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X-RAY RUNS: Apply for Beamtime

2017  Nov 1 - Dec 21

2018  Feb 7 - Apr 3
2018  Proposal/BTR deadline: 12/1/17

2018  Apr 11 - Jun 4
2018  Proposal/BTR deadline: 2/1/18

Jan 20 - Etienne Forest, KEK
Jan 27 - Darby Harris, Cornell

Feb 3 - David Schuller, Cornell
Feb 17 - Dr. Julian Becker, DESY

March 1 - Dimitre Dimitrov, Tech-X
March 16 - Alex Deyheim, ADC

April 6 - He Zhang - Michigan State University
April 13 - Konstantin Lekomtsev - Royal Holloway, University of London
April 27 - Fareh Pei-Jen Lin, Old Dominion University

May 2 - Dr. Pamela Whitfield, National Research Council Canada
May 9 - Jun-Sang Park, Cornell University
May 23 - Jacob Ruff, Argonne National Laboratory
May 24 - Steven Herron, Brigham Young University
May 29 - Thomas Roth, ESRF

June 1 - Kenneth Evans-Lutterodt - BNL
June 11 - Zhenxing Feng - MIT
June 25 - John Thornton, HiFIRE, Australia
June 26 - Ruipeng Li, King Abdullah University of Science and Technology

July 9 - Zou Finfrock, University of Washington
July 13 - Ken Finkelstein, Cornell University
July 31 - Miles Beaux, Los Alamos National Laboratory

Aug 13 - Matthew Ward, The University of Western Ontario
Aug 16 - Dwayne Miller, University of Hamburg & University of Toronto
Aug 21 - Margaret Koker, Max Planck Institute for Intelligent Systems
Aug 24 - Puneet Jain, SUNY Stonybrook

Oct 10 - Pietro Musumeci, UCLA
Oct 12 - Simon Billinge, Columbia University & BNL
Oct 15 - James Holton, Lawrence Berkeley National Laboratory
Oct 19 - Chris Ryan, CSIRO
Oct 26 - Pierre Gourdain, Cornell University    NOTE: Location

Nov 2 - Adam Bogdanove, Cornell University
Nov 11 - Unavailable
Nov 16 - Tiit Lukk, University of Illinois at Urbana-Champaign
Nov 19 - Bernhard Adams, Argonne National Laboratory    NOTE: Day
Nov 30 - Ulrich Lienert, DESY

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Friday, Nov 30, 2012

Ulrich Lienert
DESY, Germany

 

"The Swedish High-Energy Materials Science Beamline at the PETRA III Extension"

Abstract:  The PETRA storage ring at DESY has been modified to serve as a dedicated high-energy synchrotron facility with the presently lowest emittance. A first set of beamlines has been commissioned at the PETRA III facility and two extensions are planned to accommodate experimental techniques that were available at the recently shut-down DORIS facility. The project will be described with particular focus on a high-energy materials science beamline funded by a Swedish consortium. Novel optical concepts will be presented to address challenges for the optics arising from the unique beamline layout. Finally, some future developments of high-energy diffraction microscopy, looking at diffraction from individual grains within polycrystalline materials, will be presented.

 

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****NOTE: Day****

Monday, Nov 19, 2012

Bernhard Adams
Argonne National Laboratory

 

"The Hard X-ray Streak Camera at the Advanced Photon Source"

Abstract:  The combination of picosecond time resolution and sub-nanometer spatial resolution is a powerful tool to elucidate the elementary processes of chemistry and condensed-matter physics. The very fastest coherent electron dynamics take place at time scales of a few femtoseconds, and can thus only be addressed with free-electron lasers. However, incoherent electron dynamics and vibrational processes take place on the 100-fs to few-ps scale. Often a one or two ps time resolution is necessary and sufficient to distinguish from the next level of larger-scale conformational dynamics, taking place on the 100-ps time scales and longer. The native time resolution of synchrotron-radiation facilities is insufficient for study of few-ps processes, and currently an x-ray streak camera is required.

