As of September 24, 2009

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

Quick X-ray absorption spectrometry clarifies chemical reaction of environmental contaminants (September 22, 2009)

Professor D. Sparks (University of Delaware, USA) and his colleagues have reported an interesting application of quick X-ray absorption spectrometry to environmental science.  The experiment is basically a continuous monochromator scan (0.3-0.6 sec for each spectrum) at the synchrotron beamline at Brookhaven National Lab.  The main interest here is the initial oxidation rate of As(III) to As(V) by hydrous manganese(IV) oxide, because the toxicity and availability of arsenic to living organisms depends on its oxidation state at the interface to the water.  The research team found that the initial apparent As(III) depletion rate constants are nearly twice as large as those measured with conventional, but much slower techniques.  This indicates the necessity of further studies using such a rapid analytical method.  For more information, see the paper, "Quantification of rapid environmental redox processes with quick-scanning x-ray absorption spectroscopy (Q-XAS)", M. Ginder-Vogel et al., Proc Nat Aca Sci, 106, 16124 (2009).

Geochemical study on As-S system by X-ray spectroscopy (September 18, 2009)

It is known that sulfide sometimes play a significant role in the geochemistry of arsenic under reducing conditions.  So far, it has been assumed that sulfide primarily reduced the solubility and mobility of arsenic by precipitation of arsenic-sulfide minerals, As₂S₃, but recent studies indicate that under certain conditions, significant concentrations of soluble As-S compounds can exist in sulfidic waters.  Thus, the question is whether they are As(III)-S species (“thioarsenites”) or As(V)-S species (“thioarsenates”).  A research group led by Dr. B. Planer-Friedrich (University of Bayreuth, Germany) has recently reported that use of X-ray absorption spectroscopy (XANES and EXAFS) can determine the concentration ratio of each species.  The experiment was done at beamline BM20, ESRF.  For more information, see the paper, "Discrimination of Thioarsenites and Thioarsenates by X-ray Absorption Spectroscopy", E. Suess et al., Anal. Chem., Article ASAP (2009), DOI: 10.1021/ac901094b

Theoretical calculation of Cu Kα spectra (September 16, 2009)

Dr. C. T. Chanter and his colleagues have published a paper on the unresolved quantitative discrepancies between experimental and theoretical Cu Kα spectra.  For more information, see the paper, "Theoretical Determination of Characteristic X-Ray Lines and the Copper Kα Spectrum", C. T. Chantler et al., Phys. Rev. Lett. 103, 123002 (2009).
 

Soft X-ray laser produces ‘transparent aluminum’ (September 1, 2009)

In the film Star Trek IV (1986), transparent aluminum is used for the exterior portals and windows of spacecraft.  Now transparent aluminum has become a hot topic for real, rather than in science fiction.  An international team, led by Oxford University scientists, has recently reported that a short pulse from the FLASH laser (wavelength 13.5 nm) knocks out a core L-shell electron from every aluminium atom in a 50 nm Al thin film without destroying the metal’s crystalline structure.  This rendered the aluminium almost invisible for this wavelength.  This phenomenon is called saturable absorption.  The transient state of aluminium produced in this way is as dense as ordinary matter but can only exist for an extremely short period of time of 40 femtoseconds.  For more information, see the paper, "Turning solid aluminium transparent by intense soft X-ray photoionization", B. Nagler et al., Nature Physics 5, 693 (2009).
 

Coherent X-rays reveals dynamics of atomic-scale diffusion (September 1, 2009)

So far, diffusion in solids has been investigated by profiling the depth dependence of tracer atoms diffused into the sample.  Although one can obtain the diffusion constant from this, the question is how diffusion takes place on the atomic scale, rather than on the micron scale.  Sometimes quasielastic neutron scattering as well as Mobauer spectroscopy can be used in a very limited number of fortunate cases.  A research group led by Professor G. Vogl (University of Vienna, Austria) recently reported the use of X-ray photon correlation spectroscopy (XPCS) to observe the dynamics of diffusing atoms.  The research was done for intermetallic alloy Cu₉₀Au₁₀, at temperatures of around 540 K, where the system is a substitutional solid solution, that is, the Au atoms statistically occupy sites in the Cu fcc lattice.  The research gives the dynamical behavior of single atoms as a function of their neighborhood, and confirms quantitatively that Au atoms have a tendency to locally order on a certain set of sites in the crystal.  Photon correlation spectroscopy is based on analysis of 'speckle' patterns, which are fine-scale diffraction patterns that appear in the scattering of coherent light from a disordered system.  Speckle patterns are sensitive to the exact spatial arrangement of the disorder.  By observing the intensity fluctuations in the speckle pattern, the characteristic times of fluctuations in the system can be determined.  For more information, see the paper, "Atomic diffusion studied with coherent X-rays", M. Leitner et al., Nature Materials,8, 717 (2009).
 

