bluuebunny/crossref_metadata_2025 huggingface dataset:
X-ray microanalysis of right ventricular guinea pig myocytes for correllation with NMR measurements of intracellular NA changes after ouabain treatment
Authors: Hagler Herbert K. , Butwell Nina B. , Bellotto Dennis , Malloy Craig R.
Published: June 2020

It is well known that ouabain, a cardiac glycoside, can be used to increase left ventricular contractility. One of the proposed mechanisms of action is the inhibition of Na-K ATPase which leads to an accumulation of Na, which in turn stimulates Ca accumulation via Na-Ca exchange. It has been suggested that the increased calcium is responsible for the augmentation of contractile force. Preliminary studies were designed to measure the intracellular concentrations of Na, Cl, K, and Ca by X-ray microanalysis of freeze-dried cryosections and to compare this data with measurements of intracellular Na made using shift reagent aided 23Na NMR spectroscopy.

Male guinea pigs were anesthetized, the hearts excised and perfused using a Langendorff preparation at a pressure of 70cm H2O and at 37°C. A Krebs-Henseleit solution bubbled with 95% O2 - 5% CO2 was used. Ouabain at a concentration of 3 × 10-7 M was added to the perfusate for 30 minutes. This ouabain concentration produces an ionotropic effect without producing a measurable increase in the amount of intracellular sodium as measured by NMR.
Laser (micro)probe mass spectrometry (LAMMS): Achievements and future trends in life sciences
Authors: Kaufmann Raimund , Spengler Bernhard
Published: June 2020

Laser microprobe mass spectrometry (LAMMS) has by now become an established technique amongst others in the field of microprobe analysis with its own figures of merit and limitations. Its sensitivity for many trace elements is rather high and, in some instances, even exeeds the detection limits of SIMS (e.g. Pb). The ease and speed of operation and the possibility to incorporate classical or nonclassical (UV) transmission light microscopy for imaging tissue sections (LAMMA 500) has made it an useful technique in the microprobe analysis of e.g. embedded tissues or small particles. The number of original reports has reached nearly 1000 (about 350 related to life sciences).
Evaluation of the ZAF procedure employed in the NIST/NIH DTSA program
Authors: Myklebust Robert L.
Published: June 2020

The ZAF matrix correction procedure employed in the Desk Top Spectrum Analyzer program (DTSA) is considerably different from the FRAME matrix correction program from which it was derived. Enough differences exist that an evaluation of the results of quantitative analyses performed with the program needed to be done. The DTSA program is capable of providing all the peak intensities for each element analyzed; therefore, all of the peak fitting and background fitting functions were removed from the FRAME program. Also, since the database incorporated into DTSA contains all of the peak energies and the excitation energies (absorption edge energies) for all x-ray lines, the fitting procedures for computing these energies were removed from the FRAME program.

An important change now in the the ZAF procedure is the computation of the atomic number correction. The absorption correction and the characteristic fluorescence correction are unchanged. A continuum fluorescence correction has not yet been included in the program.
Electron-probe microanalysis of porous materials
Authors: Lakis Rollin E. , Lyman Charles E. , Goldstein Joseph I.
Published: June 2020

Conventional electron probe microanalysis (EPMA) requires solid, flat-polished specimens, and similarly prepared standards of known composition. Unfortunately, an increasing number of technologically important materials are particulate in nature and contain significant porosity. Supported heterogeneous catalysts are an important example. Many catalysts of industrial importance consist of a number of active metals and promoters dispersed in a porous (50% theoretical density, 200 m2/g surface area) ceramic support material. It is of great practical interest to determine the concentration and precise location of each component within the support material, but quantitative EPMA has typically been avoided because of the bulk porosity and surface roughness. In order to assess the effects which porosity and the accompanying surface roughness have upon quantitative EPMA, two types of model porous specimens were prepared; one an insulator (alpha alumina) and the other a conductor (silver). The alumina specimens (Figure l.)were prepared to between 57% theoretical density and full density by controlled sintering of 0.3 μm alumina powder.
Light-detection system in higher-plant chloroplasts : Pigment mediated or energy related
Authors: Ghoshroy Soumitra , Fagerberg Wayne R.
Published: June 2020

Light is the driving force of photosynthesis. Plants adapt to rapid changes in irradiance, quality and duration of the light environment by modulating the composition of the thylakoid membranes to make the best use of the available light energy. Each chloroplast contains a large amount of thylakoid membranes some of which may be arranged as stacks (granal thylakoids) and others as unstacked sacks (stromal thylakoids). Shaded chloroplasts develop more thylakoid surface area as compared to those growing in full sunlight. Conversion of sun-type chloroplasts to those of shade-types can occur quickly, when sun plants are shaded. However, the response mechanism of chloroplasts to changes in light levels is yet to be understood. Reports in the literature showed that plants grown in red light developed more grana compared to those grown under blue light and a pigment detection system has been postulated. While, other models propose that overall energy flux changes within the chloroplast induce sun/shade response.
Fast new simulation of x-ray signals for arbitrary geometries
Authors: Wang Xinlei , Joy David C.
Published: June 2020

The Bremsstrahlung spectrum from a bulk specimen has been successfully studied with high accuracy by Monte Carlo techniques. However, such procedures take considerable computing time since any change of experimental parameters requires a fresh computation. This paper describes an alternative approach which allows x-ray signals for a given structure to be computed within a fraction of a second. The method is illustrated here by an application to Bremsstrahlung. The procedure used is that of a diffusion matrix in which the strength of individual diffusion sources is derived by an initial Monte Carlo computation.

