bluuebunny/crossref_metadata_2025 huggingface dataset:
Osseointegration interface of calcified bone and endosseous implants
Authors: Krizan K.E. , Laffoon J.E. , Buckley M.J.
Published: June 2020

With increase use of tissue-integrated prostheses in recent years it is a goal to understand what is happening at the interface between haversion bone and bulk metal. This study uses electron microscopy (EM) techniques to establish parameters for osseointegration (structure and function between bone and nonload-carrying implants) in an animal model. In the past the interface has been evaluated extensively with light microscopy methods. Today researchers are using the EM for ultrastructural studies of the bone tissue and implant responses to an in vivo environment. Under general anesthesia nine adult mongrel dogs received three Brånemark (Nobelpharma) 3.75 × 7 mm titanium implants surgical placed in their left zygomatic arch. After a one year healing period the animals were injected with a routine bone marker (oxytetracycline), euthanized and perfused via aortic cannulation with 3% glutaraldehyde in 0.1M cacodylate buffer pH 7.2. Implants were retrieved en bloc, harvest radiographs made (Fig. 1), and routinely embedded in plastic. Tissue and implants were cut into 300 micron thick wafers, longitudinally to the implant with an Isomet saw and diamond wafering blade [Beuhler] until the center of the implant was reached.
A TEM study of the microstructure of avian eggshells
Authors: Xiao S. Q. , Baden S. , Heuer A. H.
Published: June 2020

The avian eggshell is one of the most rapidly mineralizing biological systems known. In situ, 5g of calcium carbonate are crystallized in less than 20 hrs to fabricate the shell. Although there have been much work about the formation of eggshells, controversy about the nucleation and growth mechanisms of the calcite crystals, and their texture in the eggshell, still remain unclear. In this report the microstructure and microchemistry of avian eggshells have been analyzed using transmission electron microscope (TEM) and energy dispersive spectroscopy (EDS).

Fresh white and dry brown eggshells were broken and fixed in Karnosky's fixative (kaltitanden) for 2 hrs, then rinsed in distilled H2O. Small speckles of the eggshells were embedded in Spurr medium and thin sections were made ultramicrotome.

The crystalline part of eggshells are composed of many small plate-like calcite grains, whose plate normals are approximately parallel to the shell surface. The sizes of the grains are about 0.3×0.3×1 μm3 (Fig.l). These grains are not as closely packed as man-made polycrystalline metals and ceramics, and small gaps between adjacent grains are visible indicating the absence of conventional grain boundaries.
Electron microscopy of keratinocytes cultured on a collagen substrate used as an allograft for the treatment of chronic wounds
Authors: Jennings Debby A. , Morykwas Michael J. , Argenta Louis C.
Published: June 2020

Grafts of cultured allogenic or autogenic keratlnocytes have proven to be an effective treatment of chronic wounds and burns. This study utilized a collagen substrate for keratinocyte and fibroblast attachment. The substrate provided mechanical stability and augmented graft manipulation onto the wound bed. Graft integrity was confirmed by light and transmission electron microscopy.

Bovine Type I dermal collagen sheets (100 μm thick) were crosslinked with 254 nm UV light (13.5 Joules/cm2) to improve mechanical properties and reduce degradation. A single cell suspension of third passage neonatal foreskin fibroblasts were plated onto the collagen. Five days later, a single cell suspension of first passage neonatal foreskin keratinocytes were plated on the opposite side of the collagen. The grafts were cultured for one month.

The grafts were fixed in phosphate buffered 4% formaldehyde/1% glutaraldehyde for 24 hours. Graft pieces were then washed in 0.13 M phosphate buffer, post-fixed in 1% osmium tetroxide, dehydrated, and embedded in Polybed 812.
Three-dimensional confocal microscopy in living cells: historical development, practical application and limitations
Authors: Masters Barry R.
Published: June 2020

Confocal microscopy is a rapidly evolving technique which is solving problems in the biological and material sciences. This tutorial focuses on the confocal microscopy of living cells. Both in vivo and in vitro applications of confocal microscopy will be reviewed. Applications of confocal microscopy of the eye will illustrate the concepts. Fluorescence and back scattered confocal microscopy are critically reviewed. A bibliography on confocal microscopy is given to aid the users of this technique.

Books (Optical Theory, Image Formation, Fluorescence Techniques)

•

Theory and Practice of Scanning Optical Microscopy, (eds. T. Wilson, C. Sheppard), Academic Press, London, 1984.

•

Confocal Microscopy, (ed. by T. Wilson), Academic Press, London, 1990.

•

Handbook of Biological Confocal Microscopy, (ed. J.B. Pawley), Plenum Press, New York, 1989.

•

New Techniques of Optical Microscopy and Microspectroscopy (ed. R.J. Cherry), CRC Press, Inc., Boca Raton, Florida, 1991.