The talk will present the hard-x-ray streak-camera program at the Advanced Photon Source and will showcase a few experimental examples. In particular we discuss cooperative molecular dynamics in the photoexcitation of iron pentacarbonyl ( Fe(CO)_5 ) that occur within a few ps.

Important to the success of the program was not only the streak camera itself (with 1-2 ps time resolution it is hardly the world's fastest), but also the supporting infrastructure of optimized beamline optics, pre-adjusted and rapidly interchangeable setups, laser, x-ray chopper, etc.

The program is still undergoing rapid evolution: we recently replaced the photoconductive switch that is commonly used to generate the deflection voltage with power-RF electronics to reduce the timing jitter and run the streak camera at repetition rates up to 88 MHz, i.e., far beyond the capabilities of a drive laser for the photoconductive switch. Future plans include operation with grazing incidence on the photocathode for higher photon efficiency, improved electron optics, and upgrades to the beamline x-ray optics.

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Friday, Nov 16, 2012

Tiit Lukk
University of Illinois at Urbana-Champaign

 

"Structure Guided Enzymology: Advances in the enolase superfamily"

 

 

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Friday, Nov 2, 2012

Adam Bogdanove
Plant Pathology and Plant-Microbe Biology, Cornell University

 

"Structure, Function, and Utility of the Programmable, DNA Binding Family of TAL Effector Proteins"

Abstract:  Transcription activator-like (TAL) effectors, from the plant pathogenic bacterial genus Xanthomonas, are DNA binding proteins that can be readily engineered to target novel sequences. The TAL effector’s central repeat region determines DNA binding specificity, with distinct polymorphic residues in each repeat encoding a single binding site nucleotide. Custom TAL effectors can be targeted to a specific sequence by assembling a repeat array with the corresponding sequence of polymorphisms. Therefore, TAL effector-based custom transcription factors and targeted endonucleases have become important tools for systems biology and genome engineering. Degeneracy in the TAL repeat-nucleotide specificity code as well as recently revealed differences among apparent affinities of different repeat-nucleotide interactions affect both the efficiency of design and the effectiveness of target prediction. We present results of structural and functional studies that shed light on these variables and help to refine the code. We are incorporating these findings into our popular web-based suite of computational tools for design of TAL effectors, TAL effector nucleases, and other TAL effector-based proteins, and prediction of target and off-target sites, which will also be reviewed.

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****NOTE: LOCATION****

Friday, Oct 26, 2012
374 Wilson Lab

Pierre Gourdain
Cornell University

 

 

 

"Diagnosing Warm Dense Matter using the ERL-injector Beam"

Abstract:  Warm dense matter (WDM) is a state of matter that is at the confluence between the condensed matter and plasma states. In this regime, plasma densities are close to that of a solid while temperatures vary from 0.1 to 100 eV or even higher, making WDM not only a strongly coupled but also, at the lower temperatures, a mostly degenerate state. Due to the rich interplay between both states and the difficulty of making measurements, WDM is one of the most exciting topics of high energy density physics (HEDP). At Cornell, the Laboratory of Plasma Studies routinely produces WDM using pulsed power machines to drive radial foil configurations (p ~ 0.1 Mbar), exploding wires and X-pinches (p ~ 1 Mbar). After presenting the experimental setup and basic physical properties of these plasmas, the talk will focus on how the Cornell ERL injector beam facility might be used to diagnose WDM produced by our pulsed power generators

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Friday, Oct 19, 2012

Chris Ryan
CSIRO - Commonwealth Scientific and Industrial Research Organization, Australia

Presentation:  pdf  (login required)

 

 

"Maia X-ray Fluorescence Imaging: quantitative trace element mapping at megapixels per hour"

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****NOTE: Day****

Monday, Oct 15, 2012

James Holton
Biochemistry and Biophysics
Lawrence Berkeley National Laboratory

 