The grid of a diffusion matrix Φ(yi,zj,Ek) which is established by Monte Carlo simulation contains the intensity of Bremsstrahlung x-ray coordinated at yi,zj with the photon energy of Ek. In the simplest case the matrix can be computed so that any photon crossing all the cells is accumulated. The results are stored in a 20×40×30 matrix for -R<zj<R and 0<yiR in steps of R/20 where R is the Bethe electron range, and 0<Ek<E0 in steps of E0/30. The accuracy of the matrix depends on the quality of the Monte Carlo simulation used to generate it.
IC testing: From electron-beam and ion-beam techniques to scanned probe microscopes
Authors: Vitarelli Jim , Radzimski Zbigniew , Russell P.E.
Published: June 2020

The rapid advance of IC design and fabrication technology is imposing increasing demands on the performance of electron beam testers and voltage contrast techniques. One industry survey predicts that the minimum feature size on IC's will be 0.1 μm by the year 2000. Current electron beam testers utilize a 0.1 μm electron probe to detect and measure surface voltages and thus will be inadequate for use on IC's with features of this size. Also, these small geometries result in very strong fields at the device surface. For instance, with a device line biased at 1 V adjacent to a grounded line and separated by 0.1 μm, the field strength near the surface is on the order of 10 kV/mm. Field strengths of this magnitude will make the collection of low energy secondary electrons very difficult and can cause significant beam deflections. Additionally, IC's in the near future may include up to 6 levels of metallization.
Characterization of organic monolayers on individual microparticles using microprobe mass spectrometry
Authors: Fister Thomas , Chakel John , Odom Robert , di Brozolo Filippo Radicati , Linton Richard W.
Published: June 2020

Polycyclic organic matter (POM) represents a class of compounds of environmental significance. Many of these compounds have been shown to exhibit mutagenic characteristics. POM is formed during the combustion of fossil fuels such as coal. Emitted particulate matter such as coal flyash contains surface associated POM that undergoes chemical transformations due to photolysis and exposure to gaseous pollutants. Past studies of these compounds on flyash have relied on wet chemical techniques in which POM is extracted from large quantities of flyash and then analyzed by chromatography. This technique is hindered by several problems such as the extensive heterogeneity in flyash composition. Individual flyash particles of different composition will influence POM adsorption and reactivity. Studies of the different types of particles by the wet techniques require that the particles be physically separated (density, size, magnetic properties). Microprobe secondary ion mass spectrometry (SIMS) is a technique that can potentially overcome these obstacles by permitting the in situ analysis of POM on single particle surfaces.
TEM studies of circumstellar dust
Authors: Bernatowicz Thomas J.
Published: June 2020

In recent years the development of special chemical separation techniques has permitted the isolation of material from primitive meteorites that can be unambiguously identified as pre-solar grains-that is, solids that condensed in the atmospheres of ancient stars and later became incorporated into the cloud of gas and dust which gave rise to our solar system. This identification is made possible in part by development of sophisticated mass spectrometry techniques for the analysis of ensembles of these grains and in part by ion microprobe techniques for determining the isotopic structures in single micron-sized grains. In particular, meteoritic grains which have isotopic compositions radically different from the solar system average can be assigned a pre-solar origin. In some cases, plausible astrophysical sites can be identified: for example, isotopic structures of Kr, Xe, Ba, and Nd in some grains resemble those expected to be produced by s-process nucleosynthesis in asymptotic giant branch (AGB) stars.
Energy-dispersive x-ray microanalysis in the earth sciences
Authors: Ware N. G.
Published: June 2020

The electron microprobe analyser (EMPA) is used extensively for the analysis of the constituent minerals in rocks and the samples generated by experimental petrology apparatus. These analyses, combined with the results of field observations and data from other analytical techniques, are used in petrogenetic studies and hence in the determination of planetary formation and evolution. In turn, this knowledge helps the mining industry in their mineral exploration programs.

In the 1960s almost all geological usage of the EMPA was confined to the x-ray spectrometry of L3-K lines of elements of atomic number 11 through 30 (Na through Zn). By the end of this decade semi conductor technology had advanced so that these x-ray lines could be resolved using a lithium-drifted silicon detector working as an energy dispersive spectrometer (EDS). Quantitative EDS software was developed in the early 1970s and it became possible to perform major element analyses of silicates, oxides, carbonates and sulphides using a scanning electron microscope (SEM) fitted with an EDS.
The use of x-ray microdiffraction in failure analysis
Authors: File D. M. , Denton L. R. , Henderson P. L.
Published: June 2020

X-ray microdiffraction is a tool used at NSWC to perform and support failure analyses. Our failure analysis efforts attempt to determine the primary cause(s) of the failure and to recommend corrective action(s) in a timely manner. The analytical techniques used include Secondary Ion Mass Spectrometry (SIMS), Scanning Electron Microscopy (SEM), Auger Electron Spectroscopy (AES), and Electron Probe MicroAnalysis (EPMA). The addition of x-ray microdiffraction has provided additional capability which supports the elemental analyses, and has often reduced the analysis time required to identify the failure mode.