•

Noninvasive Techniques in Cell Biology, (eds. J.K. Foskett, S. Grinstein), Wiley-Liss, New York, 1990.
SEM/FESEM imaging of lamellar structures in melt extruded polyethylene films
Authors: Chen R.T. , Jamieson M.G. , Callahan R.
Published: June 2020

“Row lamellar” structures have previously been observed when highly crystalline polymers are melt-extruded and recrystallized under high stress. With annealing to perfect the stacked lamellar superstructure and subsequent stretching in the machine (extrusion) direction, slit-like micropores form between the stacked lamellae. This process has been adopted to produce polymeric membranes on a commercial scale with controlled microporous structures. In order to produce the desired pore morphology, row lamellar structures must be established in the membrane precursors, i.e., as-extruded and annealed polymer films or hollow fibers. Due to the lack of pronounced surface topography, the lamellar structures have typically been investigated by replica-TEM, an indirect and time consuming procedure. Recently, with the availability of high resolution imaging techniques such as scanning tunneling microscopy (STM) and field emission scanning electron microscopy (FESEM), the microporous structures on the membrane surface as well as lamellar structures in the precursors can be directly examined.

The materials investigated are Celgard® polyethylene (PE) flat sheet membranes and their film precursors, both as-extruded and annealed, made at different extrusion rates (E.R.).
Errors in holz-line simulations
Authors: Eades J.A. , Moore S. , Pfullmann T. , Hangas John
Published: June 2020

In the fall 1990 issue of the EMSA Bulletin, one of us launched an appeal, asking to be sent output from programs that simulate HOLZ lines. This unusual request was prompted by the discovery that a number of such programs (including some that are well respected and widely distributed) gave different results. Several people responded and as a result we have been able to establish the reasons for the discrepancies - at least enough of them that we are confident in giving a sample result.

All the programs that we have considered are programs that calculate the positions of HOLZ lines in the kinematic approximation. However it is generally assumed that a kinematic simulation will give a result that agrees with the full dynamical theory and with experiment, provided that the kinematic calculation is carried out using an incorrect value of the accelerating voltage. This will be true for lines close enough to the zone axis and provided that a different voltage is used for each Laue zone.
Design and applications of a post-column imaging filter
Authors: Krivanek O.L. , Gubbens A.J. , Dellby N. , Meyer C.E.
Published: June 2020

We have designed and built an imaging filter which can can be attached to most standard TEMs, and is capable of operating at primary energies of up to 400 keV. The column-mounted hardware consists of 8 principal parts (Fig. 1): 1) entrance aperture, 2) pre-prism focussing and alignment coils, 3) magnetic prism, 4) spectrum-magnifying quadrupoles, 5) pneumatically retractable energy-selecting slit, 6) quadrupole-sextupole imaging assembly, 7) pneumatically retractable TV-rate CCD camera, and 8) slowscan CCD (SSC) camera. In normal operation, the entrance aperture selects a part of an image (or a diffraction pattern) that is projected by the microscope into the viewing chamber, and a doubly-focused spectrum is produced at the energy selecting slit (with a dispersion of 6 μm / eV at 200 keV). The slit width is piezoelectrically adjustable, and the whole slit assembly can be withdrawn pneumatically from the electron beam. Similar to the TEM column which can either produce an image or a diffraction pattern, the post-slit quadrupole-sextupole assembly can produce either a focussed spectrum at the SSC (or the TV), or a magnified image of the specimen.
Atomic structure images formed by core loss electrons
Authors: Hashimoto H. , Makita Y. , Nagaoka N.
Published: June 2020

Energy selected atomic structure images were first recorded with plasma loss spectrum of silicon by Ajika, Hashimoto et.al using a single sector magnetic spectrometer (Gatan 607) in 1985 without any lenses behind the narrow energy selecting slit. The distorted images were compensated by a computer. Krivanek and Ahn used three quadrupole lenses and TV camera behind an energy selecting slit, and were able to cancel the energy dispersion to first order, producing a sharp and undistorted plasma loss image of (110) planes in silicon.

In the present paper, the observations were made with a prototype of the Gatan imaging filter, which consists of a single magnetic sector of 10 cm bending radius, a pre-sector focussing and alignment coil assembly, two spectrum-magnifying quadrupoles, a piezoelectrically driven retractable energy-selecting slit, an imaging lens assembly comprising 4 quadrupoles and 5 sextupoles, a retractable TV-rate CCD camera, and a slow-scan CCD camera (Figs.1 and 2).
Energy filtered imaging of nanophase materials
Authors: Ahn C. C. , Hong L. , Eckert J. , Fultz B. , Johnson W. L.
Published: June 2020

Considerable attention and effort has been devoted to the synthesis and evaluation of nanophase materials (from 4 - 8 nm) because of their measureably altered elastic moduli, heat capacities and magnetic properties from that of larger grain sized material. Because grain boundaries represent such a large volume fraction of the consolidated material, a fundamental understanding of their nature is crucial in developing viable physical models for bulk behavior.

