First all optical synchronization in X-ray free electron laser - X-Ray News

At the soft X-ray free-electron laser (XFEL) facility, FLASH, in Hamburg, Germany, all-optical synchronization has finally been achieved.  Scientists are reporting that the timing is better than 30 fs rms for 90 fs X-ray photon pulses.  As one of the most promising experiments using XFEL is time-resolved analysis based on the pump & probe scheme, it is crucial to synchronize all independent components, including all accelerator modules and all external optical lasers, to better than the delivered free-electron laser pulse duration such as shorter than 100 fs.  For more information, see the paper, "Femtosecond all-optical synchronization of an X-ray free-electron laser", S. Schulz et al., Nature Communications, 6, 5895 (2015).
At the European Synchrotron Radiation Facility (ESRF) in Grenoble, France, scientists from Italy, Germany and France have succeeded in 'reading' letters inside a papyrus roll found in the ancient library, discovered in Herculaneum.  The experiments were done at the beamline ID17, and the X-ray phase contrast tomography technique was employed.  The team was successful in extracting words under several papyrus layers in a fragment, and finally found that they are the complete Greek alphabet.  For more information, see the paper, "Revealing letters in rolled Herculaneum papyri by X-ray phase-contrast imaging", V. Mocella et al., Nature Communications, 6, 5895 (2015).  An interesting movie has also been uploaded to Youtube, https://www.youtube.com/watch?v=d3aWBgNYOCU

Recent progress in X-ray ptychography - X-Ray News

X-ray ptychography is known as a promising lensless imaging method.  Compared with other similar techniques, it can give a rather wide viewing area with the same high-spatial-resolution in nano scale, by combining multiple coherent diffraction measurements from the illumination of several overlapping regions on the sample.  However, this apparently has to assume a highly sophisticated scanning/positioning instrumentation.  The method may suffer also from partial-coherence effects and fluctuations.  Dr. A. Menzel (Paul Scherrer Institut, Switzerland) and his colleagues have recently published an interesting report on fast measurement.  The authors discussed ptychographic on-the-fly scans, i.e., collecting diffraction patterns while the sample is scanned with constant velocity.  It was found that such a scan can be used as a model for a state mixture of the probing radiation and helps to achieve reliable image recovery.  The feasibility of on-the-fly measurements in traditional scanning transmission X-ray microscopy is already known.  This time, the research team was successful in applying these to X-ray ptychography, which usually uses reconstruction algorithms assuming diffraction data from a static sample.  Such problems were discussed in detail.  For more information, see the paper, "On-the-fly scans for X-ray ptychography", P. M. Pelz et al., Appl. Phys. Lett., 105, 251101 (2014).
A team led by Professor Harald Ade (North Carolina State University, USA) has reported that grazing resonant soft X-ray scattering (GRSoXS), a technique measuring diffusely scattered soft X-rays from grazing incidence, can reveal the statistical topography of buried thin-film interfaces.  So far, in wide variety of material systems, the internal structures of layered systems, particularly interfaces between different materials, have been critical to their functions.  However, the analysis of buried interfaces has always presented some difficulties.  It is known that X-ray electric field intensity distribution along the depth can be controlled by a change of either the incidence angle or the X-ray energy.  The research team was able to manipulate it by scanning the X-ray energy, and succeeded in identifying the microstructure at different interfaces of a model polymer bilayer system such as PMMA/PEG.  The authors attempted to gauge the feasibility of the technique for further practical systems like an organic thin-film transistor, PS[100nm]/PBTTT[50nm]/Si.  For more information, see the paper, "Topographic measurement of buried thin-film interfaces using a grazing resonant soft x-ray scattering technique", E. Gann et al., Phys. Rev. B90, 245421 (2014).

Review paper on liquid metal surface studies by using X-rays - X-Ray News

Professor P. S. Pershan (Harvard University, USA) has recently published an interesting review paper on X-ray studies of the interface between liquid metals and their coexisting vapor.  For more information, see the paper, "Review of the highlights of X-ray studies of liquid metal surfaces", P. S. Pershan, J. Appl. Phys., 116, 222201 (2014).

