Workshop Summaries X-ray Imaging and Spectro-microscopy: the Present and the Future (Chairs: John Miao and Keith Hodgson) This workshop provided a forum to discuss the scientific applications of a variety of imaging and spectro-microscopic techniques. Invited speakers discussed important results using these applications and predicted possible future scientific directions with the advance of instrumentation and x-r ay sources. The workshop was well attended with over fifty registered participants. Keith Hodgson opened the workshop with remarks about future x-ray imaging and spectro-microscopy opportunities at SSRL that will be made possible by the SPEAR3 upgrade and the LCLS project. Jo Stöhr (SSRL) presented results on imaging ferromagnetic and antiferromagnetic structures by means of x-ray magnetic linear/circular dichroism using photoemission electron microscopy (PEEM), and emphasized that futu re instruments will not only greatly improve the real space resolution, but will also provide both imaging and dynamics capability. Janos Kirz (Stony Brook) discussed scanning transmission x-ray microscopy. This zone plate-based microscope can obtain both the structure information and chemical mapping of a variety of samples from biology to environmental science. Chuck Fadley (LBL & UC Davis) gave an overview of holographic imaging of local atomic structure. He concluded that with the development of better detector systems this imaging technique will find much broader applications. The following session focused on coherent x-ray diffraction imaging and phase retrieval techniques. Ian Robinson (UIUC) discussed the principle of the oversampling method, and showed beautiful experimental results of phasing 3D diffraction patterns from gold nanocrystals. Keith Nugent (Melbourne) explained his pioneering work on the transport of intensity approach, and illus trated its applications in light microscopy, electron microscopy and x-ray imaging. John Miao (SSRL) followed with a talk on 3D structure determination of nanostructured materials by using the oversampling method and the potential of imaging single biomolecule by using the X-FELs. During the session devoted to biology and polymers, Carolyn Larabell (LBNL /UC San Francisco) compared fluorescence, electron, and x-ray microscopy for imaging cellular structures, concluding t hat while cell biology needs all three, x-ray microscopy has the advantage of imaging the 3D structures of thick samples in their natural environment. Adam Hitchcock (McMaster) further discussed the unique capability of soft x-ray microscopy for the imaging and chemical mapping of polymers and biofilms. Barry Lai (APS) reported on the powerful capability of combining the micro-probe technique with x-ray fluorescence for tracing heavy elements in biology cells. Kyle Shen (Stanford) began the final session by summarizing the impressive results achieved by the Z.-X. Shen group (Stanford) by using angle resolved photoemission spectroscopy (ARPES) in their correlated materials studies. He went on to make the point that this momentum space microscope will be even more powerful with better spectrometers and x-ray sources. Ian McNulty (APS) then discussed soft x-ray microscopy activity at APS. Their intermediate range x-ray microscope covers the absorption edge of more elemen ts than its counterpart in soft x-rays. By using magnetic x-ray microscopy, Paul Evans (Wisconsin-Madison) concluded the workshop with a report on the results of imaging antiferromagnetic domains in chromium with spatial resolution at the micron scale. Studies using magnetic x-ray microscopy show an improvement by orders of magnitude in comparison with previous experiments. Opp ortunities in Catalysis Research Using Synchrotron Radiation (Chair: Anders Nilsson) Chemical catalysis is one of the research areas of enormous importance for the industrial society. There are important challenges to be met in the near future when development of new processes and catalysts will be a necessity. For example, one needs to find a way to make methanol from methane, split water into hydrogen using sunlight, find a replacement for platinum metals, and the list goes on. The fundamental understanding of many catalytic processes is still emerging and recent developments in experimental and theoretical methods point to new opportunities to learn more. The intent of this workshop was to bring researchers from many different disciplines together to discuss how synchrotron radiation can be applied to address some f undamental questions in catalysis. There were three overview lectures on the scientific challenges and future direction in fundamental aspects of catalysis. Gabor Somorjai (UC Berkeley) presented a lecture on the "Need for new direction of research at the frontiers of catalytic science", Jens Norskov (Technical University of Denmark) on "Heterogeneous catalysis-opportunities and challenges" and Claus Jacobsen (Haldor Topsö) on "New catalyti c materials-from active sites to industrial processes". There were three additional overview lectures on synchrotron radiation-based techniques. Anders Nilsson (SSRL and Stockholm University) demonstrated how soft x-rays can be used for fundamental studies of model catalytic systems, Bjerne Clausen (Haldor Topsö) showed the usefulness of hard x-rays in the characterization of industrial catalysts and Uwe Bergmann (LBNL/UC Davis) pointed