X-ray microdiffraction can provide the following capabilities: 1) qualitative analyses, 2) quantitative analyses, 3) degree of crystallinity, 4) measurement of residual stress, 5) grain or particle size, 6) texture or preferred orientation, and 7) analysis of small samples (∼10 μm to 20 μm diameter). In addition, these analyses can usually be performed in a few minutes to an hour.

X-ray microdiffraction has evolved steadily over the past 15 years.
Quantitative electron probe microanalysis of high-Tc superconducting materials
Authors: Rehbach Werner P. , Karduck Peter
Published: June 2020

Since the discovery of ceramics with superconducting properties at rather high temperatures by Bednorz and Müller great effort has been made to find new super conducting materials and to optimize them. To achieve good superconducting properties single-phase compounds with well defined stoichiometry especially with regard to the oxygen content are needed. For the determination of these material properties several macroscopical or microscopical techniques are applied; one of these is the electron probe microanalysis (EPMA). However, most of the work by EPMA reported so far is restricted to the determination of the metal elements in the compound. Thus such analyses are somewhat incomplete and inadequate since the major information about the oxygen is lacking. On the other hand the microprobe is so far the only microanalytical technique to quantify oxide compositions with adequate accuracy as could be demonstrated recently by several authors. It is the intention of this presentation to assess the capability as well as the the limits of this technique in fully analysing the composition and the compositional microstructure of cuprate superconductors.
Basic image processing for the microscopist
Authors: Bright David S.
Published: June 2020

Images are a rich source of easily interpreted information. Equipment capable of handling pictures in computer memory (digital images) is now commonplace, and imaging is becoming an integral part of scientific computing and data analysis. Today, desk top computers are capable of displaying images with no special equipment at all. For example, NIH Image runs on a standard MAC II, and provides tools for contrast enhancement, pseudocolor, sharpening, animation, labeling and particle counting. Scanners or video cameras to input gray level (or color) images are moderately priced, and scanning microscopes are coming equipped for digital data acquisition and control. This tutorial will review some of the basic principles of image processing using example micrographs, and will illustrate how to use some readily available image processing software.

Digital images are pictures that reside in the computer as arrays of numbers, each number designating the brightness of an individual picture element or pixel.
Fundamental parameters of x-ray microanalysis: A brief introduction
Authors: Duncumb Peter
Published: June 2020

It is indeed fortunate that nature has provided us with such well-defined physical laws governing the generation of x rays and their interaction with matter. This benefit has given electron microprobe analysis two major advantages over many other techniques of analysis: it can be applied to almost all elements in the periodic table and it can be applied quantitatively. Nevertheless, we are continually striving for better and better quantitation over a wider range of conditions, and there is a corresponding pressure to improve our knowledge of the physics. The purpose of this session is to identify the fundamental parameters by which these physical laws are expressed, and to explore their relative importance in determining the accuracy of which the technique is capable.

The essential link between the basic physics of microprobe analysis and its useful application is the physical model used to represent the process numerically. Many such models have been proposed in the past 40 years and these are properly the subject of a separate session on quantitative analysis.
Electron Scattering in Solids
Authors: Shimizu Ryuichi , Ding Ze-Jun
Published: June 2020

Monte Carlo simulation has been becoming most powerful tool to describe the electron scattering in solids, leading to more comprehensive understanding of the complicated mechanism of generation of various types of signals for microbeam analysis.

The present paper proposes a practical model for the Monte Carlo simulation of scattering processes of a penetrating electron and the generation of the slow secondaries in solids. The model is based on the combined use of Gryzinski’s inner-shell electron excitation function and the dielectric function for taking into account the valence electron contribution in inelastic scattering processes, while the cross-sections derived by partial wave expansion method are used for describing elastic scattering processes. An improvement of the use of this elastic scattering cross-section can be seen in the success to describe the anisotropy of angular distribution of elastically backscattered electrons from Au in low energy region, shown in Fig.l. Fig.l(a) shows the elastic cross-sections of 600 eV electron for single Au-atom, clearly indicating that the angular distribution is no more smooth as expected from Rutherford scattering formula, but has the socalled lobes appearing at the large scattering angle.
A Wien Filter Electron Energy Loss Spectrometer for Transmission Electron Microscopy
Authors: Tsuno K. , Ohyama J. , Kato M. , Kimura J. , Kai M. , Nakanishi K. , Terauchi T. , Tanaka M.
Published: June 2020

A retarding Wien filter has been installed in the transmission electron microscope (TEM) JEM-1200EX. The filter is immersed in a high potential (-Ht + Uo ) nearly equal to the accelerating potential (-Ht) to get high energy resolution. The Wien filter consists of crossed electric (E) and magnetic (B) fields perpendicular to the optical axis. Electrons with a particular velocity v have a straight optical axis if the balancing condition between electric and magnetic forces (Wien condition: E=vB) is satisfied. Electrons with different velocity are deflected.

