As of November 20, 2012

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

Compact X-ray free electron laser by transverse gradient undulator (November 16, 2012)

The X-ray free electron laser (XFEL) is a new type of light source, which can provide coherent, high-flux, ultra-short photon pulses in the soft and hard X-ray energy region. Until now, a long linear accelerator as well as long linear undulators have been thought indispensable, because the principle is based on the self amplified spontaneous emission (SASE).  Indeed, both FLASH at DESY and LCLS at SLAC, which are the world’s first X-FEL facilities in soft and hard X-rays, respectively, are facilities on a huge scale. Recently, Dr. Z. Huang (SLAC National Accelerator Laboratory, USA) and his colleagues have published a very interesting idea for a compact XFEL facility that uses an ultra-short pulse laser instead of an ordinary linear accelerator. It is known that laser-plasma accelerators can produce high energy electron beams with low emittance, high peak current but a rather large energy spread, which makes it difficult to consider XFEL applications. Their main strategy is the introduction of a transverse field variation into the FEL undulator.  In their calculation, such a transverse gradient undulator together with a properly dispersed beam can greatly reduce the effects of electron energy spread and jitter on the performance of XFEL generation. For more information, see the paper, "Compact X-ray Free-Electron Laser from a Laser-Plasma Accelerator Using a Transverse-Gradient Undulator", Z. Huang et al., Phys. Rev. Lett. 109, 204801 (2012).

Synchrotron FTIR and XRF imaging of liver cirrhosis (November 3, 2012)

A French group has recently published an interesting report on the analysis of cirrhotic liver tissue. At the Synchrotron Soleil, near Paris in France, scientists combined synchrotron Fourier transform infrared (FTIR) microspectroscopy and synchrotron micro-X-ray fluorescence (XRF) on the same tissue section.  They found from FTIR that hepatocytes within cirrhotic nodules have quite highly concentrated esters and sugars, and in the same area, phosphorus and iron were detected by XRF. Also the research team studied their inhomogeneity.  For more information, see the paper, "In situ chemical composition analysis of cirrhosis by combining synchrotron-FTIR and synchrotron X-ray fluorescence microspectroscopies on the same tissue section", F. Le Naour et al., Anal. Chem., Just Accepted Manuscipt.  Publication Date (Web): 3 Nov 2012.

Uncertainty estimates for EPMA (October 22, 2012)

Scientists at the National Institute of Standards and Technology, USA, have recently discussed some fundamental problems in quantitative electron probe X-ray micro analysis (EPMA).  The main arguments center on two significant sources of uncertainty in the quantitative matrix correction models; the mass absorption coefficient and the backscatter coefficient.  For more information, see the paper, "Uncertainty Estimates for Electron Probe X.ray Microanalysis Measurements", N. W. M. Ritchie et al., Anal. Chem., Article ASAP, Publication Date (Web): 22 Oct 2012.
 

Further synchrotron X-ray spectromicroscopic studies on Van Gogh’s paintings  (October 10, 2012)

A research team led by Professor K. Janssens (Antwerp University, Belgium) has published several interesting results from their series of analytical work on Van Gogh’s paintings.  They were able to give more detailed insights on the chemical forms of cadmium yellow and chromium yellow, as well as the role of lead in the pigment.  For more information, see the following 3 papers, "Combined use of Synchrotron Radiation Based Micro-X-ray Fluorescence, Micro-X-ray Diffraction, Micro-X-ray Absorption Near-Edge, and Micro-Fourier Transform Infrared Spectroscopies for Revealing an Alternative Degradation Pathway of the Pigment Cadmium Yellow in a Painting by Van Gogh", G. Van der Snickt et al., Anal. Chem., Article ASAP, Publication Date (Web): 30 Aug 2012., "The Degradation Process of Lead Chromate in paintings by Vincent van Gogh studied by means of Spectromicroscopic methods. Part III: Synthesis, characterization and detection of different crystal forms of the chrome yellow pigment", L. Monico et al., Anal. Chem., Just Accepted Manuscript. Publication Date (Web): 10 Oct 2012, and "The Degradation Process of Lead Chromate in paintings by Vincent van Gogh studied by means of Spectromicroscopic methods. Part IV: Artificial ageing of model samples of co-precipitates of lead chromate and lead sulfate", L. Monico et al., Anal. Chem., Just Accepted Manuscript. Publication Date (Web): 10 Oct 2012.
 