 

"The battle of Signal vs. Noise
and how to tip the balance in your favor"

Abstract:  The success or failure of any crystal structure determination effort is dictated by the signal-to-noise ratio, so quantitative predictors of the both signal and noise on an absolute scale are needed for designing effective data collection strategies.  There are three main classes of noise in the diffraction experiment: photon-counting error or “shot noise” which is proportional to the square root of the signal, noise that is independent of the signal such as detector read-out noise, and “fractional noise” that is proportional to the signal.  This last class of error has many sources, including shutter jitter, incident beam flicker, sample vibration, detector calibration, and systematic errors such as the uncertainty in absorption correction factors and the uncorrectable “non-isomorphism” component of radiation damage.  Procedures for independently measuring all these sources of error on a given instrument are described, and it was found that the dominant source of error in measurements of weak spots is the background-scattered photons that fall into the spot area, but the dominant source of error for anomalous difference measurements is fractional noise, which is usually 2-3%.  Which of the many sources of fractional noise is most important depends on the particular experiment, and strategies for identifying and reducing the contribution of fractional noise will be discussed.

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Friday, Oct 12, 2012

Simon Billinge
Columbia University and Brookhaven National Lab

Presentation:  pdf  (login required)

 

"Atomic Structure at the Nanoscale: from fuel cells to pharmaceuticals"

Abstract:  Many modern materials under study for technologies from energy to the environment to health, are highly complex, often heterogeneous and nano structured. A full understanding of the structure requires us to go beyond crystallography and to study the local structure, which is a major experimental challenge. I will describe recent experimental developments using the atomic pair distribution function technique (PDF) giving examples from nanoscale energy materials to pharmaceutical drugs.

I will describe our efforts to improve the methodology from developments of fast data analysis, improved modeling and new experimental approaches such as obtaining ePDFs from electron diffraction data from regular laboratory electron microscopes. I will illustrate the power of these methods with scientific examples from energy materials and pharmaceuticals.

 

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****NOTE: Day & Time****

Wednesday, Oct 10, 2012
2:00 pm

Pietro Musumeci
UCLA

 

"The Development of Relativistic Ultrafast Electron Diffraction: using particle accelerators to watch atoms move in real time"

Abstract:  In this talk, I’ll present the development of a novel technique based on the use of high brightness relativistic beams from RF photoinjectors to study ultrafast structural dynamics with sub-100 fs temporal resolution. Using electron beams of relativistic energies to minimize the space charge induced pulse-lengthening, it is possible to obtain sub-100 fs bunches containing more than 10 millions electrons. These beams are intense enough to capture in a single diffraction pattern the structural information of a sample, allowing an unprecedented time resolution and enabling the study of irreversible ultrafast phenomena with single shot diffraction patterns. I’ll discuss the advances in accelerator technology and beam physics that made possible this technique, the first experiments carried out at the UCLA Pegasus Laboratory, and the future science possibilities opened by the unique characteristics of this novel source.

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Friday, Aug 24, 2012

Puneet Jain
SUNT Stonybrook

"Studies on 704 MHz Five-cell Superconducting RF Cavity"

Abstract:  Brookhaven National Laboratory is developing SRF technology for high current beams. One element of this program is a five-cell 704 MHz beta=1 cavity which is highly damped. Such a cavity can operate in Energy Recovery Linac at high currents, typically hundreds of milli-amperes. This cavity will be installed in the coherent electron cooler of Relativistic Heavy Ion Collider (RHIC) and a future electron-ion collider (eRHIC). My research at BNL has focused on the studies related to a 704 MHz five-cell superconducting RF accelerating cavity. In order to achieve the optimum performance of the cavity, it is essential to damp the unwanted higher order modes (HOMs) and microphonics. In my talk, I will present the identification and characterization of the undamped higher order modes (HOMs) using bead pull technique and the analysis of the noise data observed during several past test runs. It is crucial for the running of the cavity to keep the thermal load on cryogenics at minimum. This is achieved by a careful design of thermal intercept on the fundamental power coupler (FPC). I will illustrate thermal calculations done under static and dynamic heat loads. Then I will discuss the specifications of coolant for the effective heat removal from the FPC. I will also present a brief summary of my doctoral work – the analysis of electron cloud measurement technique at KEK B-factory.