One of the difficulties that is encountered in this endeavor is in determining the level of composition variation or contamination at boundaries that may occur during the synthesis process. While gas condensation has produced quantities of materials suitable for x-ray diffraction and TEM analysis, scale up technologies like aerosol reaction and mechanical attrition may introduce impurities which might considerably alter the desired properties. Energy filtered imaging would also be useful for studying enhanced solute solubility or segregation in nanostructured alloy systems produced by ball milling.
Quantitative parallel EELS spectrum imaging developed as a new tool in AEM
Authors: Botton Gianluigi , L'espérance Gilles
Published: June 2020

As interest for parallel EELS spectrum imaging grows in laboratories equipped with commercial spectrometers, different approaches were used in recent years by a few research groups in the development of the technique of spectrum imaging as reported in the literature. Either by controlling, with a personal computer both the microsope and the spectrometer or using more powerful workstations interfaced to conventional multichannel analysers with commercially available programs to control the microscope and the spectrometer, spectrum images can now be obtained. Work on the limits of the technique, in terms of the quantitative performance was reported, however, by the present author where a systematic study of artifacts detection limits, statistical errors as a function of desired spatial resolution and range of chemical elements to be studied in a map was carried out The aim of the present paper is to show an application of quantitative parallel EELS spectrum imaging where statistical analysis is performed at each pixel and interpretation is carried out using criteria established from the statistical analysis and variations in composition are analyzed with the help of information retreived from t/γ maps so that artifacts are avoided.
Impurity segregation to grain boundaries and defects in AIN
Authors: Callahan D. L. , Kenik E. A. , Alexander K. B.
Published: June 2020

The technological development of aluminum nitride (A1N) substrates is driven to a large extent towards the economical production of high thermal conductivity sintered ceramics for substrate applications. Stringent demands on matrix purity combined with the practical necessity of sintering additives have led to extensive analyses of property controlling matrix defect structures and of the role of additives in both matrix purification and sintering. Of particular interest are defects such as inversion domain boundaries (IDBs) and grain boundaries which may serve as segregation sites for the dominant impurities in A1N, particularly oxygen. In this work quantitative methods of analytical electron microscopy are applied to the analysis of chemical segregation in electronic grade A1N.

Energy dispersive x-ray spectroscopy (EDAX 9100) using a ∼2-nm-diam. probe (Philips EM400T/FEG) has revealed the segregation of yttrium and calcium to the grain boundaries of commercial Toshiba N-170 ceramics. This segregation was extremely localized; examination of the A1N matrix within 4 nm of the boundary revealed no clearly discernable Y or Ca and no contributing phase, either crystalline or amorphous, was distinguished by microdiffraction using the same probe.
Theoretical considerations in lattice resolution high-angle annular dark-field imaging
Authors: Amali Adam , Rez Peter
Published: June 2020

The highly coherent probe in the scanning transmission electron microscope(STEM) equipped with a with high angle annular dark field (HAADF) detector has become an important tool for high resolution work in the study of crystals.with potential for providing chemically sensitive information.The results of Pennycook and Boatner and the calculations of Kirkland et al clearly demonstrated that lattice resolution was possible using HAADF imaging.There has been other contributions since then.The theoretical interpretation of these images however remains controversial and other contributions have focussed on whether the imaging is coherent or incoherent.

In the present work we analyse the various mechanisms that contribute to the large angle signal obtained in the HAADF detector.Bloch waves are used to describe the elastic dynamical scattering; and in the abscence of any strong Bragg reflections.the amplitude observed in the detector plane in the STEM may be represented by a simple convolution between the scattering function of the object and the probe.
Application of ALCHEMI to Doped YBa2Cu3Ox superconductors
Authors: Wheelert R. , Miller D. J. , Lin C-H. , Eades J.A.
Published: June 2020

A large number of high temperature superconductors based on cation-doped YBa2Cu3Ox have been reported in the literature. The interest in these materials is due to the great sensitivity of both the structure and superconducting properties to elemental substitutions at each type of atomic site in the crystal lattice. This provides a system where controlled changes in properties can be made which could then lead to an improved understanding of the mechanisms of superconductivity.

These studies rely on accurate knowledge of dopant site location within the unit cell. Hence, ALCHEMI, which has been successfully carried out in other complex systems, has potential applications for these materials. The work reported here demonstrates the viability of the technique for providing very basic information on site selectivity in the complex perovskite structure of YBCO. Three samples have been evaluated: an electropolished YBCO single crystal, a crushed single crystal having Sr substituted for Ba and a crushed ceramic material with Co substituted for Cu.
Energy loss composition analysis of CVD silicon oxide layers
Authors: Waytena G
Published: June 2020

The potential application of Plasma Enhanced Chemical Vapour Deposition (PECVD) oxides as gate, storage mode, or isolation dielectrics in Very Large Scale Integration (VLSI) technology, and as gate dielectrics in compound semiconductors or thin film transistor devices has been documented. There is considerable evidence that the composition is not uniform in oxides grown by PECVD. As the oxide layers are very thin computer controlled parallel EELS of cross sectional specimens was used to obtain composition profiles. The films used in this study were deposited on a (100) Si substrate at 300° C under conditions that were believed to result in stoichiometrically correct SiO2 as determined by AES. The layer width was believed to be 70Å, as determined by linear extrapolation of a thickness versus deposition time curve obtained from larger deposition times.

