In This Issue
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Daniel Chemla, former director of the ALS and Materials Sciences Divisions and major intellectual driver in the establishment of the Molecular Foundry, died at home on Thursday, March 20, at the age of 67. He had been battling a series of health problems since suffering a stroke four years ago. Despite those difficulties, he continued to actively lead his research group until very recently.
As ALS Division Director, Daniel’s ambitious 20-year roadmap for the ALS laid the groundwork for new beamlines, accelerator upgrades, and expanded scientific programs in materials sciences, ultrafast science, microscopy, and protein crystallography. During his seven-year tenure at the ALS, the number of users grew from 659 to over 2000. He stepped down as director in 2005. Acknowledging Daniel’s extraordinary contributions to the ALS, current ALS Director Roger Falcone observed, “He was a visionary and tireless leader. He set the ALS on a path of frontier science that we continue today, as was pointed out explicitly in the recent BES review. As a teacher and researcher, Daniel was inspirational for his students and colleagues. Along with his extensive network of friends, I will greatly mourn his passing, while appreciating his extraordinary life.”
Daniel is survived by his wife Berit, two children, Yann, an assistant professor of physics at the University of Illinois, Urbana-Champaign, and Britt Chemla Jones, an art history lecturer in Houston, Texas. The family is planning a memorial to honor him in the near future.
The triennial ALS Basic Energy Sciences (BES) program review was held on March 4-6, 2008. Laboratory Director Steven Chu was on hand to welcome the review committee and DOE representatives to the facility. The review process gave us an opportunity to demonstrate how we accomplish our mission—to support users in doing outstanding science in a safe environment. We highlighted the research performed at the ALS, our business practices, and our renewal plans for the storage ring and beamlines. Initial comments from committee members revealed their admiration for the work of our staff and users, but we await a full report from BES.
Six ALS users gave presentations on their innovative and groundbreaking research. On Tuesday (March 4), Andrea Cavalleri of Oxford University gave a presentation on “Dynamics in Complex Solids Viewed with Femtosecond X Rays,” Zhi-Xun Shen of Stanford University spoke on “Photoemission Study of Novel Materials,” Eli Rotenberg of the ALS talked about “ARPES Studies of ‘Continuously-Doped’ 2-Dimensional Correlated Materials,” James Berger of UC Berkeley started off the Wednesday session with a presentation on “Nature’s Magicians: Understanding Type II Topoisomerases,” followed by Craig Taatjes of Sandia National Laboratory, who spoke on “Imaging Combustion Chemistry with Multiplexed Synchrotron-Photoionization Mass Spectrometry,” and Yves Acremann of Stanford, who gave a presentation on “Magnetization Dynamics: Ultrafast and Ultrasmall.” Other presentations were given by ALS staff and included “Engineering and Operations” (Peter Denes and David Robin), “Resources and Allocations” (Ben Feinberg), “Safety” (Jim Floyd), “Accelerator Science for ALS Renewal” (David Robin), “Development of Beamlines and Instrumentation for the ALS Science Program” (Howard Padmore), and “Opportunities for Soft X-Ray Science at the ALS: Present and Future” (Zahid Hussain). In addition, breakout sessions occurred on all three days, a poster session with over 50 posters was given on Tuesday evening, and a walkthrough of the facility was provided on Wednesday afternoon.
Prospective challengers to silicon, the long-reigning king of semiconductors for computer chips and other electronic devices, have to overcome silicon’s superb collection of materials properties as well as sophisticated fabrication technologies refined by six decades of effort by materials scientists and engineers. Graphene, one of the latest contenders, has a rather impressive list of features of its own but has lacked a key characteristic of all semiconductors, an energy gap (band gap) in its electronic band structure. A multi-institutional collaboration under the leadership of researchers with Berkeley Lab and the University of California, Berkeley, have now demonstrated that growing an epitaxial film of graphene on a silicon carbide substrate results in a significant band gap, 0.26 electron volts (eV), an important step toward making graphene useful as a semiconductor. Read more…
Publication about this research: S.Y. Zhou, G.H. Gweon, A.V. Fedorov, P.N. First, W.A. De Heer, D.H. Lee, F. Guinea, A.H. Castro Neto, and A. Lanzara, “Substrate-induced bandgap opening in epitaxial graphene,” Nature Materials 6, 770 (2007).
