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Links to adjunct workshops (2.28)

 

 

Workshop Summaries

Presented as received from organizers.


WK1 Toward 1-nanometer X-ray Beams (Advanced Photon Source, Center for Nanoscale Materials)
WK2 Nanomaterials for Energy (Center for Nanoscale Materials)
WK3 Nanophotonics (Center for Nanoscale Materials)
WK4 Microscopy and Imaging in Materials Science (Advanced Photon Source, Center for Nanoscale Materials)
WK5 Nanopatterning (Center for Nanoscale Materials)
WK6 Quantum Nanomagnetism (Center for Nanoscale Materials)
WK7 Texture and Strain Mapping with X-rays, Neutrons, and Electrons (Advanced Photon Source, Electron Microscopy Center, Intense Pulsed Neutron Source)
WK8 Inelastic X-ray Scattering: Present and Future at the APS (Advanced Photon Source)
WK9 X-ray Spectromicroscopy: a Tool for Environmental Science? (Advanced Photon Source)
WK10 Diffuse Scattering: Emerging Opportunities with Advanced X-ray and Neutron Sources (Advanced Photon Source)
WK11 Beamline Controls (Advanced Photon Source)
WK12 Microdiffraction in Structural Biology (Advanced Photon Source)

WK1 Toward 1-nanometer X-ray Beams

Organizers:
Paul Evans, University of Wisconsin-Madison
Jörg Maser, Argonne National Laboratory

The rapid evolution in techniques for focusing hard x-rays in the past few years has resulted in a dramatic improvement in the spatial resolution that can be obtained with hard x-ray probes. The workshop “Toward 1 nm X-ray Beams”, jointly organized by the Advanced Photon Source and the Center for Nanoscale Materials, addressed the question of what fundamental limitations will be encountered as x-ray focusing techniques evolve to ever larger numerical apertures. Both intrinsic limitations as well as fabrication challenges on the path aimed at nanometer focusing were discussed. The technical presentations on x-ray optics were put in a broader context by Eric Isaacs, (Center for Nanoscale Materials), who gave the introductory presentation to the workshop by describing the potential scientific impact that could be gained if focusing to few nanometers was possible. Efforts in adapting structural and magnetic scattering to smaller probe sizes will result in new probes for nanomagnetic and electronic devices and in probing the linked time and length scales of dynamics simultaneously.

Jörg Maser and Al Macrander (Argonne National Laboratory) presented x-rays focused to a 20 nm-wide line using multilayer optics with more than 1000 layers, strategies for reaching 5 nm spots, and an argument that the ultimate spot sizes could be one nanometer or below. The challenges in the fabrication of high-aspect ratio features for zone plate diffractive optics was discussed by Michael Feser (Xradia, Inc.) and by J. Alex Liddle (Lawrence Berkeley National Laboratory), along with novel strategies for stacking, lithographic alignment, and new structurally anisotropic optical materials. Kazuto Yamauchi (Osaka Univ.), Gene Ice (Oak Ridge National Laboratory), and Christian Morawe (European Synchrotron Radiation Facility), described the challenges involved in fabricating and characterizing mirror capable of focusing to 10 nm or better. Yamauchi in particular described the challenges associated with achieving the figure errors required for mirrors capable of this achievement. Perspectives on focusing using refraction, were presented by Christian Schroer (TU Dresden). Novel approaches in this respect include adiabatically adaptating the focal lengths of individual lenses in compound optics to reach spot sizes approaching a few nanometers. An increasingly unified perspective toward the traditional refractive, reflective, and diffractive approaches to x-ray focusing is emerging as mirror reflectivity at large incidence angles is being increased using multilayers, and the need to minimize the effective thickness of refractive optics to reduce absorption-indiced limitations to the numerical aperture limitations becomes apparent. The workshop displayed a large variety of approaches, helped to further clarify fundanelntal resolution limits, and displayed tremendous potential for adapting ideas from multiple techniques to new optical elements. While it appeared even few years ago hard x-ray spatial resolutions of 10 nm would be far in the future, the field now appears to be on the threshold of focusing to below 10 nm.

