As of September 30, 2011

for international journal X-Ray Spectrometry (John Wiley & Sons Ltd.)

Evaporation of water by extremely strong X-rays (September 26, 2011)

A Korean group led by Professor J. H. Je (Pohang University of Science and Technology) has recently reported some interesting experiments on water vaporization by X-ray photons.  The experiments were done at the undulator beamline, XSD 32-ID, Advanced Photon Source in Argonne, USA.  It was found that water is vaporized at a rate of 5.5 pL/sec at a 100 msec exposure of 1-Å-wavelength (~13 keV) X-ray irradiation of around 10⁷ photons/μm² (0.1 photons/Ų), which corresponds to a dose rate of ~50 kGy/sec.  They also confirmed that water vapor is reversibly condensed during pauses in irradiation.  This result suggests that photoionization induces vaporization through the reduction of the surface tension of water.  For more information, see the paper, "X-ray-induced water vaporization", B. M. Weon et al., Phys. Rev. E84, 032601 (2011).

X-ray emission spectroscopy clarifies local magnetism of iron-based superconductors (September 22, 2011)

Professor Young-June Kim (University of Toronto, Canada) and his colleagues have recently reported a Fe Kβ X-ray emission spectroscopy study on iron-based superconductors, such as PrFeAsO, Ba(Fe,Co)₂As₂, LiFeAs, Fe_1+x(Te,Se), and A₂Fe₄Se₅ (where A=K, Rb, and Cs).  They found that the materials possess local magnetic moments even in their paramagnetic phases.  By analyzing Fe Kβ_1,3 and Kβ' spectra using the integrated absolute difference method, the local moment size for each sample was determined.  It was found that the value is independent of temperature or carrier concentration but varies significantly across different families.  Specifically, all iron pnictide samples have local moments of about 1μ_B/Fe, while FeTe and K₂Fe₄Se₅ families have much larger local moments of ~2μ_B/Fe and ~3.3μ_B/Fe, respectively.  Such differences point to the importance of considering the contribution of multi-orbital physics in describing magnetism of these compounds.  For more information, see the paper, "Revealing the dual nature of magnetism in iron pnictides and iron chalcogenides using X-ray emission spectroscopy", H. Gretarsson et al., Phys. Rev. B84, 100509(R) (2011).

X-ray photon correlation analysis of martensitic transformation (September 1, 2011)

A German group led by Professor U. Klemradt (Aachen University) has recently performed an X-ray photon correlation spectroscopy (XPCS) experiment on martensitic transformation of a Au_50.5Cd_49.5 single crystal.  XPCS experiments basically consist of the observation of a time-dependent speckle pattern caused by scattering of coherent X-ray photons, and give information on the dynamics of phase transformations in soft and hard condensed matter at atomic length scales.  The measurement was done at ID 10A, European Synchrotron Radiation Facility (ESRF) in Grenoble, France.  A standard Bragg scattering geometry was employed to see the fluctuations of the symmetric (0 0 1) Bragg reflection from the polished surface of the Au-Cd single crystal.  The research team observed slow non-equilibrium-dynamics in a narrow temperature interval in the direct vicinity of the otherwise athermal phase transformation.  For more information, see the paper, "Slow Aging Dynamics and Avalanches in a Gold-Cadmium Alloy Investigated by X-Ray Photon Correlation Spectroscopy", L. Muller et al., Phys. Rev. Lett. 107, 105701 (2011).
 

Application of micro X-ray diffraction mapping to the exposure of counterfeit drugs (August 30, 2011)

Professor M. D. Ward (New York University, USA) and his colleagues have recently proposed an interesting and effective application of the micro X-ray diffraction technique to anticounterfeit protection of pharmaceutical products.  Counterfeit drugs have been a global threat to public health, and they undermine the credibility and the financial success of the producers of genuine products.  There have been great demands for some good methods for rapid and nondestructive screening of the products.  The research team’s idea is the use of barcodes and logos fabricated on drug tablets using soft-lithography stamping of compounds that can be read by X-ray diffraction mapping but are invisible to the naked eye or optical microscopy.  The materials used were suspensions of rutile powder mixed with corn syrup in a 1:2.5 (w/w) ratio or zinc oxide powder mixed with corn syrup at a 1:10 (w/w) ratio.  It was demonstrated that the technique is feasible for realistic screening, because of its nondestructive, automated, and user-friendly properties.  For more information, see the paper, "Anticounterfeit Protection of Pharmaceutical Products with Spatial Mapping of X-ray-Detectable Barcodes and Logos", D. Musumeci et al., Anal. Chem., Articles ASAP (DOI: 10.1021/ac201570r  Publication Date (Web): August 30, 2011).
 

