bluuebunny/crossref_metadata_2025_split huggingface dataset:
Radiotracer Methods
Authors: Das Hendrik A. 
Published: September 2006

AbstractSmall amounts of radionuclides of suitable half‐life can be used to observe the kinetics of mass transport and isotopic exchange in the equilibrium distribution of a (micro‐)component between coexistent phases.Quantitative assay of radioactivity is sensitive, precise and accurate and usually performed instrumentally. Though handling of radionuclides is restricted to authorized laboratories only, the combination of its potential and simplicity makes the radiotracer method an indispensable part of modern analytical chemistry.
Radiochemical Separation Schemes for Multielement Determination
Authors: Alfassi Zeev B. 
Published: September 2006

Abstract
Radiochemical activation analysis is a more laborious analytical method than instrumental analysis, but can be used to determine elements at lower concentrations. In most cases, the sample to be analyzed is separated into groups of elements rather than individual elements, so that the elements do not interfere with one another during the measurement of radionuclides content. Schemes for separation into multielement groups are given for metals, biological, geological and environmental samples.
Actinides and Other Alpha‐Emitters, Determination of
Authors: Vintró Luis León , Mitchell Peter I. 
Published: September 2006

AbstractTo assay an actinide or other α‐emitter at the low concentrations encountered in many environmental samples necessitates chemical separation of the actinide of interest from the bulk matrix, purification by the elimination of other interferants, mounting onto a suitable substrate for counting, and quantification by radiometric, mass spectrometric or other means. In this contribution, the chain of analysis from sampling to counting is critically reviewed and many of the most important pitfalls and sources of error are highlighted. Specifically, the pretreatment, preconcentration, separation and purification steps required for the assay of thorium, uranium, neptunium, plutonium, americium and curium in a wide range of environmental matrices are examined in detail. Emphasis is given to the need for appropriate radiochemical yield monitors and to the practical application of ion exchange, solvent extraction and extraction chromatography in the purification of these elements. This is complemented by a description of methods for the preparation of quality sources suitable for counting by α‐spectrometry, liquid scintillation α‐spectrometry and mass spectrometry. In addition, an overview is given of the operational principles and systems used in α‐radiometry and mass spectrometry, including a discussion of the practical limits of detection and quantitation achievable with these systems. Finally, the importance of traceability and good quality assurance in precision actinide assay is emphasized.
Mass Spectrometry of Long‐Lived Radionuclides
Authors: Sabine Becker H.J. , Dietze Hans‐Joachim 
Published: September 2006

Abstract

Inorganic mass spectrometric methods are powerful multielement analytical techniques for sensitive determination at the trace and ultratrace level, and for isotope ratio measurements in different materials (e.g. conducting, semiconducting and nonconducting solid samples; technical, environmental, biological, geological and water samples). An inorganic mass spectrometer consists of the following parts: the ion source for the evaporation, atomization and ionization of samples, the analyzer for the mass (and energy) separation of ion beams which are extracted from the ion source, and the ion detection system. The detection limits of solid‐state mass spectrometric techniques by thermal ionization mass spectrometry (TIMS), glow discharge mass spectrometry (GDMS), laser ablation inductively coupled plasma mass spectrometry (LA/ICPMS) for the direct analysis of solid samples were determined down to the sub‐nanogram per gram level. Resonance ionization mass spectrometry (RIMS) and accelerator mass spectrometry (AMS) are highly sensitive, selective ultrasensitive mass spectrometric techniques with detection limits up to 10
6
atoms.

