Some readers might remember the news article, "A compact synchrotron light source driven by pulse laser", in X-ray Spectrometry, Vol. 37, No.2 (2008). The essential point is that a table top pulse laser can be used as an alternative to a linear or circular electron accelerator. The article above reported the first successful synchrotron radiation generation from laser-plasma-accelerated electrons, but the wavelength was only in the visible to infrared region. Recently, an international team led by Professors S. Karsch and F. Grunera achieved a new breakthrough. The team belongs to Munich 's Cluster of Excellence "Munich Centre for Advanced Photonics" (MAP), in the Laboratory for Attosecond Physics (LAP) of Ludwig-Maximilians-Universitat (LMU) in Munich
September 2009 Archives
Professor D. Sparks (University of Delaware , USA
At Stanford's linac coherent light source (LCLS), a great deal of effort has been devoted since April this year to initial scientific tests of an X-ray laser. In September, scientists attempted to strip all ten electrons from an atom of neon. They were able to adjust the proportion of different neon species, from non-ionized Ne (no missing electrons) to Ne10+ (lacking all 10 electrons), by fine-tuning the powerful LCLS X-ray beam. For more information, visit the Web page, http://today.slac.stanford.edu/
It is known that sulfide sometimes play a significant role in the geochemistry of arsenic under reducing conditions. So far, it has been assumed that sulfide primarily reduced the solubility and mobility of arsenic by precipitation of arsenic-sulfide minerals, As2S3, but recent studies indicate that under certain conditions, significant concentrations of soluble As-S compounds can exist in sulfidic waters. Thus, the question is whether they are As(III)-S species ("thioarsenites") or As(V)-S species ("thioarsenates"). A research group led by Dr. B. Planer-Friedrich (
Dr. C. T. Chanter and his colleagues have published a paper on the unresolved quantitative discrepancies between experimental and theoretical Cu Kα spectra. For more information, see the paper, "Theoretical Determination of Characteristic X-Ray Lines and the Copper Kα Spectrum", C. T. Chantler et al., Phys. Rev. Lett. 103, 123002 (2009).
Nearly $19 million in funding through the American Recovery and Reinvestment Act is supporting the Cornell High Energy Synchrotron Source (CHESS), Cornell Electron Storage Ring (CESR) and ongoing efforts to plan and build a new linear accelerator, the Energy Recovery Linac (ERL). So far, Cornell has received more than 90 ARRA grants, totally about $76 million. For more information, visit the Web page, http://www.news.cornell.edu/
So far, diffusion in solids has been investigated by profiling the depth dependence of tracer atoms diffused into the sample. Although one can obtain the diffusion constant from this, the question is how diffusion takes place on the atomic scale, rather than on the micron scale. Sometimes quasielastic neutron scattering as well as Mobauer spectroscopy can be used in a very limited number of fortunate cases. A research group led by Professor G. Vogl (
In the film Star Trek IV (1986), transparent aluminum is used for the exterior portals and windows of spacecraft. Now transparent aluminum has become a hot topic for real, rather than in science fiction. An international team, led by Oxford University scientists, has recently reported that a short pulse from the FLASH laser (wavelength 13.5 nm) knocks out a core L-shell electron from every aluminium atom in a 50 nm Al thin film without destroying the metal's crystalline structure. This rendered the aluminium almost invisible for this wavelength. This phenomenon is called saturable absorption. The transient state of aluminium produced in this way is as dense as ordinary matter but can only exist for an extremely short period of time of 40 femtoseconds. For more information, see the paper, "Turning solid aluminium transparent by intense soft X-ray photoionization", B. Nagler et al., Nature Physics 5, 693 (2009).
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