APS Today: Archives beta

September 2008

Oct 31
Friday
Oct 20
Monday
Sep 26
Friday

User Science Seminar

APS Seminar
401/A1100 @ 12:00 PM
Sep 24
Wednesday

APS/Users Operations Monthly Meeting

APS Meeting
402/AUD @ 2:30 PM
Sep 19
Friday

User Science Seminar

APS Seminar
401/A1100 @ 12:00 PM
Sep 15
Monday

Structural Diversity in High Pressure Bi(M'1/2M''1/2)O3 Perovskites

Speaker: Matthew Suchomel, University of Liverpool, UK
XSD Presentation
431/C010 @ 10:30 AM
View Description
Recent interest in Bi-based perovskite oxides is motivated by intriguing predictions of multiferroic coupling in Bi-based oxide systems and by the possibility of replacing Pb-containing ferroelectrics with Bi analogues. The electronicconfiguration of the Bi3+ cation is similar to that of Pb2+ , and promotes polar structural distortions; while the flexibility of the trivalent M site in the A/M/O3 perovskite structure allows for a wide range of transition metal cations chemistries that may promote magnetic and/or ferroelectric responses. In this talk I report on our recent work using high pressure, high temperature solid state methods to synthesize novel Bi-based perovskite oxide compounds. This high pressure synthetic approach provides access to many new meta-stable structures which cannot be realized under ambient pressure conditions. The focus of this work is primarily on systems of the general formula Bi(M`1/2 M``1/2)O3 , where M` and M`` are 2+, 3+, and 4+ transition metal cations. Several compounds with unanticipated structures have been identified in the course of this work; including the extremely tetragonally distorted Bi(Zn1/2 Ti1/2)O3 and Bi(Co1/2 V1/2)O3. The physical properties of these new compounds will be reported and discussed. Based on these new examples and previously known Bi-based perovskite compounds, connections can be made between the B site cation chemistry, the observed structural distortions, and the resulting physical properties in these systems.
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Sep 12
Friday

User Science Seminar

APS Seminar
401/A1100 @ 12:00 PM
Sep 10
Wednesday

miniXS: A Cheaper, Smaller, and Sometimes Better High- resolution X-ray Spectrometer

Speaker: Professor Jerry Seidler, University of Washington
XSD Seminar
401/A1100 @ 11:00 AM
View Description
The use of high-resolution sources and spectrometers allows several important benefits compared to traditional broad-band detection methods in x-ray absorption spectroscopies (XAS) and related techniques. These include the suppression of spectral broadening due to the core-hole lifetime, the ability to resolve spin-dependent contributions in the near-edge structure, and the general enrichment of RIXS or resonant XES measurements. The recent discovery of ‘dispersion compensation’ by Houtari, /et al./, (Journ.Synch.Rad. 2005, Rev.Sci.Instrum. 2006) removes many long-standing roadblocks to the wider application of these methods. In this lecture, I will present an alternative but related route for improved x-ray spectrometer design when a focused beam with spot size of a few tens of microns or less is available. Recent measurements at the 20-ID microprobe endstation find that a prototype miniature x-ray spectrometer (miniXS) based on the new design strategy is competitive with the latest high-resolution apparatus based on traditional designs – despite costing three to four orders of magnitude less to construct and being much easier to assemble, align, and operate. Future applications to f-electron, nanoscale, and high-pressure studies will be discussed, as will straightforward miniXS design recipes suitable for many studies at APS.
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Sep 5
Friday

User Science Seminar

APS Seminar
401/A1100 @ 12:00 PM
Sep 3
Wednesday

New Composite Thermoelectric Materials for Macro-size Applications

Speaker: Mildred (Millie) Dresselhaus
APS Colloquium
402/AUD @ 3:00 PM
View Description
A review will be given of several important recent advances in both thermoelectrics research and industrial thermoelectric applications, which have attracted much attention, increasing incentives for developing advanced materials appropriate for large-scale applications of thermoelectric devices. One promising strategy is the development of materials with a dense packing of random nanostructures as a route for the scale-up of thermoelectrics applications. The concepts involved in designing composite materials containing nanostructures for thermoelectric applications will be discussed in general terms. Specific application is made to the Bi2Te3 nanocomposite system for use in power generation. Also emphasized are the scientific advantages of the nanocomposite approach for the simultaneous increase in the power factor and decrease of the thermal conductivity, along with the practical advantages of having bulk samples for property measurements and device applications. A straightforward path is identified for the scale-up of thermoelectric materials synthesis containing nanostructured constituents for use in thermoelectric applications. We end with some vision of where the field of thermoelectrics is now heading.
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August 2008

