As of August 16, 2012

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

Phase transition of carbon induced by X-ray free electron laser (July 11, 2012)

Extremely strong pulses from X-ray free electron laser (XFEL) can change the material structure.  Recently, scientists at LCLS (Linac Coherent Light Source), Stanford, USA, have reported the amorphous to crystalline phase transition of carbon by femtosecond 830 eV XFEL beam.  The research group employed atomic force microscopy, photoelectron microscopy, and micro-Raman spectroscopy to discuss the change of the sp²/sp³ ratio (graphitization), as well as the change of local order of the irradiated sample area.  It was found that the phase transition threshold fluence is 282 ± 11 mJ/cm², and also the transition is mainly due to thermal activation rather than a non-thermal mechanism such as ionization etc.  For more information, see the paper, "Amorphous to crystalline phase transition in carbon induced by intense femtosecond x-ray free-electron laser pulses", J. Gaudin et al., Phys. Rev. B86, 024103 (2012).

Extension of resonant X-ray scattering by using K-K relationship in soft X-ray reflectivity (July 10, 2012)

Resonant X-ray scattering is powerful technique for the study of electronic structure at the nanoscale.  However, the optical properties of the constituent components of a material must be known prior to modeling of the scattered intensity.  Professor J. B. Kortright (Lawrence Berkeley National Laboratory, USA) and his collaborator have recently proposed a method of refining electronic structure, in the form of optical properties, simultaneously with physical structure, in a Kramers-Kronig (K-K) consistent manner.  This technique has been applied to specular reflectivity from a SrTiO₃ single crystal, and both a nonresonant surface contaminant layer and a modified SrTiO₃ surface region have been evidenced.  For more information, see the paper, "Kramers-Kronig constrained modeling of soft x-ray reflectivity spectra: Obtaining depth resolution of electronic and chemical structure", K. H Stone et al., Phys. Rev. B86, 024102 (2012).

Detection of characteristic X-ray photons from a single atom (July 8, 2012)

Several electron-microscopist groups have recently reported that a Si drift detector with a 60~100 mm² effective area can be used to detect characteristic X-rays from a single atom in nanomaterials such as silicon and platinum in monolayer and multilayer grapheme, as well as erbium in a C₈₂ fullerene cage supported in a single-walled carbon nanotube.  They employed a tiny electron beam of 0.1 nm in the aberration-corrected scanning transmission electron microscope.  As will be clear for readers of X-ray Spectroscopy journal, the discussion is a kind of major and/or minor component analysis of extremely small volume rather than so-called ultra trace element analysis.  The signal intensity was apparently very weak, but was in the order of some counts/sec according to the reports.  Such high sensitivity points to the significant potential of the energy dispersive detector system.  On the other hand, further detailed analysis including the estimation of parasitic background will be necessary.  For more information, see the papers, "Single atom identification by energy dispersive x-ray spectroscopy", T. C. Lovejoy et al., Appl. Phys. Lett., 100, 154101 (2012), and "Detection of photons emitted from single erbium atoms in energy-dispersive X-ray spectroscopy", K. Suenaga et al., Nature Photonics, advanced online publication doi:10.1038/nphoton.2012.148.
 

Femtosecond imaging with X-ray free electron laser (June 29, 2012)

One very interesting outcome at LCLS (Linac Coherent Light Source), Stanford, USA has recently been published.  The experiment was single-shot imaging of ferromagnetic, nanoscale spin order taken with femtosecond X-ray free electron laser pulses.  For more information, see the paper, "Femtosecond Single-Shot Imaging of Nanoscale Ferromagnetic Order in Co/Pd Multilayers Using Resonant X-Ray Holography", T. Wang et al., Phys. Rev. Lett. 108, 267403 (2012).
 