Studying the world of the ultrasmall and the ultrafast is at the frontier of scientific research. Two x-ray approaches can be used for such examination. The first entails developing sources that have short x-ray pulses such as free-electron lasers and slicing sources, which will provide the ultrafast temporal information. The other approach is to develop a detector that is fast enough to resolve the ultrafast details of the dynamical processes. ALS researchers are doing both: developing sources and detectors with one instrument. They are developing a high-speed x-ray streak camera with high spatial resolution to watch, in real time, the motion of the atoms in materials. So far, a temporal resolution of 233 fs and a spatial resolution of 10 µm have been demonstrated. This is the first time that such a high temporal resolution has been combined with high spatial resolution in a streak camera. Read more…
Publication about this research: J. Feng, H.J. Shin, J.R. Nasiatka, W. Wan, A.T. Young, G. Huang, A. Comin, J. Byrd, and H.A. Padmore, “An x-ray streak camera with high spatio-temporal resolution,” Appl. Phys. Lett. 91, 134102 (2007).
The first commercial fungicide—the “Bordeaux mixture” of copper sulfate and lime—was used to fight downy mildew in French vineyards. The fungicide worked by catalyzing the production of free radicals that damage proteins and enzymes involved in cycling copper between Cu(I) and Cu(II) oxidation states in the cellular electron transport chain. However, not all fungi are sensitive to copper toxicity. Some, called mycorrhizae, which live underground in symbiosis with host plants through intracellular or extracellular colonization of their roots, are resistant, although it is not known why. A team from France’s National Center for Scientific Research (CNRS) and Université Joseph Fourier in Grenoble in collaboration with researchers at the University of Illinois at Chicago and in partnership with the French company Phytorestore has discovered a new form of copper—metallic nanoparticles—in the rhizosphere (soil-root interface) that may explain how mycorrhizal (symbiotic) fungi detoxify copper. Read more…
Publication about this research: A. Manceau, K.L. Nagy, M.A. Marcus, M. Lanson, N. Geoffroy, T. Jacquet, and T. Kirpichtchikova, “Formation of metallic copper nanoparticles at the soil-root interface,” Environmental Science and Technology 42, 1766 (2008).
On Monday, February 25, MERLIN (meV Resolution Beamline— Beamline 4.0.3) began its commissioning stage with the achievement of first light through its front-end optics. This project completes the development of the chicaned Sector 4 straight section and was funded by the office of Basic Energy Science (BES), Department of Energy (DOE), in response to strong demand for an ultrahigh-energy-resolution beamline to tackle the challenges in strongly correlated electron physics.
Two separate experimental techniques will be utilized at the beamline: angle-resolved photoemission spectroscopy (ARPES) and resonant inelastic x-ray scattering spectroscopy (RIXS). ARPES is a photon-in/electron-out spectroscopy, which can be used to directly study single-particle (quasiparticle) ground-state properties and important electron-boson interactions. RIXS, on the other hand, is a photon-in/photon-out spectroscopy, which is used to study two-particle (electron-hole) properties. Charge-neutral transitions allow the experiments to be carried out under applied fields, and the resonance effect provides elemental selectivity and greatly enhances weak excitations. The unique combination of ARPES and RIXS offers an opportunity to study the electronic structures of complex systems.
The beamline design was quite challenging and employs a number of novel features and developments to deliver both world-class energy resolution (R ~100,000) and robust, user-friendly operations. Starting at the source, MERLIN utilizes a quasi-periodic, 9-cm-period elliptically polarizing undulator (EPU) to cover its operational energy range of 8 to 150 eV while simultaneously shifting higher harmonics to minimize their transmission through the monochromator. This light is then focused through a series of optics to a fixed entrance slit and onto a translating spherical grating monochromator (SGM) that contains a flat premirror and two separate spherical grating substrates (one for high flux, one for high resolution). The exit slit is also stationary, and the monochromator can either be translated to maintain a high-resolution focus or fixed and operated in variable included angle (VIA) mode. Finally, the selected beam is refocused at the sample by a Kirkpatrick-Baez (KB) arrangement of mirrors that features side-contoured and bent optic substrates with a theoretical 0.1 microradian figure deviation from ideal elliptical form. This high-quality focusing will allow the spectrometer to operate at maximum resolution in a high-flux, slitless configuration.