Fig. 1 shows a schematic outline of the present instrument. It consists of (1) TEM, (2) an analyzer made of the Wien filter, deflectors and post filter lenses, and (3) a TV camera imaging system and serial detection system. The analyzer and a serial detection system are controlled by a personal computer PC-9801VX (PC). Table 1 shows currents and voltages of the filter, lenses and deflectors (upper) and those for TEM (lower).
Electron Spectroscopic Imaging and Diffraction in TEM
Authors: Reimer L.
Published: June 2020

Energy-filtering electron microscopy at 80 keV (ZEISS EM902) offers the combination of electron spectroscopic imaging (ESI) and diffraction (ESD) and electron energy-loss spectroscopy (EELS). For details the reader is referred to a description of the different modes, applications of ESI to biological and crystalline specimens and of ESD. The very important mode of elemental mapping with the difference of ESI below and beyond an edge will not be discussed in this review.

The ESI mode increases scattering contrast of stained and unstained biological sections and avoids chromatic aberration by zero-loss filtering. Filtering at ΔE=250 eV below the C edge increases the (structure-sensitive) contrast by non-carbon atoms of unstained sections (Fig.1). Phase contrast is also increased but inelastically scattered electrons show a faint phase contrast which can be explained by treating partial inelastic waves with different q as incoherent. Bragg contrast of crystalline specimens is enhanced due to avoiding chromatic aberration and a blurring by the spectrum of excitation errors of inelastically scattered electrons (Fig.2).
Lithium Detection in Aluminium Lithium Alloys Using PEELS
Authors: Wilson AR
Published: June 2020

Aluminium lithium alloys are important alloys for the aerospace industry on account of their good strength to weight properties. However, these alloys suffer from poor short-transverse fracture toughness. Segregation of Li onto the grain boundaries is one mechanism proposed to account for this. Different AlLi alloys have been studied in a 200keV TEM equipped with a Parallel Electron Energy Loss Spectrometer.

Typical Li concentrations in these alloys range from 10 to 14 atomic percent (2 to 3 weight percent). This, combined with the proximity of both the Al plasmon and Al L edge and the strong deviation of the Li K edge from the ideal sharp Fermi step makes the detection of Li difficult. Negative “jump ratios”, as shown in fig. 1, make the edge very difficult to see in an unprocessed spectrum and a cursory inspection of such a spectrum might miss the Li the edge. The presence of the Li edge, and also the edge threshold energy, is more visible if the second difference of the spectrum (obtained by convolution with a top-hat filter) is displayed as shown in fig. 2.
Desktop Generation and Analysis of Spectra
Authors: Swyt C.R. , Fiori C.E.
Published: June 2020

The computer environment which allows the analyst to interact with a program by means of windows, dialogs, pull-down menus and check boxes is probably the most comfortable to the largest number of users. This environment is becoming available to both x-ray and electron energy loss analysts in commercial products and in programs written by analysts in the field. One such program for a personal computer has been under developement by the authors as a joint project at the NIH and the NIST. This program not only enables the analyst to process and display spectral data from electron column instruments but also provides the analyst the additional powerful capability to model the physical processes involved in the generation of an x-ray spectrum. The procedure to emulate the experimental environment and specimen to generate a series of spectra reflecting the relevant physics and statistics was previously described in some detail in terms of the application to estimating detection limits under proposed experimental conditions [1].
Automation of Gunshot-Residue Analysis by Functional Integration of a Scanning Electron Microscope and an Energy Dispersive Microanalysis System
Authors: Peeters Marc H.
Published: June 2020

Over the past ten years, the combination of scanning electron microscopy and energy dispersive analysis has proven to be a good and reliable tool for elemental characterization of the different components of gunshot residue. The technique evolved from a qualitative technique, involving a large amount of operator involvement, to a higher degree of quantification and automation allowing unattended analysis of gunshot residue samples. The PHAX-Scan system is geared to automated unattended analysis, particularly suited to applications such as gunshot-residue analysis.

PHAX-Scan is a system based on a Philips scanning electron microscope and an EDAX PV9900 energy dispersive microanalyser in combination with highly optimised software. The system makes use of the dual processor structure of the EDAX analyser and of the bus structure of the Philips scanning electron microscopes. It is designed such that it performs a fully quantitative data reduction, including background subtraction, peak deconvolution, no-standards k-ratio determination and Z*A*F correction in typically 100 milliseconds.
Nuclear Reactions in Deuterium Titanium
Authors: Vanderwalker D.M.
Published: June 2020

There is a fundamental interest in electrochemical fusion of deuterium in palladium and titanium since its supposed discovery by Fleischmann and Pons. Their calorimetric experiments reveal that a large quantity of heat is released by Pd after hours in a cell, suggesting fusion occurs. They cannot explain fusion by force arguments, nor can it be an exothermic reaction on the formation of deuterides because a smaller quantity of heat is released. This study examines reactions of deuterium in titanium.

Both iodide titanium and 99% pure titanium samples were encapsulated in vacuum tubes, annealed for 2h at 800 °C. The Ti foils were charged with deuterium in a D2SO4 D2O solution at a potential of .45V with respect to a calomel reference junction. Samples were ion beam thinned for transmission electron microscopy. The TEM was performed on the JEOL 200CX.