Spectral shape of K X-rays produced by ultra short pulse laser (August 27, 2009)

When a strong laser beam hits the surface of a material, plasma is produced there, subsequently leading to the emission of a short burst of X-rays.  It is believed that the electrons in the surface plasma are accelerated by the strong electric field of the laser and then penetrate the solid behind. There, they knock out electrons from inner electronic shells, which subsequently undergo inner-shell recombination, leading to characteristic line emissions such as Kα and Kβ spectra.  A research group led by Professor U. Teubner (University of Applied Sciences, Emden, Germany) has reported detailed experimental results on copper and titanium K X-rays.  Particular attention has  been paid to the interplay between the angle of incidence of the laser beam on the target, as well as the influence of prepulses.  For more information, see the paper, "Optimized K x-ray flashes from femtosecond-laser-irradiated foils", W. Lu et al., Phys. Rev. E 80, 026404 (2009).
 

Solution of phase problem in X-ray crystallography (August 10, 2009)

In X-ray diffraction experiments, one measures the intensity (amplitude) of the diffracted X-rays as a function of position in the reciprocal space, and the information on the phase is always missing.  For many years, this so-called phase problem has been thought as one of the biggest problems in X-ray crystallography.  Professor E. Wolf (University of Rochester, New York) has recently published a very interesting and inspirational paper.  He is famous for several important textbooks on optics and also for his presidency of the Optical Society of America.  The present paper is theoretical, and starts with a criticism of basic understanding of the problem. The author says that trying to measure the phase is rather meaningless.  Almost all scientists assume that the incident X-ray beam is monochromatic in the data analysis, but the author points out that a monochromatic beam is not possible in reality.  Any beam that can be produced in a laboratory is, at best, quasimonochromatic and, therefore, even if both the amplitudes and the phases are given, it is still not possible to solve the problem.  Alternatively, the author proposes the measurement of certain correlation functions, with the use of spatially coherent beams.  While it is extremely important to think about a future strategy regarding the final solution of the phase problem as discussed in the paper, the author makes no mention of the recent significant strides in coherent X-ray scattering.  For more information, see the paper, "Solution of the Phase Problem in the Theory of Structure Determination of Crystals from X-Ray Diffraction Experimentst", E. Wolf, Phys. Rev. Lett. 103, 075501 (2009).
 

X-ray nanointerferometer (August 3, 2009)

X-ray phase-contrast imaging is extremely powerful for visualizing internal structures with low-Z matrices, which are most likely in bio-medical specimens.  The use of an X-ray interferometer is one of the most promising ways forward for this imaging technology, but resolution has been limited to the micrometer scale so far.  A research group led by Dr. A. Snigirev (European Synchrotron Radiation Facility, Grenoble, France) has recently developed a novel type of X-ray interferometer employing a bilens system with two parallel arrays of compound refractive lenses, each of which creates a diffraction limited beam under coherent illumination.  The energy of the X-rays is 10-20 keV and the material used in the refractive lenses is silicon.  When the two beams overlap, they produce an interference pattern with fringe spacing ranging from tens of nanometers to tens of micrometers.  Readers may notice that the system is similar to the model of a Billet split lens in classical optics (See Fig.7.8, page 263 in "Principle of Optics", M. Born and E. Wolf, 6^th Ed, Pergamon Press (1988)).  The use of a modern synchrotron source and this novel optical device thus opens up a new field and could revive old theorems.  Coherent moiré imaging or radiography are promising straightforward applications.  For more information, see the paper, "X-Ray Nanointerferometer Based on Si Refractive Bilenses", A. Snigirev et al., Phys. Rev. Lett., 103, 064801 (2009).
 