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****NOTE: Day & Time****

Tuesday, Aug 21, 2012
Time: 9am

Margaret Koker
Max Planck Institute for Intelligent Systems

"Diffraction Line Broadening Induced by the Elastic Loading of Polycrystalline Bodies Due to Anisotropic Elastic Grain Interactions"

Abstract:  When a stress is applied to a polycrystal, the elastically anisotropic grains in a massive body cannot deform freely to comply with an imposed state of mechanical stress; instead they must adapt their mechanical response to their surroundings. Various grain-interaction models exist to describe the stress and strain behaviour of individual grains within an aggregate. These models can be employed for calculating mechanical and diffraction (x-ray) elastic constants of polycrystalline specimens from single-crystal elastic data. Experimental investigations have revealed that the Neerfeld-Hill and Eshelby-Kröner models, for massive, bulk polycrystals, and a recently proposed effective grain interaction model for thin films provided excellent estimates for the (mechanical and) x-ray elastic constants of polycrystals. Further experimental investigations of elastically induced grain interactions are necessary to understand the heterogeneous strain and stress distributions within a specimen. This work provides a report of synchrotron diffraction investigations, as well as a computational study, of diffraction-line broadening induced by elastic loading of various polycrystalline specimens.

The results indicate that the extent of the diffraction line broadening calculated employing traditional grain interaction models is much lower than the extent of the experimentally determined broadening. The variety of environment, and thus the heterogeneity of the stress/strain states experienced by the individual grains exhibiting the same crystallographic orientation in a polycrystal, cannot be accounted for using classical grain interaction models, where all grains of the same crystallographic orientation are considered to experience the same stress/strain state. The obtained results have vast implication for diffraction line broadening analysis and modeling of the elastic behaviour of polycrystals.

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****NOTE: Day****

Thursday, Aug 16, 2012
Time: 1pm

R.J. Dwayne Miller
Max Planck Group for Atomically Resolved Dynamics,
Department of Physics, University of Hamburg
The Centre for Free Electron Laser Science, DESY and
Departments of Chemistry and Physics, University of Toronto

Presentation:  (Pdf)

"Making the Molecular Movie": First Frames.....Now with REGAE Musik

Abstract: One of the great dream experiments in Science is to watch atomic motions as they occur during structural changes. In the fields of chemistry and biology, this prospect provides a direct observation of the very essence of chemistry and the central unifying concept of transition states in structural transitions. From a physics perspective, this capability would enable observation of rarefied states of matter at an atomic level of inspection, with similar important consequences for understanding nonequilibrium dynamics and collective phenomena. This experiment has been referred to as "making the molecular movie". Due to the extraordinary requirements for simultaneous spatial and temporal resolution, it was thought to be an impossible quest and has been previously discussed in the context of the purest form of a gedanken experiment. With the development of femtosecond electron pulses with sufficient number density to execute single shot structure determinations, this experiment has been realized (Siwick et al. Science 2003). Previously thought intractable problems in attaining sufficient brightness and spatial resolution with electron sources, with respect to the inherent electron-electron repulsion or space charge broadening, has been solved. With this new level of acuity in observing structural dynamics, there have been many surprises and this will be an underlying theme. Several movies depicting atomic motions during passage through structural transitions relevant to condensed phase dynamics will be shown (Sciaini et al. Nature, 2009, Ernstorfer et al. Science 2009, Eichberger et al. Nature 2010, Jean-Ruel et al. J. Phys. Chem. A 2011). These new developments will be discussed in the context of developing the necessary technology to directly observe the structure-function correlation in biomolecules ¾ the fundamental molecular basis of biological systems. In this particular problem, the exceptionally high brightness and spatial coherence of XFELs will play an important role in expanding the basis to larger complexes, as well as open up real space imaging of time dependent spatial correlations relevant to chemical and biological processes.