Inductively coupled plasma mass spectrometry (ICPMS) has been applied as the most important and sensitive mass spectrometric technique with its multielement capability for the determination of long‐lived radionuclides in solid andaqueous samples, with detection limits the sub‐picogram per liter. Isotope ratios can be determined by ICPMS using single ion collectors and multicollectors with a precision of 0.02% and 0.006% relative standard deviation (RSD) respectively. This review discusses the most important inorganic mass spectrometric techniques and their application for the quantitative determination of long‐lived radionuclides in metals, alloys, and nonconductors, as well as in environmental, biological and geological samples, and radioactive waste materials. The application of these methods to isotope ratio measurements is also discussed.
Nuclear Detection Methods and Instrumentation
Authors: Tsechanski A. 
Published: September 2006

Abstract
Nuclear detectors and associated electronics are among the most important components of analytical chemistry involving nuclear methods. Historically, the first and simplest particle detectors were gas‐filled counters using an electric field to collect the free charge carriers, electrons and ions, produced in the counter by ionizing radiation. These detectors include ion chambers, proportional counters and Geiger counters. The charge created at the proportional counter is directly proportional to the energy deposited in the detector by a nuclear particle and, therefore, this kind of detector can be used for energy measurements of nuclear radiation (nuclear spectrometry). The main disadvantage of gas‐filled detectors is their low efficiency for γ‐rays. This is because the gas detection medium is low in density. From this point of view, solid detectors are considerably more advantageous. Of these detectors, the scintillation counter is one of the earliest and most widely used detectors of nuclear radiation. It consists of a detection medium (inorganic or organic scintillator) and a photomultiplier tube (PMT). The incident particle enters the scintillator and interacts with its atoms, raising them to excited states. De‐excitation follows very rapidly by emission of light photons. The emitted photons are multiplied in the PMT, resulting in an output pulse of up to several volts. The high efficiency scintillation detectors are widely used in instrumental analytical chemistry including neutron activation analysis (NAA), both prompt neutron activation analysis (PNAA) and delayed neutron activation analysis (DNAA), and in X‐ray flourescence analysis (XRFA). Contemporary high‐resolution γ‐spectrometry is based on solid‐state ionization chambers. Only after the successful development of the technology for production of highly purified single crystals of germanium (Ge) and silicon (Si) did it become possible to develop Ge‐ and Si‐based solid‐state detectors by forming reverse‐biased junctions and cooling the semiconductor to liquid nitrogen temperature (77 K). The most prominent feature of the semiconductor detectors is their excellent energy resolution and availability of large crystals with relative efficiencies up to 120% compared with a standard NaI(Tl) detector. High‐resolution γ‐ray spectrometry is widely used in evaluation of γ‐emitting radioactive nuclides in various samples, in NAA, in a high‐sensitivity particle‐induced X‐ray emission (PIXE) method and others. Nuclear detectors provide a variety of information on detected radiation (energy, type of the radiation, timing data, etc.) in the form of electronic signals. To obtain this information, the signal must be processed by the appropriate nuclear electronic system, which includes power supply, preamplifier, main amplifier and multichannel analyzer (MCA) for digital processing of the analog signals.
Fourier Transform
R
aman Instrumentation
Authors: Edwards Howell G.M. 
Published: September 2006

Abstract
The physical basis of the instrumentation required for the recording of Raman spectra in the near‐infrared region of the electromagnetic spectrum using an interferometer and Fourier transform (FT) techniques is described. The advantages and disadvantages of the technique compared with the recording of Raman spectra in the visible or ultraviolet (UV) region are described. The impetus provided by the nondestructive nature of this analytical method, combined with the minimization of fluorescence and the ease of sample presentation to the spectrometer is illustrated with examples from archaeological science, environmental science, and biology; accessories such as a Raman microscopic and a remote sensing fibre‐optic probe are described with relevant applications in art conservation, materials analysis, processing and biomedical diagnostics. The potential for future applications of the technique in chemical, physical and biological sciences is outlined.
Raman Microscopy and Imaging
Authors: Andrew Jeremy J. 
Published: September 2006