Figure 1 shows a cross-section high resolution electron micrographs taken taken along the (110) zone axis at a defocus of-370Å , respectively, from a slightly thick region of the specimen (150-200Å)..
The measurement of inner-shell ionization cross aections by electron impact in a TEM
Authors: Gauvin Raynald , L'Espérance Gilles
Published: June 2020

Values of cross sections for ionization of inner-shell electrons by electron impact are required for electron probe microanalysis, Auger-electron spectroscopy and electron energy-loss spectroscopy. In this work, the results of the measurement of inner-shell ionization cross-sections by electron impact, Q, in a TEM are presented for the K shell.

The measurement of QNi has been performed at 120 KeV in a TEM by measuring the net X-ray intensity of the Kα line of Ni, INi, which is related to QNi by the relation :

(1)

where i is the total electron dose, (Ω/4π)is the fractional solid angle, ω is the fluorescence yield, α is the relative intensity factor, ε is the Si (Li) detector efficiency, A is the atomic weight, ρ is the sample density, No is Avogadro's number, t' is the distance traveled by the electrons in the specimen which is equal to τ sec θ neglecting beam broadening where τ is the specimen thickness and θ is the angle between the electron beam and the normal of the thin foil and CNi is the weight fraction of Ni.
Secondary electron imaging of atomic layers on silicon surfaces
Authors: Homma Yoshikazu
Published: June 2020

We earlier reported that the atomic steps on a Si(l11) clean surface can be clearly imaged by scanning electron microscopy (SEM) with a grazing incidence of the primary electron beam. In this paper, atomic step contrast is investigated with respect to the positional effects of the secondary electron (SE) detector. SE-images of the 1×2 and 2×1 domains on Si(100) are presented for the first time.

An ultrahigh vacuum SEM equipped with a field emission electron gun (modified Hitachi S-800) is used for surface imaging. The pressure during SEM observation is about l×l0-8 Pa. The sample stage can be tilted from 0° (normal incidence) to 90° (grazing incidence). The SE-detector is placed on one side of the sample, near the tilt axis. The previous study utilized a long working distance of 35 - 40 mm between the objective lens and the sample. In the present study, the sample stage is modified so as to reduce the working distance down to 10 mm. This modification allows us to obtain higher resolution images.
Detector strategies for environmental scanning electron microscopy
Authors: Peters Klaus-Ruediger
Published: June 2020

Environmental SEM operate at specimen chamber pressures of ∼20 torr (2.7 kPa) allowing stabilization of liquid water at room temperature, working on rugged insulators, and generation of an environmental secondary electron (ESE) signal. All signals available in conventional high vacuum instruments are also utilized in the environmental SEM, including BSE, SE, absorbed current, CL, and X-ray. In addition, the ESEM allows utilization of the flux of charge carriers as information, providing exciting new signal modes not available to BSE imaging or to conventional high vacuum SEM.

In the ESEM, at low vacuum, SE electrons are collected with a “gaseous detector”. This detector collects low energy electrons (and ions) with biased wires or plates similar to those used in early high vacuum SEM for SE detection. The detector electrode can be integrated into the first PLA or positioned at any other place resulting in a versatile system that provides a variety of surface information.
Dynamic studies of silicide-mediated crystallization of amorphous silicon
Authors: Hayzelden C. , Batstone J. L.
Published: June 2020

Epitaxial reordering of amorphous Si(a-Si) on an underlying single-crystal substrate occurs well below the melt temperature by the process of solid phase epitaxial growth (SPEG). Growth of crystalline Si(c-Si) is known to be enhanced by the presence of small amounts of a metallic phase, presumably due to an interaction of the free electrons of the metal with the covalent Si bonds near the growing interface. Ion implantation of Ni was shown to lower the crystallization temperature of an a-Si thin film by approximately 200°C. Using in situ transmission electron microscopy (TEM), precipitates of NiSi2 formed within the a-Si film during annealing, were observed to migrate, leaving a trail of epitaxial c-Si. High resolution TEM revealed an epitaxial NiSi2/Si(l11) interface which was Type A. We discuss here the enhanced nucleation of c-Si and subsequent silicide-mediated SPEG of Ni-implanted a-Si.

Thin films of a-Si, 950 Å thick, were deposited onto Si(100) wafers capped with 1000Å of a-SiO2. Ion implantation produced sharply peaked Ni concentrations of 4×l020 and 2×l021 ions cm−3, in the center of the films.
Interface structure of epitaxial TiSi2 on Si(lll)
Authors: Nemanich R. J. , Jeon Hyeongtag , Honeycutt J. W. , Sukow C. A. , Rozgonyi G. A.
Published: June 2020

Among the transition metal silicides, TiSi2 is considered to be a reasonable choice for VLSI applications because it exhibits low resistivity, high temperature stability and compatibility with current processing steps. Thin film reaction of Ti on Si results in the formation of two different forms of TiSi2 which have been identified as the C49 and the C54 crystal structures. The structures are base centered and face centered orthorhombic, respectively. The C49 phase is metastable (ie. it is not represented in the binary phase diagram), and forms at temperatures of 450 to 600°C. The stable C54 phase forms after high temperature annealing to > 650°C. In this paper the relation of the morphology and interface structures of epitaxial C49 TiSi2 on Si(l11) are described.