Fine structures in Kβ spectra of chromium (August 26, 2011)

A research team led by Professor I. Tsuyumoto (Kanazawa Institute of Technology, Japan) has recently studied chromium Kβ spectra and found that the intensity of Kβ" satellite, which is observed at the higher energy side of the main Kβ_1,3 peak, is strongly correlated with the pre-edge peak of the X-ray absorption near edge structure specific for chromium (VI) compounds, such as CrO₃, Na₂CrO₇・2H₂O, Na₂CrO₄・4H₂O, K₂Cr₂O₇, K₂CrO₄, Zn₂CrO₄(OH)₂・2H₂O, PbCrO₄, and BaCrO₄.  For more information, see the paper, "X-ray Fluorescence Analysis of Hexavalent Chromium Using Kβ Satellite Peak Observed as Counterpart of X-ray Absorption Near-Edge Structure Pre-Edge Peak", I. Tsuyumoto et al., Anal. Chem., Articles ASAP (DOI: 10.1021/ac201606c  Publication Date (Web): August 26, 2011).
 

X-ray tomography reveals how Chinese jawless fish evolved (August 18, 2011)

Most living vertebrates are jawed vertebrates (gnathostomes), and only scarce information on the evolutionary origin of jaws is available from living jawless vertebrates (cyclostomes), hagfishes and lampreys.  The extinct bony jawless vertebrates, or ‘ostracoderms’, have been regarded as precursors of jawed vertebrates and provide an insight into this formative episode in vertebrate evolution. Very recently, Chinese scientists employed synchrotron radiation X-ray tomography in an effort to analyze the cranial anatomy of galeaspids, a 370-435-million-year-old ‘ostracoderm’ group from China and Vietnam.  For more information, see the paper, "Fossil jawless fish from China foreshadows early jawed vertebrate anatomy", Z. Gai et al., Nature 476, 324 (2011)
 

Quantitative X-ray reflectivity analysis of growing thin films (August 15, 2011)

Professor J. R. Engstrom (Cornell University) and his colleagues have recently published a detailed comparative study on surface morphology obtained from in-situ, time-resolved X-ray reflectivity, which is extremely feasible as a tool for investigating surface and interfaces during thin film growth, but requires some modeling of the growth process for the interpretation.  The research group prepared two sets of organic thin films, pentacene/SiO₂ and diindenoperylene SiO₂; for each system, giving a total of four films, grown to different thicknesses, under nominally identical conditions.  The X-ray reflectivity data were analyzed based on three different models, and the obtained parameters were directly compared with AFM data.  It was found that all models employed can give good agreement between the surface morphology obtained from fits with the actual morphology at early times.  On the other hand, this agreement deteriorates at later times, once the root-mean squared (rms) film roughness exceeds about 1 monolayer.  It was also found that the best fits to reflectivity data, corresponding to the lowest values of χ², do not necessarily yield the best agreement between simulated and measured surface morphologies, simply because the model reproduces all local extrema in the data.  For more information, see the paper, "Quantitative modeling of in situ x-ray reflectivity during organic molecule thin film growth", A. R. Woll et al., Phys. Rev. B84, 075479 (2011).
 

Extension of coherent X-ray diffractive imaging (August 12, 2011)

A research team led by Professors V. Holý (Charles University, Czech Republic) and T. Baumbach (ANKA-Institute for Synchrotron radiation, Germany) have recently performed some extension of coherent X-ray diffractive imaging for high-resolution strain analysis in crystalline nanostructured devices such as layered nanowires and/or dots.  Their research successfully determined the strain distribution in (Ga,Mn)As/GaAs nanowires.  The key was their improvement of the phase-retrieval algorithm, i.e., separation of diffraction signals in reciprocal spaces.  It was found that individual parts of the device can be reconstructed independently by this inversion procedure.  The method is effective even for strongly inhomogeneously strained objects.  For more information, see the paper, "Selective coherent x-ray diffractive imaging of displacement fields in (Ga,Mn)As/GaAs periodic wires", A. A. Minkevich et al., Phys. Rev. B84, 054113 (2011).
 

Quantitative analysis of photoreduction process in Cu metalloproteins (August 1, 2011)

X-ray spectroscopy is an extremely strong tool for metal speciation at the molecular level in biological and environmental samples, especially for metalloproteins.  When samples are quite easily influenced by photoreduction, however, analysis has not been straightforward.  Recently, a Chinese group has studied in detail soft X-ray induced photoreduction in organic Cu(II) compounds.  The research team measured XANES spectra at Cu-LIII, O-K, and C-K edges to see how the valence state of Cu changes.  A scanning transmission X-ray microscopy was also employed to look at specific radiation damages.  It was found that reducing the radiation dose to 0.1 MGy effectively prevented the photoreduction of organic Cu(II) compounds.  For more information, see the paper, "Soft X-ray Induced Photoreduction of Organic Cu(II) Compounds Probed by X-ray Absorption Near-Edge (XANES) Spectroscopy", J. Yang et al., Anal. Chem., Article ASAP (DOI: 10.1021/ac201622g  Publication Date (Web): August 1, 2011).
 