AbstractRaman microscopy and imaging couples the spatial resolution of optical microscopy with the spectral resolution and information content of Raman spectroscopy. Together, a powerful tool for the investigation of chemical, or molecular, heterogeneity is created. Raman microspectroscopy enables the nondestructive analysis of small quantities of sample and the identification of contaminants and inclusions in situ within a matrix – both of great importance and utility in forensic investigations. Perhaps more importantly, it has been recognized that the microheterogeneity of products has an influence on both product performance and appearance. In the analysis of complex, multiphase systems, optical microscopy contrast methods (the majority of which depend upon refractive index changes) are commonly employed to provide information on the structural organization of materials. However, information on the chemical organization of materials is then often based on conjecture. Raman microscopy is arguably the most easily applied of a family of techniques that use the innate spectral signatures of the components as a contrast element and hence provides a method for analyzing chemical heterogeneity in “real” systems.Typically, the information that would be appropriate from an investigation of chemical heterogeneity would be:the number of chemical components present;the pure spectrum of each component;spatially resolved concentration information for each individual component.Raman microscopy and imaging provides a tool to determine these important factors in complex, multiphase systems. In its simplest form, the Raman microspectroscopy experiment requires a laser to be focused down to a diffraction‐limited spot on a sample and the inelastically scattered light is collected from that point and analyzed. This generates a Raman spectrum, which is indicative of the identity and quantity of the molecular species present in that sample volume. The limiting spatial resolution that can be obtained is of the order of 1 µm in the lateral plane and 2 µm in the axial plane, the microscopes used lending themselves to a confocal optical arrangement that provides this level of depth discrimination.The information content is constrained to that available in the Raman vibrational spectra and so commonly molecules with distinct functional groups are clearly distinguished, whilst it is more difficult to distinguish specifically between molecules with very similar molecular structure and chemical functionality. It is also a commonly held belief that Ramaninvestigations are hampered by fluorescence interference, which obscures the Raman spectrum. However, with modern Raman microscopes there are few samples where this limitation becomes completely defeating.Several approaches to the generation of Raman images (images where the contrast is based on the chemical or molecular heterogeneity) have been established and are discussed in detail. A comparison is made between these different Raman imaging approaches and also with different spectral imaging methods.
Raman Scattering, Fundamentals
Authors: Popp Jürgen , Kiefer Wolfgang 
Published: September 2006

AbstractAn introduction of the fundamentals of linear and nonlinear Raman spectroscopy is given. The Raman effect is the result of inelastic light scattering. A small amount of the photon energy of the incident light wave is modulated by the molecular scattering system. An energy transfer occurs as a result of the coupling between the incident radiation and the quantized states of the scattering system. Depending on the coupling, the incident photons either gain or lose energy. The light, which has less energy than the incident laser light, is named Stokes–Raman scattering, and the radiation, which has more energy, is referred to as anti‐Stokes–Raman scattering.In the case of the coupling between strong laser fields and molecular vibrations the observation of nonlinear Raman effects such as hyper‐Raman scattering, stimulated Raman scattering (SRS), coherent anti‐Stokes–Raman spectroscopy, the Raman gain spectroscopy, etc., is possible.Apart from theoretical aspects of Raman spectroscopy an introduction into the instrumentation of linear and nonlinear Raman techniques is provided. For linear Raman spectroscopy two alternate approaches are described: dispersive Raman and Fourier transform Raman (FT‐Raman) spectroscopy. Special Raman techniques such as micro‐Raman spectroscopy and difference Raman spectroscopy are discussed.In addition, a review of the instrumentation of several nonlinear Raman methods which are based on the second‐order (χ(2)) and the third‐order nonlinear susceptibility (χ(3)) is given. These methods include coherent anti‐Stokes–Raman scattering (CARS), stimulated Raman gain spectroscopy (SRGS), inverse Raman scattering (IRS), photoacoustic Raman spectroscopy (PARS), and ionization‐detected stimulated Raman spectroscopy (IDSRS).
Differential Scanning Calorimetry and Differential Thermal Analysis
Authors: Riga Alan , Collins Ricardo 
Published: September 2006