As with static structure determinations, these new femtosecond x-ray and electron sources form a highly complementary set of tools to explore structural dynamics at the atomic level. However, they place extraordinary demands on sample handling to fully exploit the exceptional brightness. Recent advances in solid state target development as well as nanofluidics for real space imaging with both x-ray and electron sources will also be discussed in relation to the new horizons they open up, to give an impression of the potential impact of this emerging field.

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****NOTE: Day & Time****

Monday, Aug 13, 2012
Time: 9am

Matthew Ward
The University of Western Ontario, Canada

"GaN-ZnO Solid Solutions Nanostructures – What information can X-ray absorption spectroscopy give us about this important novel class of photocatalytic materials?"

Abstract:  Visible light driven photocatalytic water splitting into hydrogen and oxygen is a highly attractive process for the production of hydrogen for use as an efficient energy carrier. Solid solutions of gallium nitride - zinc oxide, (Ga1-xZnx)(N1-xOx), with transition-metal oxide nanoparticle surface modifications have a demonstrated capacity for overall water splitting into H2 and O2 under visible irradiation[1]. Gallium nitride - zinc oxide (GaN-ZnO) solid solutions exhibit band-gap energies which are significantly lower than that of the parent components, desirable visible light absorption properties, and complex luminescence properties. The visible light absorption behaviour has tentatively been attributed to the interaction between GaN and ZnO components, while visible luminescence properties appear to be of a complex nature. Recently nanostructures of GaN-ZnO solid solutions have been synthesized, which are hypothesized to have better catalytic activity over the bulk due to their substantial increase in surface to volume ratio[2]. In order to elucidate the origin of optical absorption and emission processes in these complex materials we have developed and applied a variety of synchrotron based spectroscopic techniques[3]. X-ray absorption fine structures (XAFS) measures the modulation of the absorption coefficient across a given absorption edge and thus provides elementally specific information about the electronic nature of an absorbing element in a chemical environment. X-ray excited optical luminescence (XEOL) is an X-ray photon-in optical photon-out process that can be elementally specific when combined with the tuneable excitation energy provided by a synchrotron. When XAFS and XEOL are combined into one experiment it is possible to obtain two-dimensional (2D) XAFS-XEOL intensity maps in which a XEOL spectrum is collected for every excitation energy of an X-ray absorption scan. Time-resolved (TR) XEOL makes use of the inherent time structure and energy tuneability of a synchrotron to collect elementally specific luminescence decay lifetime measurements. The addition of an optical streak camera and a spectrograph to the TR-XEOL experiment allows for the collection of 2D temporally and spectrally resolved XEOL intensity maps. Thus we can obtain both temporally resolved XEOL spectra and wavelength resolved luminescence lifetime decay spectra by integrating over appropriate slices of the resultant 2D TR-XEOL map. Herein I will present the development of these new synchrotron based spectroscopy techniques, 2D XAFS-XEOL and TR-XEOL using an optical streak camera, and what these new techniques can tell us about GaN-ZnO solid solution nanostructures.

References:
[1]  Maeda, K., Takata, T., Hara, M., Saito, N., Inoue, Y., Kobayashi, H., and Domen, K.J.; Am. Chem. Soc. 127, 8286 (2005)

[2]  Han, W., Liu, Z., and Yu, H.; Appl. Phys. Lett. 96, 183112 (2010)

[3]  (a) Ward, M. J.; Han, W. Q.; Sham, T. K. J. Phys. Chem. C 115, 20507 (2011) (b) Han, W. Q.; Ward, M. J.; Sham, T. K. J. Phys. Chem. C 115, 3962 (2011)

