43 results on '"David C., Joy"'
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2. High Resolution Imaging
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John Henry J. Scott, David C. Joy, Dale E. Newbury, Joseph R. Michael, Nicholas W. M. Ritchie, and Joseph I. Goldstein
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010302 applied physics ,Beam diameter ,Materials science ,business.industry ,Resolution (electron density) ,02 engineering and technology ,021001 nanoscience & nanotechnology ,01 natural sciences ,Secondary electrons ,Optics ,Feature (computer vision) ,Electron optics ,0103 physical sciences ,0210 nano-technology ,business ,Visibility ,Image resolution ,Beam (structure) - Abstract
“High resolution SEM imaging” refers to the capability of discerning fine-scale spatial features of a specimen. Such features may be free-standing objects or structures embedded in a matrix. The definition of “fine-scale” depends on the application, which may involve sub-nanometer features in the most extreme cases. The most important factor determining the limit of spatial resolution is the footprint of the incident beam as it enters the specimen. Depending on the level of performance of the electron optics, the limiting beam diameter can be as small as 1 nm or even finer. However, the ultimate resolution performance is likely to be substantially poorer than the beam footprint and will be determined by one or more of several additional factors: (1) delocalization of the imaging signal, which consists of secondary electrons and/or backscattered electrons, due to the physics of the beam electron specimen interactions; (2) constraints imposed on the beam size needed to satisfy the Threshold Equation to establish the visibility for the contrast produced by the features of interest; (3) mechanical stability of the SEM; (4) mechanical stability of the specimen mounting; (5) the vacuum environment and specimen cleanliness necessary to avoid contamination of the specimen; (6) degradation of the specimen due to radiation damage; and (7) stray electromagnetic fields in the SEM environment. Recognizing these factors and minimizing or eliminating their impact is critical to achieving optimum high resolution imaging performance. Because achieving satisfactory high resolution SEM often involves operating at the performance limit of the instrument as well as the technique, the experience may vary from one specimen type to another, with different limiting factors manifesting themselves in different situations. Most importantly, because of the limitations on feature visibility imposed by the Threshold Current/Contrast Equation, for a given choice of operating conditions, there will always be a level of feature contrast below which specimen features will not be visible. Thus, there is always a possible “now you see it, now you don’t” experience lurking when we seek to operate at the limit of the SEM performance envelope. more...
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- 2017
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Catalog
3. Quantitative Analysis: From k-ratio to Composition
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Joseph I. Goldstein, David C. Joy, Joseph R. Michael, John Henry J. Scott, Nicholas W. M. Ritchie, and Dale E. Newbury
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Physics ,Wavelength ,Spectrometer ,Analytical chemistry ,Composition (combinatorics) ,Quantitative analysis (chemistry) ,Energy (signal processing) ,Intensity (heat transfer) ,Line (formation) - Abstract
A k-ratio is the ratio of a pair of characteristic X-ray line intensities, I, measured under similar experimental conditions for the unknown (unk) and standard (std): $$ k={I}_{unk}/{I}_{std} $$ The measured intensities can be associated with a single characteristic X-ray line (as is typically the case for wavelength spectrometers) or associated with a family of characteristic X-ray lines (as is typically the case for energy dispersive spectrometers.) The numerator of the k-ratio is typically the intensity measured from an unknown sample and the denominator is typically the intensity measured from a standard material—a material of known composition. more...
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- 2017
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4. Backscattered Electrons
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Joseph I. Goldstein, Dale E. Newbury, Joseph R. Michael, Nicholas W. M. Ritchie, John Henry J. Scott, and David C. Joy
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- 2017
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5. Low Beam Energy X-Ray Microanalysis
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Joseph R. Michael, Joseph I. Goldstein, John Henry J. Scott, Nicholas W. M. Ritchie, Dale E. Newbury, and David C. Joy
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Physics ,Astrophysics::High Energy Astrophysical Phenomena ,Excited state ,Ionization ,Atomic physics ,Beam energy ,Energy (signal processing) ,Intensity (heat transfer) ,Beam (structure) ,Excitation ,Exponential function - Abstract
The incident beam energy, E0, is the parameter that determines which characteristic X-rays can be excited: the beam energy must exceed the critical excitation energy, Ec, for an atomic shell to initiate ionization and subsequent emission of characteristic X-rays. This dependence is parameterized with the “overvoltage” U0, defined as $$ {U}_0={E}_0/{E}_c $$ U0 must exceed unity for X-ray emission. The intensity, Ich, of characteristic X-ray generation follows an exponential relation: $$ {I}_{ch}={i}_Ba{\left({U}_0-1\right)}^n $$ where iB is the beam current, a and n are constants, with 1.5 ≤ n ≤ 2. more...