Aug 29
Friday

Developments of the Next Generation of Superconducting Undulators: Induction Shimming and Beam Heat Load Reduction

Speaker: Robert Rossmanith from Research Center Karlsruhe, Germany
APS Seminar
401/C4200 @ 9:30 AM
Aug 27
Wednesday

APS Users/Operations Monthly Meeting

APS Meeting
402/AUD @ 2:30 PM
Aug 27
Wednesday

Design and Fabrication of Crystal Analyzers for Inelastic Scattering Experiments

Speaker: Dr. Ayman Said, XOR-IXN
XSD Discussion
433/C010 @ 12:00 PM
View Description
Dr. Ayman Said, XOR-IXN, will give an introductory presentation on analyzers for the HERIX instrument in Sector 30. The floor will then be open for discussion of issues surrounding crystal analyzer in inelastic x-ray scattering experimentation. Pizza and Cold Drinks will be provided.
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Aug 26
Tuesday

X-ray Spectromicroscopy of Bacterial Interactions in the Environment

Speaker: Bjorg Larson, Dept. of Physics and Astronomy, Stony Brook University
XSD Presentation
431/C010 @ 10:00 AM
Aug 12
Tuesday

Process Technology and Food Science Research at Frito-Lay

Speaker: Dr. Ted Farrington, Director, Process Technology Research Center
Dr. Jung Han, Senior Process Engineer
Frito-Lay Research & Development, Frito Lay North America
XSD Seminar
401/A1100 @ 11:00 AM
View Description
Ted Farrington will give an overview of the global PepsiCo organization of which Frito-Lay North America (FLNA) is a division. Within FLNA R&D he is building a Process Technology Research Center to develop new technology for the processing of healthy snack foods from fruits, vegetables, legumes, etc. Collaborative research is underway at government labs, universities and other companies around the world on alternatives to frying and other high temperature processes. He will also describe previous work he has done at DOE labs in the imaging area. Jung Han will introduce the goal, mission and activities of PepsiCo Fruit and Vegetable Research Center which was established in 2006 for the purpose of advancing PepsiCos health and wellness initiatives by providing knowledge on fruits and vegetables that would permit year round manufacturing of value-added, convenient and healthful food products.
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Aug 8
Friday

User Science Seminar

APS Seminar
401/A1100 @ 12:00 PM

July 2008

Jul 29
Tuesday

Photon-assisted Electron Energy Loss Spectroscopy and Ultra-fast Microscopy

Speaker: Professor Archie Howie, Cambridge, UK
APS Presentation
401/A1100 @ 10:30 AM
View Description
Photons are superior to electrons for microscopy except at highest spatial resolution. For ancillary spectroscopy they also cover an enormous energy range with great precision and selectivity in excitation. Highly coherent photon beams with sufficient intensity can also exploit Raman spectroscopy and non-linear interactions such as multi-photon excitation and sum-difference spectroscopy. Thanks to the tip field-enhancement effect, it has been possible in scanned probe microscopy to combine the spectral advantages of photons with the superior spatial resolution provided by electrons. Some of these developments will be described as well as the more tentative steps so far taken or in progress to extend this partnership to still better spatial resolution by making use of photon interactions in SEM, TEM or STEM. The ready availability of femto-second scale photon pulses at MHz rates is also opening up new doors in ultra-fast microscopy. These can be used for example in two-photon PEEM to make movies of surface plasmon generation. Very sharp electron pulses for various forms of pump-probe imaging can be obtained by splitting these pulse trains with part going to trigger a photo-cathode and part going to the sample. In TEM operations, this procedure has yielded not only impressive TEM images at 15 nm resolution with large numbers of electrons in a single 1.5 nanosecond pulse but also images obtained by accumulating repeated single electron pulses and reaching a spatial resolution of 1.5nm with timing in the picosecond range. Finally, if time permits, a less positive possible role of photons in contributing to quantum decoherence in the electron microscope and hence to the Stobbs’ factor may be outlined.
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Jul 28
Monday

Biological Interaction of Nanomaterials: Toxicity Issues

Speaker: Dr. Saber Hussain, Applied Biotechnology, Air Force Research Laboratory, Wright Patterson Air Force Base
XSD Seminar
401/B2100 @ 11:00 AM
Jul 23
Wednesday