The structure of D charged titanium is α-Ti with hexagonal and fee deuterides.
Subcellular Calcium (Ca2+) Redistribution During Cardiac Muscle Contraction by Electron Probe Microanalysis (EPMA)
Authors: Schomisch Moravec Christine , Bond Meredith
Published: June 2020

Substantial evidence suggests that the increase in cytosolic Ca2+which occurs upon stimulation of cardiac muscle originates from the sarcoplasmic reticulum (SR) and that its release is triggered by a transient rise in cytosolic Ca2+. The junctional SR has been proposed as a Ca2+release site, based on a number of observations, e.g. measurements by EPMA have demonstrated significant Ca2+stores in the junctional SR in resting cardiac muscle; the ryanodine-sensitive Ca2+release channels are associated with junctional SR membrane and the low affinity Ca2+binding protein, calsequestrin, is localized to the junctional SR. Although considerable evidence implicates the junctional SR as an intracellular Ca2+store in cardiac muscle,releaseof Ca2+from the junctional SR, upon muscle stimulation, hasnotbeen directly demonstrated. We therefore propose to use EPMA to directly measure the Ca2+content of junctional SR in both relaxed and contracted cardiac muscle to determine whether Ca2+is released from the junctional SR during contraction.
Comparison of quantitative x-ray imaging and raster probing in heart cells exposed to sodium-free media
Authors: Carney Mary , LeFurgey Ann , Hawkey Larry , Ingram Peter , Lieberman Melvyn
Published: June 2020

Quantitative biological electron probe x-ray microanalysis (EPXMA) ideally makes use of two approaches in examination of samples: static raster probing and quantitative x-ray imaging. Efficient use of expensive microanalytical equipment requires intelligent decisions on the appropriate strategy for optimizing data collection. A low resolution, short dwell time map (for example, 64 × 64 pixels by 2 seconds) may survey one to several cells at low magnification and provide adequate statistics for most structures and elements. Elements, notably Ca, present in low concentrations within small regions may require the acquisition equivalent of long static raster probes, increased numbers of images from low resolution maps, higher resolution maps, longer dwell time maps, or a combination of these options.

We examined raster probe and mapping results in cultured heart cells. In these cells EXPMA has been demonstrated to be an appropriate tool to observe the results of perturbation of the Na-Ca gradient, brought about by incubation of cells in low Na or Na-free media.
Pathophysiological function of the mitochondria as a calcium reservoir: Quantitative x-ray microanalysis
Authors: Teraoka K. , Kaneko N. , Horikawa Y. , Uchida T. , Matsuda R. , Hosoda S. , Nakamura S.
Published: June 2020

The aim of this study was to elucidate the role of the mitochondria as a store of calcium(Ca) under the condition of pathophysiological Ca overload induced by a rise in extracellular Ca concentration and the administration of isoproterenol.

Eight rats were employed, and hearts were perfused as in the Langendorff method with Krebs-Henseleit solution gassed with 95% O2 and 5% CO2. Tow specimens were perfused with 2mM Ca for 30 min, and 2 were perfused with 5.5 mM Ca for 20 min. 4 specimens were perfused with 2 mM Ca for 5 min, and of these 4, 2 were infused with 10-7 mM/kg/min. isoproterenol for 5 min, and 2 were given a bolus injection of 3 x 10-7 mM isoproterenol. After rapid-cryofixation by the metal-mirror contact method with a Reichert-Jung KF80/MM80, and cryosectioning at -160 to -180° C with a Reichert-Jung Ultracut Fc-4E, ultrathin specimens (100nm) were free-ze-dreid for several hours at 10-5 Torr in the JEOL FD 7000, and mitochondrial Ca was determined by quantitative x-ray micranalysis (JEOL 1200EX, LINK AN 10000S).
The effect of averaging parameters on the backscatter correction
Authors: Heinrich Kurt F. J. , Myklebust Robert L.
Published: June 2020

The backscatter correction is derived from the knowledge of the backscatter coefficient, indicating the number of backscattered electrons, and from the energy distribution of the backscattered electrons. The effect of variations in the energy distribution on the accuracy of data reduction is minor. Unlike the procedure of Duncumb, newer approaches include the calculation of the backscatter coefficient. Since this parameter has been determined experimentally by various investigators this approach lends itself to a more detailed study of its effect on the correction procedure.

The backscatter coefficient varies strongly with the atomic number of the specimen, and less so with the operating voltage and the atomic weight of the elemental target. The effect of atomic weight is always neglected; that of the energy is taken into account in the procedure of Scott et al.

The method of averaging the components of a multielement target can have a significant effect on the result when major components differ considerably in the atomic number and element standards are used.
Evaluating 30mm2 Si(Li) detectors for light-element x-ray analysis
Authors: Barkan Shaul
Published: June 2020

Light element x-ray microanalysis with the Si(Li) detecor is dependent on two detector crystal characteristics. The first is resolution, which has been traditionally standardized to be FWHM at Mn Kα. The second factor is efficiency, which is primarily but not entirely established by the detector area. These two factors effect light element sensitivity in an inverse manner. A premium resolution detector can be produced by minimizing the area, but the efficiency, as previously discussed , is directly proportional to the detector area.