to new opportunities with novel applications of hard x-ray spectroscopy. Two lectures were devoted to the development of synchrotron radiation-based experimental and theoretical methods to provide important new tools in catalytic research. Miquel Salmeron (LBNL) showed how a new differential pumped photoelectron spectroscopy system can provide in situ studies of surfaces under high pressure and Lars Pettersson (Stockholm University) demonstrated how theoretical simulation of x-ray spectra provide a unique molecular orbital picture of chemical bonding on surfaces. Two presentations were focused on oxide materials: Geoff Thornton (University of Manchester) on "Influence of defects on the reactivity of ZnO" and Robert Madix (Stanford University) on the "The dynamic surface". Vittal Yachandra (LBNL) gave a presentation on x-ray absorption spectroscopy applications to understand the structure of the Mn complex and the mechanism for oxidation of water in photosystem II. Presentations on the use of x-ray absorption spectroscopy and x-ray scattering applications to studies of supported gold catalysts and sulphide catalysts were given by Javier Guzman (UC Davies) and Russell Chianelli (UT El Paso), respectively. The last presentation was given by Jim White (UT Austin) on the outcome of the recent DOE catalysis workshop held in Washington DC in May and the status of the written report. The workshop concluded with a long discussion on the role of synchrotron radi ation applications in a new initiative in catalysis. Participants agreed that in order to have an important impact it is essential to provide in situ characterization under reaction conditions using all different techniques, both for model systems and industrial catalysts. The fundamental development of new emerging techniques needs to be led by a devoted research group with a strong scientific interest, whereas application of established techniques can be organized by an efficient infras tructure provided by the facility. X-ray Absorption Near-edge Spectra in Analysis of Mixtures (Chairs: Ingrid Pickering and Graham George) X-ray absorption near-edge spectroscopy is a sensitive probe of local atomic environment, o xidation state and electronic structure, and can thus be used as a fingerprint of particular chemical environments. No special sample preparation is required and the incident x-rays probe a given element regardless of its physical form (solid, liquid or gaseous). Because of this, x-ray absorption near-edge spectroscopy can be a powerful method for analysis of chemical form in complex samples such as mixtures and has already found a wide range of applications. Least-squares fitting ca n be used to quantitatively determine the abundances of various chemical species in a mixture. In the case of a set of related mixtures, principal component analysis can be used to determine the number of individual components in the set, and target transformation can be used to test whether a given standard spectrum is one of the components. After an introductory talk by Roger Prince (ExxonMobil Research and Engineering), presentations were made concerning the methodology o f edge analysis by Graham George (SSRL) and Stephen Wasserman (Advanced X-ray Analytical Services). Applications were drawn from a broad range of disciplines and included identification of Mn particulates emitted from auto engines (Joe Wong, LLNL), arsenic speciation in Bangladeshi aquifers (Andrea Foster, USGS), elucidating the chemistry of ascidian blood cells (Pat Frank, SSRL) and proposing preservation methods for the Swedish warship Vasa (Farideh Jalilehvand, U. Calgary). During fi nal sessions, the 42 participants in attendance were given the opportunity to try out principal component analysis and other edge analysis routines using the suite of programs EXAFSPAK (written by Graham George, SSRL) running on either in-house PCs or on personal laptops. The workshop was extremely successful and provided the participants with both theoretical and practical knowledge of how to apply the unique information contained in the near edge region to their own problems that span ned a wide range of disciplines. Experimental Opportunities with LCLS (Chairs: John Galayda and Jerry Hastings) A very successful one and one half day meeting was held to begin the process of creating experiment teams to propose instruments for the LCLS experimental program. More than thirty people gathered representing most of the scientific disciplines discussed in the LCLS First Experiments document. The first afternoon was devoted to presentations of the status and plans for LCLS as well as the policy for experimental proposals. This meeting will be one of many held as we develop the instrument suite for LCLS. A major thrust of the workshop was to focus attention on the R&D needed for the experi mental program to be most successful in the early operations phase. Two key components were highlighted: detector developments, in particular 2-D detectors for scattering experiments that will permit read-out at the LCLS repletion rate (120 Hz) and development of methods for x-ray pulse length measurement and pump laser - x-ray probe timing. Discussions also included the proposal timeline and pre-proposal submission to the LCLS Science Advisory Committee in late spring 2003.         Last Updated: Content Owner: Page Editor: 31 OCT 2002 Cathy Knotts Lisa Dunn