As of March 31, 2010

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

Chemometric analysis of X-ray absorption spectra helps understanding of Li battery (March 30, 2010)

Dr. M. Giorgetti (University of Bologna and Unita di Ricerca INSTM di Bologna) and his colleagues recently reported the successful application of the chemometric approach to a series of in-situ near edge X-ray absorption spectra of a Cu_0.1V₂O₅ xerogel/Li ion battery.  The research group discusses how the multivariate curve resolution (MCR) technique and also fixed size windows evolving factor analysis (FSWEFA) are useful in determining the number of species and the ratio.  It was found that three different species co-exist during battery charging. For more information, see the paper, "Multivariate Curve Resolution Analysis for Interpretation of Dynamic Cu K-Edge X-ray Absorption Spectroscopy Spectra for a Cu Doped V₂O₅ Lithium", P. Conti et al., Anal. Chem., Article ASAP (DOI: 10.1021/ac902865h)

Ultra fast X-ray absorption spectroscopy of Ni during demagnetization (March 30, 2010)

A German group at BESSY II recently succeeded in studying the evolution of both the spin (S) and orbital angular (L) momentum of a thin Ni film during ultrafast demagnetization, by means of X-ray magnetic circular dichroism (XMCD).  It was found that both S and L components decrease by irradiating a femtosecond laser pulse, and the time constant is 130±40 fs.  For more information, see the paper, "Femtosecond x-ray absorption spectroscopy of spin and orbital angular momentum in photoexcited Ni films during ultrafast demagnetization", C. Stamm et al., Phys. Rev, B81, 104425 (2010).

Application of soft X-ray laser pulse to structure analysis of nano crystals (March 26, 2010)

Professor S. Techert (Max-Planck-Institute for Biophysical Chemistry, Goettingen, Germany) and his colleagues have reported on Bragg diffraction experiments with a soft X-ray laser (wavelength 8 nm, pulse width 30 fs, power 4×10¹¹ photons/pulse) from the free electron laser at FLASH, Deutsche Elektronen-Synchrotron (DESY) in Hamburg.  The research group studied Bragg diffraction patterns of single nano-crystal (20 nm×20 nm×20 μm) and powder with grain sizes smaller than 200 nm of silver behenate (AgC₂₂H₄₃O₂, chain length 5.8 nm).  So far, many coherent X-ray diffraction studies have been done even with soft X-ray wavelengths, but the present research aims at the analysis of periodic structures that are usually targets of X-ray diffraction with hard X-rays.  They showed an interesting comparison between the single nano crystal and the powder, and also discussed the influence of the extremely high peak power of laser pulses.  For more information, see the paper, "Diffraction Properties of Periodic Lattices under Free Electron Laser Radiation", I. Rajkovic et al., Phys. Rev. Lett. 104, 125503 (2010).
 

Novel feasible approach to refinement of atomic-scale structure of complex disordered systems (March 26, 2010)

There are still many unknown problems related to the structure of amorphous materials, because the X-ray diffraction technique has some limitations in the case of disordered systems.  A research team led by Dr. A. L. Goodwin (Oxford University, UK) recently reported a new elegant general scheme to solve the structure by successfully demonstrating its application to molecular C₆₀, a-Si, and a-SiO₂.  The team proposes to employ the information gained in spectroscopic experiments (such as EXAFS, Raman, NMR etc) regarding the number and distribution of atomic environments.  The idea is that such information can be used as a valuable constraint in the refinement of the atomic-scale structures of nanostructured or amorphous materials from the pair distribution function (PDF), which is obtained by Fourier transform of the X-ray diffraction pattern.  Although a conventional reverse Monte Carlo (RMC) approach is not always successful in obtaining the correct structure solution, the team showed that such difficulties can be removed by including the above variance term.  For more information, see the paper, "Structure Determination of Disordered Materials from Diffraction Data", M. J. Cliffe et al., Phys. Rev. Lett. 104, 125501 (2010).
 