4m length inverse-Compton scattering X-ray source - X-Ray News

In addition to large-scale X-ray facilities such as synchrotrons and X-ray FELs, there have been increasing demands for much more compact X-ray sources with high brilliance, ultra short pulse properties and coherence.  Dr. W. S. Graves (Massachusetts Institute of Technology, USA) and his colleagues have proposed a design for a compact X-ray source based on inverse Compton scattering.  The source consists of a 1m linuc and an ultra short pulse laser.  The whole size of the source including X-ray experiment space is nearly 4m.  The colliding laser is a Yb:YAG solid-state amplifier producing 1030 nm, 100 mJ pulses at 1 kHz repetition rate.  The calculation shows that X-ray intensity at 12.4 keV is 5×1011 photons/second in a 5% bandwidth.  For more information, see the paper, "Compact x-ray source based on burst-mode inverse Compton scattering at 100 kHz", W. S. Graves et al., Phys. Rev. STAB, 17, 120701 (2014).
A German and Austrian group has recently developed a table-top X-ray source based on ultra-short laser pulses.  Generation of X-ray pulses by lasers may not be a big surprise for readers (See, for example, "Ultrafast X-ray Pulses from Laser-Produced Plasmas" by M. M. Murnane, Science, 251, 531 (1991), "Microfocus Cu Kα source for femtosecond x-ray science" by N. Zhavoronkov, Opt. Letter, 30, 1737 (2005)).  However, so far, the X-ray intensity has not been sufficient for use in practical measurements such as pump-and-probe time resolved X-ray analysis.  This time, scientists employed a mid infrared wavelength (3.9 micron) to accelerate electrons from the copper tape target to very high kinetic energy by making use of its comparably long optical period.  The pulse width of the laser employed is 80 femto second.  It was found that the system gives 109 copper Kα photons per pulse generated with pulses of a peak intensity of 6×1016 W/cm2.  This is about 25 times higher than that generated by 800 nm wavelength laser pulses.  For more information, see the paper, "High-brightness table-top hard X-ray source driven by sub-100-femtosecond mid-infrared pulses", J. Weisshaupt et al., Nature Photonics, 8, 927 (2014).

Origin of broad N Kα emission spectra - X-Ray News

A team led by Dr. T. Jach (NIST, USA) and Dr. W. T. Elam (University of Washington, USA) has recently published an interesting theoretical paper discussing the broadening of N K absorption and emission spectra of NH4NO3 and NH4Cl.  The authors studied many-body lifetime effects in valence-band X-ray emission.  For more information, see the paper, "Origins of extreme broadening mechanisms in near-edge x-ray spectra of nitrogen compounds", J. Vinson et al., Phys. Rev. B90, 205207 (2014).

Chemical imaging by X-ray-excited optical luminescence - X-Ray News

Professor A. Adriaens (Ghent University, Belgium) and her colleagues have recently reported on an X-ray-excited optical luminescence microscope using synchrotron light and its applications.  The experiments were done at beamlines BM28 and BM26A at the ESRF in Grenoble, France.  A broad X-ray beam is used to illuminate large areas of ~4 mm2 of the sample, and the resulting optical emission is observed by a specifically designed optical microscope equipped with a CCD camera.  By scanning the X-ray energy near the absorption edge, the image can obtain the sensitivity of chemical states.  The authors studied copper surfaces with well-defined patterns of different corrosion products (cuprite Cu2O and nantokite CuCl).  For more information, see the paper, "Evaluation of an X-ray Excited Optical Microscope for Chemical Imaging of Metal and Other Surfaces", P-J. Sabbe et al., Anal. Chem., 86, 11789 (2014).

The 9th Asada award - X-Ray News

The recipient of the 9th 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. Susumu Imashuku (Kyoto Univ.), "Portable electron probe microanalyzer using pyroelectric crystal".  The ceremony was held during the 50th Annual Conference on X-Ray Chemical Analysis, at Tohoku University, Sendai.