APS/User Operations Monthly Meeting

APS Meeting
402/AUD @ 2:30 PM
Jul 18
Friday

User Science Seminar

APS Seminar
401/A1100 @ 12:00 PM
Jul 14
Monday

Using Resonant Inelastic X-ray Scattering (RIXS) to study electron-lattice interactions in Manganites

Speaker: Diego Casa, APS
XSD Seminar
401/A1100 @ 1:30 PM
Jul 11
Friday

User Science Seminar

APS Seminar
401/A1100 @ 12:00 PM
Jul 8
Tuesday

Application of Ultrafast Lasers in Accelerators at APS

Speaker: Yuelin Li
XSD Seminar
432/C010 @ 2:00 PM
View Description
In recent years, marriage between lasers and accelerators becomes one of the most fruitful R&D areas in accelerator research aiming at the next generation light sources.A review of application of ultrafast laser to accelerators is given, including measurement of FELs, theoretical schemes of generating ultrafast of x-ray, gamma ray, and positron sources, THz generation, spatiotemporal laser pulse shaping for photoinjector drive lasers, and simulation of laser wake field accelerators.
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Jul 8
Tuesday

X-ray Imaging: Filling in a Larger Puzzle

Speaker: Chris Jacobsen, Dept. Physics and Astronomy, Stony Brook University
XSD Seminar
440/A105 @ 11:00 AM
View Description
The natural world does not consist solely of uniform thin films; instead, nanoscale variations in chemistry and structure are the norm. As a result, the power of traditional synchrotron analysis methods including spectroscopy and diffraction can be dramatically extended by combining them with x-ray imaging techniques to gain new insights into the complexities of nature. At the same time, exciting new capabilities are emerging in electron microscopy. Exploiting these new possibilities demands that he right approach be used for the right problem, that the sample be made maximally tolerant of detailed investigation (such as through the use of cryo methods), and that the full complexity of data can be understood and exploited. Examples in x-ray spectromicroscopy, phase contrast imaging, and coherent lensless imaging will be shown to illustrate these larger goals.
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Jul 2
Wednesday

X-ray Compton Imaging

Speaker: Joseph Callerame
APS Colloquium
402/AUD @ 3:00 PM
View Description
Homeland security issues have broadened the applications of x-ray imagery from drug and contraband detection to detection of improvised explosive devices and high-atomic-number materials in cargo containers. Depending on the nature of the threat, either transmission or Compton backscatter X-ray Imagery may be used for detection. Imaging techniques based on Compton backscattered x-rays permit inspection and screening of sea containers, a wide variety of vehicles, luggage, and even people. In contrast to more commonly used transmission images, backscatter imaging requires positioning both source and detection apparatus on only one side of a target object, presenting inspection opportunities in situations that may be extremely difficult, If not impossible, for transmission systems. The backscatter image is akin to a photograph of the contents of a closed container taken through the container walls; objects composed of organic materials, including explosives and drugs, appear particularly bright and are easily detectable. The method used in scanning the target object results in an extremely low radiation dose, which significantly broadens the application spectrum for this technique. Techniques for producing x-ray images based on Compton scattering will be discussed, along with wide-ranging examples of how systems based on these principles are used to perform inspections for security applications and for detection of contraband materials at ports and borders.
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Jul 1
Tuesday

X-ray Detector Development at BNL

Speaker: D. Peter Siddons, Brookhaven National Laboratory
XSD Forum
401/A1100 @ 1:30 PM
View Description
The talk will describe a range of x-ray detector developments that are ongoing at BNL, including 1D and 2D devices for diffraction and scattering, and spectroscopic applications.
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June 2008

Jun 28
Saturday

Small-Angle Scattering Short Course

APS Course
View Description
The objective of the Small-Angle Scattering Short Course 2008 is to raise the capabilities of the small-angle scattering (SAS) community by providing an intermediate-level course for those in need of a better understanding of SAS theory, and techniques utilized at the APS. The SAS short course offers an overview of SAS theory, capabilities, and data reduction and analysis tools to enable the community to submit highly effective beam-time proposals and to facilitate better utilization of the resources at the APS.
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Jun 25
Wednesday