Coherence theory of X-ray and neutron reflectivity (March 23, 2010)

A Dutch neutron research group at Delft University of Technology, Netherlands, recently published a paper describing the extension of their coherence theory on neutron scattering to X-ray reflectivity.  For more information, see the paper, "Coherence approach in neutron, x-ray, and neutron spin-echo reflectometry", V. O. de Haan et al., Phys. Rev. B81, 094112 (2010).
 

Atomic-resolution element mapping with energy-dispersive X-ray detector (March 8, 2010)

Professor L. J. Allen (University of Melbourne, Australia) and his colleagues have recently demonstrated atomic-resolution chemical mapping in a scanning transmission electron microscope (STEM).  They obtained Sr and Ti images for SrTiO₃.  Such images are directly interpretable mainly because the effective ionization interaction is localized.  For more information, see the paper, "Atomic-resolution chemical mapping using energy-dispersive x-ray spectroscopy", A. J. D’Alfonso et al., Phys. Rev. B81, 100101(R) (2010).
 

Production of coherent soft X-rays in storage ring (March 1, 2010)

With linac-based light sources, the electron beam has a high peak current and small energy spread, and this can be used to drive a seeded single pass free electron laser.  On the other hand, the beams in a storage ring usually have a relatively low current and large energy spread.  To generate ultrashort coherent radiation, the coherent harmonic generation (CHG) technique is a promising candidate.  Dr. D. Xiang (SLAC National Accelerator Laboratory, USA) and Dr. W. Wan (Lawrence Berkeley National Laboratory, USA) have recently proposed a scheme to extend the harmonic number of the CHG technique by an order of magnitude using angular-modulated electron beams in the storage ring.  The technique has the potential of generating femtosecond coherent soft X-ray radiation directly from an infrared seed laser.  For more information, see the paper, "Generating Ultrashort Coherent Soft X-Ray Radiation in Storage Rings Using Angular-Modulated Electron Beams", D. Xiang et al., Phys. Rev. Lett. 104, 084803 (2010).
 

Accurate X-ray mass attenuation coefficients of zinc (February 22, 2010)

An Australian research group has recently published experimentally obtained X-ray mass attenuation coefficients of zinc for 7.2- 15.2 keV X-rays with an absolute accuracy of 0.044% and 0.197%.  For more information, see the paper, "X-ray mass attenuation coefficients and imaginary components of the atomic form factor of zinc over the energy range of 7.2.15.2 keV", N. A. Rae et al., Phys. Rev. A81, 022904 (2010).
 

CTR analysis of Rubrene single crystal thin films (February 12, 2010)

Rubrene (5,6,11,12-tetraphenylnaphthacene, C₄₂H₂₈) is a red colored polycyclic aromatic hydrocarbon.  As an organic semiconductor, the most promising application is in organic light-emitting diodes (OLEDs) and organic field-effect transistors, which are the core elements of flexible displays.  Recently, Professor Y. Wakabayashi (Osaka University, Japan) and his colleagues have studied the near surface structure of Rubrene single crystal by crystal truncation rod (CTR) scattering, which gives a modulated profile in the tail of a series of Bragg peaks (0 0 z).  The research group employed coherent Bragg rod analysis (COBRA) rather than conventional curve fitting analysis to determine the electron density profile along the depth.  The analysis has shown that the molecules at the surface are slightly expanded along the surface normal direction, while the second or deeper molecular layers are not affected by the existence of the surface.  Their research can be extended to applications of other similar organic semiconductors.  For more information, see the paper, "Sub-Å Resolution Electron Density Analysis of the Surface of Organic Rubrene Crystals", Y. Wakabayashi et al., Phys. Rev. Lett. 104, 066103 (2010).  For information on COBRA, see, for example, "Direct determination of epitaxial interface structure in Gd₂O₃ passivation of GaAs", Y. Yacoby et al., Nature Materials 1, 99 (2002).
 

