bluuebunny/crossref_metadata_2025_split huggingface dataset:
High‐Energy Ion Beam Analysis
Authors: Doyle Barney , McDaniel Floyd Del 
Published: October 2003

Abstract
It is very hard to identify the earliest application of high‐energy ion beam analysis (IBA), which was a natural outgrowth of accelerator‐based atomic and nuclear physics that started in the 1940s with the development of particle accelerators. In these early experiments, the composition of the target to be studied was well known, and it was the nuclear scattering or reaction cross‐section that was measured. It would not be surprising if one of the very first nuclear physics pioneers turned this emphasis around and used their beams to measure the compositional uniformity of an unknown sample. Perhaps the earliest known proposal for IBA was that of E. Rubin in 1949 at the Stanford Research Institute, which spelled out the principle of Rutherford backscattering spectrometry (RBS). Another very early application of IBA was performed by Harald Enge at MIT. Enge used mega‐electron‐volt deuterons from one of Van de Graaff's first accelerators with a magnetic spectrometer to measure the constituents of aluminized Formvar in perhaps the earliest materials analysis application of nuclear reaction analysis (NRA). It is interesting to note that the use of magnetic spectrometers to obtain ultrahigh depth resolution is now common.
High‐Energy IBA is generally thought to apply when the ion beam has energy greater than 0.5 MeV. There are several attributes of high‐energy IBA, including (1) the ability to measure virtually any element in the periodic table, at times with isotopic specificity; (2) the ability to determine concentration as a function of depth; (3) that trace element sensitivity is not uncommon; and (4)that the technique is nondestructive with respect to the chemical makeup of the sample.
The periodic table given provides a convenient overview of high‐energy IBA capabilities.
Auger Electron Spectroscopy
Authors: Grant John T. 
Published: October 2003

Abstract
Auger electron spectroscopy (AES) is a method for determining the elemental composition of the several outermost atomic layers of materials. The surface layers often have a composition that is quite different from the bulk material due to contamination, oxidation, or processing. In AES, a specimen is probed with an energetic electron beam with an energy fixed between 3 and 30 keV, resulting in the ejection of core‐level electrons from atoms. The resulting vacancy in a core level can be filled by an outer‐level electron, with the excess energy being used to emit either an x‐ray (electron probe microanalysis) or another electron from the atom (AES). This emitted electron is called an Auger electron. AES is a surface‐sensitive technique due to the strong inelastic scattering of low‐energy electrons traveling within specimens. Auger electrons from only the outermost several atomic layers are emitted from the specimen without energy loss, and contribute to the Auger peak intensities in a spectrum. The Auger electron kinetic energies are characteristic of the emitting atoms, and the measurement of their energies is used to identify the elements that produce them. The concentrations of elements detected can be determined from the intensities of the Auger peaks. Variation of composition with depth can be determined by depth profiling, which is usually accomplished by removing atomic layers by sputtering with inert gas ions and monitoring the Auger signals from the newly created surfaces. For most elements, the detection limit with AES is between 0.1 and 1 at.%.
Radiation Effects Microscopy
Authors: Breese Mark B.H. 
Published: October 2003

AbstractRadiation effects microscopy is a general name that includes both ion‐beam‐induced charge (IBIC) microscopy and single‐event upset (SEU) imaging. Ion‐beam‐induced charge microscopy was initially developed as a means of imaging the distribution of buriedpnjunctions in microelectronic devices and dislocation networks in semiconductors. More recently it has found a wider range of applications, e.g., in the study of solar cells, segmented silicon detectors, and chemical vapor deposition (CVD) diamond films.Ion‐beam‐induced charge microscopy uses a beam of mega‐electron‐volt light ions, mainly protons or helium, to create electron‐hole pairs in semiconductor material. This energy transfer from the incident ions to the material causes them to lose energy and eventually stop in the material at a well‐defined distance called the ion range. The number of these electron or hole charge carriers that are collected at a junction within the sample is measured and displayed as a function of position of the focused beam within the scanned area.As microelectronic device features continually shrink, the amount of charge that defines the different logic levels becomes smaller. This means that the charge generated by the passage of ionizing radiation through the device is more likely to cause a change in its logic state, called a soft upset, or a SEU. This phenomenon is particularly important for satellite‐based devices, which are exposed to a high flux of ionizing cosmic radiation. It is a serious problem in the design of high‐density semiconductor memories. The lack of spatially resolved information led to difficulties in determining which part of the device caused the upsets. Single‐event upset analyses with collimated heavy‐ion beams revealed the benefits of spatially resolving the results. This prompted the development of SEU microscopy at Sandia. This has many similarities to IBIC, which is usually performed in conjunction with SEU microscopy to image the device components present within the area analyzed for upsets. The two techniques use almost all the same nuclear microprobe hardware and electronics. Whereas IBIC mainly uses mega‐electron‐volt light‐ion beams for analysis, SEU analysis uses heavier ions, such as carbon or silicon, to create a plasma density of electron‐hole charge carriers high enough to cause upsets.A major advantage of IBIC and SEU microscopy over competing electron beam techniques is their ability to give high‐spatial‐resolution analysis in thick layers. This is due to the different shapes of the charge carrier generation volume of mega‐electron‐volt ions compared with kilo‐electron‐volt electrons.
Ion‐Beam Techniques
Authors: Doyle Barney L. , Horn Kevin M. 
Published: October 2003