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- 2017
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6. Energy Dispersive X-ray Spectrometry: Physical Principles and User-Selected Parameters
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Joseph I. Goldstein, David C. Joy, Joseph R. Michael, John Henry J. Scott, Nicholas W. M. Ritchie, and Dale E. Newbury
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Materials science ,Binding energy ,Charge carrier ,Electron hole ,Atomic physics ,Ionization energy ,Photon energy ,Kinetic energy ,Valence electron ,Semiconductor detector - Abstract
As illustrated in Fig. 16.1, the physical basis of energy dispersive X-ray spectrometry (EDS) with a semiconductor detector begins with photoelectric absorption of an X-ray photon in the active volume of the semiconductor (Si). The entire energy of the photon is transferred to a bound inner shell atomic electron, which is ejected with kinetic energy equal to the photon energy minus the shell ionization energy (binding energy), 1.838 keV for the Si K-shell and 0.098 keV for the Si L-shell. The ejected photoelectron undergoes inelastic scattering within the Si crystal. One of the consequences of the energy loss is the promotion of bound outer shell valence electrons to the conduction band of the semiconductor, leaving behind positively charged “holes” in the valence band. In the conduction band, the free electrons can move in response to a potential applied between the entrance surface electrode and the back surface electrode across the thickness of the Si crystal, while the positive holes in the conduction band drift in the opposite direction, resulting in the collection of electrons at the anode on the back surface of the EDS detector. This charge generation process requires approximately 3.6 eV per electron hole pair, so that the number of charge carriers is proportional to the original photon energy, Ep: $$ n={E}_p/3.6\ eV $$ For a Mn K-L3 photon with an energy of 5.895 keV, approximately 1638 electron–hole pairs are created, comprising a charge of 2.6 × 10−16 coulombs. Because the detector can respond to any photon energy from a threshold of approximately 50 eV to 30 keV or more, the process has been named “energy dispersive,” although in the spectrometry sense there is no actual dispersion such as occurs in a diffraction element spectrometer. more...
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7. Image Formation
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Joseph I. Goldstein, Dale E. Newbury, Joseph R. Michael, Nicholas W. M. Ritchie, John Henry J. Scott, and David C. Joy
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- 2017
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8. Compositional Mapping
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Joseph I. Goldstein, Dale E. Newbury, Joseph R. Michael, Nicholas W. M. Ritchie, John Henry J. Scott, and David C. Joy
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- 2017
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9. SEM Case Studies
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John Henry J. Scott, David C. Joy, Dale E. Newbury, Joseph R. Michael, Nicholas W. M. Ritchie, and Joseph I. Goldstein
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Crystal ,Optical axis ,Surface (mathematics) ,Software ,business.industry ,Computer graphics (images) ,Stereo pair ,Microscopist ,business ,Anaglyph 3D ,Geology - Abstract
When studying the topographic features of a specimen, the microscopist has several useful software tools available. Qualitative stereomicroscopy provides a composite view from two images of the same area, prepared with different tilts relative to the optic axis, that gives a visual sensation of the specimen topography, as shown for a fractured galena crystal using the anaglyph method in Fig. 15.1 (software: Anaglyph Maker). The “3D Viewer” plugin in ImageJ-Fiji can take the same members of the stereo pair and render the three-dimensional surface, as shown in Fig. 15.2, which can then be rotated to “view” the surface from different orientations (Fig. 15.3). more...
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- 2017
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10. SEM Image Interpretation
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Dale E. Newbury, Nicholas W. M. Ritchie, Joseph R. Michael, John Henry J. Scott, David C. Joy, and Joseph I. Goldstein
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Physics ,Specimen characteristics ,Image (category theory) ,Electron ,Atomic physics ,Secondary electrons ,Interpretation (model theory) - Abstract
Information in SEM images about specimen properties is conveyed when contrast in the backscattered and/or secondary electron signals is created by differences in the interaction of the beam electrons between a specimen feature and its surroundings. The resulting differences in the backscattered and secondary electron signals (S) convey information about specimen properties through a variety of contrast mechanisms. Contrast (Ctr) is defined as $$ {C}_{\mathrm{tr}}=\left({S}_{\mathrm{max}}-{S}_{\mathrm{min}}\right)/{S}_{\mathrm{max}} $$ where is Smax is the larger of the signals. By this definition, 0 ≤ Ctr ≤ 1. more...