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****NOTE: Day & Time****

Tuesday, July 31, 2012
Time: 9am

Miles Beaux
Los Alamos National Laboratory

"Electronic Structure of Polycrystalline δ-Pu Metal: a review of photoemission spectra interpretations"

Abstract:  We exploit our capability for photoemission spectroscopy (PES) measurements of Pu materials to present a systematic study of polycrystalline δ-Pu metal. Laser ablation was used to clean the surface of Ga stabilized δ-Pu and cleanliness was monitored through O 1s and Pu 4f core levels, as well as valence band features. Observation of these spectra provides better insight into the differentiation of contaminant features versus the strong correlation effects within Pu metal. Comparison to the Pu chalcogenide PuTe is used to better understand the origin of the three-peak structure observed in the valence band regions of both these and other Pu materials. Previously published interpretations of this three peak structure, as well as the Pu 4f core levels, are discussed relative to more recent experimental spectral data. A new spectral interpretation is presented that better correlates 5f occupancy and final state effects across a broad range of Pu materials.

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Friday, July 13, 2012

Ken Finkelstein
Cornell University

 

"Using Resonant & Anomalous X-ray Diffraction to Probe Electrons at 'Ultrafast' Time Scales"

 

Abstract:  We report results of several experiments, conducted at APS 7ID, where 50 femtosecond, 800nm (1.55eV) laser pulses are synchronized to overlap on the sample with x-rays pulses, in space & time. We studied diffraction at three types of reflections in germanium, tuning x-ray energy very close to the K-edge at 11.104KeV. In general, reflections can be allowed by the rules of the space group, forbidden, or VERY forbidden. Forbidden means scattering from spherically symmetric atoms, occupying certain “special positions” will cancel out. VERY forbidden means general symmetry properties (glide planes or screw axes) lead to cancellation of the reflection even when the atomic charge density is not spherical.

We show how certain allowed reflections are ALMOST cancelled out by tuning energy just below the K edge. Under this condition, we think our results show diffraction to be very sensitive to scattering from valence electrons, and that these electrons are profoundly perturbed by the laser. We discuss the physics of this effect. For better understanding we measured diffraction at both types of forbidden reflections. Diffraction at the former type is well known to be sensitive to valence electrons and fairly insensitive to x-ray energy. Signals at the latter reflections has been seen at resonance; i.e. in a very narrow energy band associated with the k-absorption edge. We describe the connection between scattering in the two cases, discuss effect of the laser, and speculate on why all this may be important.

 

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****NOTE: Day & Time****

Monday, July 9, 2012
Time: 9am

Zou Finfrock
Physics Department,
University of Washington

"Mitigation of X-ray Damage in Macromolecular Crystallography by sub-µm Line Focusing"

Abstract: Radiation damage is a major limiting factor in macromolecular crystallography using synchrotron x-ray source, especially with the third generation undulator beamline. Experiments with the third generation synchrotron x-ray source showed that the high flux of x-rays causes significant damage to macromolecular crystals during short exposures. A new strategy is presented to reduce primary x-ray damage in macromolecular crystallography using synchrotron radiation. The basic principle is to separate as much as possible the x-ray irradiated region, where the diffracted signal originates, from the region where damage accumulates. This is possible since, by far, most of the damage is caused by the photo-electrons (PE’s) excited as an x-ray photon is absorbed, and distributes its damage typically over several µm’s. At synchrotrons the PE’s travel preferentially along the horizontal polarization vector of the x-ray beam. In principle the optimum method to accomplish this is to focus the x-rays to a vertical line of sub-µm width. We designed and fabricated a prototype of the required instrumentation to minimize the deleterious effects of radiation damage in x-ray macromolecular crystallography. Diffraction experiments performed recently at the Advanced Photon Source, accurately measured for the first time the penetration depth and distribution of photoelectron (PE) damage excited by 18.6 keV photons in a lysozyme crystal with a vertical sub-µm line focus beam. The mitigation of radiation damage by focusing was determined by comparing the damage between focused and unfocused cases leading to a large mitigation factor of 4.4 ± 0.4. It was also noted that there is a relatively small time and temperature dependence of the damage indicating that secondary mechanism/s of damage are present that are triggered by the essentially instantaneous primary ones.