Navigating IT at the APS

APS Workshop
401/A1100 @ 1:30 PM
View Description
The goal of this workshop is to provide new APS users with information needed to make effective use of computing and networking at the APS. This workshop will present a current snapshot of the APS IT environment, provide tips for keeping up to date with this dynamic environment and where to find and obtain IT assistance. The presentation will be demonstration based with questions addressed throughout the workshop. Computing topics to include: user accounts, password resets, IT services, such as email, calendar, printing, and Argonne/DOE cyber security policies Networking topics to include: firewalls, wired and wireless networking, spam filtering, and remote access The workshop is directed toward users who have joined the APS in the past year, however any user may benefit from the content. Slides will be made available in ICMS, with a link from the APS Intranet, following the presentation. No registration required.
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Jun 23
Monday

Understanding Condensed Matter Dynamics at the Microscopic Level

APS Workshop
View Description
Understanding material behavior under extreme conditions is central to modern materials research, as highlighted in a recent DOE workshop on "Basic Research Needs for Materials under Extreme Environments" (June, 2007, Washington D.C., http://www.sc.doe.gov/bes/reports/list.html.) Over the past decade or two, a large number of new materials and novel phenomena have been discovered and predicted at extreme conditions, paralleling advancements in high-pressure technologies, the nation's large-scale experimental user facilities, condensed matter theories, and high-performance computers. Yet, because of the single event and destructive nature of the experiments, gaining microscopic insights into dynamic materials response has been a significant scientific challenge, despite unprecedented scientific opportunities for mechanistic understanding of material phenomena in short time and length scales.
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Jun 17
Tuesday

A CW Normal-Conductive RF Gun For Free Electron Laser and Energy Recovery Linac Applications

Speaker: Fernando Sannibale (LBNL)
APS Seminar
401/B4100 @ 1:30 PM
Jun 17
Tuesday

Radiation Worker 1 Training

APS Course
402/E1100 @ 9:00 AM
View Description
Live Rad Worker 1 course given by the Laboratory at APS. Please enroll with your TMS Representative as soon as possible.
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Jun 16
Monday

Mass and Wavelength Standards: Metrology with X-ray Interferometry, Status Report

Speaker: Peter Becker (Physikalisch-Technische Bundesanstalt, Braunschweig, Germany)
APS Seminar
401/A1100 @ 1:30 PM
Jun 16
Monday

Radiation Worker 1 Training

APS Course
402/E1100 @ 1:00 PM
View Description
Live Rad Worker 1 course given by the Laboratory at APS. Please enroll with your TMS Representative as soon as possible.
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Jun 16
Monday

New Rigid Body Constraints in GSAS - Life with Quaternions

Speaker: Robert VonDreele
APS Discussion
433/C010 @ 12:00 PM
View Description
Powder Diffraction Study Group discussion
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Jun 13
Friday

Radiation Worker 1 Training

APS Course
402/E1100 @ 9:00 AM
View Description
Live Rad Worker 1 course given by the Laboratory at APS. Please enroll with your TMS Representative as soon as possible.
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Jun 12
Thursday

Origin Pro Tutorial

Speaker: Scott Plotkin, Origin Labs
APS Presentation
431/C010 @ 10:00 AM
View Description
Question and answer period after tutorial
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Jun 9
Monday

Chirality in Dy/Y Multilayers Studied by Neutron Reflectometry

Speaker: Dieter Lott
XSD Presentation
431/C010 @ 11:00 AM
Jun 6
Friday

SUF ISM Day

APS Presentation
402/AUD @ 10:30 AM
Jun 4
Wednesday

Biomedical Imaging with Partially Coherent, Laser-Driven Plasma X-Ray Sources

Speaker: Christoph Rose-Petruck , Brown University
APS Colloquium
402/AUD @ 3:00 PM

May 2008

May 31
Saturday

High-Resolution Inelastic X-ray Scattering on Earth Materials using Synchrotron Radiation

APS Workshop
View Description
This two-day workshop is organized within the COMPRES infrastructure development initiative, which is aimed at creating state-of-the-art high-resolution inelastic x-ray scattering (IXS) techniques for characterizing the properties of materials under the high-P-T conditions of planetary interiors.
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May 28
Wednesday

