As of July 30, 2011

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

Absolute K-shell photoionization for gas-phase atomic nitrogen (July 11, 2011)

So far, because of the difficulty of creating a target of neutral atomic nitrogen, there have been no reports on the details of high-resolution K-edge spectra.  Recently, scientists at Lawrence Berkeley National Laboratory have performed both experimental and theoretical studies on the strong 1s→np resonance features throughout the threshold region.  The absolute value of the K-shell binding energy was experimentally obtained for the first time, and it was 409.64±0.02 eV.  For more information, see the paper, "K-Shell X-Ray Spectroscopy of Atomic Nitrogen", M. M. Sant’Anna et al., Phys. Rev. Lett. 107, 033001 (2011).

Real-time analysis of martensitic phase transition of cobalt (June 30, 2011)

Professor K. F. Ludwig (Boston University, USA) and his colleagues have recently reported their real-time X-ray scattering studies on heterogeneous microscale dynamics in the martensitic phase transition of cobalt.  During the transformation of the high-temperature fcc phase to the low-temperature hcp phase, first, a rapid local transformation happens, and then, strains are relaxed slowly.  The research group employed coherent X-ray scattering measurements to see the latter part of the transformation.  It was found that the kinetics is dominated by discontinuous sudden changes - avalanches.  The spatial size of observed avalanches varies widely, from 100 nm to 10μm, the size of the X-ray beam.  For more information, see the paper, "Direct Measurement of Microstructural Avalanches during the Martensitic Transition of Cobalt Using Coherent X-Ray Scattering", C. Sanborn et al., Phys. Rev. Lett. 107, 015702 (2011).

3D micro analysis of the Dead Sea Scrolls  (June 29, 2011)

The Dead Sea Scrolls are a collection of 972 texts from the Hebrew Bible and extra-biblical documents found between 1947 and 1956 at Khirbet Qumran on the northwest shore of the Dead Sea from which it derives its name, in the British Mandate for Palestine, in what is now named the West Bank.  Recently, a research group led by Professor B. Kanngiesser (Technische Universität Berlin, Germany) has investigated the feasibility of merging two X-ray techniques, ordinary micro XRF and confocal 3D micro XRF for optimized analysis of highly inhomogeneous samples such as the Dead Sea Scrolls.  Ordinary micro XRF lacks information on the depth, but the measurement is efficient and rather quick.  On the other hand, confocal 3D micro XRF has depth resolution, but the measurement takes very long.  The authors found that the reliability of the analysis of highly heterogeneous samples can be improved by quantitatively combining both data.  For more information, see the paper, "3D Micro-XRF for Cultural Heritage Objects: New Analysis Strategies for the Investigation of the Dead Sea Scrolls", I. Mantouvalou et al., Anal. Chem., Article ASAP (DOI: 10.1021/ac2011262  Publication Date (Web): June 29, 2011).
 

3D micro X-ray spectroscopic analysis of natural diamond formed in ultra-deep underground (June 27, 2011)

A research group led by Professor L. Vincze (Ghent University, Belgium) has recently reported the interesting analysis of 1-20 μm sized inclusions in natural diamond crystals from Rio Soriso (Juina area, Mato Grosso State, Brazil).  The crystals are called ultra-deep diamond, because they were formed in the astenospheric upper mantle, the transition zone (410-670 km), and even the lower mantle (>670 km) of the Earth.  The experiment is basically 3D imaging by confocal X-ray fluorescence suing synchrotron radiation.  By scanning X-ray energy near the Mn and Fe K absorption edges, the authors obtained chemical information on the inclusion cloud in the crystal.  It was found that the observed Fe-rich inclusions were ferropericlase (Fe,Mg)O, hematite and a mixture of these two minerals.  Another finding was that significant overprint of inclusions along pre-existing planar features is possible without changing their outer shape.  For more information, see the paper, "Three-Dimensional Fe Speciation of an Inclusion Cloud within an Ultradeep Diamond by Confocal μ-X-ray Absorption Near Edge Structure: Evidence for Late Stage Overprint", G. Silversmit et al., Anal. Chem., Article ASAP (DOI: 10.1021/ac201073s  Publication Date (Web): June 27, 2011).
 

Resolution enhancement in ptychographic X-ray diffraction microscopy (June 13, 2011)

Ptychographic X-ray diffraction microscopy is known as an extension of so-called X-ray diffraction microscopy, which is a lensless X-ray imaging technique based on coherent diffraction measurements and iterative phasing methods.  The technique employs sample scanning to see a large viewing area, but so far, the spatial resolution has been rather limited mainly because of positioning errors due to the drift between the sample and illumination optics.  Recently, Professor Y. Takahashi (Osaka University, Japan) and his colleagues have published an experimental way to resolve the problem.  The research group has developed a method of correcting positioning errors, and made it possible to illuminate a highly focused hard X-ray beam at the exact position on the samples.  The spatial resolution achieved is as good as 10 nm or even better in a viewing area of larger than 5 μm.  For more information, see the paper, "Towards high-resolution ptychographic X-ray diffraction microscopy", Y. Takahashi et al., Phys. Rev. B83, 214109 (2011).
 

