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 (6th and 5th 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).

X-ray frequency comb - X-Ray News

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).

Synchrotron imaging of birds' ancestor - X-Ray News

At ESRF in Grenoble, France, several very interesting imaging experiments are going on.  Some fossils of Archaeopteryx, which were believed to live 150 million years ago, are being imaged by using a pin-hole X-ray camera at synchrotron beamlines BM5 and ID19.  The main question is about their wings - whether they could fly or not.  So far, the research has encountered a number of challenges.  The project is conducted by Germany's Burgermeister-Muller-Museum (the Solnhofen Museum).  For more information, see the following Web site, http://www.solnhofen.de/index.php?id=0,49

Electrochemical X-ray fluorescence - X-Ray News

A group led by Prof. Julie V. Macpherson (Warwick University, England) has reported electrochemical X-ray fluorescence, which can quantitatively detect heavy metals in solution.  In this technique, electrochemical preconcentration of a species of interest onto the target electrode is achieved by cathodic electro-deposition.  X-ray fluorescence can then help unambiguous elemental identification and quantification of metal concentration.  The key is that the electrochemical preconcentration step improves the detection limit by over 4 orders of magnitude, and it can reach the sub-ppb level.  For more information, see the paper, "Electrochemical X-ray Fluorescence Spectroscopy for Trace Heavy Metal Analysis: Enhancing X-ray Fluorescence Detection Capabilities by Four Orders of Magnitude", L. A. Hutton et al., Anal. Chem., 86, 4566 (2014).

Application of TXRF to the determination of halide in liquid - X-Ray News

Prof. K. Binnemans (KU Leuven, Heverlee, Belgium) and his colleagues have published several papers on the application of TXRF to the determination and quantification of halide impurities in liquid.  So far, the detection of halide ions in solution has been problematic because volatile hydrogen halide compounds are formed when the sample is mixed with the acidic metal standard solution. The loss of hydrogen halide during the drying step of the sample preparation procedure gives imprecise and inaccurate results.  To avoid this, the research group is proposing to introduce an alkaline copper standard Cu(NH3)4(NO3)2.  For more information, see the papers, "Determination of Halide Impurities in Ionic Liquids by Total Reflection X-ray Fluorescence Spectrometry", T. V. Hoogerstraete et al., Anal. Chem., 86, 3931 (2014), and "Determination of Halide Ions in Solution by Total Reflection X-ray Fluorescence (TXRF) Spectrometry", T. V. Hoogerstraete et al., Anal. Chem., 86, 1391 (2014).

Podcast on wavelength-dispersive X-ray fluorescence spectroscopy - X-Ray News

An interesting and useful tutorial on X-ray analytical methods for newcomers is now available in the Materials Today Podcast.  Dr. Ravi Yellepeddi (Thermo Fisher Scientific) explains the principle of X-ray fluorescence, recent progress in instruments, and the variety of applications in industry and research laboratories.  The talk is around 30 min.  Visit the following Web site,

http://www.materialstoday.com/characterization/podcasts/wavelength-dispersive-xray-fluorescence/

An interesting application of confocal micro-X-ray fluorescence has been reported by Dr. Tianxi Sun (Beijing Normal University, China) and his colleagues.  The technique employs a polycapillary focusing X-ray lens and a polycapillary parallel X-ray lens, as well as the laboratory X-ray source (Mo tube).  In the present research, the scan of the confocal point can give the Cu2+ ion distribution near the surface of the electrode in a steady-state diffusion in an electrolytic tank.  The research group studied the effects of the concentration of the electrolyte and the bath voltage on the shape of the layer on the nonuniform distribution of the Cu2+ ions.  For more information, see the paper, "Spatially Resolved In Situ Measurements of the Ion Distribution Near the Surface of Electrode in a Steady-State Diffusion in an Electrolytic Tank with Confocal Micro X-ray Fluorescence", S. Peng et al., Anal. Chem., 86, 362 (2014).