Table-top soft X-ray laser (June 8, 2012)

High-harmonic generation (HHG) is a universal response of atoms and molecules in strong femtosecond laser fields, and can be used to generate coherent photons in the soft X-ray region.  Simply speaking, HHG is the coherent version of an X-ray tube; instead of accelerating thermal electrons emitted from the filament and generating incoherent X-rays by hitting a metallic target, HHG begins with tunnel ionization of an atom in a strong laser field.  The portion of the electron wave function that escapes the atom is accelerated by the laser electric field and, when driven back to its parent ion by the laser, can coherently convert its kinetic energy into a high-harmonic photon.  So far, for many cases, around 100 near-infrared laser photons have been combined to generate bright, phase-matched, extreme ultraviolet beams when the emission from many atoms is added constructively.  Recently, a team led by Professor H. C. Kapteyn and Professor M. M. Murnane (University of Colorado at Boulder, USA) have employed a mid-infrared femtosecond laser in a high-pressure gas, and succeeded in getting ultrahigh harmonics up to orders greater than 5000, resulting in a bright continuum spectra ranging from 0.2 to around 1.6 keV.   The energy has still not yet reached the hard X-ray regime, but this would be a very attractive coherent ultra short pulse source for soft X-rays.  For more information, see the paper, "Bright Coherent Ultrahigh Harmonics in the keV X-ray Regime from Mid-Infrared Femtosecond Lasers", T. Popmintchev et al., Science, 336, 1287 (2012).
 

Quantitative grazing-incidence small angle X-ray scattering analysis (June 7, 2012)

Dr. D. Babonneau (PhyMat, CNRS UMR 6630, Université de Poitiers, France) and his colleagues have recently analyzed morphological characteristics of nanoripple patterns prepared by broad beam-ion sputtering of Al₂O₃ and Si₃N₄ amorphous thin films as well as 2D arrays of Ag nanoparticles obtained by glancing angle deposition on Al₂O₃ nanorippled buffer layers.  They employed 3D reciprocal space mapping in the grazing incidence small-angle X-ray scattering geometry.  For more information, see the paper, "Quantitative analysis of nanoripple and nanoparticle patterns by grazing incidence small-angle x-ray scattering 3D mapping", D. Babonneau et al., Phys. Rev. B85, 235415 (2012).
 

Continuous-flow sample cell for X-ray absorption spectroscopy (May 22, 2012)

A Swiss group has reported on the design and performance of a novel high-temperature and high-pressure continuous-flow reactor, which allows for X-ray absorption spectroscopy or diffraction in supercritical water and other fluids under high pressure (up to 30 MPa) and temperature (up to 500 ^oC).  For more information, see the paper, "Design of a continuous-flow reactor for in situ x-ray absorption spectroscopy of solids in supercritical fluids", M. Dreher et al., Rev. Sci. Instrum. 83, 054101 (2012).
 

Real time observation of copper corrosion by synchrotron X-ray diffraction (May 9, 2012)

A research team led by Professor A. Adriaens (Ghent University, Belgium) has developed a number of useful techniques based on synchrotron X-ray diffraction to see the growth of synthetic corrosion layers in real time.  The observation was done for copper, and the final products were identified as mixtures of nantokite (CuCl), cuprite (Cu₂O), and paratacamite (Cu₂(OH)₃Cl).  The team employed a highly sophisticated instrument for growing corrosion using a spin coater, and it could be used for many other similar applications.  Experiments were done at both SRS, Daresbury and ESRF, Grenoble.  For more information, see the paper, "The Use of Synchrotron X-rays To Observe Copper Corrosion in Real Time ", M. Dowsett et al., Anal. Chem. 84, 4866 (2012).
 

Synchrotron XRF mapping of large paintings (March 7, 2012)

An Australian team has reported on its study of a historical self-portrait by Sir Arthur Streeton (1867-1943) with fast-scanning X-ray fluorescence microscopy using synchrotron radiation.  They employed the event-mode Maia X-ray detector, which has the capability to record elemental maps at megapixels per hour with the full X-ray fluorescence spectrum collected per pixel.  The 25 megapixel elemental maps were obtained across the 200 × 300 mm² scan area.  The size of the beam used was 10 × 10 μm².  As heavy brushstrokes of lead white overpaint conceal the portrait, the excitation energy was chosen as 12.6 keV in order to avoid the influence of extremely strong Pb L fluorescence as well as Raman inelastic scattering.  For more information, see the paper, "High-Definition X-ray Fluorescence Elemental Mapping of Paintings", D. L. Howard et al., Anal. Chem. 84, 3278 (2012).
 