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- 2017
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11. Trace Analysis by SEM/EDS
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Joseph I. Goldstein, John Henry J. Scott, Nicholas W. M. Ritchie, Joseph R. Michael, David C. Joy, and Dale E. Newbury
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Materials science ,Analytical chemistry ,Mass concentration (chemistry) ,Trace analysis - Abstract
«Trace analysis” refers to the measurement of constituents presents at low fractional levels. For SEM/EDS the following arbitrary but practical definitions have been chosen to designate various constituent classes according to these mass concentration (C) ranges more...
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- 2017
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12. Qualitative Elemental Analysis by Energy Dispersive X-Ray Spectrometry
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Dale E. Newbury, David C. Joy, John Henry J. Scott, Joseph R. Michael, Nicholas W. M. Ritchie, and Joseph I. Goldstein
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Range (particle radiation) ,Materials science ,Photon ,chemistry ,Elemental analysis ,Calibration ,Linearity ,chemistry.chemical_element ,Atomic physics ,Photon energy ,Copper ,Energy (signal processing) - Abstract
Before attempting automatic or manual peak identification, it is critical that the EDS system be properly calibrated to ensure that accurate energy values are measured for the characteristic X-ray peaks. Follow the vendor’s recommended procedure to rigorously establish the calibration. The calibration procedure typically involves measuring a known material such as copper that provides characteristic X-ray peaks at low photon energy (e.g., Cu L3-M5 at 0.928 keV) and at high photon energy (Cu K-L3 at 8.040 keV). Alternatively, a composite aluminum-copper target (e.g., a copper penny partially wrapped in aluminum foil and continuously scanned so as to excite both Al and Cu) can be used to provide the Al K-L3 (1.487 keV) as the low energy peak and Cu K-L3 for the high energy peak. After calibration, peaks occurring within this energy range (e.g., Ti K-L3 at 4.508 keV and Fe K-L3 at 6.400 keV) should be measured to confirm linearity. A well-calibrated EDS should produce measured photon energies within ±2.5 eV of the ideal value. Low photon energy peaks below 1 keV photon energy should also be measured, for example, O K (e.g., from MgO) and C K. For some EDS systems, non-linearity may be encountered in the low photon energy range. Figure 18.1 shows an EDS spectrum for CaCO3 in which the O K peak at 0.523 keV is found at the correct energy, but the C K peak at 0.282 keV shows a significant deviation below the correct energy due to non-linear response in this range. more...
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13. Variable Pressure Scanning Electron Microscopy (VPSEM)
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Nicholas W. M. Ritchie, Joseph I. Goldstein, John Henry J. Scott, Dale E. Newbury, David C. Joy, and Joseph R. Michael
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Materials science ,Scanning electron microscope ,Torr ,Variable pressure ,Analytical chemistry ,Sample chamber - Abstract
The conventional SEM must operate with a pressure in the sample chamber below ~10−4 Pa (~10−6 torr), a condition determined by the need to satisfy four key instrumental operating conditions
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- 2017
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14. X-Ray Microanalysis Case Studies
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John Henry J. Scott, Joseph R. Michael, Dale E. Newbury, David C. Joy, Joseph I. Goldstein, and Nicholas W. M. Ritchie
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Materials science ,Chemical engineering ,fungi ,Alloy ,technology, industry, and agriculture ,engineering ,Substrate (chemistry) ,engineering.material ,X ray microanalysis ,Characterization (materials science) - Abstract
Background: As part of a study into the in-service failure of the bearing surface of a large water pump, characterization was requested of the hard-facing alloy, which was observed to have separated from the stainless steel substrate, causing the failure. more...
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15. Cathodoluminescence
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Joseph I. Goldstein, Dale E. Newbury, Joseph R. Michael, Nicholas W. M. Ritchie, John Henry J. Scott, and David C. Joy
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- 2017
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16. Ion Beam Microscopy
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Joseph I. Goldstein, Dale E. Newbury, Joseph R. Michael, John Henry J. Scott, David C. Joy, and Nicholas W. M. Ritchie
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Materials science ,Microscope ,Ion beam ,business.industry ,Scanning electron microscope ,Scanning confocal electron microscopy ,Focused ion beam ,law.invention ,Ion beam deposition ,Optics ,law ,Microscopy ,Electron microscope ,business - Abstract
Electron beams have made possible the development of the versatile, high performance electron microscopes described in the earlier chapters of this book. Techniques for the generation and application of electron beams are now well documented and understood, and a wide variety of images and data can be produced using readily available instruments. While the scanning electron microscope (SEM) is the most widely used tool for high performance imaging and microanalysis, it is not the only option and may not even always be the best instrument to choose to solve a particular problem. In this chapter we will discuss how, by replacing the beam of electrons with a beam of ions, it is possible to produce a high performance microscope which resembles an SEM in many respects and shares some of its capabilities but which also offers additional and important modes of operation. more...