WK3 Nanophotonics

Organizers:
Gary Wiederrecht and Stephen Gray, Argonne National Laboratory

The talks at the nanophotonics workshop touched on several cutting-edge issues in nanoscale photophysics and photochemistry. New technologies and materials were described for devices biomedical and sensor applications. Professor Nick Fang at UIUC described new nanoscale plasmonic structures that function as analogs of metamaterials, which are materials with a negative index of refraction. These are man–made materials as all natural systems have a positive index of refraction. Professor George Schatz (Northwestern), recently appointed to the National Academy of Sciences, described new theoretical efforts to describe closely coupled plasmonic materials. Such systems have large enhancements of the optical near-field, on the order of 100, to produce unique environments for surface enhanced Raman scattering (SERS) or to do unique photochemistries. Professor James Merz (Notre Dame), described near-field scanning optical microscopy studies (NSOM) of emission from semiconductor quantum dots at low temperature and high magnetic field. Professor Norbert Scherer (University of Chicago) discussed ultrafast nonlinear responses of single metal nanorods and optical trapping of nanorods, with applicationssuch as nanoscale switching elements. Professor Sandra Bishnoi discussed the use of SERS for studying peptide-metal interfaces with nanoparticles. Dr. Ulrich Welp (Argonne) described recent advances for manipulating and controlling plasmon propagation in nanostructured thin films.

WK4 Microscopy and Imaging in Materials Science

Organizers:
Qun Shen and Brian Stephenson, Argonne National Laboratory

The APS/CNM Joint Workshop on X-ray Microscopy and Imaging in Materials Science, organized by Qun Shen (APS) and G. Brian Stephenson (MSD), held on Tuesday, May 2, 2006, highlighted the most recent advances in areas of materials science with synchrotron x-ray microscopy and imaging, which included both novel materials applications using existing well-established techniques and emerging developments that would open up new areas of materials research. After an early morning welcome by Murray Gibson, Director of the APS, and a brief introduction by Qun Shen on microscopy and imaging capabilities at the APS, eleven invited presentations showcased exciting topics such as high-resolution 3D X-ray microscopy for investigating materials microstructures by Ben Larson (ORNL), in-situ synchrotron microtomography studies of corrosions in alloys by Alison Davenport (Birmingham, UK), defect engineering in Si solar cells with XBIC and XRF mapping by Tonio Buonassisi (UC Berkeley), imaging nanomagnetic systems and dynamics by Samuel Bader (MSD, ANL), X-ray reflection phase-contrast microscopy of interfaces by Paul Fenter (Chemistry, ANL), combinatorial synthesis of novel epitaxial films of magnetic semiconductors by Frank Tsui (North Carolina), X-ray imaging with USAXS as contrast mechanism by Gabrielle Long (XSD, ANL), structure and dynamics in functional materials by Paul Evans (UW - Madison), fluctuation X-ray microscopy and medium-range order in self-assembled materials by Michael Treacy (Arizona State), nondestructive 3D imaging of nanostructured materials by using coherent x-rays by Jianwei Miao (UCLA), and first results on ultrafast coherent diffraction imaging using a free-electron laser by Stefano Marchesini (LLNL). These highlights underscored an emerging trend in synchrotron science that, as materials researchers focus more attentions on the structure-function correlations in functional materials, spatially-resolved in-situ structural studies at micro to nanometer length scales on nonuniform, heterogeneous materials are becoming increasingly more important.

WK5 Nanopatterning

Organizers:
Leonidas Ocola, Argonne National Laboratory
John Rogers, University of Illinois at Urbana-Champaign

Progress in nanoscience and nanotechnology depends strongly on the capabilities of techniques for patterning and chemically modifying materials at the nanoscale. The methods that are currently available span a very wide range, from those that have emerged from research and development in the microelectronics area (e.g., electron beam lithography, photolithography, etc.) to newer classes of low-cost techniques designed to enable manipulation of soft materials. This workshop covered, in a broad way, recent developments in nanopatterning with applications.

