Elements, isotopic composition interaction between

Overall, isotope and trace element data have led to the conclusion that the mantle sources beneath the Sicily Province are heterogeneous and result from the interaction between various mantle compositions or reservoirs. There is a lively debate on the origin and physical nature of these mantle compositions, not only in Sicily, but at a global scale (e.g. Hofmann 1997 Meibom and Anderson 2003). 

Interaction between cosmic rays and terrestrial matter The Earth s atmosphere and, to a lesser extent, its surface are constantly bombarded with cosmic radiation which interacts with terrestrial material, resulting in isotopic variations in some elements. The best known example is the production of C from by (n,p) reaction in the atmosphere, with the neutron involved created by cosmic ray-induced spallation. a radionuclide with a half-life of 5730 years, is oxidized to CO2 and enters the food chain via photosynthesis, thus affecting the isotopic composition of C in all living organisms. 

The best known example of interactions between cosmic rays and terrestrial matter affecting the isotopic composition of an element is the production of from by (n,p) reactions in the atmosphere. The neutrons involved in the... 

The interactions between medium energy (1-5 MeV) atomic ions and the atoms of a sample produce a wide variety of reaction products electromagnetic radiation from the electron shells or gamma rays from the nucleus, scattered particles from the pri mary beam which may be modified in direction and energy, or particles of a different species emitted from the nucleus. Any of these may be analysed spec troscopically using suitable detectors to provide information about the elemental and in some cases isotopic composition of the sample. 

In this review results from two surface science methods are presented. Electron Spectroscopy for Chemical Analysis (ESCA or XPS) is a widely used method for the study of organic and polymeric surfaces, metal corrosion and passivation studies and metallization of polymers (la). However, one major accent of our work has been the development of complementary ion beam methods for polymer surface analysis. Of the techniques deriving from ion beam interactions, Secondary Ion Mass Spectrometry (SIMS), used as a surface analytical method, has many advantages over electron spectroscopies. Such benefits include superior elemental sensitivity with a ppm to ppb detection limit, the ability to detect molecular secondary ions which are directly related to the molecular structure, surface compositional sensitivity due in part to the matrix sensitivity of secondary emission, and mass spectrometric isotopic sensitivity. The major difficulties which limit routine analysis with SIMS include sample damage due to sputtering, a poor understanding of the relationship between matrix dependent secondary emission and molecular surface composition, and difficulty in obtaining reproducible, accurate quantitative molecular information. Thus, we have worked to overcome the limitations for quantitation, and the present work will report the results of these studies. 

The conservative behavior and chemical inertness of noble gases has led to their extensive use to provide information on the fluxes, movement and interactions of contemporary crustal fluids. A major advance has been in extending these studies to characterize ancient waters in fluid inclusions (Turner et al. 1993). The principal aims of these studies are to provide data on the noble gas geochemistry of inclusion fluids and understand the observations in terms of likely sources and interactions. This information provides novel insight into a palaeofluid s evolutionary history and can assist in discriminating between different models for the formation of hydrothermal mineral deposits. Because of the large differences in end-member isotopic and elemental compositions, He and Ar are the most informative and widely studied noble gases in... 

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