Theoretical X-ray absorption spectra of water and ice (October 8, 2012)

One of the remarkable instances of progress in soft-X-ray spectroscopy recently is the successful high-resolution measurement of O-K edge absorption spectra of liquid water and ice, which have some disordered hydrogen-bonds.  Professor R. Car (Princeton University) and his colleagues have recently reported their theoretical studies into the quantum dynamics of the nuclei and inhomogeneous screening effects. They found that the inclusion of quantum disorder is essential to bring the calculated spectra in close agreement with the experiment. In particular, the intensity of the pre-edge feature, a spectral signature of broken and distorted hydrogen bonds, is accurately reproduced, in water and hexagonal ice, only when quantum nuclei are considered. The effect of the inhomogeneous screening is less important but non-negligible, particularly in ice.  For more information, see the paper, "Roles of quantum nuclei and inhomogeneous screening in the x-ray absorption spectra of water and ice", L. Kong et al., Phys. Rev. B86, 134203 (2012).
 

Cross sections for K-shell ionization (October 2, 2012)

An Argentinean group has reported the experimental determination of cross sections for K-shell ionization by electron impact for Al, Si, and Ti and their oxides deposited on carbon substrates, for incident energies between 2.5 and 25 keV.  For more information, see the paper, "Experimental determination of cross sections for K-shell ionization by electron impact for C, O, Al, Si, and Ti", S. P. Limandri et al., Phys. Rev. A86, 042701 (2012).
 

Refractive X-ray imaging with multiple pencil beams (September 25, 2012)

When spatially coherent X-ray beams pass through a sample, edge-enhancement is observed in the transmission X-ray image because of the refraction effect.  At Canadian Light Source (Saskatoon, Saskatchewan, Canada), Professor P. C. Johns (Carleton University) and his colleague have recently reported an interesting extension of this type of X-ray refractive imaging.  They used multiple pencil beams (up to five) to create both transmission and refractive projection images, simultaneously, during the sample scan crossing the beams. The radial data were extracted from the overlapped image by a Maximum Likelihood-Expectation Maximization (MLEM) algorithm.  For more information, see the papers, "Synchrotron-based coherent scatter x-ray projection imaging using an array of monoenergetic pencil beams", K. Landheer et al., Rev. Sci. Instrum., 83, 095114 (2012).
 

High-repetition rate femtosecond pump-probe setup (September 13, 2012)

In time-resolved X-ray analysis based on the pump-probe scheme, an increase in the repetition rate is crucial for improving efficiency. At the same time, it is crucial to maintain or improve pulse to pulse stability.  Recently a Swiss research team developed a fast multichannel detection system for pump-probe spectroscopy, capable of detecting single shot super-continuum spectra at the repetition rate (10-50 kHz) of an amplified femtosecond laser system.  The setup is not for synchrotron X-rays, but many points discussed in the report will be useful.  For more information, see the papers, "Femtosecond pump/supercontinuum-probe setup with 20 kHz repetition rate", G. Aubock et al., Rev. Sci. Instrum., 83, 093105 (2012).
 