Theory of Kα emission efficiency under the irradiation of ultra short pulse laser (June 6, 2011)

When laser light hits thin solid foil, one can obtain soft X-rays, and this is sometimes called a laser plasma X-ray source.  When the peak power of the laser becomes extremely high by shortening the pulse duration, it is also possible to observe hard X-ray spectra including Kα and Kβ emission.  A team at Sandia National Laboratory has recently reported some calculations on the efficiency of Kα emission.  The conversion efficiency of laser energy into Kα X-ray energy is clearly a critical parameter for designing an X-ray source.  Basically the value is fairly small, but the team’s simulations indicate that an enhancement of efficiency greater than tenfold over conventional single targets may be possible by introducing a two-phase target concept.  For more information, see the paper, "Efficiency Enhancement for Kα X-Ray Yields from Laser-Driven Relativistic Electrons in Solids", A. B. Sefkow et al., Phys. Rev. Lett. 106, 235002 (2011).
 

Quantitative chemical imaging of trace elements using advanced synchrotron X-rays  (May 31, 2011)

A Swiss group has recently published many interesting chemical images of trace elements in heterogeneous media.  The authors combined several techniques; laser ablation inductively coupled plasma mass spectrometry (LA-ICPMS), synchrotron radiation based micro-X-ray fluorescence and extended X-ray absorption fine structure spectroscopy.  The analysis was done for Opalinus clay, which has been proposed as the host rock for high-level radioactive waste repositories.  2D images were shown for the matrix elements Ca, Fe, and Ti, as well as for the trace element, Cs.  The synchrotron experiments were performed at Sector 20 (PNC-CAT), Advanced Photon Source (APS), and microXAS beamline at the Swiss Light Source (SLS).  The beam size was 4×3 μm² and 3×3 μm², respectively.  For more information, see the paper, "Quantitative Chemical Imaging of Element Diffusion into Heterogeneous Media Using Laser Ablation Inductively Coupled Plasma Mass Spectrometry, Synchrotron Micro-X-ray Fluorescence, and Extended X-ray Absorption Fine Structure Spectroscopy", H. A. O. Wang et al., Anal. Chem., Article ASAP (DOI: 10.1021/ac200899x  Publication Date (Web): May 31, 2011).
 

Tissue imaging with X-ray excited optical luminescence  (May 27, 2011)

Professor J. N. Anker (Clemson University, South Carolina, United States) and his colleagues have recently reported an interesting application of optical luminescence excited by X-rays.  So far, the spatial resolution of conventional florescence microscopy for tissue has been fairly limited.  This is mainly due to the spread of the excitation light, which is scattered by the sample itself, particularly in the case of thick tissue.  The novel idea is to use X-ray excited optical luminescent light from the scintillator plate placed at the back of the tissue.  X-rays are not scattered very much even in thick tissue, and such a small spread leads to high-resolution chemical imaging of the tissue.  The authors demonstrated an interesting application as a pH imager using methyl-red dyed paper.  For more information, see the paper, "High-Resolution Chemical Imaging through Tissue with an X-ray Scintillator Sensor", H. Chen et al., Anal. Chem., 83, 5045 (2011).
 

Pump-probe X-ray reflectivity  (March 10, 2011)

A research team led by Professor J. Larsson (Lund University, Sweden) has recently performed time-resolved X-ray reflectivity measurements with 100 picosecond resolution at ID09B, at the European Synchrotron Radiation Facility (ESRF).  The experiment is a so-called pump-probe measurement, i.e., the repetition of the measurement with systematic change of the delay time of the pump (laser light) and probe (X-ray) pulses.  In their research, amorphous carbon films with a thickness of 46 nm were excited with laser pulses (100 fs duration, 800 nm wavelength, and 70 mJ/cm² fluence).  Here, the laser-induced stress caused a rapid expansion of the thin film followed by a relaxation of the film thickness as heat diffused into the silicon substrate.  The researchers succeeded in measuring changes in film thickness by X-ray reflectivity with a short X-ray pulse (100 ps duration).  It was observed that thermal stress generated by laser excitation causes the film to rapidly expand and increases the surface roughness substantially.  The subsequent relaxation of film thickness is governed by heat diffusion into the substrate.  For more information, see the paper, "Picosecond time-resolved x-ray reflectivity of a laser-heated amorphous carbon film", R. Nuske et al., Appl. Phys. Lett. 98, 101909 (2011).
 

Ultra fast X-ray camera designed for European XFEL (July 27, 2011)

JEOL has developed a new generation of energy-dispersive X-ray spectrometer, Centurio, for the element analysis and mapping of electron microscope samples.  The detector is a silicon drift detector that collects X-rays from samples at an unprecedented large solid angle of up to 0.98 steradians from a detection area of 100mm².  For further information, visit the web page, http://www.jeolusa.com/
 

Amptek’s new detector for low energy X-ray spectra (March 7, 2011)

Amptek Inc has introduced a new series of low energy X-ray windows.  The new "C Series" represents a new technology that extends the low energy response of the Amptek Super SDD down to carbon. These windows can be used in SEMs, benchtops, or hand-held analyzers.  For further information, visit the web page, http://www.amptek.com/press.html
 

JEOL’s new large angle SDD for TEM samples (July 7, 2011)

PANalytical has released new hardware and software for small-angle X-ray scattering (SAXS) measurements on their range of X-ray diffraction (XRD) systems.  For existing users, the SAXS capability is a straightforward addition to the instrument.  With the release of software, EasySAXS v2.0, nanoparticle analysis could become easier.  For further information, visit the web page, http://www.panalytical.com/
 

GE moves X-ray business to China (July 25, 2011)

General Electric Healthcare has announced the transition of the 115-year-old X-ray business from Waukesha, Wisconsin to Beijing, China.  This is the first GE business to be headquartered there.  For further information, visit the web page, http://www.genewscenter.com/Press-Releases/GE-Healthcare-Global-X-ray-Business-Announces-Leadership-Move-to-China-324f.aspx
 

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/