Double L-shell ionization Kα satellites in electron-excited X-ray emission spectrum of metallic cobalt

The Kα5−8 satellite spectrum of metallic cobalt, excited by a 25 keV electron beam was recorded photographically on a 40 cm bent crystal spectrograph of the Cauchois-type. Three new satellites were observed at 1.7747, 1.7691, and 1.7634 Å (1 Å = 10−10 m). These are identified as α5, α6, and α7, respectively, and assigned mainly to the 2D5/2 – 2D5/2, 2P3/2 – 2D5/2, and 2P1/2 – 2D3/2 transitions, respectively, of 1s−12p−2 – 2p−3 array.

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L-shell ionization of Cd: Structure of the x-ray emission spectrum

Ultramicroscopy ◽

10.1016/j.ultramic.2021.113401 ◽

2022 ◽

Vol 232 ◽

pp. 113401

Author(s):

F. Fernandez ◽

A. Sepúlveda ◽

J. Trincavelli ◽

G. Castellano

Keyword(s):

Emission Spectrum ◽

X Ray ◽

Shell Ionization

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Analytical Electron Microscopy (AEM) of Meningeal Cells Exposed to Particulate Cobalt During Studies of Experimental Epilepsy

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100053590 ◽

1982 ◽

Vol 40 ◽

pp. 186-187

Author(s):

R.G. Frederickson ◽

R.G. Ulrich ◽

J.L. Culberson

Keyword(s):

Electron Microscopy ◽

Analytical Electron Microscopy ◽

Experimental Epilepsy ◽

Metallic Cobalt ◽

Experimental Animals ◽

X Ray ◽

Brain Surface ◽

Meningeal Cells ◽

Analytical Electron ◽

The Brain

Metallic cobalt acts as an epileptogenic agent when placed on the brain surface of some experimental animals. The mechanism by which this substance produces abnormal neuronal discharge is unknown. One potentially useful approach to this problem is to study the cellular and extracellular distribution of elemental cobalt in the meninges and adjacent cerebral cortex. Since it is possible to demonstrate the morphological localization and distribution of heavy metals, such as cobalt, by correlative x-ray analysis and electron microscopy (i.e., by AEM), we are using AEM to locate and identify elemental cobalt in phagocytic meningeal cells of young 80-day postnatal opossums following a subdural injection of cobalt particles.

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Aspects of microanalysis in a transmission electron microscope

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100109690 ◽

1978 ◽

Vol 36 (1) ◽

pp. 510-511

Author(s):

R. Sinclair ◽

B.E. Jacobson

Keyword(s):

Grain Size ◽

Electron Beam ◽

Electron Microscope ◽

Chemical Analysis ◽

Transmission Electron Microscope ◽

Vapor Deposition ◽

Critical Currents ◽

X Ray ◽

Fine Grain ◽

Transmission Electron

INTRODUCTIONThe prospect of performing chemical analysis of thin specimens at any desired level of resolution is particularly appealing to the materials scientist. Commercial TEM-based systems are now available which virtually provide this capability. The purpose of this contribution is to illustrate its application to problems which would have been intractable until recently, pointing out some current limitations.X-RAY ANALYSISIn an attempt to fabricate superconducting materials with high critical currents and temperature, thin Nb3Sn films have been prepared by electron beam vapor deposition [1]. Fine-grain size material is desirable which may be achieved by codeposition with small amounts of Al2O3 . Figure 1 shows the STEM microstructure, with large (∽ 200 Å dia) voids present at the grain boundaries. Higher quality TEM micrographs (e.g. fig. 2) reveal the presence of small voids within the grains which are absent in pure Nb3Sn prepared under identical conditions. The X-ray spectrum from large (∽ lμ dia) or small (∽100 Ǻ dia) areas within the grains indicates only small amounts of A1 (fig.3).

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X-ray micro tomography in the scanning electron microscope

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100107678 ◽

1978 ◽

Vol 36 (1) ◽

pp. 106-107 ◽

Cited By ~ 1

Author(s):

W. Brünger

Keyword(s):

Electron Beam ◽

Electron Microscope ◽

Scanning Electron Microscope ◽

Target Surface ◽

The Body ◽

X Rays ◽

Cross Sectional ◽

X Ray ◽

Micro Tomography ◽

Scanning Electron

Reconstructive tomography is a new technique in diagnostic radiology for imaging cross-sectional planes of the human body /1/. A collimated beam of X-rays is scanned through a thin slice of the body and the transmitted intensity is recorded by a detector giving a linear shadow graph or projection (see fig. 1). Many of these projections at different angles are used to reconstruct the body-layer, usually with the aid of a computer. The picture element size of present tomographic scanners is approximately 1.1 mm2.Micro tomography can be realized using the very fine X-ray source generated by the focused electron beam of a scanning electron microscope (see fig. 2). The translation of the X-ray source is done by a line scan of the electron beam on a polished target surface /2/. Projections at different angles are produced by rotating the object.During the registration of a single scan the electron beam is deflected in one direction only, while both deflections are operating in the display tube.