X-ray nanofocusing by kinoform lenses (February 1, 2010)

Dr. H. Yan (National Synchrotron Light Source II, Brookhaven National Laboratory, USA) has recently reported a comparative study on various kinoform lenses for X-ray nanofocusing.  He employed the geometrical theory, the dynamical diffraction theory, and the beam propagation method, and showed that the geometrical theory becomes invalid.  The influence of the edge diffraction effect from the individual lens element was studied in view of the limit of the focus size.  It was also shown that the length of the lenses can be optimized to reduce the wave field distortion.  For more information, see the paper, "X-ray nanofocusing by kinoform lenses: A comparative study using different modeling approaches", H. Yan, Phys. Rev. B81, 075402 (2010).

The 4th X-ray reflectivity school in Japan (March 16, 2010)

Demand for learning analytical techniques for surfaces and interfaces appears to be on the increase.  In Tokyo, Japan, the 4th tutorial course on the analysis of thin films and multilayers by X-ray reflectivity was held on March 16.  The first Japanese textbook that serves as an introduction to X-ray reflectivity was published in 2009 (also translated into Korean in 2010), and the 8 authors gave lectures as part of the course.  Further information is available at http://www.nims.go.jp/xray/ref/ (in Japanese only).
 

Japanese and US scientists awarded 2010 Japan Prize (January 15, 2010)

The Science and Technology Foundation of Japan has announced that Japanese and US scientists have been named as laureates of the 2010 (26th) Japan Prize.  Dr. Shun-ichi Iwasaki, 83, Director of Tohoku Institute of Technology in Japan, and also Professor Emeritus, Tohoku University, has received the prize in this year’s category of "Industrial production and production technology" for his contributions to high-density magnetic recording technology by developing a perpendicular magnetic recording method.  Dr. Peter Vitousek, Professor of Biology, Stanford University in the United States, 60, was selected in the other prize category of "Biological production and environment" for his contributions to solving global environmental issues based on the analysis of nitrogen and other substances’ cycles.  They will receive certificates of merit, and commemorative medals.  There is also a cash award of fifty million Japanese yen for each prize category.  The presentation ceremony is scheduled to be held in Tokyo on Wednesday 21st April, 2010.  The prize categories for the 2011 (27th) Japan Prize will be "Information and communications" and "Bioscience and medical science".  For further information, visit the Web page, http://www.japanprize.jp/en/index.html

Bruker releases new D8 DISCOVER (March 23, 2010)

Bruker AXS has announced the introduction of its next-generation D8 DISCOVER diffraction system.  It comes with a two-dimensional VANTEC-500 detector with 2048×2048 channels at 144 cm² active area.  For further information, visit the web page, http://www.bruker-axs.de/new_d8_discover.html
 

SII’s new coating thickness gauge (March 15, 2010)

SII Nano Technology has announced the release of its SFT-110 coating thickness gauge, which determines the thickness of each layer by analyzing X-ray fluorescence intensity from each element.  One newly introduced function is automatic positioning of the sample.  The system includes software for analysis based on the fundamental parameter method.  The price is around 6 million JPY.  For further information, visit the web page, http://www.siint.com/en/
 

PANalytical introduces 3D detector for X-ray diffraction (March 1, 2010)

PANalytical has announced the introduction of its new PIXcel^3D detector for its X-ray diffraction system.  The PIXcel^3D detector is the result of the Medipix2 collaboration - a consortium of more than 16 leading particle physics research institutes across Europe, headed by CERN.  It is the only detector that offers four modes – in addition to 0D (point detector), 1D (line detector), and 2D (area detector) modes, it has 3D mode.   The new detector can be used for computed tomography (CT) on a diffraction platform.  For further information, visit the web page, http://www.panalytical.com/

PANalytical and SODERN form alliance in neutron spectrometers (March 24, 2010)

PANalytical (Almelo, the Netherlands) and SODERN (Limeil-Brevannes, France) have recently agreed an alliance for the distribution and support of SODERN’s neutron-based cross-belt analyzers, which are used in the cement, minerals and coal industries. For further information, visit their web pages, http://www.panalytical.com/ and http://www.sodern.com

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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/