Re-Examination of the Slow Mode in Semidilute Solutions

Speaker: Chi Wu, Professor of Chemistry, The Chinese University of Hong Kong
XSD Seminar
432/C010 @ 11:00 AM
View Description
Semidilute solutions are characterized by the overlapping of linear polymer chains with each other. Dynamics of semidilute solutions has been well described by the Brownian motion of monomer units (“blob”) between two neighboring entanglement points and the reptation of the entire chain in a “tube” made of other surrounding chains. In the past, many dynamic laser light-scattering (LLS) measurements showed that besides the fast relaxation related to the “blobs”, there exists an additional slow relaxation mode. In the earlier time, such a slow mode was wrongly identified as the reptation. LLS cannot distinguish one chain from another in a semidilute solution so that it cannot observe the chain reptation. Later, this slow mode was attributed to possible problems in the sample preparation, such as dust particles or a concentration gradient. Whether this slow mode is real has remained a challenging problem since 80’s. To avoid these potential problems, we used different un-conventional ways, instead of a simple increase of polymer concentration, to induce an in situ dilute-semidilute transition. These methods include the temperature-induced coil-to-globule transition of long polystyrene chains, in situ high-vacuum anionic polymerization of styrene in cyclohexane, and in situ RAFT living bulk polymerization of methyl methacrylate. Our results confirm that this slow mode is real with no ambiguity and showed that it appears whenever the solvent quality becomes less good. Our study leads to a fundamental question whether semidilute solutions are “homogeneous” as stated in textbooks and previous theories. By considering that the segments or monomer units near the entanglement points are different from those in the middle between two neighboring entanglement points; namely, semidilute solutions are “inhomogeneous”, we can satisfactorily explain the existence of the two modes.
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May 9
Friday

Short Pulse X-rays at the APS

APS Workshop
401/A5000 @ 8:45 AM
May 4
Sunday

Users Week 2008 Begins

APS Meeting
401/ATRIUM @ 11:00 AM

April 2008

Apr 30
Wednesday

Users/Operations Monthly Meeting

APS Meeting
402/AUD @ 2:30 PM
Apr 30
Wednesday

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

Speaker: Jun Feng, Advanced Light Source, Berkeley National Laboratory, CA
XSD Seminar
401/A1100 @ 10:00 AM
Apr 25
Friday
Apr 21
Monday

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

Speaker: Jun-Dar Su, School of Applied & Engineering Physics
XSD Seminar
432/C010 @ 11:00 AM
View Description
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.
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Apr 14
Monday

Tolerancing Reflective Optics with Partially Coherent Illumination

Speaker: Olivier Hignette, Chief Technical Officer, WinlightX Corporation, France
XSD Presentation
401/B4100 @ 3:30 PM
View Description
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.
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Apr 4
Friday
Apr 3
Thursday

X-ray Rotational Microrheology of Fatty Acids

Speaker: Mengning Liang, UIUC
XSD Presentation
401/B4100 @ 2:00 PM
View Description
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.
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Apr 3
Thursday

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

Speaker: John Scott Okasinski, Max-Planck-Institut für Metallforschung, Stuttgart, Germany
XSD Presentation
401/B4100 @ 11:00 AM
View Description
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.
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Apr 2
Wednesday

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

Speaker: Uwe Bergmann, SLAC
APS Colloquium
402/AUD @ 3:00 PM
View Description
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 Greeks 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.
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Apr 1
Tuesday

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

Speaker: Hu Cao, Virginia Tech, Blacksburg, VA
XSD Presentation
431/C010 @ 11:00 AM
View Description
Solid solutions of (1-x)Pb(Mg1/3Nb2/3)-xPbTiO3 (PMN-xPT) and (1-x)Pb(Zn1/3Nb2/3O3)- 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 MC or orthorhombic (O) phase is always observed to be associated with the T phase, whereas the monoclinic MA or MB 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.
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March 2008

Mar 25
Tuesday

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

Speaker: Xianghui Xiao
APS Conference
401/B4100 @ 2:00 PM
View Description
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.
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Mar 25
Tuesday

Advanced Mass Spectrometry Study of Selenium Incorporation in Yeast

Speaker: Dr. Zoltan Mester, Institute of National Measurement Standards, National Research Council
XSD Presentation
438/C010 @ 1:00 PM
Mar 25
Tuesday

X-ray Optical Devices for Imaging & Materials Science Applications

Speaker: Marcello Honnicke, Universidade Federal do Parana, Curitiba Brazil
XSD Seminar
401/B4100 @ 10:00 AM
Mar 24
Monday

Understanding the Scaling Limit of PcRAM of Chalcogenide Materials

Speaker: Ya-Hong Xie, Dept. of Materials Science & Engineering, UCLA
XSD Presentation
402/E1100 @ 2:00 PM
Mar 21
Friday

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

Speaker: Steven Johnson, Swiss Light Source, Paul Scherrer Institut
XSD Seminar
432/C010 @ 1:30 PM
Mar 19
Wednesday