The TiSi2/Si structures were prepared in a UHV system. The TiSi2 surface morphologies were examined by SEM and plan view TEM, and the interfaces were studied by TEM and HRTEM. The phase identification was obtained from the TEM and with ex situ Raman spectroscopy.
Microstructure of silicon proximity bonded in the presence of interfacial oxide
Authors: Sharma Renu , David Theodore N. , Secco Frank
Published: June 2020

Wafer bonding is of interest for the bonding of similar and dissimilar materials to create novel structures. Since the first use of the technique for creation of silicon-on-insulator structures, there have been a variety of applications such as the formation of p-n junctions, GaAs/Si, Si/glass, MOSFETs and capacitors. The present study was performed to evaluate interfacial regions of Si-wafers bonded by proximity-adhesion. The microstructure and behavior of the Si-wafers and the interfacial-layers was of interest.

The conditions investigated in this study consisted of silicon bonded to silicon possessing hydrophobic surfaces, silicon bonded to silicon in the presence of native-oxide layers, and silicon bonded to silicondioxide/ silicon wafers. The Si-wafers were {100} lightly doped n-type, or {111} and n/n+ (Float-zone/ Czochralski). Cross-section TEM specimens were prepared in the <110> substrate-geometry. These were then analyzed using bright-field, dark-field and weak-beam images under varying conditions of electron-beam tilt. A JEOL JEM 200CX transmission electron microscope was used for analysis, operating at 200 kV.
Ion thinning of integrated circuit transverse specimens for transmission electron microscopy
Authors: Shaapur F.
Published: June 2020

Non-uniform ion-thinning of heterogenous material structures has constituted a fundamental difficulty in preparation of specimens for transmission electron microscopy (TEM). A variety of corrective procedures have been developed and reported for reducing or eliminating the effect. Some of these techniques are applicable to any non-homogeneous material system and others only to unidirectionalfy heterogeneous samples. Recently, a procedure of the latter type has been developed which is mainly based on a new motion profile for the specimen rotation during ion-milling. This motion profile consists of reversing partial revolutions (RPR) within a fixed sector which is centered around a direction perpendicular to the specimen heterogeneity axis. The ion-milling results obtained through this technique, as studied on a number of thin film cross-sectional TEM (XTEM) specimens, have proved to be superior to those produced via other procedures.

XTEM specimens from integrated circuit (IC) devices essentially form a complex unidirectional nonhomogeneous structure. The presence of a variety of mostly lateral features at different levels along the substrate surface (consisting of conductors, semiconductors, and insulators) generally cause non-uniform results if ion-thinned conventionally.
Ab initio structure analysis of copper perbromophthalocyanine
Authors: Tivol W.F. , Turner J.N. , Dorset D.L.
Published: June 2020

The use of high-energy (1200 kV) electrons has been shown to be advantageous in the ab initio structure analysis from electron diffraction of organic compounds. Dynamical scattering from compounds containing heavy atoms may make such an analysis difficult or impossible with data obtained at conventional voltages. In the case that even high-energy electrons do not produce diffraction intensities sufficiently close to the kinematic values, criteria other than the simple minimization of the R-factor must be used to seek the correct structure solution.

Copper perbromophthalocyanine (Cu-BrPTCY) was grown epitaxially from the vapor phase onto a clean KCl crystal face. Electron diffraction patterns were obtained from crystals tilted at 26.5° and oriented so that the electron beam was parallel to the c-axis. The AEI EM7 high-voltage electron microscope was used at a voltage of 1200 kV in diffraction mode with a 10 μm selected area aperture. The data were obtained using a minimal electron dose and recorded on DuPont Lo-dose Mammography film (See Fig. 1). Intensities were measured on a Joyce-Loebl MkIIIC flat bed microdensitometer by integrating under the peaks.
A method for avoiding errors in measurements of dislocation density in specimens with a high dislocation density
Authors: Botros K. Z. , Sheinin S. S.
Published: June 2020

The measurement of dislocation density from electron microscope images of dislocations is an important tool in the hands of the materials scientist. Weak beam images are often chosen for this purpose. In cases where the dislocation density is high, there is a strong possibility that the imaging electrons propagating through the thin foil would encounter several dislocations before emerging from the bottom surface. A question which arises is what effect this may have on image contrast and whether this affects measurements of dislocation density.The authors of this paper have addressed this question by examining the contrast obtained in the case where two dislocations overlap so that the imaging electrons encounter two dislocations before reaching the bottom surface of the specimen. The details of these calculations are presented elsewhere and will not be repeated here. For purposes of this paper, the results can be summarized by stating that, for certain diffraction conditions and dislocation separations, the contrast exhibited by the overlapping dislocation configuration is very weak with the result that the dislocations would not be observed.
AEM: From microns to atoms
Authors: Cliff Graham , Lorimer Gordon W.
Published: June 2020

The “Manchester Connection” with analytical electron microscopy (AEM) goes back to 1913 and the work of Moseley which was carried out in the Physics Department of the University of Manchester. It was Moseley who first pointed out that there is a simple relationship between Z, the atomic number of an element, and Ek,the energy of the characteristic K-shell X-ray. This relationship is enshrined in Moseley's Law, Ek = 10.3(Z-1).