Calculation of resonance X-ray fluorescence spectra excited by X-ray free electron laser pulses (September 4, 2012)

Readers might recall several previous news articles on X-ray spectra of neon excited by ultra-short, high-intensity pulses from an X-ray free electron laser source at LCLS, Stanford ("Observation of non-linear resonances of inner-shell electrons by X-ray free electron laser", No.1, Vol. 41 (2012), "Calculation of X-ray emission from doubly ionized neon", No.1, Vol. 40 (2011), ""Hollow" neon atom created by X-ray laser excitation", No.5, Vol. 39 (2010) and "Removing all electrons from neon by X-ray laser", No.6, Vol. 38 (2009) ).  Recently, a research team led by Professor C. H. Keitel (Max-Planck-Institut für Kernphysik, Germany) has published its calculation of the resonance X-ray fluorescence spectra of neon, based on a so-called two-level model, which is used to study the transition of 1s2p_z^-1→1s^-12p_z in Ne⁺ at an energy of 848 eV.  As X-rays induce Rabi oscillations so fast, they compete with Ne 1s-hole decay.  The research group discusses resonance X-ray fluorescence spectra for two different cases; the first is chaotic pulses, which are most likely based on the SASE principle employed in the present XFEL facilities, and the second is Gaussian pulses available from the more ideal types of X-ray lasers expected in the future.  For more information, see the paper, "Resonance fluorescence in ultrafast and intense x-ray free-electron-laser pulses", S. M. Cavaletto et al., Phys. Rev. A86, 033402 (2012).
 

The 7th Asada award (November 2, 2012)

The recipient of the 7th 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. Shinsuke Kunimura (Tokyo Univ. of Science, "Development of a portable TXRF spectrometer with pg detection limits and its applications").  The ceremony was held during the 48th Annual Conference on X-Ray Chemical Analysis, Japan, at Nagoya University, Nagoya.
 

X-ray scientist named as SLAC director (October 24, 2012)

Professor Chi-Chang Kao has been named as the fifth director of the SLAC National Accelerator Laboratory, USA, which is one of the world’s largest facilities for experimental particle physics.  This reflects its change of mission from a dedicated particle physics lab to a multipurpose laboratory with an emphasis on X-ray studies.  Similar policy can be a world trend - at DESY, Germany, Prof. Helmut Dosch, who is a world leader in X-ray surface physics and condensed matter physics, has already been a director since 2009.  For more information, visit the Web page, http://www6.slac.stanford.edu/news/2012-10-24-DirectAnnounce-CCK.aspx
 

The SPring-8 Angstrom Compact free electron LAser (SACLA) - Japanese XFEL facility (June 24, 2012)

A new X-ray free electron laser facility at the SPring-8 campus in Harima, Japan, has started its user run.  This is the world’s second XFEL facility in the hard X-ray region after the LCLS at Stanford, USA.  One of the most important properties of this new Japanese facility is the short wavelength of the X-ray photon; the shortest wavelength attained is 0.634 Å (63.4 pm), which is almost half that achieved at Stanford. The facility uses a 400m linear accelerator as well as a short-gap and very long undulator (periodic length 18mm, minimum gap 3.5 mm, total number of periods 4,986).  The maximum power exceeds 10 GW with a pulse duration of 10-14 s.  For more information, see the paper, "A compact X-ray free-electron laser emitting in the sub-angstrom region", T. Ishikawa et al., Nature Photonics, 6, 540 (2012).  Also visit the Web page, http://xfel.riken.jp/eng/
 

Rigaku introduces new compact WDXRF spectrometer, Supermini200 (September 5, 2012)

Rigaku has announced the release of the Supermini200 wavelength dispersive X-ray fluorescence (WDXRF) spectrometer.  For further information, visit the web page, http://www.rigaku.com/
 

Shimadzu releases ultra high-speed camera  (September 3, 2012)

Shimadzu has released its new ultra high-speed CMOS camera, HyperVision HPV-X.  The maximum frame rate is 10 M fr./sec.  For further information, visit the web page, http://www.shimadzu.co.jp/ (though Japanese only)
 

Launch of the HORIBA Europe Research Center at Paris Saclay  (October 4, 2012)

HORIBA has opened its brand new 7500m² European research center near Paris, France close to the renowned French Ecole Polytechnique Campus.  For further information, visit the web page, http://www.horiba.com/reset/
 

PANalytical relocates Houston office (September 24, 2012)

PANalytical Inc. has moved its Houston area office to a new and larger office at 4802 North Sam Houston Parkway West, Suite 100, in Houston, TX. For further information, visit the web page, http://www.panalytical.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/