metal compounds, ruthenium trichloride and vanadium disulphide, and from a biological sample are presented as examples of the application of this software.

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“…The outer shell excitations, on the other hand, are more complex because the states of valence electrons depends on the chemical environment of the atom under study. These excitations are typically collective in nature and in many cases, including the case of insulators and polymers, these are treated as plasmons with energy loss E ∼ 20eV [59]. Because of the dependence on chemical bonding to neighboring atoms, inelastic scattering cross sections are difficult to predict with certainty [60].…”

Section: Effect Of Inelastic Scattering a A Brief Reviewmentioning

confidence: 99%

Measurement errors in entanglement-assisted electron microscopy

Okamoto

2014

Phys. Rev. A

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The major resolution-limiting factor in cryoelectron microscopy of unstained biological specimens is radiation damage by the very electrons that are used to probe the specimen structure. To address this problem, an electron microscopy scheme that employs quantum entanglement to enable phase measurement precision beyond the standard quantum limit has recently been proposed [Phys. Rev. A 85, 043810]. Here we identify and examine in detail measurement errors that will arise in the scheme. An emphasis is given to considerations concerning inelastic scattering events because in general schemes assisted with quantum entanglement are known to be highly vulnerable to lossy processes. We find that the amount of error due both to elastic and inelastic scattering processes are acceptable provided that the electron beam geometry is properly designed. I IntroductionIn cryoelectron microscopy, unstained biological specimens are rapidly vitrified at cryogenic temperatures [1,2]. Consequently, artefacts due to heavymetal staining, desiccation, and other sample preparation processes are no longer an issue. However, the frozen, hydrated biological specimen, consisting mostly of light elements, scatters electrons weakly. Hence biological specimens generally are weak phase objects associated with low image contrast [3]. In this setting, the resolution is limited by radiation damage by the probe electrons [4] to approximately 5-10 nm in the case of single objects [5]. This leaves much to be desired because 2 nm resolution would be needed to identify molecules in frozen vitrified slices of the cell in cryoelectron tomography [6], or 0.8 nm resolution would be required to observe the secondary structure of a single protein molecule. The reason why radiation damage limits the resolution is that the 'safe' electron dose, which does not cause sizable damage to the specimen, is so small that the low-contrast image is dominated by shot noise. Shot noise is a manifestation of the particle nature of the electron and hence is fundamental.Several approaches to address the radiation damage problem are known. First, methods based on averaging, such as two-dimensional crystallography [7] and single-particle analysis [8], represent an established branch of methodology in structural biology. In favorable cases, these methods essentially attained atomic resolution [9]. However, in order to average out the noise, this approach requires at least thousands of copies of the molecule of interest without much structural variance and hence is not suited for soft or unique objects. Second, the advent of in-focus phase contrast electron microscopy [10,11,12] enabled researchers to see weak phase objects much clearer than hitherto possible. The reason is that it provides a well-behaving phase contrast transfer function (CTF) that does not fall to zero at low resolutions and does not oscillate at high resolutions. However, this method does not go beyond the standard quantum limit, as will be mentioned. Third and finally, the use of low acceleration vo...

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Electron energy loss studies of polymers during radiation damage

Cited by 46 publications

References 22 publications

Measurement of radiation damage by electron energy‐loss spectroscopy

Measurement of radiation damage by electron energy‐loss spectroscopy

EELS data acquisition, processing and display for the Zeiss CEM 902 based on lotus 1–2‐3®: application examples from a biological system and inorganic transition metal compounds

Measurement errors in entanglement-assisted electron microscopy

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