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SIGMAL: A Program for Calculating L-Shell lonization Cross-Sections

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100097600 ◽

1981 ◽

Vol 39 ◽

pp. 198-199 ◽

Cited By ~ 3

Author(s):

R.F. Egerton

Keyword(s):

Cross Sections ◽

Fortran Program ◽

Absorption Data ◽

X Ray ◽

Atomic Electrons ◽

Energy Dependent ◽

Hydrogenic Model ◽

Electron Energy Loss ◽

X Ray Absorption ◽

Shell Ionization

SIGMAL is a short (∼ 100-line) Fortran program designed to rapidly compute cross-sections for L-shell ionization, particularly the partial crosssections required in quantitative electron energy-loss microanalysis. The program is based on a hydrogenic model, the L1 and L23 subshells being represented by scaled Coulombic wave functions, which allows the generalized oscillator strength (GOS) to be expressed analytically. In this basic form, the model predicts too large a cross-section at energies near to the ionization edge (see Fig. 1), due mainly to the fact that the screening effect of the atomic electrons is assumed constant over the L-shell region. This can be remedied by applying an energy-dependent correction to the GOS or to the effective nuclear charge, resulting in much closer agreement with experimental X-ray absorption data and with more sophisticated calculations (see Fig. 1 ).

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X-ray diffraction properties of curved crystal diffractors

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100133308 ◽

1992 ◽

Vol 50 (2) ◽

pp. 1734-1735

Author(s):

W. Z. Chang ◽

D. B. Wittry

Keyword(s):

Diffraction Theory ◽

X Rays ◽

Diffraction Image ◽

X Ray Diffraction ◽

Rocking Curve ◽

X Ray ◽

Bent Crystal ◽

Diffraction Geometry ◽

Crystal Parameter ◽

Quantitative Procedure

Since Du Mond and Kirkpatrick first discussed the principle of a bent crystal spectrograph in 1930, curved single crystals have been widely utilized as spectrometric monochromators as well as diffractors for focusing x rays diverging from a point. Curved crystal diffraction theory predicts that the diffraction parameters - the rocking curve width w, and the peak reflection coefficient r of curved crystals will certainly deviate from those of their flat form. Due to a lack of curved crystal parameter data in current literature and the need for optimizing the choice of diffraction geometry and crystal materials for various applications, we have continued the investigation of our technique presented at the last conference. In the present abstract, we describe a more rigorous and quantitative procedure for measuring the parameters of curved crystals.The diffraction image of a singly bent crystal under study can be obtained by using the Johann geometry with an x-ray point source.

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Searching for the causes why some of the paintings by Mihaly Munkacsy are darkening

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100134612 ◽

1990 ◽

Vol 48 (2) ◽

pp. 204-205

Author(s):

Imre Pozsgai ◽

Klara Erdöhalmi-Torok

Keyword(s):

Electron Beam ◽

Cross Section ◽

Polyester Resin ◽

National Gallery ◽

X Ray ◽

Art Historians ◽

Made In ◽

Grinding And Polishing

The paintings by the great Hungarian master Mihaly Munkacsy (1844-1900) made in an 8-9 years period of his activity are deteriorating. The most conspicuous sign of the deterioration is an intensive darkening. We have made an attempt by electron beam microanalysis to clarify the causes of the darkening. The importance of a study like this is increased by the fact that a similar darkening can be observed on the paintings by Munkacsy’s contemporaries e.g Courbet and Makart. A thick brown mass the so called bitumen used by Munkacsy for grounding and also as a paint is believed by the art historians to cause the darkening.For this study, paint specimens were taken from the following paintings: “Studio”, “Farewell” and the “Portrait of the Master’s Wife”, all of them are the property of the Hungarian National Gallery. The paint samples were embedded in a polyester resin “Poly-Pol PS-230” and after grinding and polishing their cross section was used for x-ray mapping.

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Electron Beam-Induced Mass Loss in Freeze-Dried Tissue and Protein Samples

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s042482010011917x ◽

1985 ◽

Vol 43 ◽

pp. 470-471

Author(s):

M.E. Cantino ◽

M.K. Goddard ◽

L.E. Wilkinson ◽

D.E. Johnson

Keyword(s):

Electron Beam ◽

Salivary Gland ◽

Mass Loss ◽

Counting Rate ◽

Dose Dependence ◽

X Ray ◽

Large Samples ◽

Freeze Dried ◽

Muscle Homogenate ◽

Large Muscle

Quantification in biological x-ray microanalysis depends on accurate evaluation of mass loss. Although several studies have addressed the problem of electron beam induced mass loss from organic samples (eg., 1,2). uncertainty persists as to the dose dependence, the extent of loss, the elemental constituents affected, and the variation in loss for different materials and tissues. in the work described here, we used x-ray counting rate changes to measure mass loss in albumin (used as a quantification standard), salivary gland, and muscle.In order to measure mass loss at low doses (10-4 coul/cm2 ) large samples were needed. While freeze-dried salivary gland sections of the required dimensions were available, muscle sections of this size were difficult to obtain. To simulate large muscle sections, frog or rat muscle homogenate was injected between formvar films which were then stretched over slot grids and freeze-dried. Albumin samples were prepared by a similar procedure. using a solution of bovine serum albumin in water. Samples were irradiated in the STEM mode of a JEOL 100C.

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