Abstract

The importance of thermal analysis methods in thermal and material science has proved awesome. Differential thermal analysis (DTA) and differential scanning calorimetry (DSC) have had a great impact on material science by enabling the measurement of a great number of physical and chemical properties. These techniques have allowed elucidation of endothermic and exothermic processes at temperatures ranging from very low (−120°C) to high (DSC 600°C and DTA 1800°C).
1–6
Some of the physical properties measured by these thermal analytical methods include melting transitions, crystallization temperatures, enthalpy of fusion and crystallization, specific heat capacity, liquid crystal transitions, vaporization, sublimation, solid–solid transitions, thermal conductivity and the glass transition temperature.
7–14
Chemical properties monitored by DSC and DTA are dehydration, decomposition, oxidative reactions, solid state reactions, chemisorption, combustion, polymerization, curing and catalyzed reactions.
15–19

In DTA, the temperature difference between the substance and a reference material is measured as a function of temperature, while the substance and reference material are subjected to a controlled temperature program.
20

In DSC, the difference in energy input into a substance and a reference material is measured as a function of temperature, while the substance and reference material are subjected to a controlled temperature program.
21
Two modes, power compensation DSC and heat flux DSC, can be distinguished, depending on which method of measurement is used.
22,23

The following is a review of DSC and DTA and their role in thermal science. The root of thermal analysis is the determination of heat and temperature. Heat is a macroscopic quantity and has its origin in molecular motion.
24
DTA measures the temperature difference between a sensitive reactive material and an inert reference as a function of time and temperature. DTA measurements provide information about transition temperatures as well as kinetic time‐based phenomena and thermodynamic properties. DSC is a step above DTA in that it measures quantitative heats of reaction and transitions. Both thermal methods can differentiate first order thermodynamic changes like fusion, and second order thermodynamic changes like a glass transition temperature, T

g

. This chapter will focus mainly on fundamentals, instrumentation and applications of DSC.
Thermogravimetry
Authors: Dunn Jeffrey G. 
Published: September 2006

Abstract

Thermogravimetry (TG or TGA) is a technique in which the mass of a substance is measured as a function of temperature whilst the substance is subjected to a controlled temperature program.1, 2 Commonly materials can be heated or cooled in the temperature range from −160 to 1600°C at rates of fractions of a degree per minute up to 100°C min
−1
. Sample sizes are from 10–100 mg, although apparatus is available which can take larger sample masses. Different atmospheres can be used, from inert gases such as nitrogen, to reactive gases such as oxygen, hydrogen and vapors. The sensitivity of the apparatus is usually in the microgram range, with an accuracy of ±1% and a similar level of precision. The results obtained from TG experiments are subject to a variety of experimental variables, and an understanding of the effects of these is essential to a correct interpretation of the results. TG can be used to study any physical or chemical reaction which gives a mass change, and includes absorption and desorption of gases, sublimation and vaporization, the thermal decomposition of a wide range of materials from inorganic compounds to polymers, the reaction between a gas and a solid, and solid–solid reactions. TG has also been widely used to carry out kinetic studies on solid materials, with the aim of determining the reaction model and the kinetic parameters of activation energy (
E
) and frequency factor (
A
). However, considerable care is required in the interpretation of the results obtained.
Absorption Techniques inX‐Ray Spectrometry
Authors: Kawai Jun 
Published: September 2006

AbstractX‐ray absorbance depends on the wavelength of the X‐rays, atomic number, chemical environment, and concentration of analyte. X‐ray absorption spectrometry is a technique for analyzing the chemical environment of an element in an unknown material. This method is closely related to photoelectron spectroscopy, Auger electron spectroscopy, and X‐ray fluorescence spectroscopy.Chemical information in the chemical shift and line shape of XANES (X‐ray absorption near‐edge structure) spectra is described. The history and theory of EXAFS (extended X‐ray absorption fine structure) are discussed in relation to other experimental techniques. Data analysis methods, databases, software packages, instrumentation, and synchrotron radiation facilities for X‐ray absorption analysis are overviewed. Alternative methods such as electron energy loss spectroscopy (EELS), self‐absorption effect, extended X‐ray emission fine structure (EXEFS), X‐ray Raman scattering, diffraction anomalous fine structure (DAFS), β‐environment fine structure (BEFS), and inverse photoemission spectroscopy (IPES) are also described.
Structure Determination,
X
‐Ray Diffraction for
Authors: Chung D.D.L. 
Published: September 2006