The origin of the modern bulk microprobe analyzer lies in the Ph.D. project of Castaing. Under the supervision of Guinier, Castaing combined an electron microscope and an X-ray spectrometer and obtained a current of a few nA in an electron beam under a micron in diameter. Although enormous advances were made in instrumentation and quantification in the 1950's and 1960's, the spatial resolution for microprobe analysis remained at about 1 μm3 or a mass of about 10-12g, no matter how small the diameter of the incident electron beam. This limitation arises from the physics of the interaction of a high energy electron beam with a solid sample.
Three-dimensional reconstruction of atomic-scale composition with the position-sensitive atom probe
Authors: Smith G.D.W. , Cerezo A. , Grovenor C.R.M. , Godfrey T.J. , Setna R.P.
Published: June 2020

The combination of a field ion microscope with a time-of-flight mass spectrometer provides the capability for chemical microanalysis at the single atom level. Such an instrument is termed an Atom Probe. Conventionally, the connection between the microscope and the mass spectrometer is made via a small aperture hole in the imaging screen. This defines a region on the specimen, typically about 2nm across, from which the analysis is obtained. The disadvantage of this arrangement is that other regions of the specimen cannot be examined, as ions from all but the selected area strike the image screen and therefore do not pass into the mass spectrometer. In order to overcome this problem, we have developed a version of the Atom Probe which incorporates a wide-angle position sensitive detector system. This instrument, which we have termed the POSAP, is shown schematically in figure 1. Typically, the field of view in this instrument is about 20nm across. The number of ions collected per atom layer removed from the specimen surface is therefore approximately 5,000.
Local geometric and electronic structure of oxides using scanning tunneling microscopy/spectroscopy
Authors: Bonnell Dawn A. , Zhong Qian
Published: June 2020

The potential of scanning tunneling microscopy (STM) and related scanning probe microscopies is amply demonstrated by the geometric increase in the number of papers utilizing the techniques that are published each year. The power of STM derives, not only from imaging capabilities, but also from associated spectroscopies which can provide local information about the density of states and work function. Although the technique has been applied to a wide range of metal and semiconductor surfaces, application to large bandgap materials such as oxides is difficult. We demonstrate the successful application of STM/STS to oxides with an analysis of the effect of reduction mechanism on the geometric and electronic structure of TiO2 (110). The structure of defects in oxides is critical in that it affects many properties of practical interest including catalysis, photoelectrolysis, and electron transport. The presence of defects can affect the local cation valence, such that the variation of d-orbital occupation results in a range of electronic properties, from insulating to semiconducting in nature. STM/STS is the ideal tool to probe the structure of these defects.
Minimum-size detection limit for volcanic glass particles using automated scanning electron microscopy
Authors: Germani Mark S.
Published: June 2020

Ice cores contain a detailed record of fallout from large volcanic eruptions. Identification of volcanic glass particles is used to aid in dating ice cores (tephrachronology). In addition, it should be possible to relate concentrations of volcanogenically-derived species; silicate glass particles, sulfate (from oxidation of SO2), chloride and fluoride to atmospheric levels which existed shortly after eruption. This information, coupled with proxy meteorological records from the core, can be used to assess the climatic impact from major volcanic eruptions.

Automated scanning electron microscopy has been used to detect volcanic glass particles >1 μm in diameter in ice core meltwater samples filtered onto Nuclepore filters. It is important to be able to detect submicrometer volcanic glass particles because of their longer atmospheric residence time and the fact that they comprise a significant portion of the number of glass particles deposited in an ice core. Existing procedures for automated analysis of micrometer size particles need to be modified to efficiently analyze submicrometer particles.
Automated digital electron microscope used to establish cleanliness levels of disk drive components
Authors: Monson Gene
Published: June 2020

Establishing a cleanliness level is a critical function that must be satisfied for quality manufacturing. It is used for bench marking and setting vendor qualifying specifications. The liquid particle counter (LPC) is used to quantify the particle count of a part that has been extracted with water and ultrasonic energy. Then the liquid is filtered into a small pore filter (0.4um). The filter can be analyzed with scanning electron microscopy (SEM). Additionally particles that are found can be analyzed with energy dispersive x ray spectroscopy (EDS). With the use of an automated digital SEM with image analyzer it is possible to analyze a statistically significant portion of the particles to have confidence in the resulting data.

With a totally automated SEM parameters of operation such as beam accelerating voltage, current, emission, spot, filament temperature, gun bias, are stored to memory. Magnification, scan speed, stigmator, detector, and condenser settings, and stage geometry are also stored.
The characterization of lead smelter dusts by automated scanning electron microscopy
Authors: Vander Wood Tim B.
Published: June 2020

The dust derived from smelting and other mining/metallurgical processes is increasingly viewed as a resource rather than a hazardous waste. In order to determine the most appropriate technologies for resource recovery from these dusts and other hazardous wastes, they must be examined in some detail for particle size, chemistry, phase composition, etc. Automated scanning electron microscopy combined with energy-dispersive x-ray spectrometry (ASEM-EDS) provides a tool for rapidly determining the particle size distribution and chemistry on a representative dust sample so that the most appropriate processing methods can be chosen.