MERLIN’s success is due to the teamwork led by Yi-De Chuang as Project Scientist and Nicholas Kelez as Project Engineer, and the following individuals: Derek Yegian, Frederic Gicquel, Troy Stevens, Tom Miller, Alexis Smith-Baumann, Keith Franck, and Rob Duarte (Beamline Design Team); Steve Marks, Ross Schlueter, Soren Prestemon, and Mark Coleman (Undulator Design); Ruben Reinniger, John Bozek, and Malcolm Howells (Optical Design); and M. Zahid Hasan, Alessandra Lanzara, and Zahid Hussain (Scientific Team). Project funding was provided by the Office of Basic Energy Sciences under Lab03 program within the DOE Office of Science.
King Abdullah University of Science and Technology (KAUST) announced on March 13 the names of the winners of its Global Research Partnership (GRP) Investigator competition. Paulo Monteiro—ALS User and University of California, Berkeley, Professor of Civil and Environmental Engineering—was one of the 12 international scientists who were selected as KAUST Investigators for the 2007 round of nominations, which featured more than 60 submissions from 38 of the world’s leading research universities. The awardees are dedicated to a wide range of research topics of global significance with particular importance to Saudi Arabia and the region. Their research areas include water desalination, renewable and sustainable next-generation energy sources, genomics of salt-tolerant plants, durable and environmentally friendly construction materials, sustainable utility of hydrocarbons, low-cost high-efficiency solar technology, and the application of computational science to human health and biotechnology.
It’s not too early to mark your calendar for this years ALS Users’ Meeting, to be held at Berkeley Lab, October 13–14. Organizers are already planning an exciting program of highlight talks, poster sessions, and workshops. Anyone interested in proposing a workshop topic can contact the organizers at firstname.lastname@example.org.
New ALS Lobby Look. The ALS lobby has recently undergone a “makeover” in order to better showcase ALS science and engineering to visitors. The first stage of the redesign—installation of a new science highlight display area, banners, and signage—was completed at the end of February, just in time for the triennial BES Review. The next step will be to create content for a flat-screen display that will provide tour guides and visitors with an introduction to the ALS, an overview of recent science highlights, and facility information. The renovation project was funded by the Berkeley Lab Directorate and spearheaded by the ALS Communications group. Go here to view images of the Lobby upgrade.
Send Us Your Highlights. ALSNews, with a readership of over 4,000, reaches the synchrotron community, Department of Energy funders, scientists in other disciplines, and a wide array of general audience readers. Each month we feature science highlights from ALS users. Help us to help you highlight your ALS research by contacting us as soon as a paper has been accepted for publication so that we may consider it for an ALS highlight. We are especially interested in journal ublications that report important new research as well as research of inerest to a general audience. These highlights not only appear in ALSNews, but on posters and ALS print publications. In addition, decision-makers at the DOE receive ALS highlights in viewgraph form for use in presentations. If you would like your work to be highlighted, send us an email containing the publication citation and a brief description of the work. ALS Communications group.
For the user runs from February 20 to March 16, 2008: Beam reliability*: 96.0%; Completion**: 92.2%.
This period included the first of week of 2-bunch user operations. There were no significant interruptions. Note: this is the first time ALS has run in 2-bunch-mode at full-energy injection (1.9 GeV).
Questions about beam reliability should be sent to David Richardson.
Requests for special operations use of the “scrubbing” shift should be sent to Rick Bloemhard (ALS-CR@lbl.gov, x4738) by 1:00 p.m. Friday.
*Time delivered/time scheduled