10th Ewald prize - A. Janner and T. W. J. M. Janssen - X-Ray News

The International Union of Crystallography (IUCr) has announced that Professors A. Janner and T. W. J. M. Janssen (both from the Institute for Theoretical Physics, University of Nijmegen, The Netherlands) have been awarded the tenth Ewald prize for the development of superspace crystallography and its application to the analysis of aperiodic crystals.  The presentation of the Ewald Prize will be made during the Montreal Congress Opening Ceremony on 5 August 2014.  The Ewald prize consists of a medal, a certificate and an award of USD 30,000.  Former recipients are E. Dodson (UK), C. Giacovazzo (Italy), G. M. Sheldric (Germany) in 2011, D. Sayre (USA, 2008), P. Coppens (USA, 2005), M. M. Woolfson (UK, 2002), G. N. Ramachandran (India, 1999), M. G. Rossmann (USA, 1996), N. Kato (Japan, 1993), B. K. Vainshtein (Russia, 1990), J. M. Cowley (USA) and A. F. Moodie (Australia) in 1987.    For further information, visit the Web page, http://www.iucr.org/people/ewald-prize/10th-ewald-prize

The 8th Asada award - X-Ray News

The recipient of the 8th Asada Award, which is presented by the Discussion Group of X-ray Analysis, Japan, in memory of the late Professor Ei-ichi Asada (1924-2005) to promising young scientists in X-ray analysis fields in Japan, is Dr. Hironori Ohashi (Kyushu Univ.), "Characterization of gold catalysts by the combined use of X-ray and Mossbauer spectroscopy"). The ceremony was held during the 49th Annual Conference on X-Ray Chemical Analysis and the 15th International Conference on Total Reflection X-Ray Fluorescence Analysis and Related Methods (TXRF2013), at Osaka City University, Osaka.

Denver X-ray conference awards - X-Ray News

During the plenary session of the 63rd Annual Denver X-Ray Conference, three awards were presented.  The 2013 Barrett Award was presented to Vaclav Petricek of the Institute of Physics, Academy of Sciences of the Czech Republic, Praha, Czech Republic, for developing the theory of incommensurate/modulated/composite crystal structures and its implementation in the computing system Jana2006 (the most widely-used system for solving and refining aperiodic structures), and for making possible the correct archival of such structures in the Powder Diffraction FileTM".  The 2013 Jenkins Award was presented to Rene Van Grieken of the University of Antwerp, Antwerp, Belgium, for contributions to the development and application of X-ray methods to a wide variety of topics, from aerosols in the environment to conservation and from new techniques and microanalysis to biomedical applications.  He has been a leader in the X-ray community and has served it in many capacities over the years, including Editor-in-Chief of X-ray Spectrometry as well as being a member of various national and international commissions involved in analytical and environmental chemistry.  He has disseminated his knowledge in an impressive list of papers, books, and invited lectures.  The 2013 Hanawalt Award was presented to Robert B. Von Dreele of Argonne National Laboratory, Lemont, IL, USA, for his insight, courage and creativity in bringing powder diffraction to the macromolecular community.  For further information, visit the Web page, http://www.dxcicdd.com/

The 2013 Compton award - X-Ray News

The Advanced Photon Source (APS) and APS Users Organization have announced that the 2013 Arthur H. Compton Award has been presented jointly to David E. Moncton, John N. Galayda, Michael Borland, and Louis Emery. The award recognizes the recipients' visionary leadership and technical ingenuity in introducing "top-up" operation to the synchrotron radiation community.  The award consists of a plaque and $2500.  Former recipients of this award are: Edward Stern, Farrel Lytle, Dale Sayers (posthumously), John Rehr (2011); Simon Mochrie, Mark Sutton, Gerhard Grubel  (2009); Andrzej Joachimiak, Gerold Rosenbaum (2007); Gunter Schmahl and Janos Kirz (2005); Martin Blume, Doon Gibbs, Kazumichi Namikawa, Denis McWhan (2003); Wayne A. Hendrickson (2001); Sunil K. Sinha (2000); Donald H. Bilderback, Andreas K. Freund, Gordon S. Knapp, Dennis M. Mills (1998); Philip M. Platzman, Peter M. Eisenberger (1997); Nikolai Vinokurov, Klaus Halbach (1995).

Professor Y. Takahashi (Osaka University, Japan) and his colleagues have recently reported that coherent X-ray imaging using Bragg diffraction can aid the observation of nanoscale dislocation strain fields in a silicon single crystal.  The experiments were done with 11.8 keV micro-focused X-ray photons, around 1 μm in both directions, using KB mirrors at BL-29XUL, SPring-8, Japan.  In this research, a 1 μm thick silicon (100) single crystal was placed in the X-ray path so that X-rays could pass through it and the 220 Bragg reflection spot was observed by a CCD camera 2 m behind the sample. The sample was scanned in XY directions as well.  The research team found phase singularities, i.e., two pairs of vortices with opposite directions in the phase map, that corresponded to the locally dark positions in the intensity map.  It was concluded that this corresponded to the projection of the {111} dislocation loops.  For more information, see the paper, "Bragg x-ray ptychography of a silicon crystal: Visualization of the dislocation strain field and the production of a vortex beam", Y. Takahashi et al., Phys. Rev. B87, 121201(R) (2013).