A special effect of efficiency degradation exists in the very low energy end of the spectrum where the x-ray energy pulses are approximately equal to the electronic noise level. The detector dead layer plays an important role in the low energy detection efficiency, since good, low energy efficiency is much more important than good manganese resolution or good electronic noise resolution.

In a common 10mm2 Kevex detector, ~135 eV resolution at Mn is obtainable and the electronic noise resolution is 65 eV.
SEM-EDX: A Simple And Fast Method To Assess Catalyst Poisoning
Authors: Boéchat J. - M. , Cotting J. - A.
Published: June 2020

A Rhodium on carbon catalyst is used to hydrogenate epoxy compounds in order to selectively obtain saturated cycloaliphatic products leaving the epoxy groups almost untouched. This reaction works well when the catalyst is fresh but it fails to go to completion when the catalyst is used for the second time. A reactivation method was then seeked to get rid of this catalyst poisening. In order to assess the quality of the “cleaned” catalyst, we developped a fast method using the SEM-EDX combination to avoid the long way through the chemical reaction itself and the required analysis.

We built sample holders to support the catalyst for analysis. It is a carbon stub with a calibrated cavity in the middle. The catalyst required for analysis is poured in the cavity and the excess is removed so that the surface obtained is flat and flush with the carbon stub itself. It is then loaded in the SEM and an EDX spectrum is acquired with preseted conditions.
Molecular Microanalysis of Tissues
Authors: Reffner John A. , Wihlborg William T.
Published: June 2020

Fourier transform infrared (FT-IR) microspectroscopy is the most direct and facile technology available for detecting, identifying and mapping molecular species. Biologists have a need to relate molecular chemistry with a tissue's microstructure. While electron microbeam analyses provide elemental maps and both SIMS and micro-Raman spectroscopy demonstrated limited molecular mapping capabilities, complex inorganic and organic materials are not readily amenable to these techniques. Infrared spectroscopic analyses of micro-domains have gained wide-spread acceptance since high sensitivity FT-IR spectrometers and research quality, reflecting optical microscopes were united.

Morphologically distinct parts of plant tissue can vary in their chemical composition and these variations can effect the plant's value. Plant biologists and agronomists have been endeavoring to localize the chemical species to individual botanical parts. While microscopy has been useful in establishing plant microstucture, chemical information on cellular components has been difficult to obtain. Molecular microspectral mapping renders these chemical analyses more tractable.

The microstructure of the outer portion of a cereal grain consists of four distinct regions, see Figure 1.
Morphometric approaches to the cell biology of normal and injured pulmonary epithelium
Authors: Hyde Dallas M. , Harkema Jack R. , Plopper Charles G. , George Judith A. St.
Published: June 2020

A comparative overview of the epithelial composition of the respiratory airways emphasizes the complexity and diversity found in different species of mammals. Airway epithelium varies in (1) types of cells present, (2) the same airway level in different species, (3) different airway levels in the same species, (4) abundance and type of both secretory cell and stored secretory product, (5) composition of secretory product, (6) organization at the terminal respiratory bronchiole and alveolar duct junction, and (7) ultrastructure of the same cell type in different species. It is unclear what impact this diversity in the airways of different species has, but it strongly suggests the potential for wide variation in the cellular response to injury. These data emphasize the necessity for careful selection of model species and a thorough knowledge of species-specific cellular morphometric and morphologic characteristics when studying the tracheobronchial epithelium.

A critical step in obtaining these data is the use of morphometric and electron microscopic techniques. Fixation and sampling are critical aspects of any morphometric study of the lung.
Laser Microprobe Mass Spectrometry for Spatially Resolved Organic Analysis
Authors: Karas Michael
Published: June 2020

Within the last twenty years, lasers were used for sample ionization in mass spectrometry by coupling nearly any available type of laser to the different kinds of available mass analyzers. There is a broad area of applications of the so-called laser ionization/desorption mass spectrometry (LIMS, LDMS) in a large variety of fields, such as geology, mineralogy, material research, general chemistry and biochemistry ranging from determination of bulk elemental composition to molecular weight determination of biological macromolecules. By combining an UV-microscope with a short-pulse UV-laser (for sample observation and focused irradiation of selected sample areas within μm-resolution) and a time-of-flight mass spectrometer, the technique of laser microprobe mass spectrometry was established (LAMMA-, LIMAtechnique). Also laser microprobe mass spectrometry was applied in very different fields. Most of the work dealt with the determination of element distributions within biological samples, usually prepared as thin sections and examined with a transmission geometry, i.e. by perforating the compartment of sample to be analyzed with a high intensity laser beam.
Cryofixation and X-Ray Microanalysis of Thin Cryosections Applied to Biopsies from the Human Prostate
Authors: Tvedt Kåre E. , Halgunset Jostein , Kopstad Gunnar
Published: June 2020

In order to make needle biopsies more readily applicable to cryo-ultramicrotomy and x-ray microanalysis, we have developed a method which permits biopsy specimens to be frozen immediately after removal from the patients, using metal mirror freezing.