Removing all electrons from neon by X-ray laser (September 18, 2009)

At Stanford’s linac coherent light source (LCLS), a great deal of effort has been devoted since April this year to initial scientific tests of an X-ray laser.  In September, scientists attempted to strip all ten electrons from an atom of neon.  They were able to adjust the proportion of different neon species, from non-ionized Ne (no missing electrons) to Ne¹⁰⁺ (lacking all 10 electrons), by fine-tuning the powerful LCLS X-ray beam.  For more information, visit the Web page, http://today.slac.stanford.edu/
 

Stimulus funds help Cornel’s ERL (September 14, 2009)

Nearly $19 million in funding through the American Recovery and Reinvestment Act is supporting the Cornell High Energy Synchrotron Source (CHESS), Cornell Electron Storage Ring (CESR) and ongoing efforts to plan and build a new linear accelerator, the Energy Recovery Linac (ERL).  So far, Cornell has received more than 90 ARRA grants, totally about $76 million.  For more information, visit the Web page, http://www.news.cornell.edu/
 

X-ray imaging of Ashura sculpture (September 8, 2009)

Japan is celebrating the 1,300th anniversary of Kohfukuji Temple in Nara.  The temple’s sculpture of Ashura, one of the greatest treasures of the early to mid-7th century, is on exhibition at Kyushu National Museum in September. The exhibition features some X-ray imaging results of non-destructive observation of the interior of the sculpture. The images establish that the sculpture is still in good condition and also give a lot of information on the materials and methods used in its creation.  Information on Ashura is available at the following Web page, http://en.wikipedia.org/wiki/Asura_(Buddhism)
 

Chandrayaan-1’s mission declared over (August 31, 2009)

Chandrayaan-1 was a lunar probe launched by the Indian Space Research Organization (ISRO).  It was equipped with advanced X-ray spectrometers for investigation.  After suffering from several technical problems including failure of the star sensors and insufficient thermal shielding, Chandrayaan stopped sending radio signals on August 29, 2009 shortly after which the ISRO officially declared the mission over.  Chandrayaan operated for 312 days from October 2008.  For more information, visit the Web page, http://www.isro.org/Chandrayaan/htmls/home.htm
 

Denver X-ray conference awards (July 29, 2009)

The following awards were presented during the plenary session of the 58th Annual Denver X-Ray Conference:
The 2009 Barrett Award was presented to Robert Von Dreele, Argonne National Laboratory, Argonne, IL.
The 2009 Jenkins Award was presented to Tim Fawcett, International Centre for Diffraction Data, Newtown Square, PA.
There was no winner for the 2009 Jerome B. Cohen Student Award.
 

Nature News on the application of carbon nanotube X-ray source (July 28, 2009)

A recent edition of Nature News featured the successful application of a carbon nanotube (CNT)-based X-ray source to medical imaging.  A group led by Professor O. Zhou (University of North Carolina in Chapel Hill, USA) has developed a micro 3D CT system.  The main idea behind such very rapid scanning is simply electronic switching of 3D arrayed CNT X-ray sources, rather than mechanical motion.  For more information, see the article, "Nanotubes sharpen X-ray vision", Zeeya Merali, Nature News, doi:10.1038/news.2009.744  The original research papers were published in April 2009 ("A dynamic micro-CT scanner based on a carbon nanotube field emission X-ray source", G Cao et al Phys. Med. Biol. 54, 2323 (2009))

 

HiTek Power’s new 70 kV power supply (September 9, 2009)

HiTek Power has recently extended its comprehensive Series XRG70 by introducing the XRG70-703, a compact high voltage power supply that has been specifically developed for high performance analytical X-ray applications.  The maximum output power is 70W.  For further information, visit the web page, http://www.hitekpower.com/

 

Horiba’s new facility in Paris (September 16, 2009)

Horiba has recently announced that the company will build a new research facility on the Campus of Ecole Polytechnique, in Saclay near Paris, France.  The 7500 m² facility will open its doors in late 2011.  For further information, visit the web page, http://www.horiba.com/
 

SII Nanotech to market Bruker’s S1 TURBO and S1 SORTER (August 25, 2009)

SII Nanotechnology has recently decided to market Bruker AXS’s S1 TURBO and S1 SORTER handheld XRF analyzers in Japan. For further information, visit the web page, http://www.siint.com/en/index.shtml  Technical information on the SI TURBO can be found at http://www.bruker-axs.de/handheldx-rayspectrometry.html
 

Rigaku’s new EDXRF Center in Austin, Texas (July 27, 2009)

Rigaku Corporation has recently formed a new research and development, manufacturing, sales, service and support subsidiary - Applied Rigaku Technologies, Inc. (ART), which is dedicated to energy dispersive X-ray fluorescence (EDXRF) and related elemental analysis technologies.  The new company is located in the northwest quadrant of Austin, Texas.  For further information, contact: Robert Bartek, President, Applied Rigaku Technologies, Inc., Phone: +1-512-633-4325, E-mail, robert.bartek@rigaku.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/