As of April 12, 2011

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

Trace determination of perchlorate in water by TXRF (April 4, 2011)

Recently, a research group led by Professor N. Kallithrakas-Kontos (Technical University of Crete, Greece) reported successful total-reflection X-ray fluorescence (TXRF) analysis of perchlorate.  In the present research, perchlorate anions were concentrated on anion-selective membranes prepared on a mirror-polished quartz substrate.  Then the quartz reflectors were taken out of the solution and analyzed by measuring Cl Kα intensity under the total-reflection condition, using a copper X-ray tube and helium atmosphere.  The effects of many experimental parameters were discussed in detail, and even the possible capability of discrimination between chloride and perchlorate anions was suggested.  The minimum detection limit was lower than 1 ng/mL.  For more information, see the paper, "Determination of Trace Perchlorate Concentrations by Anion-Selective Membranes and Total Reflection X-ray Fluorescence Analysis", V. S. Hatzistavros et al., Anal. Chem., Article ASAP (DOI: 10.1021/ac103295a  Publication Date (Web): April 4, 2011).

Confocal XRF imaging of forensic samples (March 25, 2011)

A Japanese group led by Professor K. Tsuji (Osaka City University, Japan) recently reported an interesting application of 3D micro X-ray fluorescence (XRF) imaging.  One should note that their research employed low-power laboratory X-ray sources (30-50W, Mo tube) instead of synchrotron X-rays.  They also used two polycapillary lenses for both incoming and outgoing directions to limit the viewing volume in 3D.  The research group measured some forensic samples such as multilayered automotive paint fragments, leather samples etc., which have different color coatings.  They analyzed 3D profiles of many elements (Si, S, Cl, K, Ca, Ti, Mn, Fe, Zn, and Ba) and discussed the relationship with the coating.  For more information, see the paper, "Depth Elemental Imaging of Forensic Samples by Confocal micro-XRF Method", K. Nakano et al., Anal. Chem., Article ASAP (DOI: 10.1021/ac1033177  Publication Date (Web): March 25, 2011).

Observation of laser-driven electron acceleration (March 13, 2011)

It is extremely important to develop new X-ray sources for future X-ray spectrometry.  One promising direction is a table-top synchrotron X-ray source, which consists of a high-power pulse laser and an undulator.  The method uses acceleration of electrons by pulse laser photons.  The idea becomes realistic once the energy reaches GeV and other properties such as stability, emittance etc are improved sufficiently.  For such development, it is indispensable to establish the method for quantitatively investigating the structure of the electron beam in time and space.  Recently, a German group succeeded in taking snapshots of the magnetic field generated by an accelerated electron bunch and simultaneously of a plasma wave by a combination of two techniques: time-resolved polarimetry and plasma shadowgraphy.  For more information, see the paper, "Real-time observation of laser-driven electron acceleration", A. Buck et al., Nature Physics (Published online, March 13, 2011  DOI:10.1038/nphys1942).
 

How to use XFEL to determine the structure of a single molecule (March 9, 2011)

One of the hottest topics in X-ray crystallography in the early 21^st century is coherent X-ray diffraction imaging and its application to the determination of atomic structures of non-crystalline materials - the ultimate goal can be a single molecule.  The technique appears to require non-ordinary coherent photon sources, such as X-ray free-electron lasers (XFEL), which are now in operation at Stanford.  On the other hand, there are several challenging questions basically concerning sample damage, Coulomb explosion, and the role of nonlinearity.  Recently, Dr. A. Fratalocchi and his colleague published their calculations showing that XFEL-based single-molecule imaging will only be possible with a few-hundred long attosecond pulses, due to significant radiation damage and the formation of preferred multisoliton clusters which reshape the overall electronic density of the molecular system at the femtosecond scale.  For more information, see the papers, "Single-Molecule Imaging with X-Ray Free-Electron Lasers: Dream or Reality?", A. Fratalocchi et al., Phys. Rev. Lett. 106, 105504 (2011).
 

X-ray spectrometry aids understanding of how iron gall ink degrades paper (March 4, 2011)

A French-Belgian joint group led by Dr. V. Rouchon (Centre de Recherche sur la Conservation des Collections, MNHN-MCC-CNRS, France) and Professor K. Janssens (Universiteit Antwerpen, Belgium) recently published an interesting paper on the application of X-ray spectrometry to cultural heritage.  For many years, in Europe, iron gall inks have been used for writing manuscripts, and they could damage the paper via two major ways: (i) acid hydrolysis, enhanced by humidity, and (ii) oxidative depolymerization provoked by the presence of oxygen and free Fe(II) ions.  The present research aimed to give some quantitative evidence for each contribution by studying depolymerization of cellulose under various environmental conditions, with viscometry and related changes in the oxidation state of iron determined by X-ray absorption near-edge spectrometry.  It was found that residual amounts of oxygen (less than 0.1%) promote cellulose depolymerization, whereas the level of relative humidity has no impact.  For more information, see the paper, "Room-Temperature Study of Iron Gall Ink Impregnated Paper Degradation under Various Oxygen and Humidity Conditions: Time-Dependent Monitoring by Viscosity and X-ray Absorption Near-Edge Spectrometry Measurements", V. Rouchon et al., Anal. Chem., 83, 2589 (2011).
 