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- 2017
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17. Electron Beam—Specimen Interactions: Interaction Volume
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Joseph I. Goldstein, Joseph R. Michael, David C. Joy, John Henry J. Scott, Nicholas W. M. Ritchie, and Dale E. Newbury
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Range (particle radiation) ,Materials science ,Optics ,business.industry ,Atom ,Ultra-high vacuum ,Cathode ray ,Physics::Accelerator Physics ,Electron ,Residual ,business ,Beam (structure) ,Electron gun - Abstract
By selecting the operating parameters of the SEM electron gun, lenses, and apertures, the microscopist controls the characteristics of the focused beam that reaches the specimen surface: energy (typically selected in the range 0.1–30 keV), diameter (0.5 nm to 1 μm or larger), beam current (1 pA to 1 μA), and convergence angle (semi-cone angle 0.001–0.05 rad). In a conventional high vacuum SEM (typically with the column and specimen chamber pressures reduced below 10−3 Pa), the residual atom density is so low that the beam electrons are statistically unlikely to encounter any atoms of the residual gas along the flight path from the electron source to the specimen, a distance of approximately 25 cm. more...
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- 2017
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18. Characterizing Crystalline Materials in the SEM
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Dale E. Newbury, John Henry J. Scott, David C. Joy, Joseph I. Goldstein, Joseph R. Michael, and Nicholas W. M. Ritchie
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Diffraction ,Crystal ,Materials science ,Crystal structure ,Electron ,Microstructure ,Molecular physics ,Charged particle ,Electron backscatter diffraction ,Amorphous solid - Abstract
While amorphous substances such as glass are encountered both in natural and artificial materials, most inorganic materials are found to be crystalline on some scale, ranging from sub-nanometer to centimeter or larger. A crystal consists of a regular arrangement of atoms, the so-called «unit cell,» which is repeated in a two- or three-dimensional pattern. In the previous discussion of electron beam–specimen interactions, the crystal structure of the target was not considered as a variable in the electron range equation or in the Monte Carlo electron trajectory simulation. To a first order, the crystal structure does not have a strong effect on the electron–specimen interactions. However, through the phenomenon of channeling of charged particles through the crystal lattice, crystal orientation can cause small perturbations in the total electron backscattering coefficient that can be utilized to image crystallographic microstructure through the mechanism designated «electron channeling contrast,» also referred to as «orientation contrast» (Newbury et al. 1986). The characteristics of a crystal (e.g., interplanar angles and spacings) and its relative orientation can be determined through diffraction of the high-energy backscattered electrons (BSE) to form «electron backscatter diffraction patterns (EBSD). more...
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- 2017
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19. ImageJ and Fiji
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Dale E. Newbury, David C. Joy, John Henry J. Scott, Joseph R. Michael, Joseph I. Goldstein, and Nicholas W. M. Ritchie
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Focus (computing) ,Microscope ,Computer science ,business.industry ,Interface (computing) ,USB ,law.invention ,Software ,law ,Computer graphics (images) ,Microscopist ,Instrumentation (computer programming) ,business ,Graphical user interface - Abstract
Software is an essential tool for the scanning electron microscopist and X-ray microanalyst (SEMXM). In the past, software was an important optional means of augmenting the electron microscope and X-ray spectrometer, permitting powerful additional analysis and enabling new characterization methods that were not possible with bare instrumentation. Today, however, it is simply not possible to function as an SEMXM practitioner without using at least a minimal amount of software. A graphical user interface (GUI) is an integral part of how the operator controls the hardware on most modern microscopes, and in some cases it is the only interface. Even many seemingly analog controls such as focus knobs, magnification knobs, or stigmators are actually digital interfaces mounted on hand-panel controllers that connect to the microscope control computer via a USB interface. more...
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- 2017
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20. DTSA-II EDS Software
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David C. Joy, Dale E. Newbury, Joseph I. Goldstein, John Henry J. Scott, Joseph R. Michael, and Nicholas W. M. Ritchie
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Software ,Ms excel ,Computer science ,Vendor ,business.industry ,Nothing ,Reading (process) ,media_common.quotation_subject ,Subject (documents) ,Software engineering ,business ,Subject matter ,media_common - Abstract
Reading about a new subject is good but there is nothing like doing to reinforce understanding. With this in mind, the authors of this textbook have designed a number of practical exercises that reinforce the book’s subject matter. Some of these exercises can be performed with software you have available to you—either instrument vendor software or a spreadsheet like MS Excel or LibreOffice/OpenOffice Calc. Other exercises require functionality which may not be present in all instrument vendor’s software. Regardless, it is much easier to explain an exercise when everyone is working with the same tools. more...