Final magnet girders installed at NSLS II, Brookhaven - X-Ray News

The construction of Brookhaven's National Synchrotron Light Source II is approaching its final stage. Recently the last of 150 magnet girders was installed in the storage ring.  Magnets traveled from across the globe, supplied by ring magnet vendors based in six countries: Buckley Systems Ltd (New Zealand), Budker Institute of Nuclear Physics (Russia), Danfysik (Denmark), Everson Tesla Incorporated (U.S.), Institute of High Energy Physics (China), and Tesla Engineering (U.K.).  In the experimental hall, meanwhile, 17 hutches have been delivered and constructed for seven beamlines; CSX1 and CSX2 (two branches of Coherent Soft X-ray Scattering and Polarization),     CHX (Coherent Hard X-ray Scattering), IXS (Inelastic X-ray Scattering), HXN (Hard X-ray Nanoprobe), SRX (Submicron Resolution X-ray Spectroscopy) and XPD (X-ray Powder Diffraction).  For further information, visit the Web page, http://www.bnl.gov/ps/news/news.php?a=23725

  An explanation of the CSX beamline construction can be viewed on You Tube.

http://www.youtube.com/watch?feature=player_embedded&v=rximpW0aR9A

X-ray fluorescence holography with 50W low power X-ray source - X-Ray News

Dr. P. Korecki (Jagiellonian University, Poland) and his colleagues have recently published a fairly  impressive, successful 3D analysis of Cu3Au (001) single crystal by white-beam X-ray fluorescence holograms measured using a 50W tungsten X-ray tube (50 kV, 1 mA, with 0.8mm Al filter).  Primary X-ray photons at the aperture, which is placed at 340 mm from the source, are around 2×108 counts/sec.  The sample was positioned 610 mm from the sample, and was rotated relative to the incident beam around two axes (θ, φ).  The X-ray fluorescence intensity of Cu K and Au L lines was measured by a Si drift detector (SDD) with a 25 mm2 effective area, placed at a distance of 12 mm from the sample. The typical counting rate was around 105 counts/sec, and the total acquisition time was ~90 h, i.e., 4 days.  It was demonstrated that a 3D image of the sample was reconstructed from the recorded holograms.  Readers might be surprised to know that such a non-efficient experiment can be done even with a low power source.  As the authors claim at the end of this paper, the measuring time can be reasonably shortened by the use of more powerful laboratory X-ray sources.  For more information, see the paper, "Element sensitive holographic imaging of atomic structures using white x rays", K. M. Da.browski et al., Phys. Rev. B87, 064111 (2013).

Dr. B. Kanngießer (Technische Universität Berlin, Germany) and her colleagues have recently reported further advances in 3D chemical mapping using a confocal X-ray fluorescence setup.  The research group has obtained nondestructive reconstruction of stratified systems with constant elemental composition but with varying chemical compounds.  For more information, see the paper, "Three-Dimensional Chemical Mapping with a Confocal XRF Setup", L. Luhl et al., Anal. Chem., Article ASAP (DOI: 10.1021/ac303749b).

Accuracy and uncertainties of V Kβ spectral profile - X-Ray News

A team led by Professor C. T. Chantler (University of Melbourne, Australia) has published vanadium Kβ spectra from metallic foil, measured with medium energy resolution but with high accuracy.  For more information, see the paper, "Characterization of the Kβ spectral profile for vanadium", L. F. Smale et al., Phys. Rev. A87, 022512 (2013).

The extremely high peak power of an X-ray free electron laser pulse can be an attractive tool for clarifying the core-level excitation and relaxation process.  Recently, Dr. B. Rudek and his colleagues have reported their time-of-flight ion spectroscopy studies on sequential inner-shell multiple ionization of krypton at photon energies at 2 keV and 1.5 keV, which are higher than the LI (~1.92 keV) and lower than the LIII (~1.67 keV) edges for ordinary neutral krypton, respectively.  The experiments were done with two X-ray pulse widths (5 and 80 fs) and various pulse energies (from 0.07 to 2.6 mJ), at the Linac Coherent Light Source (LCLS), Stanford, USA.  The highest charge state observed at 1.5 keV photon energy (below the LI edge) is Kr17+; at 2 keV photon energy (above the LIII edge), it is Kr21+.  It was found that theoretical calculations based on a rate-equation model can explain the obtained experimental data for 1.5 keV, but fails to do so at 2 keV, where the experimental spectrum shows higher charge states. They discussed that this enhancement is due to a resonance-enhanced X-ray multiple ionization mechanism, i.e., resonant excitations followed by autoionization at charge states higher than Kr12+, where direct L-shell photoionization at 2 keV is energetically closed.  For more information, see the paper, "Resonance-enhanced multiple ionization of krypton at an x-ray free-electron laser", B. I. Cho et al., Phys. Rev. A87, 023413 (2013).

In spite of the recent advent of few fs pulse X-ray free-electron laser sources, so far, synchronization between optical lasers and X-ray pulses has been challenging, and the jitter, typically, 100~200 fs r.m.s., has limited the time-resolution of the measurement.  At the Linac Coherent Light Source (LCLS), Stanford, scientists have recently solved this problem by introducing a "measure-and-sort" approach, which records all single-shot data with time information to ensure resorting of the data.  In the beamline, the same optical laser beam is split into three beams: with the first, the relative delay between laser and X-ray is encoded into wavelength by using a broadband chirped supercontinuum; in the second, the temporal delay is spatially encoded; in the third, pump-probe experiments are performed with time-sorting tools.  It was concluded that the error in the delay time between optical and X-ray pulses can be substantially improved to 6 fs r.m.s., leading to time-resolved measurement with only a few fs resolution.  For more information, see the paper, "Achieving few-femtosecond time-sorting at hard X-ray free-electron lasers", M. Harmand et al., Nature Photonics, doi:10.1038/nphoton.2013.11; published online, February 17, 2013.

One promising application of laser-matter interactions is generating hot suprathermal electrons with keV-MeV energy, which enables excitation of the K shell of the target material.  Recently, Dr. G. Cristoforetti (Intense Laser Irradiation Laboratory, Italy) and his colleagues have reported some interesting experiments on the laser pulse polarization effect on the Kα yield and line shape.  The research group studied the interaction of an ultrashort laser pulse (λ = 800 nm, τ = 40 fs) with a Ti foil under intense irradiation.  The K X-ray emission was analyzed by a quartz crystal and a CCD camera, and it was found that the energy of Kα lines shift a few eV up to around 15 eV, depending on the pulse polarization.  Such dependence can be discussed by considering the efficiency of hot electron generation.  For more information, see the paper, "Spatially resolved analysis of Kα x-ray emission from plasmas induced by a femtosecond weakly relativistic laser pulse at various polarizations", G. Cristoforetti et al., Phy. Rev. E87, 023103 (2013).

Coherent X-ray diffractive imaging has made remarkable progress over the past 15 years.  The technique basically reconstructs real space microscopic images with the spatial resolution of nm without the use of lenses, mainly because of the ability to retrieve phases.  However, it relies on the degree of high coherence of the available X-ray photon beam, and, until now, almost all experimental studies have been subject to some limits.  It is not very easy to satisfy the ideal conditions, mainly because of the partial coherence of the beam itself and some decoherence caused by imperfect detection as well as the dynamic motions of the sample.  Dr. P. Thibaut (Technische Universität München, Germany) and his colleague have recently reported their analytical studies into extending ptychography by formulating it as low-rank mixed states.  The procedure is closely related to quantum state tomography and is equally applicable to high-resolution microscopy, wave sensing and fluctuation measurements.  They concluded that some of the most stringent experimental conditions in ptychography can be relaxed, and susceptibility to imaging artifacts is reduced even when the coherence conditions are not ideal.  For more information, see the paper, "Reconstructing state mixtures from diffraction measurements", P. Thibault et al., Nature, 494, 68 (2013).

Three US scientists awarded 2013 Japan Prize - X-Ray News

The Science and Technology Foundation of Japan has announced that three US scientists have been named as laureates of the 2013 (29th) Japan Prize.  Professors Grant Willson (University of Texas at Austin) and Jean Fre'chet (King Abdullah University of Science and Technology) have received the prize in this year's category of "Materials and Production" for their development of chemically amplified resist polymer materials for innovative semiconductor manufacturing process.  Professor John Frederick Grassle (The State University of New Jersey) was selected in the other prize category of "Biological Production and Biological Environment" for his contributions to marine environmental conservation through research on ecology and biodiversity of deep-sea organisms. 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 24th, April, 2013.  The prize categories for the 2014 (30th) Japan Prize will be "Electronics, Information and Communications" and "Life Science".  For further information, visit the Web page, http://www.japanprize.jp/en/index.html. Selected scenes from the 2012 ceremony can be viewed on You Tube.