ASEM-EDS analyses were performed on five dust samples that had previously been examined by traditional techniques of ore microscopy. Each sample was from a distinct area of the Herculaneum Lead Smelter: 1) Blast Furnace Area, #2) Dross Furnace Area, #3) Refinery Area, 4) Sinter Plant near the scrubber and #5) Sinter Plant near the crusher. Approximately 200 mg of each dust were dispersed in 100 ml of 20 ppm methyl cellulose/water solution, and a droplet of each dispersion was placed on a polished carbon planchet.
Confocal Raman mapping
Authors: Barbillat J. , Delhaye M. , Dhamelincourt P.
Published: June 2020

Raman mapping, with a spatial resolution close to the diffraction limit, can help to reveal the distribution of chemical species at the surface of an heterogeneous sample.

As early as 1975,three methods of sample laser illumination and detector configuration have been proposed to perform Raman mapping at the microscopic level (Fig. 1),:

- Point illumination:

The basic design of the instrument is a classical Raman microprobe equipped with a PM tube or either a linear photodiode array or a two-dimensional CCD detector. A laser beam is focused on a very small area ,close to the diffraction limit.In order to explore the whole surface of the sample,the specimen is moved sequentially beneath the microscope by means of a motorized XY stage. For each point analyzed, a complete spectrum is obtained from which spectral information of interest is extracted for Raman image reconstruction.

- Line illumination

A narrow laser line is focused onto the sample either by a cylindrical lens or by a scanning device and is optically conjugated with the entrance slit of the stigmatic spectrograph.
New frontiers in infrared microspectroscopy
Authors: Harthcock M. A. , McKelvy M. L. , Pell R. J.
Published: June 2020

Infrared microspectroscopy has become a common technique for the microanalysis of material. Characterization of spatially specific areas using infrared spectroscopy has been applied to a wide range of materials/systems including, for example, multi-layer films, silicon wafer contamination and inclusions in a variety of systems, surface contamination, orientation in single fibers. In addition, infrared microspectroscopy mapping experiments have been used to obtain images of materials based on functional group absorptions that characterize system composition.

The spatial resolution of the technique is limited to approximately 10-20 micrometers experimentally, due to diffraction limitations. Infrared ultra-microspectroscopy has been mentioned by Messerschmidt as a technique to achieve resolution below the diffraction limit of the radiation (e.g. 5 micrometers). However, in the absence of experimental technology to routinely increase the spatial resolution from which unique infrared spectra can be obtained, we have applied factor analysis techniques to effectively increase the spatial resolution from which an infrared spectrum could be obtained.
Near-IR imaging microscopy using an acousto-optic tunable filter (AOTF)
Authors: Treado Patrick J. , Levin Ira W. , Neil Lewis E.
Published: June 2020

Near-infrared spectroscopy is a sensitive and non-invasive probe for chemical analyses. The integration of spectroscopic and imaging technologies is a potent tool for the study of a wide range of biological materials.

Continuously tunable acousto-optic filters operable in the ultraviolet, visible and infrared are now widely available. These computer controlled notch filters provide random wavelength access, wide spectral coverage and moderate spectral resolution. AOTFs potentially have a wide range of spectroscopic applications. We employ AOTF technology for visible/NIR absorption microscopy between 600-2000 nm.

The microscope is constructed around an acousto-optic device coupled to an infinity corrected microscope employing either silicon or indium antinomide focal-plane array detectors. In operation, the AOTF is used to spectrally filter a quartz halogen light source. Under computer control the AOTF is swept through a wavelength range and at predetermined intervals images are recorded. Hundreds of frames may be collected, and the spectral image data set can readily comprise many megabytes of data.
High-performance time - of - flight SIMS
Authors: Benninghoven A.
Published: June 2020

Progress in many fields of science and technology strongly depends on the availability of appropriate analytical techniques. This becomes increasingly true for all surface related technologies. A most important analytical information concerns the chemical composition of the uppermost monolayers. This information should be supplied with high sensitivity and high resolution, not only for the elemental but also for the molecular surface composition.

Time - of - Flight SIMS supplies this molecular information, which cannot be obtained by other surface analytical techniques as AES (Auger electron spectroscopy), XPS (photoelectron spectroscopy), electron microscopy or the electron microprobe. The extremely high transmission allows static SIMS surface analysis with high lateral and mass resolution. Depending on the primary ion source, lateral resolutions below 100 nm are achieved. The Time - of - Flight technique allows parallel acquisition of a large number of ion images. It features an unlimited mass range obtained with an ultimate sensitivity based upon the parallel mass registration and the high transmission.
Molecular surface analysis by TOF-SIMS
Authors: Odom Robert W.
Published: June 2020