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- 2017
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21. Focused Ion Beam Applications in the SEM Laboratory
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Nicholas W. M. Ritchie, David C. Joy, Joseph R. Michael, John Henry J. Scott, Joseph I. Goldstein, and Dale E. Newbury
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Materials science ,Ion beam ,business.industry ,Optoelectronics ,Sample preparation ,Plasma ,Large range ,business ,Focused ion beam ,Secondary electrons ,Ion source ,Ion - Abstract
The use of focused ion beams (FIB) in the field of electron microscopy for the preparation of site specific samples and for imaging has become very common. Site specific sample preparation of cross-section samples is probably the most common use of the focused ion beam tools, although there are uses for imaging with secondary electrons produced by the ion beam. These tools are generally referred to as FIB tools, but this name covers a large range of actual tools. There are single beam FIB tools which consist of the FIB column on a chamber and also the FIB/SEM platforms that include both a FIB column for sample preparation and an SEM column for observing the sample during preparation and for analyzing the sample post-preparation using all of the imaging modalities and analytical tools available on a standard SEM column. A vast majority of the FIB tools presently in use are equipped with liquid metal ion sources (LMIS) and the most common ion species used is Ga. Recent developments have produced plasma sources for high current ion beams. The gas field ion source (GFIS) is discussed in module 31 on helium ion microscopy in this book. more...
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- 2017
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22. Quantitative Analysis: The SEM/EDS Elemental Microanalysis k-ratio Procedure for Bulk Specimens, Step-by-Step
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John Henry J. Scott, Joseph R. Michael, Joseph I. Goldstein, Dale E. Newbury, Nicholas W. M. Ritchie, and David C. Joy
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Materials science ,Analytical chemistry ,Microanalysis - Abstract
This module discusses the procedure used to perform a rigorous quantitative elemental microanalysis by SEM/EDS following the k-ratio/matrix correction protocol using the NIST DTSA-II software engine for bulk specimens. Bulk specimens have dimensions that are sufficiently large to contain the full range of the direct electron-excited X-ray production (typically 0.5–10 μm) as well as the range of secondary X-ray fluorescence induced by the propagation of the characteristic and continuum X-rays (typically 10–100 μm). more...
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- 2017
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23. X-Rays
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Joseph I. Goldstein, Dale E. Newbury, Joseph R. Michael, Nicholas W. M. Ritchie, John Henry J. Scott, and David C. Joy
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- 2017
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24. SEM Imaging Checklist
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David C. Joy, Joseph R. Michael, Dale E. Newbury, John Henry J. Scott, Nicholas W. M. Ritchie, and Joseph I. Goldstein
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Outgassing ,Materials science ,Optics ,Ground ,business.industry ,Airlock ,Magnification ,Electron ,Adhesive ,business ,Stub (electronics) ,Shrinkage - Abstract
A conducting or semiconducting specimen must maintain good contact with electrical ground to dissipate the injected beam current. Without such an electrical path, even a highly conducting specimen such as a metal will show charging artifacts, in the extreme case acting as an electron mirror and reflecting the beam off the specimen. A typical strategy is to use an adhesive such as double-sided conducting tape to both grip the specimen to a support, for example, a stub or a planchet, as well as to make the necessary electrical path connection. Note that some adhesives may only be suitable for low magnification (scanned field dimensions greater than 100 × 100 μm, nominally less than 1,000× magnification) and intermediate magnification (scanned field dimensions between 100 μm x 100 μm, nominally less than 1,000X magnification and 10 μm × 10 μm, nominally less than 10,000× magnification) due to dimensional changes which may occur as the adhesive outgases in the SEM leading to image instability such as drift. Good practice is to adequately outgas the mounted specimen in the SEM airlock or a separate vacuum system to minimize contamination in the SEM as well as to minimize further dimensional shrinkage. Note that some adhesive media are also subject to dimensional change due to electron radiation damage during imaging, which can also lead to image drift. more...