http://www.youtube.com/watch?v=E6PhvtTdgt8&feature=youtu.be

The synchrotron song published on YouTube - X-Ray News

Perhaps some readers already know Dr. Ken Lea's synchrotron song, but now it is available on YouTube. The song is about synchrotron radiation and many scientific studies, which have been done at The Synchrotron Radiation Source (SRS), Daresbury Laboratory in UK, from 1980 to 2008.  As so many scientific terms (such as wavelength, beamline, monochromator, polarization, collimation, surface acoustic wave, sample chamber etc) are included in the lyrics, it may not be easy for ordinary people to sing this song.  Visit the following You Tube site and have fun!

http://www.youtube.com/watch?v=-Rc5OfEcSZk

Ti Kβ and X-ray Raman spectra from BaTiO3 nano particles - X-Ray News

Recently a research group led by Okayama University in Japan has reported the successful application of resonant X-ray emission spectroscopy (RXES) to BaTiO3 nanoparticles of various sizes ranging from a bulk-like 200 nm to a paraelectric 50 nm.  While it is well known that the crystal structure changes from tetragonal to cubic as the particle size decreases, some recent reports indicated that a very large enhancement of the dielectric constant was observed at a specific particle size of around 70 nm.  The research was done to clarify the above problem.  In the X-ray emission spectra measured with monochromatic excitation near the sharp peak of the Ti-K absorption edge, two small Raman peaks were observed between Kβ2,5 (4962.6 eV) and elastic scattering of (for example, 4983.6 eV) peaks.  It was found that the higher energy Raman peak (5.3 eV lower than incident X-ray energy) still exists at a size of 85 nm, even though the intensity basically diminishes for the small particle size BaTiO3, which corresponds to the extraordinary large crystal structure change.  The results suggest that Raman peak intensity is correlated to the large enhancement of the dielectric constant.  For more information, see the paper, "Enhancement of dielectric constant of BaTiO3 nanoparticles studied by resonant x-ray emission spectroscopy", N. Nakajima et al., Phy. Rev. B86, 224114 (2012).

Focusing XFEL pulses with mirrors - X-Ray News

In Japan, a research team led by Professor K. Yamauchi (Osaka University) and Professor T. Ishikawa (Riken, Harima, Japan) has recently succeeded in focusing ultra short X-ray laser pulses from the SPring-8 Angstrom Compact free electron LAser (SACLA).  With reflective optics comprising elliptically figured mirrors with nm accuracy to preserve a coherent wavefront, they have obtained a focused small beam of 0.95 × 1.20 μm2 at 10 keV.  The estimated achievable power density at the sample position is 6 × 1017 W/cm2.  For more information, see the paper, "Focusing of X-ray free-electron laser pulses with reflective optics", H. Yumoto et al., Nature Photonics, 7, 43 (2013).


At Linac Coherent Light Source (LCLS), Stanford, USA, a series of experimental works has been carried out based on the core-level excitation and relaxation process.  One recently published paper from Stanford reports the resonant generation of Kα emission from aluminum foil (1μm thick) in a solid-plasma state created by irradiating very strong X-ray free-electron laser pulses (less than 80 fs time width, 1.6×1012 photons/pulse).  In the experiment, quasimonochromatic (0.5% bandwidth) X-ray pulses in the energy range of 1480-1580 eV (below and slightly above the K edge of ground state Al) were focused onto a 3μm diameter spot on the sample, with a corresponding peak intensity in excess of 1017 W/cm2.  To analyze the X-ray spectra, the research group employed a wavelength-dispersive X-ray spectrometer with a flat ADP (101) crystal and an X-ray CCD camera. Since the same atom can absorb multiple photons contained in the single pulse time width, with L-shell holes being created and leading to the excitation of a K-shell electron into one of these L-holes, the Kα X-rays are produced. The research group studied many such emission spectra produced by tuning the XFEL energy to the K-L transitions of those highly charged ions that have transition energies below the K edge of the cold material.  It was also found that resonance emission peaks broaden significantly, and this was explained as opacity effects.  Because of the intensity-dependent optical depth, the transparent sample at low intensity thickens optically with an intense XFEL pulse.  For more information, see the paper, "Resonant Kα Spectroscopy of Solid-Density Aluminum Plasmas", B. I. Cho et al., Phys. Rev. Lett., 109, 245003 (2012).

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