Time-of-flight secondary ion mass spectrometry (TOF-SIMS) performs surface sensitive analysis of the elemental and molecular composition of solids. TOFSIMS is a relatively new embodiment of static secondary ion mass spectrometry (SSIMS) in which the dose of primary ions incident on the surface is typically less than 1012 ions/cm2. Since typical solid surfaces have an atomic density of 1015 atoms/cm2, this primary ion dose nominally removes less than 0.1% of a monolayer. Hence, SIMS analyses performed under these static conditions represent near surface analysis in which secondary ions are produced from the top few monolayers of the surface. The actual sampling depth is determined by the primary ion momentum, angle of incidence and chemistry of the surface. Since low dose primary ions cause minimal perturbation of the chemistry of the solid surface, SSIMS analyses often produce molecular or pseudo-molecular ions characteristic of the chemical composition of the surface. Thus, molecular ions or structurally significant fragment ions are often observed in SSIMS analyses of surfaces containing inorganic and organic residues, polymers surfaces, coatings, and biological materials such as tissues and membranes.
Microanalysis of individual silver halide microcrystals
Authors: Wu S. , Van Daele A. , Jacob W. , Gijbels R. , Verbeeck A. , De Keyzer R.
Published: June 2020

There is a considerable interest for the study of the elemental distribution and composition in silver halide photographic emulsions, particularly for the microanalysis of individual microcrystals. In this work, elemental distributions and contents of tabular and cubic silver halide microcrystals were obtained by backscattered electron imaging (BSEI), scanning transmission electron imaging (STEI), x-ray mapping and x-ray microanalysis in a scanning electron microscope (STEM) combined with energy-dispersive x-ray analysis (EDX).

Several kinds of silver halide microcrystals were prepared, After removing the gelatin, repeated centrifugation and washing in distilled water, the grains were resuspended and dispersed onto carbon coated 50 mesh copper grids. All analyses were carried out on a JEOL 1200 EX electron microscope equipped with detectors for backscattered, secondary and transmitted electrons and an energy dispersive x-ray analysis system. An image processing system was used for acquiring and processing BSE images, STE images and x-ray maps. The role of the image processing computer system (IBAS Kontron) is twofold: it allows to optimize the acquisition conditions and to process the images afterwards.
Three-dimensional compositional mapping using ion microscopy and volume-rendering techniques
Authors: Linton Richard W.
Published: June 2020

Secondary ion mass spectrometry (SIMS), using ion microprobe or microscope instrumentation, couples lateral imaging and dynamic ion beam sputtering to provide 3-D compositional maps (image depth profiles). A data set acquired with an ion microscope may involve more than 100 massresolved ion images, each containing at least 64,000 pixels, with typical lateral and depth resolutions of 1 μm and 10 nm, respectively. The vast majority of prior quantitative surface analysis studies have addressed depth profiling, thin film, or overlayer measurements without the additional feature of laterally resolved imaging. The ability to create 3-D compositional maps using SIMS creates enormous challenges for quantification. In principle, each volume element requires individual calibration reflecting the combined effects of spatial resolution, sample heterogeneity, and variations in instrumental response. An overview of analytical considerations will be presented involving aspects of data acquisition, display, and processing, with a special emphasis on sector field mass spectrometers that provide high dynamic range image depth profiles.
Precision and bias in quantitative EDS: ASTM results
Authors: Friel John J.
Published: June 2020

Committee E-04 on Metallography of the American Society for Testing and Materials (ASTM) conducted an interlaboratory round robin test program on quantitative energy dispersive spectroscopy (EDS). The test program was designed to produce data on which to base a precision and bias statement for quantitative analysis by EDS. Nine laboratories were sent specimens of two well characterized materials, a type 308 stainless steel, and a complex mechanical alloy from Inco Alloys International, Inconel® MA 6000. The stainless steel was chosen as an example of a straightforward analysis with no special problems. The mechanical alloy was selected because elements were present in a wide range of concentrations; K, L, and M lines were involved; and Ta was severely overlapped with W. The test aimed to establish limits of precision that could be routinely achieved by capable laboratories operating under real world conditions. The participants were first allowed to use their own best procedures, but later were instructed to repeat the analysis using specified conditions: 20 kV accelerating voltage, 200s live time, ∼25% dead time and ∼40° takeoff angle. They were also asked to run a standardless analysis.
Ziebold-ogilvie after 25 years: A new superior α-factor correction for the quantitative analysis of metal alloys and compounds
Authors: Armstrong John T.
Published: June 2020

One of the first empirical correction procedures for quantitative electron microprobe analysis was the Ziebold-Ogilvie or so-called α-factor correction. This procedure assumed that in binary element systems (AB) there is a hyperbolic relation between relative emitted x-ray intensity (KA,AB) and relative concentration (CA,AB) such that:

or

where αA,AB is a constant for the binary AB. However, evidence developed that, for binary metal alloys when matrix corrections (particularly characteristic fluorescence) were high, the assumption that a is composition-independent was incorrect and the procedure produced significant systematic errors. Therefore, the α-factor procedure has never been widely-used for the analysis of metal alloys or similar samples. This paper proposes that if the constant α-factor in the Ziebold-Ogilvie procedure were replaced by a simple, composition-dependent polynomial expression, the resulting procedure were replaced by a simple, composition-dependent polynomial expression, the resulting correction procedure would be of equal accuracy to any of the currently-used correction methods.

Armstrong proposed that the α-factor procedure could be made more accurate if the constant αA,AB is replace by a polynomial (composition dependent) expression: