APS Today

User Science Seminar resumes

Thu, 20 Mar 2008 15:14:52 -0500

Run 2008-01 Begins

Thu, 20 Dec 2007 00:00:00 -0600

Application of Computational Science for Fossil Fuel Conversion Processes with Carbon Capture

Thu, 03 Jan 2008 00:00:00 -0600

Projections indicate that fossil fuel use will be an important part of the energy portfolio for the US and the world. Advanced fossil-fuel technologies are being developed to improve the efficiency and reduce CO2 emissions. NETL is applying computational science at different scales to facilitate the development of these advanced technologies. At atomic-scales, computational chemistry is used for developing better CO2 and H2 membranes, CO2 sorbents, and catalysts. At device-scales, computational methods for modeling multiphase flow phenomena enable the description of gas-solids flows occurring in devices such as coal gasifiers. At the plant-scale, steady-state and dynamic models are used for the optimization and control of coal conversion plants. The APECS technology developed at NETL improves the fidelity of plant-scale models by including device-scale models. This presentation will describe the use of models at different scales and outlines a vision for combining models at different scales to accelerate fossil energy technology development.

Application of Non-resonant Inelastic X-ray Scattering (NIXS) to Rare Earth Systems

Mon, 07 Jan 2008 00:00:00 -0600

Resonant inelastic x-ray scattering (RIXS), and the related resonant x-ray emission spectroscopy (RXES) have proven themselves to be valuable means by which to study the electronic behavior of rare-earth containing materials, but what about non-resonant techniques? Applying bulk-sensitive, non-resonant inelastic x-ray scattering (NIXS) to rare earth materials, particularly cerium-containing ones, yields considerable information for resonances corresponding to N and O-shell initial states. A survey of the momentum-transfer dependence of these resonances will be presented with emphasis on the cerium valence and hybridization sensitivity of the 4d initial states.

Science with Nuclear Resonance Spectroscopy at Future Sources

Tue, 08 Jan 2008 00:00:00 -0600

From the beginning of its discovery the Mössbauer effect has continued to be one of the most powerful tools with broad applications in diverse areas of science and technology. With the advent of synchrotron radiation sources, the tool has enlarged its scope and delivered new capabilities. The popular techniques most generally used in the field of materials physics, chemical physics, geoscience, and biology are hyperfine spectroscopy via elastic nuclear forward scattering (NFS), vibrational spectroscopy via nuclear inelastic scattering (NRIXS), and, to a lesser extent, diffusional dynamics from quasielastic nuclear forward scattering (QNFS). As we look ahead, new storage rings with enhanced brilliance such as PETRA-III under construction at DESY, Hamburg, and PEP-III in its early design stage at SLAC, Stanford, will provide new and unique science opportunities. In the next two decades, x-ray free-electron lasers (XFELs), based both on self-amplified spontaneous emission (SASE-XFELs) and a seed (SXFELs), with unique time structure, coherence and a 5-6 orders higher average brilliance will truly revolutionize nuclear resonance applications in a major way. This overview is intended to briefly address the unique radiation characteristics of new sources on the horizon and to provide a glimpse of scientific prospects and dreams in the nuclear resonance field from the new radiation sources. We anticipate an expanded nuclear resonance research activity with applications such as spin and phonon mapping of a single nanostructure and their assemblies, interfaces, and surfaces; spin dynamics; nonequilibrium dynamics; photochemical reactions; excited-state spectroscopy; and nonlinear phenomena.