The workshop was an opportunity to bring in researchers outside of Argonne to showcase novel methods of micro- and nano- fabrication and to foment new collaborations between the CNM and their institutions. There were talks ranging from organic semiconductor patterning by Zhenan Bao (Stanford) and block copolymer lithography by Paul Nealy (U. Wisconsin) to three dimensional lithography with the talks from Jennifer Lewis (UIUC) and Paul Braun (UIUC). The Keynote talk was given by Don Tennant (Bell Labs) on electron beam lithography, where he covered many aspects related to nanopatterning and lithography. The workshop had great attendance (~ 100 in the audience).

WK6 Quantum Nanomagnetism

Organizers:
Eric Isaacs and Axel Hoffmann, Center for Nanoscale Materials, Argonne National Laboratory

The aim of this workshop was to highlight the role of quantum effects and nanosized confinement for magnetism. Dragomir Davidovic (Georgia Institute of Technology) showed how quantum interference results in conductance fluctuations in cobalt nanoparticles, indicating an unusually short spin dephasing time. Coherent X-ray speckle measurements of Cr by Oleg Shpyrko (Argonne National Laboratory) indicate that the dynamics of spin density wave domains may be governed by quantum tunneling of domain walls below 30 K. Likewise quantum fluctuations coupled with disorder in highly diluted spin-systems can give rise to the formation of a quantum spin-liquid, whose spectral response can be easily manipulated for information encoding in spin-states as shown by Thomas F. Rosenbaum (University of Chicago). Interestingly, geometric frustration can also give rise to spin liquid behavior and Peter Schiffer (Pennsylvania State University) showed how lithographically defined nanomagnetic model systems can be utilized to obtained detailed insight into geometrically frustrated systems. Similarly patterened nanomagnetic systems provide an ideal test bed for studying soliton dynamics and interactions as presented by Kristin Buchanan (Argonne National Laboratory). Moving from basic science more towards increasing data storage in magnetic recording applications Alejandra Lukaszew (University of Toledo) developed a novel fabrication route for decoupled FePt nanoparticles via ion implantation and x-ray rapid thermal annealing.

WK7 Texture and Strain Mapping with X-rays, Neutrons, and Electrons

Organizers:
Dean R. Haeffner, Advanced Photon Source, Argonne National Laboratory
James W. Richardson, Jr., Intense Pulsed Neutron Source, Argonne National Laboratory
Dean J. Miller, Electron Microscopy Center, Argonne National Laboratory

This workshop dealt with advances in texture and strain characterization as functions of position in engineered materials using x-ray, neutron and electron diffraction. Among the 12 presentations from experts in the three areas were introductory discussions, detailed reports of current research, descriptions of existing and under-development user programs, and forward-looking discussions highlighting future research directions.

X-ray diffraction has been used for decades for texture and strain measurements, but generally limited to near-surfaces. Over the past 10-20 years, neutron diffraction has established itself as an effective technique for measuring bulk texture and through-depth strain mapping, but with limited spatial resolution. Electron microscopy has always had a niche in the realm of individual grain diffraction, but with limited scope in polycrystalline materials. This workshop demonstrated how new advances are dramatically changing the landscape.

The unprecedented brilliance of APS, allowing ever-greater depth of penetration, and the development of systematic relationships between crystallographic and sample orientations in complex materials, are leading to computed lattice strain distribution functions that are directly comparable with Finite Element Analysis models. Ongoing developments at neutron sources, including construction of the SNS at ORNL, have highlighted the importance of anisotropic strain behavior and grain-to-grain interactions. Finally, electron backscatter diffraction (EBSD) has revolutionized thin film microscopy with detailed through-thickness grain misorientation mapping.