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- 2017
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25. Energy Dispersive X-Ray Microanalysis Checklist
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John Henry J. Scott, Dale E. Newbury, Joseph R. Michael, David C. Joy, Joseph I. Goldstein, and Nicholas W. M. Ritchie
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Materials science ,Analytical chemistry ,Checklist ,Energy (signal processing) ,X ray microanalysis - Published
- 2017
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26. Secondary Electrons
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Joseph I. Goldstein, Dale E. Newbury, Joseph R. Michael, Nicholas W. M. Ritchie, John Henry J. Scott, and David C. Joy
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- 2017
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27. Image Defects
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Joseph I. Goldstein, Dale E. Newbury, Joseph R. Michael, Nicholas W. M. Ritchie, John Henry J. Scott, and David C. Joy
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- 2017
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28. Low Beam Energy SEM
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Joseph I. Goldstein, Nicholas W. M. Ritchie, Joseph R. Michael, Dale E. Newbury, John Henry J. Scott, and David C. Joy
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Physics ,Range (particle radiation) ,Incident beam ,Electron ,Atomic number ,Atomic physics ,Beam energy ,Atomic mass ,Energy (signal processing) - Abstract
The incident beam energy is one of the most useful parameters over which the microscopist has control because it determines the lateral and depth sampling of the specimen properties by the critical imaging signals. The Kanaya–Okayama electron range varies strongly with the incident beam energy: $$ {R}_{K-O}(nm)=\left(27.6\ A/{Z}^{0.89}\rho \right){E_0}^{1.67} $$ where A is the atomic weight (g/mol), Z is the atomic number, ρ is the density (g/cm3), and E0 (keV) is the incident beam energy, which is shown graphically in Fig. 11.1a–c. more...
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- 2017
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29. Analysis of Specimens with Special Geometry: Irregular Bulk Objects and Particles
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Nicholas W. M. Ritchie, David C. Joy, Joseph I. Goldstein, Joseph R. Michael, John Henry J. Scott, and Dale E. Newbury
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Materials science ,Basis (linear algebra) ,Astrophysics::High Energy Astrophysical Phenomena ,Geometry ,Microanalysis ,Special geometry - Abstract
There are two “zero-th level” assumptions that underpin the basis for quantitative electron-excited X-ray microanalysis
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- 2017
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30. Attempting Electron-Excited X-Ray Microanalysis in the Variable Pressure Scanning Electron Microscope (VPSEM)
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Joseph R. Michael, John Henry J. Scott, Joseph I. Goldstein, Dale E. Newbury, David C. Joy, and Nicholas W. M. Ritchie
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Materials science ,Scanning electron microscope ,Excited state ,Variable pressure ,Composite number ,Electron ,Atomic physics ,Microanalysis ,Electron scattering ,Beam (structure) - Abstract
While X-ray analysis can be performed in the Variable Pressure Scanning Electron Microscope (VPSEM), it is not possible to perform uncompromised electron-excited X-ray microanalysis. The measured EDS spectrum is inevitably degraded by the effects of electron scattering with the atoms of the environmental gas in the specimen chamber before the beam reaches the specimen. The spectrum is always a composite of X-rays generated by the unscattered electrons that remain in the focused beam and strike the intended target mixed with X-rays generated by the gas-scattered electrons that land elsewhere, micrometers to millimeters from the microscopic target of interest. more...
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- 2017
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31. The Visibility of Features in SEM Images
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Joseph R. Michael, Joseph I. Goldstein, Nicholas W. M. Ritchie, Dale E. Newbury, John Henry J. Scott, and David C. Joy
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Physics ,Signal processing ,Noise (signal processing) ,business.industry ,media_common.quotation_subject ,Signal ,Secondary electrons ,Optics ,Digital image processing ,Contrast (vision) ,Imaging Signal ,Visibility ,business ,media_common - Abstract
The detection in SEM images of specimen features such as compositional differences, topography (shape, inclination, edges, etc.), and physical differences (crystal orientation, magnetic fields, electrical fields, etc.), depends on satisfying two criteria: (1) establishing the minimum conditions necessary to ensure that the contrast created by the beam–specimen interaction responding to differences in specimen features is statistically significant in the imaging signal (backscattered electrons [BSE], secondary electrons [SE], or a combination) compared to the inevitable random signal fluctuations (noise); and (2) applying appropriate signal processing and digital image processing to render the contrast information that exists in the signal visible to the observer viewing the final image display. more...