Then tissue sample is quickly transferred from the biopsy needle to a formvar film which in advance has been supplied with a drop of standard solution containing PVP and inorganic salts. Freezing is performed by clamping the sample between the cylindrical copper jaws of a pair of pliers, precooled in liquid nitrogen (fig.l). The flat specimen is cut in a Reichert-Jung Ultracut/FC4 cryosystem. The section is collected on a grid/retainer assembly, which is mounted inside a. transportable press. Secured between two grids inside the press, the sections are transferred to an external freeze-drier.

This system makes it possible to freeze,even small pieces of tissue using the metal mirror freezing method. The pliers produce a flat specimen containing the tissue and the elemental standard, with two well-frozen surfaces which readily can be sectioned using a flat specimen holder.
Investigation of Ion Beam Sputter Mechanisms by Electron Beam Techniques
Authors: Guerlin Th. , Niedrig H. , Sternberg M.
Published: June 2020

The mechanisms of unisotropic atomic emission from single crystals under ion bombardment (Ar+, E < 25keV) have been investigated by depositing the sputtered atoms in a semi-spherical collector. A subsequent determination of the thickness distributions of the deposited films by electron backscattering gives the total angular atomic emission distribution, showing maxima in certain crystallographic directions of the sputtered target crystal: Wehner spots.

Several mechanisms for the appearance of spot patterns are discussed in the literature:

1.

For normal incidence of the ions collision cascades are assumed with finally isotropic momentum distributions within the target crystal. Then a momentum transfer to atoms near the target surface may be possible by the following models (fig. 1):

1a.

Collision sequences along close packed atomic chains (e.g. the <110> direction in fcc crystals). If the residual collision energy exceeds the surface binding energy the atom at the surface end of the chain is emitted into the chain direction: Focusson model (fig. 1a).

1b.

Emission of subsurface atoms through potential minima between surface atoms (fig. 1b), and emission of surface atoms by central collision of subsurface atoms (fig. 1c). Both processes lead to emission into preferred directions: Surface model.
Inelastic Electron Scattering and Total Reflectivity in RHEED
Authors: Yao Nan , Cowley John M.
Published: June 2020

The detailed studies of the electron energy distribution of the specular reflected beam and the total reflectivity for a platinum single crystal (111) surface under a variety of diffraction conditions were carried out on a JEM-2000FX transmission electron microscope equipped with a Gatan 666 paralleldetection electron energy loss spectrometer.

Five different diffraction conditions are characterized as D1-D5. With D1, the specular reflected spot falls in an intersection of a parallel Kikuchi line with a parabola; with D2, the specular reflected spot coincides with an intersection of the Kikuchi lines running parallel to and inclined to the crystal surface; with D3, that is pure specular Bragg reflection (the specular reflected spot crosses only the parallel Kikuchi line); with D4, the specular reflected spot intersects only with a parabola; and with D5, the specular reflected spot falls only on the oblique K-lines. A series of specular reflected beam energy loss spectra collected from the first four different diffraction conditions is shown in figure 1, where the spectra 1-4 correspond to conditions D1-D4, respectively.
Electron Beam Damage of Multiple Monolayers
Authors: Ohno Tamotsu
Published: June 2020

Previous studies on electron beam damage of organic crystals have indicated that the rate of fading of electron diffraction patterns is dependent on specimen thickness. In our previous work we had investigated behenic acid monolayer crystals as well as multilayer crystals. The experimental result showed that the critical dose. De, defined as the dose at which the peak intensity of the first order diffraction spot falls to 1/e of the initial value, increased linearly with specimen thickness in the range of 1-4 layers. The present experiment was carried out using the thicker specimen in order to investigate the decay process of multilayer crystals as well as the upper 1imit of critical dose.

The multiple monolayers of behenic acid were prepared with the same technique used in the previous experiment. Examined specimens were z-type Langmuir-Blodgett films. The specimens were mounted on carbon coated formvar support films. To avoid charging of the specimen, thick specimens were coated by thin evaporated carbon film.
Characterization and Reissue of SRM 2063 Thin-Film Glass Standard
Authors: Phelps J. M. , Steel E. B.
Published: June 2020

X-ray energy-dispersive spectrometry (EDS) is an essential tool for chemical analysis .with an electron microscope. Quantification of an acquired spectrum is typically preformed using a “relative elemental sensitivity factor” or “k factor” approach. Because of differing instrumental and detector configurations, detector efficiencies and ionization cross sections, these sensitivity factors must be determined for individual instruments. SRM 2063 is the reissue of a thin film Standard Reference Material of known chemical composition, density, thickness, stability, and homogeneity to provide characteristic x-ray peak locations and intensities for elements in the 1 - 8 keV region. The experimental procedure utilizes several different techniques to characterize the samples and limit analytical bias.

The original issue of SRM 2063 was produced by NIST personnel at a commercial laboratory using their ion beam deposition system. For the reissue of SRM 2063, a 10 cm diameter ion beam deposition system was acquired by NIST and used to sputter a fully characterized silicon, magnesium, calcium, and iron glass.
Comparison of experimental and theoretical XEDS k-factors as a function of accelerating voltage
Authors: Zaluzec Nestor J.
Published: June 2020

For nearly fifteen years k-factor measurements have been made by varying the composition of the standards at fixed accelerating voltage and measuring the change in the experimental k-factor with atomic number. From this data a “best model” of the ionization cross-section is frequently proposed for use in quantitative analysis, however it is valid only at that fixed voltage. Few if any studies seek to determine the systematic variation in the k-factor with accelerating voltage. In this paper experimental measurements of the variation in the k-factor as a function of accelerating voltage are reported. With the advent of medium voltage analytical microscopes routinely available to the microscopy community, it becomes essential to understand how the k-factor varies with accelerating voltage in order that errors in quantitative analysis can be avoided should experimental or theoretical k-factors from lower voltage instruments are applied to the medium voltage regime.