Abstract
X‐ray diffraction is a widely used experimental method for materials analysis. The scope of materials analysis that can be provided by X‐ray diffraction includes crystalline phase identification, lattice parameter measurement, grain size measurement, and texture analysis. In particular, crystalline phase identification is a basic form of materials analysis that is critically important for metals, ceramics, and other crystalline materials. In contrast, elemental analysis, as provided by X‐ray spectroscopy, atomic absorption, etc., provides information on the composition but not the phases. Because a material frequently consists of more than one phase, the composition of the multiphase mixture is not the same as the composition of an individual phase. A true understanding of a crystalline material cannot be obtained until one knows what phases are present in the material. Even if two phases have the same composition, their difference in crystal structure can make them have very different electrical, magnetic, thermal, mechanical, or chemical properties.
Total Reflection
X
‐Ray Fluorescence
Authors: Wobrauschek Peter , Streli Christina 
Published: September 2006

Abstract

Total reflection X‐ray fluorescence (TXRF) analysis is an energy‐dispersive (ED) X‐ray fluorescence (XRF) technique using a special excitation geometry. The narrow collimated beam impinges at grazing incidence on a special sample carrier. This is a flat polished quartz plate on which the sample is deposited. The most significant advantages of TXRF over conventional XRF analysis are the improved detection limits achieved by inherent signal increase and reduced background. Detection limits are in the picogram range for X‐ray tube excitation and even down to femtograms for excitation using synchrotron radiation (SR). The main application is the analysis of some microliters of a liquid sample deposited and dried on the quartz reflector or of some microliters of slurry or microgram grains of solid samples. The most widely used application is the quality control of contaminations on Si wafer surfaces. The detection limits demanded by the semiconductor industry can be reached today using X‐ray tube excitation, but metrology shows that in the future SR is required or special preconcentration techniques. Straight TXRF is the only analytical technique offering nondestructive and spatial resolved analysis. A special ED detector with an ultrathin window is suitable for the detection of low atomic number,
Z
elements (C upwards) using TXRF. Another promising application is the characterization of thin layers on a reflecting surface or implanted atoms in Si by variation of the incidence angle and measurement of the fluorescence signal. It is possible to determine the elements forming the layer, the layer thickness and its density. For thin layered samples as well as implantations, thickness, depth and depth profile for implanted atoms can be evaluated by comparing experimental results with theoretical models.
Energy Dispersive,X‐Ray Fluorescence Analysis
Authors: Lindgren E. Selin 
Published: September 2006

AbstractEnergy‐dispersive X‐ray fluorescence (EDXRF) is an analytical method for qualitative as well as quantitative determination of elements in a sample, independent of their chemical form. It is built on the fact that elements that are irradiated with energetic X‐rays have a certain probability of emitting characteristic X‐rays, the energies of which are unique for each element. In the energy‐dispersive systems, the emitted X‐rays are detected by their energies. Use of the EDXRF technique has accelerated since the 1960s as a result of the development of solid‐state detectors, nuclear electronics and small computers. EDXRF is multielemental and nondestructive and can be applied to large as well as small samples of different composition and character. If conditions are optimized, minimum detection limits (MDLs) can be below the nanogram level for small laboratory instruments and into the femtogram region for more advanced instrumentation [total reflection X‐ray fluorescence (TXRF), synchrotron radiation].EDXRF spectrometers exist at many degrees of sophistication, ranging from advanced laboratory instruments to small portable instruments for field observations. They can be designed for analysis of bulk material or for scanning and elemental mapping of small areas.Typical applications for EDXRF are analysis of agricultural material, medical samples, archaeological and historical objects and environmental samples such as soil, ores, water and aerosol particles.