WK9 X-ray Spectromicroscopy: a Tool for Environmental Science?

Organizers:
Juergen Thieme, Institute for X-Ray Physics, University of Goettingen, Goettingen, Germany
Ian McNulty, APS, Argonne National Laboratory, Argonne, USA
David Paterson, Australian Synchrotron, Melbourne, Australia
Stefan Vogt, APS, Argonne National Laboratory, Argonne, USA

The aim of this workshop has been to bring together experts in environmental sciences and synchrotron radiation techniques. A secondary aim was to improve accessibility to these methods to researchers in these fields. The results of the workshop has been numerous, the most important are as follows:

The x-ray energy range of E = 0.25 keV to E = 8 keV seems to cover around 90% of the current research interests. For spectromicroscopy, the energy has to be tunable; the spatial resolution should be below 100 nm. This size range is where the behavior of particles such as colloids are determined not by their bulk properties but by their surfaces, and where the interface between local chemistry and macroscopic processes often occurs. The instrumentation must have the flexibility to do fast, wide-range scans as well as slower high-resolution scans to obtain overview maps of a sample as well as to zoom into a detailed area of interest. Tomography studies of systems from the environment is highly desirable, e.g. to understand transport processes. It will be necessary to handle with a vast sample heterogeneity and complexity and radiation damage of the sample has to be taken into account.

It is necessary to go beyond an only descriptive science and to develop predictive hypotheses and models. To consider an up-scaling from the submicron world accessible by microscopy to the large field is crucial. Heterogeneity exists over a wide range of length-scales. Biological and microbial effects are crucial to most areas of environmental science. It became clear that an integrated approach is essential for studying biological as well as other aspects of environmental problems. Metals and metalloids constitute a core interest in the field of environmental sciences. Iron appears to be most ubiquitous and of broadest interest. In addition, spatially resolved sulfur and phosphorus speciation is important to very wide range of problems. Organic halogens are of great interest within environmental science, e.g. the chlorine speciation in plants.

A repeated complaint of environmental scientists is the poor access to the necessary instruments due to oversubscription, which might get worse when the dissemination of knowledge by this workshop will be successful. Therefore, an expansion of the already available techniques not only in quality but also time-wise is absolute necessary.

WK12 Microdiffraction in Structural Biology

Organizers:
Stephen C. Harrison, Harvard University
Steven E. Ealick, Cornell University

The final workshop of the APS users meeting, organized by Steven Ealick (Cornell) and Stephen Harrison (Harvard Medical School), was devoted to microdiffraction in macromolecular crystallography. Technology for recording accurate diffraction data from protein crystals 20 microns or less in typical dimension is likely to change dramatically the course of protein crystallographic studies. Qun Shen (APS) began the workshop with an overview of current APS capabilities in microdiffraction, most of them with applications in areas other than macromolecular structure. Ehmke Pohl (Swiss Light Source) followed, with a description of the way the MD-2 diffractomer has been installed and used at SLS. Michael Sawaya (UCLA) then described a specific application -- determining the structure of an amyloidogenic peptide, yeast Sup35, at ESRF beamline ID-13. The very small crystals (50x2x2 microns) yielded an excellent, high-resolution structure, with SAD phasing from a Zn ion. David Flot (ESRF) concluded the morning session with a description of the new, dedicated microdiffraction beamline for protein crystallography at at ESRF. It takes advantage of innovations adopted at ID-13. In the afternoon, Florent Cipriani (ESRF), who designed the microdiffraction instruments at ID-13, outlined the design principles and described the differences between the initial instruments and the current MD2x generation of microdiffractometers. K. Rajashankar (APS and Cornell) described plans at NE-CAT for microdiffraction, and Gwyndaf Evans (Diamond, UK), plans for its implementation at Diamond. Gerd Rosenbaum (APS and Univ. of Georgia) concluded with a talk on tradeoffs between damage and signal in the context of plans for a new microdiffraction facility at the APS Structural Biology Center.