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- 2017
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32. Operating the Helium Ion Microscope
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David C. Joy
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Range (particle radiation) ,Microscope ,Materials science ,business.industry ,Analytical chemistry ,chemistry.chemical_element ,Ion source ,law.invention ,Optics ,chemistry ,law ,Chromatic aberration ,Bibliography ,Particle beam ,business ,Helium ,Field ion microscope - Abstract
As noted in the previous section, the present ALIS helium ion source is a descendant of the original work based on FIM technology (for a historical overview see Muller and Tsong 1993) although important research in this area has also been carried out by several other prominent groups (e.g. Orloff and Swanson 1977). In order to be suitable for application, in a high-performance particle beam microscope, the source should ideally not only be bright, but also be as compact as possible to ensure mechanical stability, provide highly stable emission over time periods of several hours, be capable of operating at energies at least in the 10–50 keV range, and be capable of being re-formed and then reused multiple times without a significant change in performance. An overview of history of the helium ion microscope can be found in the literature (Economou 2011), while other technical details can be found in the published patents listed at the end of the bibliography. more...
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- 2013
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33. Charging and Damage
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David C. Joy
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Materials science ,Scanning electron microscope ,business.industry ,Optoelectronics ,Ion microscopy ,business ,Sample (graphics) - Abstract
A major concern in both scanning electron and scanning ion microscopy is that of sample charging, but strategies to eliminate this problem are available.
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- 2013
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34. Working with Other Ion beams
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David C. Joy
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Range (particle radiation) ,Optics ,Materials science ,Feature (computer vision) ,business.industry ,Signal production ,business ,Ion source ,Energy (signal processing) ,Field ion microscope ,Ion - Abstract
A feature of the GFIS ion source is that every aspect of its operation and behavior—from its imaging resolution, the energy range over which it operates, the efficiency of signal production, and the damage it does to the materials that it examines—is ultimately affected by the choice of imaging gas. Ideally, the same source could rapidly be reconfigured to select and generate any one of a number of different ion beams. Because each type of ion has its own strengths and weaknesses, this feature would add substantially to the utility of the ion microscope. more...
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- 2013
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35. Introduction to Helium Ion Microscopy
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David C. Joy
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Microscope ,Materials science ,Ion beam ,Scanning electron microscope ,chemistry.chemical_element ,Electron ,Absolute limit ,law.invention ,chemistry ,law ,Microscopy ,Atomic physics ,Ion microscopy ,Helium - Abstract
The scanning electron microscope (SEM) has become the most widely used high-performance microscope. However because of the fundamental limitations of electron beams the new technology of ion beam microscopy is being developed more...
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- 2013
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36. Patterning and Nanofabrication
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David C. Joy
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Materials science ,Nanolithography ,business.industry ,Transmission electron microscopy ,Optoelectronics ,business ,Nanoscopic scale ,Ion - Abstract
As seen above, ion beams can rapidly remove material from a specimen placed in the HIM. Depending on the proposed application, this could then be considered either as damage—and so be undesirable—or as a unique tool to pattern material. The use of Ga+ beams for thinning or cross sectioning materials prior to examination in a transmission electron microscope is well known and in widespread use. As noted earlier, less known is the fact that light ions such as He+ can also remove material from a surface, although at a much reduced rate, providing a method to shape, mark, and pattern materials on nanoscale. more...
- Published
- 2013
- Full Text
- View/download PDF
37. Microscopy with Ions: A Brief History
- Author
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David C. Joy
- Subjects
Brightness ,Materials science ,Microscope ,Scanning electron microscope ,business.industry ,Beam source ,Ion ,law.invention ,Quality (physics) ,Optics ,law ,Microscopy ,business ,Field ion microscope - Abstract
Every microscope requires a high brightness, reliable, stable source of illumination in order to function, and both the quality and the quantity of the illumination provided will determine, and ultimately limit, the performance of the instrument. Each type of microscope will have its own type of illuminating source. For a high-performance scanning electron or ion microscope, the most desirable property of the beam source is that the source must have a high brightness. more...
- Published
- 2013
- Full Text
- View/download PDF
38. Helium Ion Microscopy
- Author
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David C. Joy
- Subjects
Materials science ,chemistry ,Analytical chemistry ,chemistry.chemical_element ,Ion microscopy ,Helium - Published
- 2013
- Full Text
- View/download PDF
39. Ion–Solid Interactions and Image Formation
- Author
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David C. Joy
- Subjects
Physics ,Image formation ,Electron ,Beam energy ,Signal ,Image resolution ,Secondary electrons ,Beam (structure) ,Computational physics ,Ion - Abstract
Both electron and ion beams can be used to provide a number of different modes of imaging and microanalysis In every case, and in order to properly optimize and interpret the data generated by the instrument, it is necessary to know something about what kinds of beam interactions are involved, what information may be obtained from each, and how the signal yields and spatial resolution can be optimized in each case. Images whose origins are neither known nor understood can never be any more than just a pretty picture. more...