Promotion of Tissue Ingrowth Into Synthetic Scaffolds by Transient Compressions

Fri, 11 Jan 2008 00:00:00 -0600

APS/Users Monthly Operations Meeting

Fri, 25 Jan 2008 00:00:00 -0600

Scattering curves in a Rietveld structure refinement of NaNO₃ and quartz

Fri, 25 Jan 2008 00:00:00 -0600

Run 2008-2 General User Proposal Deadline

Wed, 30 Jan 2008 15:51:58 -0600

X-rays and Magnetism - A Perfect Match

Mon, 04 Feb 2008 11:51:57 -0600

The Synchrotron Light Source ANKA

Mon, 11 Feb 2008 13:24:21 -0600

Ordering of Gold Nanoparticles at the Toluene-Water Interface

Thu, 14 Feb 2008 11:32:09 -0600

We discuss here the results of a synchrotron X-ray scattering study of the formation and ordering of gold nanoparticles at the toluene-water interface through a reduction reaction. The observed X-ray reflectivity and diffuse scattering data show the formation of a monolayer of "magic clusters" at the water-toluene interface. Each cluster consists of 13 nanoparticles with about 12 Å diameter, similar to Au-55 nanoparticles, with about an 11 Å organic layer and an in-plane cluster-cluster separation of 180 Å. The electron density profile of the monolayer of these clusters exhibits three layers of nanoparticles as a function of depth that evolves with time.

NSLS-II: An Evolutionary Light Source Design

Fri, 15 Feb 2008 14:28:34 -0600

Beams and Applications Seminar Series

Chemical Vapor Synthesis of complex oxides and their structural characterization

Mon, 18 Feb 2008 12:31:42 -0600

Functional nanomaterials are often based on complex materials such as doped or multinary oxides. The synthesis of such materials is highly demanding because it requires the control of composition / stoichiometry on the level of a few thousand atoms per nanoparticle. We discuss approaches to solve this challenge and show detailed structural investigations with emphasis on EXAFS and data analysis using physical models.

High-throughput powder diffraction on 11-BM: What, How and Why

Mon, 18 Feb 2008 12:32:43 -0600

Abstract: The 11-BM diffractometer produces high-throughput powder diffraction data without compromising resolution or sensitivity. Staring with "Why", this talk will provide examples of how structure determination from high resolution powder diffraction allows otherwise insolvable molecular structures to be determined and will show how this scientific knowledge drives technological innovation. This type of research drove the creation of the 11-BM instrument, which will provide world-class capabilities for such measurements to users on a mail-in basis. The talk will present some of the unique design features and will summarize recent commissioning results. To run an instrument that can accommodate at least 150 samples per week, likely serving multiple research groups every day, will require innovations in management of user-supplied metadata, as well as automated data reduction and data quality analysis procedures, only some of which have yet been developed.

Progress in the Development of High-throughput Florescence Imaging...

Mon, 18 Feb 2008 16:27:56 -0600

Progress in the Development of High-throughput Florescence Imaging Using Massively Parallel Detector Arrays and Real-time Spectral Deconvolution

Targeting Single Molecule Detection Limit with Hard X-ray Microscopy

Mon, 18 Feb 2008 16:36:15 -0600

Science with Nuclear Resonance Spectroscopy at Future Sources

Wed, 20 Feb 2008 10:38:52 -0600

From the beginning of its discovery the Mössbauer effect has continued to be one of the most powerful tools with broad applications in diverse areas of science and technology. With the advent of synchrotron radiation sources such as the Advanced Photon Source (APS), the European Synchrotron Radiation Facility (ESRF) and the Super Photon Ring-8 (SPring-8), the tool has enlarged its scope and delivered new capabilities. The popular techniques most generally used in the field of materials physics, chemical physics, geoscience, and biology are hyperfine spectroscopy via elastic nuclear forward scattering (NFS), vibrational spectroscopy via nuclear inelastic scattering (NRIXS), and, to a lesser extent, diffusional dynamics from quasielastic nuclear forward scattering (QNFS). As we look ahead, new storage rings with enhanced brilliance such as PETRA-III under construction at DESY, Hamburg, and PEP-III in its early design stage at SLAC, Stanford, will provide new and unique science opportunities. In the next two decades, x-ray free-electron lasers (XFELs), based both on self-amplified spontaneous emission (SASE-XFELs) and a seed (SXFELs), with unique time structure, coherence and a 5-6 orders higher average brilliance will truly revolutionize nuclear resonance applications in a major way. This overview is intended to briefly address the unique radiation characteristics of new sources on the horizon and to provide a glimpse of scientific prospects and dreams in the nuclear resonance field from the new radiation sources. We anticipate an expanded nuclear resonance research activity with applications such as spin and phonon mapping of a single nanostructure and their assemblies, interfaces, and surfaces; spin dynamics; nonequilibrium dynamics; photochemical reactions; excited-state spectroscopy; and nonlinear phenomena.