Abstract

Ion Beam Analysis (IBA) involves the use of a well‐defined
Beam
of energetic
Ions
for the purpose of
Analyzing
materials. In general, it is the combined attributes of the incident ions' energy, mass, and mode of interaction with the target that distinguish each of the analytic techniques described in this chapter. The range of possible ion‐atom interactions that can occur in a target, and the results of that interaction that produces the detected signal, give each technique specific advantages under specific circumstances. In the articles in this section, IBA techniques are described which utilize ion species spanning nearly the entire periodic table, ion energies which extend from several electron volts to several million electron volts, and detected signals consisting of nuclei, electrons, γ rays, x rays, optical photons, collected electrical charge, and even logic states in digital circuits.
Elastic Ion Scattering for Composition Analysis
Authors: Barbour J.C. 
Published: October 2003

Abstract
Composition analyses for virtually all of the elements on the periodic table can be performed through a combination of elastic ion‐scattering techniques: Rutherford backscattering spectrometry (RBS), elastic recoil detection (ERD), and enhanced‐cross‐section backscattering spectrometry (EBS). This article reviews the basic concepts used in elastic ion scattering for composition analysis and give examples of their use. Elastic ion scattering is also used for structure determination utilizing techniques such as ion channeling. Composition determination using ion‐beam analysis (IBA) falls into two categories: composition‐depth profiling and determination of the total integrated composition of a thin region. Unknown species in a sample may be identified using elastic ion‐scattering techniques, but in general, analyses involving characteristic x rays or γ rays are more accurate for determining the presence of unknown constituents. For elastic ion scattering, if the ion beam and ion energy are chosen to have sufficiently high energy loss in the sample, then a composition profile is determined as a function of depth by collecting one ion‐scattering spectrum. To represent accurately the composition profile as a function of depth in the sample, an accurate knowledge of the sample's volume density is required because IBA techniques are insensitive to density. If the density of the sample is unknown, then the depth in the sample is given in terms of an areal density: depth times volume density. When the incident ion beam is very light or the ion energy very high, then the composition as a function of depth may not be resolved fully, in which case the average composition of the layer of interest is determined by integrating the signal. In this way, the number of atoms per unit area (areal density) is determined from the integrated signal.
Nuclear Reaction Analysis and Proton‐Induced Gamma Ray Emission
Authors: Vizkelethy György 
Published: October 2003

Abstract
Nuclear reaction analysis (NRA) and proton‐ (particle‐) induced gamma ray emission (PIGE) are based on the interaction of energetic (from a few hundred kilo‐electron‐volt to several mega‐electron‐volt) ions with light nuclei. Every nuclear analytical technique that uses nuclear reactions has a unique feature—isotope sensitivity. Therefore, it is insensitive to matrix effects, and there is much less interference than in methods where signals from different elements overlap. In NRA the nuclear reaction produces charged particles, while in PIGE the excited nucleus emits gamma rays. Sometimes the charged particle emission and the gamma ray emission occur simultaneously. Both NRA and PIGE measure the concentration and depth distribution of elements in the surface layer (few micrometers) of the sample. Both techniques are limited by the available nuclear reactions. Generally, they can be used for only light elements, up to calcium. This is the basis for an important property of these methods: the nuclear reaction technique is one of the few analytical techniques that can quantitatively measure hydrogen profiles in solids. Since these techniques are sensitive to the nuclei in the sample, they are unable to provide information about the chemical states and bonds of the elements in the sample. For the same reason they cannot provide information about the microscopic structure of the sample. Combined with channeling, NRA or PIGE can provide information about the location of the measured element in a crystalline lattice.
The sensitivity and depth resolution of these methods depend on the specific nuclear reaction.
Although NRA and PIGE are quantitative, in most cases standards have to be used.
These techniques require a particle accelerator capable of accelerating ions up to several mega‐electron‐volts. This limits their availability to laboratories dedicated to these methods or that have engaged in low‐energy nuclear physics in the past (i.e., they have a particle accelerator that is no longer adequate for modern nuclear physics experiments because of its low energy but is quite suitable for nuclear analytical techniques).
This article concentrates on the specific aspects of these two nuclear analytical techniques.
Particle‐Induced X‐Ray Emission
Authors: Campbell John L. 
Published: October 2003

