Synchrotron techniques

Several analytical techniques are based on X-rays emitted from high-energy synchrotron electrons. These have been used to study IDPs and are an important part of the analytical arsenal being used on the Stardust samples. Three of these are discussed here. 

Micro-XRF uses a monochromatic X-ray beam focused to a few microns in diameter. The principle is the same as for the XRF system discussed earlier. A typical analytical mode is to raster the sample under the X-ray beam to produce element maps of the samples. This technique is used to determine bulk compositions of IDPs and the material in the Stardust tracks. 

Mass spectrometers are used primarily as tools for measuring isotopic compositions, although some kinds can also be used to determine elemental abundances. Mass spectrometers have three basic components (1) a means of ionizing the sample (2) a mass analyzer that separates atoms based on their masses and (3) a detector. Most of the time, the mass spectrometer is identified by its source, although the mass analyzer can also be identified. In the next few paragraphs, we will describe the various sources, the different mass analyzers, and the detectors, and then describe the most common configurations used in cosmochem-istry. For more details, see Gross (2008). 

Thermal-ionization mass spectrometers use a hot filament to ionize the sample. The element of interest is first purified using wet chemistry and then is loaded onto a source filament, often along with another substance that makes ionization easier and a more stable function of temperature. The filament is heated and as the sample evaporates, it is ionized. Both positive and negative ions can be created by thermal ionization, depending on the electronegativity of the element to be measured. Thermal-ionization mass spectrometers are used to measure a wide variety of elements, including magnesium, calcium, titanium, iron, nickel, rubidium, strontium, neodymium, samarium, rhenium, osmium, uranium, lead, and many others. 

Inductively coupled plasma (ICP) mass spectrometers use a hot plasma to ionize the sample. The plasma is generated by electromagnetic induction. The plasma source operates at 

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Melendres C A and Tadjeddine A (eds) 1994 Synchrotron Techniques in Interfacial Electrochemistry (NATO ASI Series C432) (Dordrecht Kluwer)... 

The speciation of trace elements in solid phases determines their mobility and toxicity. Spectroscopic techniques such as XANES and XAFS, can be used to determine directly the oxidation and structural state of elements in coal combustion byproducts. For example, Huggins et al. (2000) used these synchrotron techniques to determine that Cr and As occur predominately in the less toxic oxidation states Cr(IIl) and As(V) in CCBs. In addition, they found As, Cd, Cr, Ni, and Zn were present primarily as oxidized species (i.e., as oxides, sulphates, arsenates, etc.) in unweathered CCBs. 

The present version of the book represents a completely revised update of the first edition as it appeared in 1993, and the second from 2000. Significant new developments in, for example, electron and scanning probe microscopy, synchrotron techniques and vibrational techniques called for revision and additions to the respective chapters. However, the other chapters have also been updated with recent examples, and references to relevant new literature. Many figures from the first two editions have subsequently been improved to make them more informative. 

In situ Electrochemical X-ray Diffraction (XRD) and Synchrotron Techniques [viii]... 

D.C. Kinongsberger, In Synchrotron Techniques in Interfacial Electrochemistry (C.A. Melendres, C.A. Tadjeddine, eds.), Kluwer Academic Press, Dordrecht, Netherlands, pp 181-198 (1994). 

One should also specifically note that coherent radiology is quite easy to use. It has no vacuum requirements as many other synchrotron techniques, and it delivers results rapidly with instrumentation that is simpler than most other synchrotron beamlines. It can be readily applied [1-21,41] to a variety of condensed-matter systems including liquids and mixed liquids and solids. 

Sciences de TUnivers. His research interests focus on environmental mineralogy and biogeochemistry of metal contaminants and trace elements using X-ray structural techniques. In the mid-80s, he initiated a new research program on the structure and surface reactivity of poorly crystallized Fe oxides. In the early 90s, this program was extended to Mn oxides, and specifically to minerals of the bimessite family. In the mid-90s, he pioneered the application of synchrotron techniques to determination of the speciation of heavy metals in natural systems. In the last two years, he was a key developer of an X-ray microprobe at the Advanced Light Source of the Lawrence Berkeley National Laboratory dedicated to the study of complex environmental materials. He is also co-lead PI of the French Absorption spectroscopy beamline in Material and Environmental sciences (FAME) at the European Synchrotron Radiation Facility (ESRF) in Grenoble. 

B.M. Ocko, J. Wang, in Synchrotron Techniques in Interfacial Electrochemistry, ed. by C.A. Melendres, A. Tadjeddine (Kluwer Academic, Dordrecht, 1994), p. 127... 

McBreen J (1995) In situ synchrotron techniques in electrochemistry. In Rubinstein I (ed) Physical electrochemistry. Marcel Dekker, New York, p 339... 

X-ray scattering can be measured by the classical Kratky camera or more modem synchrotron techniques. Technical details can be found in a number of books, e.g., those by Guinier and Fouret, Chen and Yip, or Glatter and Kratky. ... 

C. A. Melendres and A. Tadjeddine (Eds.), Synchrotron Techniques in Interfacial Electrochemistry, Kluwer, Dordrecht, 1993. 

A better understanding of NNSM-induced morphological changes has been initiated by employing synchrotron-based infrared micro-spectroscopy. In this recent study [17], authors have chosen three common semi-crystalline and amorphous polymers for blending Hydrophobic polymers polystyrene (PS), polyethylene terephthalate (PET), and poly(methyl-methacrylate) (PMMA) labelled hereafter PS/PET and PET/PMMA. The results of such studies clearly show the potential of the synchrotron technique to detect the transition region between the two polymers, and provide evidence for the fluctuations in blend concentration for PS/PMMA. 

The orientation properties polymer are relevant to many lines of inquiry about these materials, and we expect an increase in this field of research and its use of synchrotron techniques in the coming years. 

Strehblow, H.-H., Borthen, R, Druska, P. (1994), in Synchrotron Techniques in Intematiorud Electrochemistry, Vol. 432 Melendres, C. A., Tahdjeddine, A. (Eds.), Kluwer Academic, The Netherlands NATO ASI Series C, Mathematical and Physical Sciences, p. 295. 

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