- Published
- 2013
- Full Text
- View/download PDF
40. Ion-Generated Damage
- Author
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David C. Joy
- Subjects
chemistry.chemical_classification ,Materials science ,Low dose ,food and beverages ,Polymer ,Electron ,Carbon nanotube ,Molecular physics ,law.invention ,Ion ,Metal ,chemistry ,law ,visual_art ,visual_art.visual_art_medium ,Atomic number - Abstract
It has to be expected that both ions and electrons will damage specimens under examination to a greater or lesser degree. Electrons are low in mass but can travel at velocities which are a significant fraction of the speed of light. In general, electrons do not significantly damage metallic or inorganic specimens, but even relatively low doses of electrons can be expected to chemically alter or destroy organic materials such as polymers and biological samples. more...
- Published
- 2013
- Full Text
- View/download PDF
41. Microanalysis with HIM
- Author
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David C. Joy
- Subjects
Periodic table (crystal structure) ,Optics ,Materials science ,business.industry ,Energy-dispersive X-ray spectroscopy ,High spatial resolution ,Cathode ray ,business ,Microanalysis ,Chemical composition ,Ion - Abstract
For many users, the most important application of an SEM is its ability to identify the chemical composition of a specimen. Energy dispersive spectroscopy (EDS) of the X-rays fluoresced from samples of interest by the incident electron beam provides chemical microanalysis combining unparalleled sensitivity together with high spatial resolution for elements across the entire periodic table. This technique would therefore also be the automatic first choice for microanalysis when using ion beams if it were a viable option. more...
- Published
- 2013
- Full Text
- View/download PDF
42. Noise and Its Effects on the Low-Voltage SEM
- Author
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David C. Joy
- Subjects
Materials science ,Optics ,Scanning electron microscope ,business.industry ,Secondary emission ,Detector ,Resolution (electron density) ,business ,Low voltage ,Image resolution ,Noise (radio) ,Beam (structure) - Abstract
Noise is the single most important limiting factor in scanning electron microscopy. Because of the presence of noise, we are forced to operate the SEM to maximize the available beam current and the beam dose (current × time) at the expense of degraded image resolution, increased charging, and more sample damage. Recent developments in high-performance electron guns, aberration correctors, and lenses are all part of an attempt to attain control of the noise while still achieving ever higher levels of resolution. In this chapter, we will examine noise in the SEM, its origin and properties, its measurement, and how the properties of the detectors used for the collection of secondary emission (SE) electrons and backscatter electrons (BSE) signals affect the noise. more...
- Published
- 2007
- Full Text
- View/download PDF
43. Biological Low-Voltage Scanning Electron Microscopy
- Author
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James B. Pawley and Heide Schatten
- Subjects
business.industry ,Chemistry ,Scanning electron microscope ,Science and engineering ,Correlative microscopy ,High resolution ,Nanotechnology ,law.invention ,Optics ,law ,Specimen preparation ,Electron microscope ,business ,Low voltage - Abstract
Table of Contents 1. Low Voltage Scanning Electron Microscopy In Biology--Historical Preface : The Early Development of the Scanning Electron Microscope to 1965...1 Dennis McMullan 2. LVSEM For Biology...27 James B. Pawley, PhD 3. The Aberration-Corrected SEM...101 David Joy Science and Engineering Research Facility, University of Tennessee 4. Noise and its effects on the Low Voltage SEM...121 David C Joy 5. High-Resolution Low Voltage Field-Emission Scanning Electron Microscopy (HRLVFESEM) Applications for Cell Biology and Specimen Preparation Protocols...146 Heide Schatten, PhD 6. Molecular labeling for Correlative Microscopy: LM, LVSEM, TEM, EF-TEM and HVEM...173 Ralph Albrecht and Daryl Meyer 7. Low kV and video-rate, beam-tilt stereo for viewing live-time experiments in the SEM...209 Alan Boyde 8. CryoSEM of Chemically Fixed Animal Cells...228 Stanley L. Erlandsen 9. High resolution and low voltage SEM of plant cells...249 Guy Cox, Peter Vesk, Teresa Dibbayawan, Tobias I. Baskin and Maret Vesk 10. High Resolution Cryo-Scanning Electron Microscopy of Biological Samples...268 Paul Walther 11. Developments in Instrumentation for Microanalysis in Low Voltage Scanning Electron Microscopy...305 Dale E. Newbury more...
- Published
- 2008
- Full Text
- View/download PDF
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