So far, monochromatic X-rays have been used for 3D micro X-ray fluorescence analysis based on confocal geometry.  Dr. P. Wrobel (AGH University of Science and Technology, Poland) and his colleagues have recently discussed the feasibility of polychromatic excitation.  The research group described the full theoretical expression of matrix effects and geometrical effects for polychromatic X-ray photons in confocal arrangement.  It was demonstrated that the introduction of effective energy approximation works well.  For more information, see the paper, "Depth Profiling of Element Concentrations in Stratified Materials by Confocal Microbeam X-ray Fluorescence Spectrometry with Polychromatic Excitation", P. Wrobel et al., Anal. Chem., 86, 11275 (2014).

Pin-hole X-ray camera - X-Ray News

Dr. F. P. Romano and his colleagues have reported full-field X-ray fluorescence imaging based on the principle of the pin-hole camera.  The instrument consists of a low power X-ray source (W anode, 50kV-2mA), a pinhole (50 micron dia) and a CCD camera (back illuminated type, 1024 × 1024 pixels, pixel size 13 micron square).  To obtain good energy resolution (133 eV at 5.9 keV), the research team took a number of images in single photon counting mode.  The team also obtained a reasonable spatial resolution down to 30 microns.  The system can change the magnification ratio from 0.35 to 6, depending on the viewing area of interest and the required spatial resolution.  For more information, see the paper, "Macro and Micro Full Field X-Ray Fluorescence with an X-Ray Pinhole Camera Presenting High Energy and High Spatial Resolution", F. P. Romano et al, Anal. Chem., 86, 10892 (2014).

Micro analysis of heterogeneous aerosol particles - X-Ray News

So far, high-resolution microscopic analysis of individual atmospheric particles has been fairly difficult because of problems with the filters used for capturing particles.  The research group in the National Institute for Standards and Technologies, United States, is proposing a multiplatform approach for microscopically assessing chemical and optical properties of individual heterogeneous urban dust particles.  The procedures described in the paper could also be useful for similar analysis.  The method uses 5 steps; (i) particles embedded in fibrous filters are transferred to polished silicon/germanium wafers with electrostatically-assisted high-speed centrifugation, (ii) particles with light absorbing/scattering behavior are identified from bright/dark field light-microscopy, (iii) particles identified from light microscopy are compositionally mapped at high-definition with field-emission scanning electron microscopy and energy-dispersive X-ray spectroscopy, (iv) compositionally-mapped particles are further analyzed with focused ion-beam (FIB) tomography whereby a series of thin slices from a particle are imaged, and the resulting image stack is used to construct a 3-dimensional model of the particle, and (v) particle chemistry is assessed over two distinct regions of a thin FIB slice of a particle with energy-filtered transmission electron microscopy (TEM) and electron energy-loss spectroscopy associated with scanning TEM.  For more information, see the paper, "Qualitative Multiplatform Microanalysis of Individual Heterogeneous Atmospheric Particles From High-Volume Air Samples", J. M. Conny et al., Anal. Chem., Just Accepted (DOI: 10.1021/ac5022612 Publication Date (Web): September 14).

Full-field XANES imaging - X-Ray News

Professor L. Vincze (Ghent University, Belgium) and his colleagues have reported on the latest fluorescence mode XANES imaging using the SLcam, which is an energy dispersive pnCCD detector.  At BM26A, ESRF, the measurements were done for iron foil with some oxides and geological standard samples.  The typical detection limit and measuring time were 0.5 wt% and 15 h, respectively.  Readers might think that energy-resolution can be sacrificed near the absorption edges of interest in order to shorten the measuring time in the same way as ordinary XANES measurement by means of X-ray fluorescence.  Although the use of ordinary X-ray CCD in accumulation mode for a very similar experiment was published 10 years ago (for example, M. Mizusawa et al, J. Synchrotron Rad. 11, 209 (2004)), the present system has the advantage of being able to reduce the background from the major light elements contained in the sample.  For more information, see the paper, "Full-Field Fluorescence Mode Micro-XANES Imaging Using a Unique Energy Dispersive CCD Detector", P. Tack et al, Anal. Chem., 86, 8791(2014).