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****NOTE: Day & Time****

Tuesday, June 26, 2012
Time: 9am

Ruiping Li
Material Science & Engineering,
King Abdullah University of Science and Technology,
Saudi Arabia

 

"Synchrotron Based Characterization on The Solution Processing of Organic Electronics"

Abstract:  In organic electronics, the solution processing shows the promising advantages on the low cost and the easy manufacture. The high performance of organic thin film transistor (OTFT) requires the microstructure and morphology of solution-cast thin films to exhibit a high degree of crystallinity, a low density of grain boundaries and high surface coverage of the substrate. Efforts to tune the microstructures and morphologies of solution-cast thin films have been hampered by the lack of understanding and control over the nucleation and growth of the thin films as the solution undergoes phase transformation.

This presentation shows several approaches based on grazing incident X-ray diffraction/scattering to investigate the structure and morphology in solution-processed OTFTs. A variety of material from small molecule to polymer are in situ characterized in drop-casting processing and solvent vapor annealing. Also, a microbeam, with the spatial resolution of 10 microns, is used to characterize the interface of a solution drop, as well as the morphology of a real OTFT device. In the end, a new casting method, doctor blading, is discussed when the microbeam meets the in situ measurement.

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****NOTE: Day & Time****

Monday, June 25, 2012
Time: 11am

John Thornton
Air Vehicles Division, HiFIRE, Australia

 

"The Tomography of Coated and Uncoated C-C and C-SiC"

Abstract:  HiFIRE is a Australian and US research program on hypersonic flight. The scramjets that are being tested in this program and the leading edges of the test vehicles experience extremely high temperatures. Carbon-carbon and carbon-silicon carbide composites are two materials that maintain their strength at such extreme temperatures and may be suitable for use in the HiFIRE program. In air these temperature can lead to rapid oxidation and thus coatings are employed to improve durability. This presentation reports on the study of these materials using tomography before and after exposure to oxy-acetylene flames. The tomography results are compared to images obtained using electron microscopy.

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****NOTE: Day & Time****

Monday, June 11, 2012
Time: 9am

Zhenxing Feng, Electrochemical Energy Lab
MIT

 

"In Situ Studies of Energy Materials Using Synchrotron Techniques"

Abstract:  Synchrotron X-ray has become the widely used tool in physical, biophysical and electrochemical research. Its high flux, tunable energy and coherence enable many challenging studies, such as ultra thin film as solid oxide fuel cell (SOFC) and ferroelectric devices, sub-monolayer nanoparticles as catalysts, and dilute solution in biological or Li-battery systems. As research scale goes down to nanometer, researchers are more interested in separating the surface and bulk effects, and monitoring in situ processes. In this talk, I will discuss my work of using different synchrotron techniques for energy materials studies. These mainly include (1) in situ studies of catalysts using X-ray standing wave (XSW); (2) atomic-scale investigation of enhanced oxygen reduction reaction mechanism in SOFC cathode materials using crystal truncation rod (CTR); (3) tuning resonant inelastic X-ray scattering (RIXS) for surface and in situ studies of electrocatalysts in fuel cell applications. Finally I will briefly discuss how to adapt these techniques for current CHESS and future ERL beamlines, and their applications in physical, chemical and biological fields.