How to reconstruct 3D chemical map from confocal micro XAFS (January 18, 2012)

A research group led by Professor B. Kanngießer (Technische Universität Berlin, Germany) has reported on a new approach for chemical speciation in stratified systems using 3D Micro-XAFS spectroscopy.  As X-ray fluorescence mode in XAFS measurement generally leads to distorted spectra due to absorption effects, they developed a reliable reconstruction algorithm.  For more information, see the paper, "Reconstruction Procedure for 3D Micro X-ray Absorption Fine Structure", L. Lühl et al., Anal. Chem. 84, 1907 (2012).
 

Denver X-ray conference awards (August 8, 2012)

During the plenary session of the 61st Annual Denver X-Ray Conference, 2012 Birks Award was awarded posthumously to John Criss, and 2012 Jerome B. Cohen Student Award was given to  Magnus Menzel, Institut für Anorganische und Angewandte Chemie, Universität Hamburg, Hamburg, Germany, for his work, “Confocal μ-XRF XANES Analysis of the Cathode Electrolyte Interface of Lithium-ion Batteries”.  For further information, visit the Web page, http://www.dxcicdd.com/
 

15^th international conference on X-ray absorption fine structure (July 28, 2012)

The 15th international conference on X-ray absorption fine structure was recently held in Beijing, China, from July 22 to 28, 2012.  In addition to many applications of the XAFS technique in a variety of scientific fields, reports and discussions were held on progress in theory and software, as well as some advanced experiments such as time-resolved XAFS.  The next conference will take place at Karlsruhe, Germany in summer 2015.  For further information, visit the web page, http://www.ixasportal.net/ixas/index.php?option=com_content&view=article&id=90&Itemid=134
 

2012 workshop on buried interface science with X-rays and neutrons (June 28, 2012)

The 2012 workshop on buried interface science with X-rays and neutrons was held at KEK, Tsukuba, Japan, on June 26-28, 2012. This was the latest in a series of 18 workshops held since 2001.  There are increasing demands for sophisticated metrology in order to observe multilayered materials with nano-structures (dots, wires, etc), which are finding applications in electronic, magnetic, optical and other devices.  X-ray and neutron analysis is known for its ability to observe in a nondestructive manner even ‘buried’ function interfaces as well as the surface.  In addition to such inherent advantages, recent remarkable advances in micro analysis and quick time-resolved analysis in X-ray reflectometry are extremely important.  The latest progress in novel quantum beam technologies, such as XFELs, ERLs, as well as many other table-top laser-like machines could push such techniques towards further sophisticated applications.  The present workshop gathered together those with different research backgrounds, i.e., from semiconductor electronics to chemical bio materials, and even theoretical groups were invited to give insights into unsolved problems on buried interfaces.

Bruker’s micro CT accessory for scanning electron microscopes (July 30 2012)

Bruker has introduced its new micro-computed tomography (CT) accessory for scanning electron microscopes (SEM).  Micro-CT for SEM can add 2D and 3D high-resolution X-ray imaging capabilities to third-party SEMs, allowing the nondestructive analysis of internal microstructures of specimens.  For further information, visit the web page, http://www.bruker-axs.com/
 

5^th generation of Rigaku’s MiniFlex (January 15, 2012)

Rigaku Corporation has announced additions to its MiniFlex series of benchtop X-ray diffraction analyzers.  For further information, visit the web page, http://www.rigaku.com/
 

Varian launches on-line X-ray product finder (June 25, 2012)

Varian Medical Systems has launched an on-line product finder tool giving customers the ability to quickly locate needed replacement X-ray tubes as well as flat panel detectors for digital imaging. The product finder showcases all of Varian's X-ray product offerings and can be found on the company's website at: http://www.varian.com/us/xray/products/
 

e2v sells three businesses to Baird (May 16, 2012)

e2v technologies plc has announced the sale of e2v Scientific Instruments, e2v microsensors and its industrial gas sensing businesses,to SGX Sensortech Limited, a company backed by Baird Capital Partners Europe. Those companies provide a range of professional sensing products for x-ray spectroscopy and gas sensing for automotive and environmental safety applications.  For further information, visit the web page, http://www.sgxsensortech.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/