As of January 23, 2015

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

First all optical synchronization in X-ray free electron laser (January 20, 2015)

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).

Synchrotron light unveils hidden letters inside a carbonized ancient papyrus scroll discovered in Herculaneum (January 20, 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 (December 22, 2014)

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).
 

Novel approach to see topographic shape of buried interfaces – grazing resonant soft X-ray scattering (December 15, 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).
 

4m length inverse-Compton scattering X-ray source (December 1, 2014)

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).
 

Generation of copper Kα and Kβ pulses by the use of middle infrared laser system (November 10, 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 (November 10, 2014)

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 (November 6, 2014)

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).
 

Quantitative confocal micro X-ray fluorescence with polychromatic excitation (October 11, 2014)

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 (October 4, 2014)

Review paper on liquid metal surface studies by using X-rays (December 8, 2014)

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).
 

The 9th Asada award (October 30, 2014)

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.
 

Popular YouTube video of SLAC’s public lecture on X-ray studies on battery materials (May 24, 2014)

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)

Popular YouTube video of SLAC’s public lecture on the application of synchrotron X-ray fluorescence to paintings (October 1, 2013)

EDAX’s new silicon drift detector (December 11, 2014)

EDAX, Inc., has introduced the Element Silicon Drift Detector (SDD).  The chip size is 25mm², and it is designed with a silicon nitride (Si₃N₄) window to optimize low energy X-ray transmission for light element analysis.  For further information, visit the web page, http://www.edax.com/
 

Rigaku launches SmartSite RS, a portable stress analyzer (October 1, 2014)

Rigaku Corporation has announced the release of the Rigaku SmartSite RS portable stress analyzer, which is especially designed for on-site analysis.  For further information, visit the web page, http://www.rigaku.com/
 

Bruker’s SDD based handheld XRF analyzer (September 15, 2014)

Bruker Elemental has introduced the new S1 TITAN model 500 handheld XRF analyzer equipped with a large silicon drift detector.  For further information, visit the web page, http://www.bruker.com/hhxrf

AMETEK acquires Amptek (August 4, 2014)

AMETEK, Inc. (NYSE: AME) has acquired Amptek, Inc.  Amptek joins AMETEK as a unit of its Materials Analysis Division within AMETEK’s Electronic Instruments Group.  For further information, visit the web page, http://www.ametek.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/