Application of energy-dispersive 2D detector to X-ray color imaging (February 28, 2011)

A German group recently developed an X-ray fluorescence imaging system with a pnCCD-based camera.  They performed a test using a laboratory 30 μm microfocus X-ray tube and synchrotron radiation at the BAM beamline, BESSY II.  It was found that the system simultaneously records ca. 70,000 spectra with an energy resolution of 152 eV (at Mn Kα) with a spatial resolution of 50 μm over a viewing area of 12.7 mm squared.  For more information on pnCCD detectors, for example, the following Web page could be useful, http://www.pnsensor.de/Welcome/Detector/pn-CCD/index.html  For more information on the whole system for X-ray fluorescence imaging, see the paper, "Compact pnCCD-Based X-ray Camera with High Spatial and Energy Resolution: A Color X-ray Camera", O. Scharf et al., Anal. Chem., 83, 2532 (2011).
 

In-situ X-ray spectrometry of reacting catalysts (January 19, 2011)

Recently, a research group at Lawrence Berkeley National Laboratory reported an interesting application of X-ray absorption spectrometry to studies on the oxidation states of Co and CoPt nanoparticles in the presence of H₂ andO₂ at a controlled pressure.  The key to the research lies in the specially developed gas reaction cell.  For more information, see the paper, "In-situ X-ray Absorption Study of Evolution of Oxidation States and Structure of Cobalt in Co and CoPt Bimetallic Nanoparticles (4 nm) under Reducing (H₂) and Oxidizing (O₂) Environment", F. Zheng et al., Nano Lett., 11, 847 (2011).
 

New theoretical expression of X-ray reflectivity by using Green function (September 22, 2010)

X-ray reflectivity is one of the most power analytical tools for observing the layered structures of thin films.  So far, many calculations have been done by combining Parratt’s recursive formalism with Nevot-Croce corrections on the Fresnel coefficients.  The technique basically provides detailed information on the roughness of the surface and interfaces, in addition to the precise thickness values of each layer.  However, the analysis of the roughness has not been always straightforward, because it is also necessary to consider multiple diffuse scattering.  Recently, Dr. A. M. Polyakov (National University of Science and Technology ‘MISiS’, Russia) and his colleague published an interesting paper describing a novel approach to the calculation of X-ray reflectivity.  Their method is based on the Green function formalism using Kirchhoff’s integral equation for describing the X-ray wavefield propagation through a random rough surface separating vacuum and medium.  Readers would find it interesting that the influence of multiple diffuse scattering effects upon grazing X-ray specular scattering is essential for the correlation lengths that are of the order of, and/or less than, the X-ray absorption length.  Although the present calculation is only valid for the random surface heights described in the frame of Gaussian statistics, the present approach can be further extended in the future.  For more information, see the papers, "X-ray specular scattering from statistically rough surfaces: a novel theoretical approach based on the Green function formalism", F. N. Chukhovskii et al., Acta Cryst., A66, 640 (2010).
 

Influence of the M9 class earthquake on synchrotron facilities in Japan (March 11, 2011)

As a result of the Tohoku Region Pacific Coast Earthquake in Japan, which took place on March 11, 2011, nearly 30,000 people were killed or are still missing.  As can be clearly seen from the map of the magnitude of shaking intensity (see, for example, http://www.scientificamerican.com/article.cfm?id=fast-facts-japan), several research facilities were affected by this disaster.  Very strong quakes took place in Tsukuba, Ibaraki prefecture, where the Photon Factory, a synchrotron source, is located.  However, first of all, the map does not correspond very well to the loss of lives and damage to buildings, roads, railways and other infrastructure.  While the coastal areas of Miyagi, Iwate and Fukushima prefectures were destroyed by the tsunami, many cities and towns in the inland area were quite safe.  In spite of the largest earthquake since scientific surveys started, damage was minimal.  No lives were lost, and no buildings were completely destroyed in the campus of the Photon Factory.  The detailed status of the facility is available in the following Web page, http://pfwww.kek.jp/whats_new/earthquakeinfo/announce_e.html. All beamtime allocated in the term from May to September has been cancelled.  On the other hand, another Japanese synchrotron radiation facility, SPring-8 had no damage, because the location is far from the source of the earthquake.  The SPring-8 plans to accept some users of the Photon Factory for experiments.  For further information, visit the Web page, http://www.spring8.or.jp/en/urgentnews/110401
 

NSLS-II passes the halfway stage of construction (March 22, 2011)

In 2009, the U.S. Department of Energy’s Brookhaven National Laboratory started construction of the National Synchrotron Light Source II (NSLS-II), which is a new advanced synchrotron X-ray source with a 3 GeV storage ring and around 30 beamlines.  Construction has now passed the halfway stage, and magnet installation has just started.  The completion of the facility is expected in 2015.  For further information, visit the web page, http://www.bnl.gov/nsls2/
 

Princeton releases new direct detection X-ray cameras for extremely low flux applications (March 25, 2011)

Princeton Instruments has announced the new PIXIS-XB series of direct detection cameras.  The PIXIS-XB series is designed for extremely low flux imaging and spectroscopy applications in the X-ray energy range of 3-20 keV.  The new PIXIS-XB models feature front-illuminated and back-illuminated, deep depletion CCDs with a wide variety of formats from 1340×400 to 1340×1300 pixels.  For further information, visit the web page, http://www.princetoninstruments.com/
 

Bruker’s new handheld XRF spectrometer (March 14, 2011)

Bruker has announced the introduction of the new TRACER IV-GEO handheld XRF system, which is equipped with 30 mm² Silicon Drift Detector (SDD), achieving about three times the sensitivity of previous products.  For further information, visit the web page, http://www.bruker-axs.com/
 

Oxford Instruments allies with Vericheck in handheld XRF business (April 3, 2011)

Oxford Instruments Industrial Analysis has announced an agreement with Verichek Technical Services based in Jefferson Hills, PA USA, to sell the X-MET handheld XRF analyzer in the scrap metal and positive material identification (PMI) markets.  For further information, visit the web page, http://www.oxinst.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/