X-ray parametric down-conversion for atom-scale resolution in the extreme-ultraviolet region (July 17, 2011)

Parametric down-conversion is a quantum-optical process in which a 'pump' photon splits spontaneously into two (the 'signal' and 'idler') in a nonlinear optical medium.  Recently, Professor T. Ishikawa (RIKEN, Harima, Japan) and his colleagues reported their experiments with X-ray photons.  They have visualized three-dimensionally the local optical response of diamond at wavelengths between 103 and 206 Å with a resolution as fine as 0.54 Å.  This corresponds to a resolution from λ/190 to λ/380, an order of magnitude that is the best ever achieved.  For more information, see the paper, "Visualizing the local optical response to extreme-ultraviolet radiation with a resolution of λ/380", K. Tamasaku et al., Nature Physics 7, 705 (2011).
 

MOU between EMBL and European XFEL (September 13, 2011)

The European Molecular Biology Laboratory (EMBL) and the European XFEL have signed a Memorandum of Understanding, thereby laying the foundation for close future collaboration in deciphering the structure and dynamics of biomolecules.  For further information, visit the Web page, http://www.xfel.eu/
 

Denver X-ray conference awards (August 3, 2010)

The following awards were presented during the plenary session of the 60th Annual Denver X-Ray Conference: The 2011 Barrett Award was presented to Dr. Juan Rodriques-Carvajal, Institute Laue-Langevin, Grenoble, France to honor his exceptional contributions to the field of X-ray diffraction, in particular for his work on characterization of the structural and magnetic properties of strongly correlated oxides using diffraction techniques and for writing and freely disseminating FULLPROF, the most widely used Rietveld refinement program for analysis of crystallographic and magnetic structures.  The 2011 Jenkins Award was given to Dr. Paul K. Predecki to honor his contributions to the development of X-ray methods for a wide variety of materials, and his generosity in teaching and inspiring others in X-ray materials analysis both at the University of Denver and through organization and management of the Denver X-ray Conference.  The 2011 Jerome B. Cohen Student Award was given to Vallerie Ann Innis-Samson, University of Tsukuba, Ibaraki, Japan, for her work, X-ray Reflection Tomography: A New Tool for Surface Imaging.  For further information, visit the Web page, http://www.dxcicdd.com/
 

Vacuum system for open X-ray tube (September 22, 2011)

X-RAY WorX GmbH has introduced electronically controlled venting valves for open X-ray tubes. This avoids the manual venting typically performed during X-ray tool maintenance. The new venting method considers the turbo pump's rotation speed and automatically optimizes tube venting.  For further information, visit the web page, http://www.x-ray-worx.com/
 

SII’s new X-ray particle inspection system for battery applications (August 30, 2011)

SII Nano Technology Inc. (SIINT) has announced that it has recently developed an X-ray Inspection System which enables detection of any metal particles of about 20 μm diameter contained in fuel cell electrodes and lithium ion rechargeable battery electrodes within a few minutes, as well as carrying out automatic elemental analysis.  For further information, visit the web page, http://www.siint.com/en/
 

Fujifilm’s new subsidiary in Vietnam (September 21, 2011)

FUJIFILM Corporation has announced that it has established FUJIFILM MEDICAL SYSTEMS VIETNAM Co., Ltd. in Ho Chi Minh City, Socialist Republic of Vietnam to further expand its business in the fast-growing economy of Vietnam.  The business operation will launch in October 2011.  For further information, visit the web page, http://www.fujifilm.com/
 

PANalytical expands with X-ray tube factory in Eindhoven, The Netherlands (September 15, 2011)

PANalytical has relocated its X-ray tube manufacturing to a new factory in Eindhoven, The Netherlands.  For further information, visit the web page, http://www.panalytical.com/
 

Bruker acquires Center for Tribology (September 12, 2011)

Bruker Corporation has announced the signing of a purchase agreement to acquire Center for Tribology, Inc. (CETR), which is a privately held corporation located in Silicon Valley in Campbell, CA, USA.  Bruker intends to continue to operate CETR in Silicon Valley and to integrate its business management, operations, research and development, sales and support with the current AFM (atomic force microscope) and SOM (stylus and optical metrology) businesses in the Bruker Nano Surfaces division.  For further information, visit the web page, http://www.bruker.com/
 

SpectroscopyNow.com

For additional news about X-ray analysis and other spectroscopy sciences, browse the Wiley website.

Kenji Sakurai
Director, X-Ray Physics Group, National Institute for
Materials Science (NIMS)
and Professor, Doctoral Program in Materials Science and
Engineering, Graduate School of Pure and Applied Sciences,
 University of Tsukuba
1-2-1, Sengen, Tsukuba, Ibaraki 305-0047 Japan
Phone : +81-29-859-2821, Fax : +81-29-859-2801
sakurai@yuhgiri.nims.go.jp
http://www.nims.go.jp/xray/lab/