Search Results for neutron activation analysis

This article provides a detailed account of the concepts and applications of neutron activation analysis (NAA), covering the basic principles and neutron reactions of NAA as well as calibration methods used for NAA. The discussion also covers the factors pertinent to analytical sensitivity achievable with NAA, common neutron sources, sample-handling technique, and automated systems of NAA. The categories of NAA covered are instrumental neutron activation analysis, epithermal neutron activation analysis, radiochemical neutron activation analysis, 14 MeV fast neutron activation analysis, delayed neutron activation analysis, and prompt gamma activation analysis.

Neutron activation analysis (NAA) is a highly sensitive and accurate method of assaying bulk materials for trace levels of many elements. This article provides a detailed account on several types of NAA, namely, nondestructive and radiochemical thermal neutron activation, delayed neutron counting, epithermal and 14-MeV fast neutron activation, and prompt gamma activation analysis. It also includes application examples, explaining where and how each method is used and the types of elements on which they are effective.

This article introduces various analytical techniques commonly used in the characterization of organic solids and liquids and discusses the challenges in performing the analysis, with examples. Some general advice in approaching a material analysis is also provided.

This article briefly discusses popular techniques for metals characterization. It begins with a description of the most common techniques for determining chemical composition of metals, namely X-ray fluorescence, optical emission spectroscopy, inductively coupled plasma optical emission spectroscopy, high-temperature combustion, and inert gas fusion. This is followed by a section on techniques for determining the atomic structure of crystals, namely X-ray diffraction, neutron diffraction, and electron diffraction. Types of electron microscopies most commonly used for microstructural analysis of metals, such as scanning electron microscopy, electron probe microanalysis, and transmission electron microscopy, are then reviewed. The article contains tables listing analytical methods used for characterization of metals and alloys and surface analysis techniques. It ends by discussing the objective of metallography.

Radionuclide methods for wear measurement are used to measure wear continuously throughout a tribological experiment at a resolution of nanometers or micrograms per hour. This article presents an overview of radionuclide methods for wear measurement. It discusses complementary wear measurement methods to introduce the advantages of using radioactive isotopes (RI) for wear or corrosion measurements in comparison to other methods. The article provides information on radiation safety regulations and approaches to minimize external radiation exposure. It describes neutron activation, thin layer or surface layer activation, and ultrathin layer or recoil activation that are used to create radioactive isotopes in the samples to be tested. The article reviews the two common types of wear measurement setup configurations: the direct method and the indirect method. It concludes with a discussion on the practical application of wear measurement using radioactive isotopes.

The characterization, testing, and nondestructive evaluation of ceramics and glasses are vital to manufacturing control, property improvement, failure prevention, and quality assurance. This article provides a broad overview of characterization methods and their relationship to property control, both in the production and use of ceramics and glasses. Important aspects covered include the means for characterizing ceramics and glasses, the corresponding rationale behind them, and relationship of chemistry, phases, and microconstituents to engineering properties. The article also describes the effects that the structure of raw ceramic materials and green products and processing parameters have on the ultimate structure and properties of the processed piece. The effects that trace chemistry and processing parameters have on glass properties are discussed. The article describes mechanical tests and failure analysis techniques used for ceramics.

This article is a compilation of definitions of terms related to materials characterization techniques.

This article is a compilation of terms and definitions related to materials characterization.

This article provides a detailed account of particle-induced x-ray emission (PIXE), covering the basic principles of PIXE analysis and calibration and quality-assurance protocols employed. A comparative study on PIXE and x-ray fluorescence is then presented. The article also discusses the applications of PIXE in atmospheric physics and chemistry, external proton milliprobes and historical analysis, and PIXE microprobes.

This article provides a brief introduction to neutron diffraction as well as its state-of-the-art capabilities. The discussion covers the general principles of the neutron, neutron-scattering theory, generation of neutrons, types of incident radiation, and purposes of single-crystal neutron diffraction, powder diffraction, and pair distribution function analysis. The relationship between detector space and reciprocal space are presented. Various factors involved in sample preparation, calibration, and techniques used for analyzing diffraction data are described. The article also presents application examples and possible future developments in neutron diffraction.

The diffraction pattern of any material contains structural and chemical property information that can be extracted using radial distribution function analysis. This article provides an introduction to the technique and presents several examples highlighting various ways in which it can be used. It begins with a discussion on the principles of diffraction and scattering and the effectiveness of x-ray, neutron, and electron energy sources for different types of measurements. It provides information on data collection and reduction and explains how to create atomic distribution plots from intensity and scattering angle data. The article also presents application parameters for defining short distances and background intensity and describes a procedure for generating pair distribution functions.

Neutrons are a principal tool for the study of lattice vibrational spectra in materials. This article provides a detailed account of fission and spallation methods of neutron production that are capable of producing sufficient intensity to be useful in neutron scattering research. It describes the instrumentation required for, and advancements made in, neutron powder diffraction. The article further explains the texture and residual stress (macrostresses and microstresses) problems that are analyzed using the neutron powder diffraction method. It also outlines the single-crystal neutron diffraction technique, and provides examples of the applications of neutron diffraction.

Particle-induced x-ray emission (PIXE) is one of several quantitative analyses based on characteristic x-rays. This article provides a detailed account on the principles of PIXE, discussing the data-reduction codes used to identify, integrate, and reduce x-ray peaks into elemental concentrations. It provides information on the calibration of PIXE analysis, which is mostly performed using gravimetric standards to avoid serious absorption, refluorescence, or ion energy change corrections. A comparative study on PIXE and x-ray fluorescence is also included. Finally, the article discusses the applications of PIXE in three areas, namely, atmospheric physics and chemistry, external proton milliprobes and historical analysis, and PIXE microprobes.

Radioanalysis is an analytical technique that uses energy emitted by radioactive isotopes to measure the concentration of related elements in test samples. This article begins with a discussion on the principles of radioactive decay and various forms of emission, including alpha and beta-particle emission, positron emission, and gamma and x-ray emission. It compares and contrasts measurement techniques based on various detectors, namely, charged-particle detectors, photon detectors, counting and recording instruments, and radioactive decay spectrometers. It also addresses sample preparation, equipment and process safety, and the handling of radioactive gasses and materials. The article concludes with application examples involving the analysis of rare-earth elements and nuclear fuels.