Electropolished specimens of β-NiAl were studied in a Philips CM30T electron microscope, equipped with a Be-Window Si(Li) detector interfaced to an EDAX 9900 Energy Dispersive Analysis System.
Channelling Enhanced X-Ray Microanalysis of the Preferred Substitution of Ti, Cr and Co Atoms in Sendust (Fe-9.6wt.%Si-5.5wt.%Al) Alloys
Authors: Sato Kaoru
Published: June 2020

Sendust (Fe-9.6wt%Si-5.5wt%Al) is a well-known soft magnetic material. Attempts have been made recently to improve the corrosion resistance of this alloy by adding a fourth and/or a fifth element. Since the excellent magnetic properties of Sendust have been reported to be deeply related to its crystal structure, the DO3 structure, it is of vital importance to determine the crystallographic sites those additional elements occupy. In the present work I will report the results obtained for the site occupation of Ti, Cr and Co in Sendust alloys using the ALCHEMI method.

Sendust containing 4.0%Cr, 3.0%Co+0.5%Nb and 2.0%Ti alloys were arc melted, then furnace-cooled from 1250°C. TEM specimens were prepared in a twin jet electropolisher using 5% perchrolic-acetic acid and the final thinning was done using an ion milling machine. The ALCHEMI experiment was performed in a Philips EM420T equipped with an EDAX 9900 system.

All the specimens observed exhibited the diffraction spots which are associated with the DO3 structure (Fig. 1).
Identification by Electron Microdiffraction of Intermetallic Phases in a Duplex Stainless Steel
Authors: Redjaïmia A. , Morniroli J.P. , Metauer G. , Gantois M.
Published: June 2020

2D and especially 3D symmetry information required to determine the crystal structure of four intermetallic phases present as small particles (average size in the range 100-500nm) in a Fe.22Cr.5Ni.3Mo.0.03C duplex stainless steel is not present in most Convergent Beam Electron Diffraction (CBED) patterns. Nevertheless it is possible to deduce many crystal features and to identify unambiguously these four phases by means of microdiffraction patterns obtained with a nearly parallel beam focused on a very small area (50-100nm).

From examinations of the whole pattern reduced (RS) and full (FS) symmetries the 7 crystal systems and the 11 Laue classes are distinguished without ambiguity (1). By considering the shifts and the periodicity differences between the ZOLZ and FOLZ reflection nets on specific Zone Axis Patterns (ZAP) which depend on the crystal system, the centering type of the cell and the glide planes are simultaneously identified (2). This identification is easily done by comparisons with the corresponding simulated diffraction patterns.
Thickness Measurement in the AEM by Macintosh-Based Analysis of Two-Beam Convergent Beam Patterns
Authors: Mansfield John F. , Crawford Douglas C.
Published: June 2020

A method has been developed that allows on-line measurement of the thickness of crystalline materials in the analytical electron microscope. Two-beam convergent beam electron diffraction (CBED) patterns are digitized from a JEOL 2000FX electron microscope into an Apple Macintosh II microcomputer via a Gatan #673 CCD Video Camera and an Imaging Systems Technology Video 1000 frame-capture board. It is necessary to know the lattice parameters of the sample since measurements are made of the spacing of the diffraction discs in order to calibrate the pattern. The sample thickness is calculated from measurements of the spacings of the fringes that are seen in the diffraction discs. This technique was pioneered by Kelly et al, who used the two-beam dynamic theory of MacGillavry relate the deviation parameter (Si) of the ith fringe from the exact Bragg condition to the specimen thickness (t) with the equation:

Where ξg, is the extinction distance for that reflection and ni is an integer.
The EISI Index: A Search/ Match Tool for Electron Diffraction Phase Analysis
Authors: Anderson Ron , Carr M. J. , Himes V. L. , Mighell A. D.
Published: June 2020

The identification of unknown phases using diffraction data and the JCPDS-ICDD Powder Diffraction File (PDF)[1] is a three-step process. First, the Search step rapidly screens the entire PDF to produce a list of candidate solutions that correspond to the unknown phase’s d-spacings and chemistry. Second, the Match step examines closely every aspect of each phase in the candidate list, vs. the unknown, to make the identification. Third, the Decision step: does the solution found make crystal-chemical-thermodynamic sense? A hindrance to the identification process for electron diffraction applications is that the PDF consists of X-ray powder diffraction data. There are two problems: First, while X-ray diffraction intensity data compares well to electron diffraction intensities for randomly-oriented, small-grained specimens, in the main, intensities from the two methods are not the same. The differing intensities exacerbate the problem of unknown phase searching for electron diffraction because X-ray derived Search/Matching methods rely heavily on intensity information.