Determining the Structure of Individual Macromolecules and Nanoparticles

Tue, 26 Feb 2008 13:44:44 -0600

Ever shattered a valuable vase into 106 pieces and tried to reassemble it under a light providing a mean photon count of 10-2 per detector pixel with shot noise? If you can do that, you can do single-molecule crystallography. This talk will outline how this can be done in principle. In more technical terms, the talk will describe how the combination of scattering physics and Bayesian algorithms can be used to reconstruct the 3-D diffracted intensity distribution from a collection of individual 2-D diffraction patterns down to a mean photon count of 10-2 per pixel, the signal level anticipated from the Linac Coherent Light Source, and hence determine the structure of individual macromolecules and nanoparticles.

Advanced Laser Development at Aculight

Tue, 26 Feb 2008 14:02:50 -0600

Science Challenges Far From Equilibrium Using Future Light Sources

Tue, 01 Apr 2008 16:32:36 -0500

X-ray Optical Devices for Imaging & Materials Science Applications

Thu, 06 Mar 2008 08:57:14 -0600

APS, ESRF, SPring-8 Three-Way Workshop

Thu, 06 Mar 2008 08:58:53 -0600

Users Week 2008 Poster Abstracts Due

Mon, 31 Mar 2008 11:12:28 -0500

Use and misuse of Rietveld R- factors

Fri, 07 Mar 2008 09:02:37 -0600

Dynamical reconstruction of the valence exciton in LiF

Tue, 11 Mar 2008 16:43:14 -0500

The absorption of light by materials proceeds through the formation of excitons, which are states in which an excited electron is bound to the valence hole it vacated. Understanding the structure and dynamics of excitons is important, for example, for developing technologies for light emitting diodes or solar energy conversion. However, there has never been an experimental means to study the time-dependent structure of excitons directly. In this talk causality-inverted inelastic x-ray scattering (IXS) is used to reconstruct the exciton in the prototype insulator LiF, with resolutions Dt = 20.67 as (2.067 x 10^-17 s) in time and Dx = 0.533 Å (5.33 x 10^-11 m) in space. The exciton has a modulated internal structure and is coherently delocalized over two unit cells of the LiF crystal (8 Å). This structure changes only modestly during the course of its life, establishing it unambiguously as a Frenkel exciton and thus amenable to a simplified theoretical description. This study resolves an old controversy about excitons in the alkali halides and demonstrates the utility of IXS for imaging electron dynamics in condensed matter.

Structural Dynamics in Bismuth and Tellurium Studied by Femtosecond X-ray Diffraction

Tue, 18 Mar 2008 13:32:02 -0500

Recent developments on the Hard X-ray Imaging Instrument and Phasing Algorithms

Thu, 20 Mar 2008 15:34:30 -0500

X-ray imaging techniques play important roles in modern science for which can provide high-resolution, element-sensitive structure information with long penetration length, in a non-destructive manner. X-ray coherent diffraction imaging technique (XCDI), taking advantage of coherence illumination delivered from 3rd generation synchrotron sources, has been growing rapidly in the recent years. XCDI is a lensless imaging technique and has potential to achieve atomic resolution, therefore it attracts more and more attentions from many different communities, from biology to material science. However, there are some difficulties in hard-x-ray CDI in both experimental and data-processing stages, for examples, avoiding parasitic scattering in the collected data and solving structure from the data with missing data caused by the beamstop. In this presentation, the developments made at APS that aim to solve these problems will be presented and discussed.

Advanced Mass Spectrometry Study of Selenium Incorporation in Yeast

Fri, 21 Mar 2008 09:13:20 -0500

Understanding the Scaling Limit of PcRAM of Chalcogenide Materials

Fri, 21 Mar 2008 10:55:12 -0500

High-Energy X-Rays, a probe for Bulk Materials and Surfaces

Tue, 25 Mar 2008 10:40:32 -0500

In addition to using high-energy x-rays to study bulk materials, the structure of surfaces and buried interfaces can also be explored. The penetrating power of high-energy x-rays permit not only bulk materials to be studied but also enables buried interfaces to be examined. Some examples will be shown that demonstrate other advantages, such as decreased scattering angles and flatter Ewald spheres, which facilitate real-time measurements.

