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Soldati A.L.,Johannes Gutenberg University Mainz | Goettlicher J.,Institute for Synchrotron Radiation ISS | Jacob D.E.,Johannes Gutenberg University Mainz | Vilas V.V.,University of Valencia
Journal of Synchrotron Radiation

X-ray absorption near-edge spectroscopy (XANES) at the Mn K-edge was used to investigate the environment of Mn in situ within the growth increments of the long-lived freshwater bivalve species Diplodon chilensis patagonicus. Single XANES spectra and Mn Kα fluorescence distributions were acquired at submillimetre resolution (up to 100 μm × 50 μm), at Mn concentrations below the weight percent range (100-1000 μg g-1) in a high Ca matrix. The position and intensity of the pre-edge feature in the shell spectrum resembles best that of the Mn(II)-bearing reference compounds, suggesting that this is the oxidation state of Mn in the bivalve shells. By comparison with the XANES spectra of selected standard compounds, hypotheses about Mn speciation in the shell are also reported. In particular, different factors, such as provenance, ontogenetic age, variable Mn-concentrations or seasonal shell deposition seem not to influence the speciation of the metal in this bivalve species. © 2010 International Union of Crystallography Printed in Singapore - All rights reserved. Source

Snellings R.,Catholic University of Leuven | Mertens G.,Catholic University of Leuven | Gasharova B.,Institute for Synchrotron Radiation ISS | Garbev K.,Institute of Technical Chemistry | Elsen J.A.N.,Catholic University of Leuven
European Journal of Mineralogy

The pozzolanic reaction of a natural zeolite-rich tuff and portlandite was investigated by means of IR spectroscopy. The zeolite tuff consisted mainly of Ca-rich clinoptilolite. A detailed analysis of the changes in the bonding environment during reaction presented by the IR spectra showed that the vibrations assigned to the reactant phases were progressively consumed and implied that Si-rich environments were preferentially depleted. The contemporaneous appearance and rise of vibration bands characteristic for calcium-silicate-hydrates and calcium-aluminate-hydrates demonstrated the formation of reaction products. Changes in bonding environment were spatially visualized by means of synchrotron-IR microspectroscopy. Promising results showed the distribution of reactants and reaction products and allowed to analyze spatial trends in IR-vibration frequencies. A shift in calcium-silicate-hydrate mean peak position from 972 to 968 cm-1 indicated a decrease in silicate chain length with increasing distance from the clinoptilolite-matrix interface. © 2010 E. Schweizerbart'sche Verlagsbuchhandlung, D-70176 Stuttgart. Source

Walter W.,Babcock Noell GmbH | Boffo C.,Babcock Noell GmbH | Borlein M.,Babcock Noell GmbH | Baumbach T.,Institute for Synchrotron Radiation ISS | And 6 more authors.
IEEE Transactions on Applied Superconductivity

Superconducting insertion devices (IDs) are very attractive for synchrotron light sources since they allow increasing the flux and/or the photon energy with respect to permanent magnet IDs. Babcock Noell GmbH (BNG) is completing the fabrication of a 1.5 m long unit for ANKA at the Research Center in Karlsruhe (FZK). The period length of the device is 15 mm for a total of 100.5 full periods plus an additional matching period at each end. The key specifications of the system are: a K-value higher than 2, the capability of withstanding a 4 W beam heat load and a phase error smaller than 3.5 degrees. The magnet is in the final stages of the winding process and will be soon tested at CERN in liquid helium in vertical configuration. This paper describes the main features of the system, the results of the prototyping phase and details of manufacturing process. © 2006 IEEE. Source

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