X-ray analysis on Mars is hot - X-Ray News

Most X-ray experiments can be done at high quality with ease in an ordinary laboratory.  Some experiments, however, have to be done in the field.  It is hard to imagine a more extreme definition of "in the field" than the planet of Mars, which is why exciting times have come about since NASA's Mars rover "Curiosity" landed on Mars in August 2012.  It has since recorded and sent back a large number of datasets including X-ray fluorescence (XRF) and X-ray diffraction (XRD) data.  Naturally, the scientists involved with the projects have been speaking globally since.  During EXRS 2014 (June, Bologna, Italy), Professor J. L. Campbell (University of Guelph, Canada) gave a keynote lecture entitled "XRF and PIXE on the Mars Science LAB Curiosity Rover".  At the Denver X-ray conference (July, Big Sky, Montana), the Plenary Session was "X-rays on Mars", and 3 scientists gave lectures. Professor D. L. Bish (Indiana University) gave a talk entitled "The First X-ray Diffraction Results From Mars".  Professor J. L. Campbell's talk on "XRF Combines with PIXE in Curiosity's Alpha Particle X-ray Spectrometer" was the extension on his talk at EXRS 2014, and further detailed and specific discussion was done there. Professor S.M. Clegg talked about "Exploring Mars with ChemCam on the Curiosity Rover" (ChemCam enables quick element determination by the laser-induced plasma emission spectroscopy).  In August, at Montreal, during the International Union of Crystallography's congress, Professor D. L. Bish gave a talk entitled "The First X-ray Powder Diffraction Measurements on Mars".  These talks highlighted many interesting technological aspects of the measurements: XRF analysis is done first by the same CCD camera, which works as an energy-dispersive 2D X-ray detector, even when the main aim of the measurement is obtaining the XRD pattern.  In the analysis of unknown samples, generally both chemical composition and the crystal structure are indispensable.  Another reason is that XRF helps the systematic use of single photon counting mode of the CCD camera to get a good quality XRD pattern.  Secondly, the samples are vibrated all the time to ensure a smooth and continuous Debye ring.  The rover furthermore contains a series of standard samples to check the reliability and reproducibility of the measurements.  The readers might be interested in such a compact X-ray analyzer, which combined both XRD and XRF machine.  Very similar system is now commercially available.  For further information on the scientific activity on Mars, visit the Web page, http://mars.jpl.nasa.gov/msl/

Gunshot residue analysis by X-ray fluorescence - X-Ray News

Professor J. Wang (University of California San Diego, USA) and his colleagues have applied X-ray fluorescence to the analysis of gunshot residue, which has been usually detected based on the analysis trace amounts of metallic and organic species deposited on the hands, face, hair, and clothing of the shooter.  The researchers tried to couple square-wave stripping voltammetry (SWSV) and scanning electron microscopy (SEM) plus energy dispersive X-ray spectroscopy (EDX).  The former method can be used as a rapid screening tool, while the latter contributes to confirmation of the presence of the characteristic morphology and metal composition of gunshot residue particles.  For more information, see the paper, "Orthogonal Identification of Gunshot Residue with Complementary Detection Principles of Voltammetry, Scanning Electron Microscopy, and Energy-Dispersive X-ray Spectroscopy: Sample, Screen, and Confirm", A. M. O'Mahony et al., Anal. Chem., 86, 8031 (2014).

A research team led by Professor I. Nakai (Tokyo University of Science, Japan) has recently clarified the detailed chemical nature of radioactive aerosol microparticles emitted during the Fukushima Daiichi Nuclear Power Plant accident.  They collected three fine particles of 2 microns in dia, containing radioactive cesium, on March 14th and 15th, 2011, in Tsukuba, 172 km away from the power plant.  In addition to Fe, Zn, Rb, Zr, Mo, Sn, Sb, Te, Cs, and Ba, U was detected in two particles.  The oxidation states of the heavy elements were also studied by X-ray absorption spectra.  The experiments were done at BL37XU, SPring-8, Japan.  For more information, see the paper, "Detection of Uranium and Chemical State Analysis of Individual Radioactive Microparticles Emitted from the Fukushima Nuclear Accident Using Multiple Synchrotron Radiation X-ray Analyses", Y. Abe et al., Anal. Chem., 86, 8521 (2014).