Secrets in the Ancient Goatskin: X-Rays Reveal Archimedes' Oldest Writings

Tue, 25 Mar 2008 10:45:03 -0500

Archimedes of Syracuse (287-212 B.C.) is considered one of the most brilliant thinkers of all time. The tenth-century parchment document known as the Archimedes Palimpsest is by far the oldest surviving manuscript containing works of Archimedes. It is also the unique source for three of the Greek's treatises; the "Stomachion," "The Method of Mechanical Theorems," and the Greek version of "On Floating Bodies." The privately owned palimpsest is the subject of an integrated campaign of conservation, imaging, and scholarship being undertaken at the Walters Art Museum in Baltimore. Much of the text has been imaged by various optical techniques, but significant gaps in our knowledge ofthe writings of Archimedes remained. A breakthrough in uncovering the missing Archimedes writings was achieved at the Stanford Synchrotron Radiation Laboratory. Using x-ray fluorescence imaging, writings from faint traces of the partly erased iron gall ink were brought to light. The x-ray image revealed Archimedes writings from some of his most important works covered by twelfth-century biblical texts and twentieth-century gold forgeries. This talk will focus on the fascinating journey of a 1,OOO-year-old parchment from its origin in the Mediterranean city of Constantinople to an x-ray beamline at the Stanford Linear Accelerator Center.

Fragile Phase Stability in Ferroelectric Crystals: a Comparison of Field-Cooled Phase Diagrams

Mon, 31 Mar 2008 11:07:50 -0500

Solid solutions of (1-x)Pb(Mg_1/3Nb_2/3)-xPbTiO₃ (PMN-xPT) and (1-x)Pb(Zn_1/3Nb_2/3O₃)- xPbTiO₃ (PZN-xPT) have attracted much interests as high performance piezoelectric actuator and transducer materials. Recent x-ray and neutron diffraction studies have shown various intermediate monoclinic (M) phases that structurally ‘bridge’ the rhombohedral (R) and tetragonal (T) ones across the morphtropic phase boundary (MPB). Systematic investigations of (001) and (110) electric (E) field-temperature phase diagrams of PMN-xPT crystals have demonstrated that the phase stability of PMN-xPT crystals is quite fragile: depending not only on modest changes in E (≤0.5kV/cm), but also on the direction along which E is applied. Following the two phase diagrams, the monoclinic M_C or orthorhombic (O) phase is always observed to be associated with the T phase, whereas the monoclinic M_A or M_B phase is always observed to be associated with the R phase. These observations demonstrate the existence of an important crystallographic relationship/transformation. An alternative interpretation for the observed phase fragility is the “ferroelectric adaptive phase” model, which theorized that the monoclinic phases are miniaturized T or R nanotwins (~10nm) determined by elastic lattice accommodation under the misfit strain and electric field. Our investigations provide significant insights of how to design materials with better performance through the domain engineering and may stimulate further research interest in the x-ray diffraction of nanotwins in ferroelectrics.

Tolerancing Reflective Optics with Partially Coherent Illumination

Wed, 02 Apr 2008 11:28:27 -0500

The degree of coherence of third generation sources over the acceptance of mirrors used to manipulate X-ray beam properties is medium to large, depending on the applications. With the improvement of metrology and manufacturing techniques used by the optics industry, coherence preservation by these devices becomes possible. The traditional way of specifying mirrors deserves a second look. A simplified formalism is presented, permitting the prediction of the effects of figure errors on wavefront and intensity distributions. Applications are presented for projection imaging, KB nanofocusing and elliptical toroid. Several X-ray in situ methods measuring the wavefront distortions and resulting effects on the beam are discussed, including one involving an APS beamline and an optics manufactured by the optics group. Several reflective systems produced by the WinlightX Corporation are described.

X-ray Rotational Microrheology of Fatty Acids

Wed, 02 Apr 2008 11:31:12 -0500

Microrheology is a method of characterizing fluids by studying the motion of an embedded particle. Advances in the synthesis of new high viscosity fluids have increased the need to extend the applicability of this technique beyond currently accessable viscosities and moduli. X-rays are used to do single particle tracking of the rotational orientation of a tracer particle in fatty acids by tracking the Bragg intensity of alumina crystals in diffraction geometry. This technique allows the tracking of particles to sub-milliradian precision allowing for the determination of shear moduli in high viscosity fluids. We have observed multiple time scales of relaxation which is evidence of subdiffusive behavior.