Dynamical reconstruction of the valence exciton in LiF

Speaker: Professor Peter Abbamonte, University of Illinois at Urbana/Champaign
XSD Forum
433/C010 @ 12:00 PM
View Description
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.
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Mar 17
Monday

APS, ESRF, SPring-8 Three-Way Workshop

APS Workshop
402/AUD @ 5:00 PM
Mar 10
Monday

Use and misuse of Rietveld R- factors

Speaker: Brian H. Toby, Argonne National Laboratory
XSD Discussion
433/C010 @ 12:00 PM
Mar 5
Wednesday

Determining the Structure of Individual Macromolecules and Nanoparticles

Speaker: Abbas Ourmazd
APS Colloquium
402/AUD @ 3:00 PM
View Description
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.
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Mar 5
Wednesday

Science with Nuclear Resonance Spectroscopy at Future Sources

Speaker: Gopal Shenoy, APS/XSD
XSD Seminar
401/A1100 @ 10:00 AM
View Description
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.
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Mar 4
Tuesday

Science Challenges Far From Equilibrium Using Future Light Sources

Speaker: Gopal Shenoy
XSD Seminar
431/C010 @ 10:30 AM

February 2008

Feb 28
Thursday

Advanced Laser Development at Aculight

Speaker: Andrew Brown, Aculight Corporation
APS Seminar
401/B4100 @ 3:30 PM
Feb 26
Tuesday

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

Speaker: Brian Toby, XSD/Materials Characterization
XSD Seminar
401/A1100 @ 10:00 AM
View Description
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.
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Feb 22
Friday

Ordering of Gold Nanoparticles at the Toluene-Water Interface

Speaker: Professor Milan K. Sanyal, Saha Institute of Nuclear Physics
XSD Seminar
401/A1100 @ 3:00 PM
View Description
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.
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Feb 22
Friday

Chemical Vapor Synthesis of complex oxides and their structural characterization

Speaker: Dr. Markus Winterer, University Duisburg-Essen
XSD Seminar
433/C010 @ 2:00 PM
View Description
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.
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Feb 22
Friday

NSLS-II: An Evolutionary Light Source Design

Speaker: Steve Kramer (NSLS, BNL)
APS Seminar
401/B2100 @ 1:30 PM
View Description
Beams and Applications Seminar Series
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Feb 20
Wednesday

Targeting Single Molecule Detection Limit with Hard X-ray Microscopy

Speaker: Professor Yeukuang Hwu, Academia Sinica, Taiwan
XSD Seminar
401/A1100 @ 2:00 PM
Feb 20
Wednesday

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

Speaker: Dr. Chris Ryan, CSIRO
XSD Seminar
431/C010 @ 11:00 AM
View Description
Progress in the Development of High-throughput Florescence Imaging Using Massively Parallel Detector Arrays and Real-time Spectral Deconvolution
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Feb 15
Friday

The Synchrotron Light Source ANKA

Speaker: Professor Tilo Baumbach, Institute for Synchrotron Radiation, Research Centre Karlsruhe / K.I.T.
XSD Seminar
431/C010 @ 2:00 PM
Feb 5
Tuesday

X-rays and Magnetism - A Perfect Match

Speaker: Dr. Hendrik Ohldag, Stanford Synchrotron Radiation Laboratory
XSD Seminar
431/C010 @ 11:00 AM

January 2008

Jan 29
Tuesday

Run 2008-01 Begins

APS Operations
Jan 28
Monday

Scattering curves in a Rietveld structure refinement of NaNO3 and quartz

XSD Discussion
433/C010 @ 12:00 PM
Jan 23
Wednesday

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

Speaker: Robert A. Gordon, Simon Fraser University
XSD Forum
430/C010 @ 2:00 PM
View Description
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.
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Jan 16
Wednesday

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

Speaker: Anthony Cugini, DOE/NETL
XSD Seminar
205/Y-AUD @ 11:00 AM
View Description
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.
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Jan 16
Wednesday

Science with Nuclear Resonance Spectroscopy at Future Sources

Speaker: Gopal Shenoy
XSD Seminar
401/A1100 @ 11:00 AM
View Description
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.
[ Hide ]
Jan 16
Wednesday

Promotion of Tissue Ingrowth Into Synthetic Scaffolds by Transient Compressions

Speaker: Dr. Erik Ritman, Mayo Clinic, Dept. of Physiology and Biophysics
XSD Seminar
431/C010 @ 11:00 AM
Jan 1
Tuesday

User Science Seminar resumes

APS Seminar
401/A1100 @ 12:00 PM