June 2014 Archives

Dr. V-D. Hodoroaba (BAM, Berlin, Germany) and his colleague have published a report on the feasibility of quantitative X-ray fluorescence (XRF) analysis using coherent (Rayleigh) and incoherent (Compton) X-ray scattering. They have evaluated the ratio of the Compton-to-Rayleigh intensity observed in XRF spectra and also have discussed its relation to the average atomic number. In so-called reference-free XRF analysis, which uses only fundamental parameters and a theoretical formula and does not rely on the calibration curve, there still exist many difficulties, particularly for matrices of lower mean atomic numbers. The analysis presented in this research has sufficiently high sensitivity to distinguish the average atomic number of specimens even within the 0.1 difference. For more information, see the paper, "Gaining Improved Chemical Composition by Exploitation of Compton-to-Rayleigh Intensity Ratio in XRF Analysis", V-D. Hodoroaba et al., Anal. Chem., 86, 6858 (2014).

The Ultrafast X-ray Summer Seminar (UXSS) 2014 took place from June 15 to 19 at SLAC National Accelerator Laboratory, California, United States. The program is organized specifically to train students and post-docs on new opportunities in ultrafast science, particularly using X-ray Free Electron Lasers. Almost all the lectures presented by expert scientists are now available as videos on YouTube. The lecture by Dr. Pieter Glatzel (ESRF) on "Hard X-ray Spectroscopy" (https://www.youtube.com/watch?v=0sMD8lZzuTE) is surely useful for young X-ray spectroscopists. Other exciting lectures are available from Dr. Oleg Shpyrko (UCSD) on "Coherent X-ray Scattering at Ultrafast Timescales" (https://www.youtube.com/watch?v=OIR_ltSOl2U), Dr. Michael Odelius (Stockholm University) on "Electronic Structure & Ultrafast Solution Dynamics in Xray vision w/ theoretical spectacles" (https://www.youtube.com/watch?v=ITIzAmYuyWA), Dr. Alexander Fohlisch (Helmholtz Zentrum Berlin) on "Soft X-ray General and Solid State Aspects" (https://www.youtube.com/watch?v=xTz1oCV5cWI), Dr. Philippe Wernet (Helmholtz Zentrum Berlin) on "Ultrafast Molecular Spectroscopy with X-rays: Experiment", and Prof. Claudio Pellegrini (UCLA) on "X-ray Free Electron Lasers" (https://www.youtube.com/watch?v=5v68nuOTwns). For more information on this summer seminar, visit the following Web site, https://conf-slac.stanford.edu/uxss-2014/

Dr. B. Kanngießer (Technische Universität Berlin, Germany) and her colleagues have recently reported an interesting archaeological application of 3D chemical analysis based on confocal X-ray absorption near edge spectroscopy. This is highly significant for clarifying the technological background of the decorated black- and red-figured Athenian vases (6^th and 5^th century BC) and the plain black glaze. The research team discussed the correlation of the iron oxidation state in the black glaze layer with the manufacturing process. The 3-stage firing process, which was used in the modern reproduction, was retraced by correlating selected attic black glazed (BG) specimens from different periods (Archaic, Classical, Hellenistic). For more information, see the paper, "Confocal XANES and the Attic Black Glaze: The Three Stage Firing Process through Modern Reproduction", L. Luhl et al., Anal. Chem., Article ASAP (DOI: 10.1021/ac500990k).

So far, laser combs in visible light wavelength have been known as an extremely precise measure of dimensions. What would happen if they move into the X-ray region? The advent of an X-ray free electron laser (XFEL) may realize an X-ray frequency comb in the near future. Dr. S. M. Cavalettobe (Max-Planck-Institut fur Kernphysik, Heidelberg, Germany) is proposing such an ambitious experiment. The research could open up wide-ranging applications; ultraprecise X-ray atomic clocks, determination of many X-ray fundamental parameters, quantitative understanding of astrophysical models and quantum electrodynamics etc. For more information, see the paper, "Broadband high-resolution X-ray frequency combs", S. M. Cavaletto et al, Nature Photonics, June 2014 (DOI: 10.1038/nphoton.2014.113).