January 2010 Archives

Since 2004, NASA's Mars Exploration Rovers Opportunity and Spirit have continued to transmit a wealth of exciting images and extremely valuable analytical data on the surface of Mars, including several pieces of evidence pointing to the existence of water in sedimentary rock. Unfortunately, Spirit recently got stuck in a sand trap, from which it was helpless to extricate itself because two of its six wheels are not working any more. Scientists hope that, even in its marooned state, Spirit will be able to measure Martian gravity to determine if the planet is solid or liquid at its core. For further information, visit the Web page, http://www.nasa.gov/rovers

Extended X-ray absorption fine-structure (EXAFS) is a powerful tool for the analysis of atomic-scale structure around specific atoms. In addition to the determination of the atomic distance for the nearest neighboring atoms, it can give some information on the local dynamical properties of crystals. Recently, Dr. A. Sanson (Universita degli Studi di Verona, Italy) has published the results of the molecular dynamics (MD) simulation in the case of crystalline germanium. By comparing experimental EXAFS data, he could discuss the radial distribution functions of the first six coordination shells, as well as their parallel and perpendicular mean-square relative displacements as a function of temperature. For more information, see the paper, "Local dynamical properties of crystalline germanium and their effects in extended x-ray absorption fine structure", A. Sanson, Phys. Rev. B81, 012304 (2010).

Professor M. A. Castro (Instituto de Ciencia de los Materiales de Sevilla, CSIC-Universidad de Sevilla, Spain) and his colleagues are proposing to employ micro X-ray fluorescence as a feasible and efficient solution to classify waste and also to survey the problems in the production process. For more information, see the paper, "Application of micro-X-ray fluorescence analysis for the characterization of industrial wastes", M. D. Alba et al., Ind. Eng. Chem. Res., Article ASAP (DOI: 10.1021/ie901716w).

Argentinian scientists have recently published a paper on the emission of X-rays in the Kβ region of Mg, Al, Si, Sc, Ti, Cr, Fe, Ni, and Zn induced by electron bombardment. The research includes the Kβ^III and Kβ^IV spectator hole transitions, the 1s→3s quadrupole decay, the Kβ₂ and Kβ₅ diagram transitions, the structures related to radiative Auger processes, and the Kβ' and Kβ" lines. For more information, see the paper, "Kβ satellite and forbidden transitions in elements with 12<Z<30 induced by electron impact", S. P. Limandri et al., Phys. Rev. A81, 012504 (2010).

So far, it has been understood that the only way to realize hard-X-ray mirrors with near 100% reflectivity is the use of total external reflection at grazing incidence to a surface. Dr. Y. V. Shvyd'ko (Argonne National Lab, USA) and his colleagues have recently proposed to use Bragg reflections from synthetic diamond crystal. They discussed how it shows an unprecedented reflecting power at normal incidence with meV order narrow bandwidths for hard X-rays. The optics might be a good candidate for X-ray free-electron laser oscillators (X-FELO). For more information, see the paper, "High-reflectivity high-resolution X-ray crystal optics with diamonds", Y. V. Shvyd'ko et al., Nature Physics, doi:10.1038/nphys1506; published online, 17 January 2010.

The Science and Technology Foundation of Japan has announced that Japanese and US scientists have been named as laureates of the 2010 (26th) Japan Prize. Dr. Shun-ichi Iwasaki, 83, Director of Tohoku Institute of Technology in Japan, and also Professor Emeritus, Tohoku University, has received the prize in this year's category of "Industrial production and production technology" for his contributions to high-density magnetic recording technology by developing a perpendicular magnetic recording method. Dr. Peter Vitousek, Professor of Biology, Stanford University in the United States, 60, was selected in the other prize category of "Biological production and environment" for his contributions to solving global environmental issues based on the analysis of nitrogen and other substances' cycles. They will receive certificates of merit, and commemorative medals. There is also a cash award of fifty million Japanese yen for each prize category. The presentation ceremony is scheduled to be held in Tokyo on Wednesday 21st April, 2010. The prize categories for the 2011 (27th) Japan Prize will be "Information and communications" and "Bioscience and medical science". For further information, visit the Web page, http://www.japanprize.jp/en/index.html

Laser sources in the hard X-ray region have already become a reality at some free electron laser (FEL) facilities. However, typical hard X-ray FELs use an accelerator that is several km long to generate a ~10 GeV electron beam with ~kA peak current to drive the FEL. Dr. D. Xiang (SLAC National Accelerator Laboratory, USA) is proposing an alternative technique to generate an electron beam. He discusses the possibility of downsizing an X-ray FEL by this method. In his calculation, a 1.5 Å X-ray FEL with a saturation length within 30 m using a 3.8 GeV electron beam could be feasible. For more information, see the paper, "Laser assisted emittance exchange: Downsizing the x-ray free electron laser", D. Xiang, Phys. Rev. ST Accel. Beams 13, 010701 (2010).

A research group led by Professors Y. Takanishi (Kyoto University, Japan) and A. Iida (Photon Factory, KEK, Japan) has recently published its successful investigation into the local layer structure of bent-core liquid crystal, 4-Br-14-O-PIMB, which includes Br atoms. The group employed a monochromatic X-ray microbeam (3 μm × 4 μm), and observed X-ray scattering from the cell near the Br K absorption edge. They were able to discover some satellite peaks reflecting the superlattices. For more information, see the paper, "Microbeam resonant x-ray scattering from bromine-substituted bent-core liquid crystals", Y. Takanishi et al., Phys. Rev. E81, 011701 (2010).

X-ray Photon Correlation Spectroscopy (XPCS) is a novel technique which reveals the slow dynamics of equilibrium and non-equilibrium processes in condensed matter systems. A group led by Professor N. P. Balsara (University of California, Berkeley, USA) has recently published research on a polystyrene-polyisoprene block copolymer melt in the vicinity of the order-disorder transition. The group combined several techniques in addition to XPCS; time-resolved small angle X-ray scattering and rheology. During their studies of ordering kinetics, it was found that two qualitatively different regimes exist, i.e., shallow and deep quench regimes, respectively. For more information, see the paper, "Dynamic signatures of microphase separation in a block copolymer melt determined by X-ray photon correlation spectroscopy and rheology", A. J. Patel et al., Macromolecules, Article ASAP (DOI: 10.1021/ma902343m).