AbstractParticle‐induced x‐ray emission (PIXE) is an elemental analysis technique that employs a mega‐electron‐volt energy beam of charged particles from a small electrostatic accelerator to induce characteristic x‐ray emission from the inner shells of atoms in the specimen. The accelerator can be single ended or tandem. Most PIXE work is done with 2‐ to 4‐MeV proton beams containing currents of a few nanoamperes within a beam whose diameter is typically a few millimeters; a small amount of work with deuteron and helium beams has been reported, and use of heavier ion beams has been explored. The emitted x rays are nearly always detected in the energy‐dispersive mode using a Si(Li) spectrometer. Although wavelength‐dispersive x‐ray spectrometry would provide superior energy resolution, its low geometric efficiency is a significant disadvantage for PIXE, in which potential specimen damage by heating limits the beam current and therefore the emitted x‐ray intensity. In the proton microprobe, magnetic or electrostatic quadrupole lenses are employed to focus the beam to micrometer spot size; this makes it possible to perform micro‐PIXE analysis of very small features and, also, by sweeping this microbeam along a preselected line or over an area of the specimen, to determine element distributions in one or two dimensions in a fully quantitative manner. Most proton microprobes realize a beam spot size smaller than a few micrometers at a beam current of at least 0.1 nA. In trace element analysis or imaging by micro‐PIXE, the high efficiency of a Si(Li) detector, placed as close to the specimen as possible, is again mandatory for x‐ray collection. To date, PIXE and micro‐PIXE have most often been used to conduct trace element analysis in specimens whose major element composition is already known or has been measured by other means, such as electron microprobe analysis. However, both variants are capable of providing major element analysis for elements of atomic number down to.
Medium‐Energy Backscattering and Forward‐Recoil Spectrometry
Authors: Weller Robert A. 
Published: October 2003

Abstract

Medium‐energy backscattering spectrometry is a variation of Rutherford backscattering spectrometry (RBS) using ions with energies ranging from a few tens to a few hundreds of kilo‐electron‐volts. The ion beam, frequently He
+
, is directed onto a specimen and the number of backscattered ions per incident ion is measured as a function of scattered‐ion energy at one or more angles relative to the beam direction. The fundamental physical process being used is that of a binary collision between the nuclei of an ion in the beam and a near‐stationary atom in the target. In such a collision, the energy of the backscattered ion is determined uniquely by its original energy, the scattering angle (which is the angle between the ion's trajectories before and after the collision), and the ratio of the masses. Consequently, a measurement of the energy of a backscattered ion at a specific angle may be used to infer the mass of the target atom with which it collided. The number of backscattered ions is proportional to the collision cross‐section and the total number of available scattering centers. Since collision cross‐sections are known
a priori
in this energy range, the number of backscattered ions with a given energy is a direct measure of the number of atoms of the corresponding mass in the target.

The method achieves additional richness as the result of a second physical phenomenon, the gradual loss of kinetic energy through collisions as an ion penetrates through matter. This is measured by stopping power (also called linear energy transfer), which is the average energy lost, typically in electron volts per unit of length (measured in atoms per square centimeter) of trajectory in the target. A second factor controlling the energy of backscattered ions is the depth within the target at which the collision occurs. As a result, it is usually possible to extract quantitative information about the distribution of specific species within the near‐surface region of the specimen. For the purposes of this article, it is sufficient to note that for medium‐energy ions the stopping power is dominated by collisions between the nucleus of the projectile and the electrons of the target, so‐called electronic stopping, which results in relatively uniform loss of energy with minimal angular divergence of the beam. Widely accepted semiempirical procedures are available for computing electronic stopping power.
Particle detection technology is an extremely important issue in medium‐energy ion beam analysis. This article also is focus on time‐of‐flight spectrometry optimized for high‐resolution measurements. Other methods, including magnetic and electrostatic spectrometers, pulsed‐beam accelerator systems, and time‐of‐flight spectrometry optimized for other measurements, are discussed briefly along with several other methods for depth profiling, trace‐element identification, and hydrogen measurement. Throughout, special attention is paid to the relationship between medium‐energy backscattering and conventional high‐energy RBS.
Neutron Techniques
Authors: Goldman Alan I. 
Published: October 2003

Abstract
This section explores the wide range of applications of elastic and inelastic neutron scattering to the study of materials. Neutron scattering provides information complementary to several other techniques found in the Encyclopedia. Perhaps most closely related are the x‐ray scattering methods. The utility of both x‐ray and neutron scattering methods in investigations of atomic scale structure arises from the close match of the wavelength of these probes to typical interatomic distances (a few Ångstroms). The differences between these two techniques are discussed.
Neutron Powder Diffraction
Authors: Vogt Thomas 
Published: October 2003