Denver X-ray conference awards - X-Ray News

During the plenary session of the 65th Annual Denver X-Ray Conference, two awards were presented.  The 2014 Birks Award was presented to George Havrilla, Los Alamos National Laboratory for his many contributions to microXRF, especially the development of the confocal XRF microscope. Dr. Havrilla has been a leader in the field of analytical XRF; including 19 years on the Denver X-ray Conference Organizing Committee; nine years as North American Editor of X-ray Spectrometry; and six years as Co-Editor-in-Chief for Advances in X-ray Analysis.  The ICDD Fellow Award was presented to John Getty, Instructor in Geophysical Engineering and Principal Investigator in the Proppant Research Group at Montana Tech. John has played a key role in the planning and execution of the Denver X-ray Conference for more than 30 years.  For further information, visit the Web page, http://www.dxcicdd.com/

It is now known that X-ray free-electron lasers can produce ultrafast X-ray pulses as short as 3 fs in FWHM.  Scientists at the Linac Coherent Light Source (LCLS), Stanford are trying to reduce delay time errors in optical-pump & X-ray probe measurements to the 1 fs level, by 2D spectrogram measurement of the relative X-ray/optical delay.  For more information, see the paper, "Sub-femtosecond precision measurement of relative X-ray arrival time for free-electron lasers", N. Hartmann et al., Nature Photonics, 8, 706 (2014).

Professor T. M. Cahill (Arizona State University) and his colleagues have recently compared the performance of the different excitation modes of synchrotron radiation X-ray fluorescence.  The research team evaluated four different beamline configurations for the analysis of three representative environmental samples; a thin aerosol sample, an intermediate thickness biological sample, and a thick rare earth mineral specimen.  They found that white beam excitation is optimal for the analysis of thin samples with little mass, and that filtered white beam excitation (removing lower energy X-rays by absorber) gives better sensitivity for elements emitting more energetic X-rays.  In their study, monochromatic excitation, which tends to be the standard mode of operation, did not give good results in terms of sensitivity.  For more information, see the paper, "Evaluation of Different Synchrotron Beamline Configurations for X.ray Fluorescence Analysis of Environmental Samples", S. R. Barberie et al., Anal. Chem., 86, 8253 (2014).
A Spanish group has recently published a very interesting application of total-reflection X-ray fluorescence (TXRF).  The research team has evaluated the bioaccumulation kinetics of gold nanorods (GNRs) in various tissues upon intravenous administration in mice.  It was found that the main achievement was clearly differentiating two kinds of behaviors; gold nano rods were quickly bioaccumulated by highly vascular filtration organs such as the liver and spleen, while they do not show bioaccumulation rates in the brain and lung for the period of time investigated.  For more information, see the paper, "Evaluation of Bioaccumulation Kinetics of Gold Nanorods in Vital Mammalian Organs by Means of Total Reflection X-Ray Fluorescence Spectrometry", R. Fernandez-Ruiz et al., Anal. Chem., 86, 7383 (2014).

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).

YouTube videos of Ultrafast X-ray Summer Seminar 2014 - X-Ray News

he 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 (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).

Lecture Date: Tuesday May 27, 2014.  Dr. Johanna Nelson Weker, SLAC, delivered the SLAC public lecture, "X-rays Reveal Secret Life of Batteries" (https://www.youtube.com/watch?v=V8lSTLRkKEk)

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

The use of X-ray free-electrons has enabled plenty of fascinating science, such as watching non-equilibrium excited-state dynamics in complexes of 3d transition metals.  Scientists at LCLS, Stanford have performed femtosecond resolution X-ray fluorescence spectroscopy, with its sensitivity to spin state, elucidating the spin crossover dynamics of [Fe(2, 2ˈ-bipyridine)3]2+ on photoinduced metal-to-ligand charge transfer excitation.  For more information, see the paper, "Tracking excited-state charge and spin dynamics in iron coordination complexes", W. Zhang et al., Nature, 509, 345 (2014).

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

Lecture Date: Tuesday October 1, 2013. Jennifer Mass of the Winterthur Museum in Wilmington, Delaware, delivered the SLAC public lecture, "Don't Fade Away: Saving the Vivid Yellows of Matisse and Van Gogh." (https://www.youtube.com/watch?v=RiASAbniQYw)

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).


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