Ultra-fast X-ray Streak Camera Development and its Application at the ALS

Wed, 09 Apr 2008 11:21:06 -0500

Resonant X-Ray Diffraction from Charge Density Waves in 1T-TaS₂

Wed, 16 Apr 2008 09:01:41 -0500

By tuning the incident x-ray energy close to the Ta-LIII edge, we studied resonant (elastic) x-ray diffraction (RXD) from the charge density waves (CDWs) of 1T-TaS2. Our goal was to separate the scattering from the periodic modulation of the conduction electron density from that of the lattice distortion wave. In addition to resonant diffraction studies, various x-ray techniques, including XANES, polarization analysis, and a temperature study, were utilized. We find that two physical effects prevent separating the CDW charge modulation scattering using energy or polarization. (i) The core-hole lifetime of the Ta-LIII resonance is much larger than the CDW band gap in 1T-TaS2 and smears out the CDW anomaly in the electronic density of states. (ii) Resonant scattering from Ta 5d band states not associated with the CDW dominate over resonant scattering from the CDW, smearing out the polarization signature. Our results highlight the principles of RXD when the technique is used to study novel states found in the conduction bands of transition metal compounds and point out which types of systems are most promising.

Deadline for Users Week 2008 Registration

Wed, 16 Apr 2008 09:02:28 -0500

APS Today

User Science Seminar resumes

Run 2008-01 Begins

Application of Computational Science for Fossil Fuel Conversion Processes with Carbon Capture

Application of Non-resonant Inelastic X-ray Scattering (NIXS) to Rare Earth Systems

Science with Nuclear Resonance Spectroscopy at Future Sources

Promotion of Tissue Ingrowth Into Synthetic Scaffolds by Transient Compressions

APS/Users Monthly Operations Meeting

Scattering curves in a Rietveld structure refinement of NaNO3 and quartz

Run 2008-2 General User Proposal Deadline

X-rays and Magnetism - A Perfect Match

The Synchrotron Light Source ANKA

Ordering of Gold Nanoparticles at the Toluene-Water Interface

NSLS-II: An Evolutionary Light Source Design

Chemical Vapor Synthesis of complex oxides and their structural characterization

High-throughput powder diffraction on 11-BM: What, How and Why

Progress in the Development of High-throughput Florescence Imaging...

Targeting Single Molecule Detection Limit with Hard X-ray Microscopy

Science with Nuclear Resonance Spectroscopy at Future Sources

Determining the Structure of Individual Macromolecules and Nanoparticles

Advanced Laser Development at Aculight

Science Challenges Far From Equilibrium Using Future Light Sources

X-ray Optical Devices for Imaging & Materials Science Applications

APS, ESRF, SPring-8 Three-Way Workshop

Users Week 2008 Poster Abstracts Due

Use and misuse of Rietveld R- factors

Dynamical reconstruction of the valence exciton in LiF

Structural Dynamics in Bismuth and Tellurium Studied by Femtosecond X-ray Diffraction

Recent developments on the Hard X-ray Imaging Instrument and Phasing Algorithms

Advanced Mass Spectrometry Study of Selenium Incorporation in Yeast

Understanding the Scaling Limit of PcRAM of Chalcogenide Materials

High-Energy X-Rays, a probe for Bulk Materials and Surfaces

Secrets in the Ancient Goatskin: X-Rays Reveal Archimedes' Oldest Writings

Fragile Phase Stability in Ferroelectric Crystals: a Comparison of Field-Cooled Phase Diagrams

Tolerancing Reflective Optics with Partially Coherent Illumination

X-ray Rotational Microrheology of Fatty Acids

Ultra-fast X-ray Streak Camera Development and its Application at the ALS

Resonant X-Ray Diffraction from Charge Density Waves in 1T-TaS2

Deadline for Users Week 2008 Registration

Scattering curves in a Rietveld structure refinement of NaNO₃ and quartz

Resonant X-Ray Diffraction from Charge Density Waves in 1T-TaS₂