AbstractThe first powder diffraction studies on simple materials such as iron metal using x rays were done independently by Debye and Scherrer (1916) in Germany and by Hull (1917) in the United States. For a long time x‐ray powder diffraction was primarily used for qualitative purposes such as phase identification and the assessment of crystallinity. The use of neutrons for such powder diffraction work has advanced significantly over the past 50 years.The continuing efforts made in unraveling the structural details of superconducting oxides and the recently discovered oxides exhibiting colossal magnetoresistance have demonstrated the indisputable usefulness of high‐resolution neutron powder diffraction. Modern powder diffraction using neutrons, x rays, and synchrotron x‐ray radiation has developed from a qualitative method some 20 years ago to a quantitative method now used to detect new phases and determine their atomic, magnetic, and mesoscopic structure as well as their volume fractions if they are present in a mixture.Neutron powder diffraction is a complementary technique to x‐ray powder diffraction and electron diffraction. The greater penetration depth of neutrons, the fact that the neutron‐nucleus interaction is a point scattering process implying no variation of the nuclear scattering length with scattering angle, the independence of the scattering cross‐section from the number of electrons (Z) of an element, and therefore the stronger interaction of neutrons with “light” elements such as oxygen and hydrogen, and its isotope specificity as well as its interaction with unpaired electrons (“magnetic scattering”) make neutrons a unique and indispensable probe for structural condensed matter physics and chemistry. However, x‐ray powder diffraction and, in particular, synchrotron x‐ray powder diffraction can investigate samples many thousand times smaller and have an intrinsic resolution at least one order of magnitude better than the best neutron powder diffractometer. A major drawback for neutron scattering is that it can presently only be done at large facilities (research reactors and spallation sources), whereas laboratory‐based x‐ray scattering equipment provides the same flux much more conveniently. Current governmental policies will not permit the construction or upgrade of present‐day research reactor sources in the United States. The future of U.S. neutron scattering therefore relies solely on accelerator‐based spallation sources. Electron diffraction is a very powerful tool to obtain both real and reciprocal space images of minute amounts of powders. In combination with other supplementary techniques such as solid‐state nuclear magnetic resonance (NMR), which allows, e.g., the determination of Wyckoff multiplicities and interatomic distances by exploiting the nuclear Overhauser effect (NOE), physicists, chemists, and materials scientists have a powerful arsenal to elucidate condensed matter structures.
Phonon Studies
Authors: Stassis C. 
Published: October 2003

AbstractUntil the beginning of this century, the models used to understand the properties of solids were based on the assumption that atomic nuclei are fixed at their equilibrium positions. These models have been very successful in explaining many of the low‐temperature properties of solids, and especially those of metals, whose properties are determined to a large extent by the behavior of the conduction electrons. Many well‐known properties of solids (such as sound propagation, specific heat, thermal expansion, conductivity, melting, and superconductivity), however, cannot be explained without considering the vibrational motion of the nuclei around their equilibrium positions. The study of lattice dynamics—or of phonons, which are the quanta of the vibrational field in a solid—was initiated by the seminal papers of Einstein, Debye, and Born and von Kármán. Initially, most of the theoretical and experimental studies were devoted to the study of phonons in crystalline solids, as the name lattice dynamics implies. At present, the field encompasses the study of the dynamical properties of solids with defects, surfaces, and amorphous solids. It is impossible in a single article to present even a brief overview of this field. The discussion in this article is therefore limited to a brief outline of the neutron scattering techniques used for the study of phonons in crystalline solids.Indirect information about the lattice dynamical properties of solids can be obtained from a variety of macroscopic measurements. For instance, in some cases, the phonon contribution to the specific heat or resistivity can be easily separated from other contributions and can provide important information about the lattice dynamical properties of a solid. In addition, measurements of sound velocities are particularly useful, since they provide the slopes of the acoustic phonon branches. Since such macroscopic measurements are relatively easy and inexpensive to make in a modern materials science laboratory, they should, in principle, be performed before one undertakes a detailed phonon study by spectroscopic techniques. Direct measurement of the frequencies of long‐wavelength optical phonons can be obtained by Raman scattering and infrared spectroscopy. These experiments provide essential information for solids containing several atoms per unit cell and should be performed, if possible, before one undertakes a time‐consuming and expensive detailed neutron scattering study. Also, for simple solids, information about the phonon dispersion curves can be obtained from x‐ray diffuse scattering experiments.Presently, the most powerful technique for the study of phonons is the inelastic scattering of thermal neutrons. The technique directly determines the dispersion relation, that is, the relationship between the frequency and propagation vector of the phonons.