 

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Friday, June 1, 2012

Kenneth Evans-Lutterodt
Photon Sciences, Brookhaven National Laboratory

 

 

 

"Micro-fabrication of Hard X-ray Optics and Micro-diffraction"

Abstract:  Hard X-rays are a traditional tool for materials characterization, and one can extend the usefulness of these methods by using smaller x-ray beams. Optics allow more optimal utilization of existing and new x-ray sources, for example by creating focused beams. By applying micro-fabrication methods, we have fabricated a variety of hard x-ray optical elements, such as refractive lenses, kinoform lenses, prisms, interferometers and Fabry-Perot resonators. Our kinoform lenses have been shown to focus to below 100nm, with photon energies as high as 30keV, and as low as 7.35keV, and can also be large enough to collect all the light from the brighter 3rd generation sources. We have also microfabricated bi-prisms to perform a virtual Young's double slit experiment, and deduce the transverse coherence length of the source from the interference patterns. A recent development is an improved phase contrast method with a monolithic optical element. Finally, we use phase retrieval methods to measure the size of a focused spot, in anticipation of measuring spot sizes in the sub-10nm range that will be difficult to measure with conventional methods.

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****NOTE: Day & Time****

Tuesday, May 29, 2012
Time: 9am

Thomas Roth, Beamline Scientist at ID06
European Synchrotron Radiation Facility

 

"The ESRF Techniques and Instrumentation Test Beamline ID06 and Experiments with Pulsed and Rotating Magnetic Fields"

Abstract:  My talk will be divided into two parts. First, I will present the beamline ID06, which is a dedicated beamline for the test of new instrumentation and the development of new measurements techniques. It houses a white beam test station, a monochromator test station, a microoptics test bench and a large volume press. I will describe our high heat load monochromator and a feedback system using beam position monitors. As examples from the microoptics test bench, I will present work on Si bilenses and on Bragg diffraction microscopy.

In the second part, I will speak about experiments with pulsed or rotating magnetic fields. Using a miniature pulsed magnet XMCD studies on Er_3Fe_5O_{12} have been performed at up to 30 Tesla. Erbium Iron Garnet can be interpretated as an effective two sublattice ferrimagnetic system. Our XMCD results allow an element selective magnetometry of the sample, i.e. the field dependance of the sublattice magnetisations could be measured.

Then, at much lower magnetic fields, a simultaneous XMCD/XMLD study on amorphous TbFe_2 placed in the field of a rotating permanent magnet will be presented.

I will finish with showing the development of a split coil pulsed magnet in Voigt geometry for single crystal diffraction experiments.

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****NOTE: Day & Time****

Thursday, May 24, 2012
Time: 1pm

Steven Herron, Asst. Research Professor
Brigham Young University

 

"The Search for an Inhibitor of Aminoglycoside 6'-acetyltransferase Type Ib"

Abstract:  Aminoglycoside 6’-acetyltransferase type Ib (AAC) is a bacterial enzyme that catalyzes the acetylation of the aminoglycoside antibiotics, particularly amikacin, kanamycin, and tobramycin. The aminoglycoside antibiotics are used predominantly against aerobic gram-negative bacteria, especially the genuses; Pseudomonas, Acinetobacter, Enterobacter, and Mycobacteria. AAC has been isolated from several mobile genetic elements found in the bacterial families Pseudomonadaceae, Enterobacteriaceae, and Vibrionaceae. Of the bacteria found to contain the AAC enzyme, Pseudomonas aeruginosa, Klebsiella pneumoniae, and Vibrio cholerae, have the greatest potential to cause human disease. Recently, a double mutant of AAC, Trp102Arg and Asp179Tyr, has been shown to acetylate and inactivate the antibiotic Ciprofloxacin (Cipro). This represents a new mechanism for the inactivation of cipro. This added function makes AAC the first documented enzyme to directly inactivate two different classes of antibiotics. My lab has screened the active pocket of AAC with the ChemBridge chemical library (~1.6 million compounds) using both Autodock and Sybyl/FlexX. We purchased the top 40 scoring compounds and tested each for enzymatic inhibition. We identified two inhibitors with uM affinity and another 14 inhibitors with mM affinity. We recently identified two drug like compounds that restore kanamycin susceptibility in vivo against gram-negative bacterial harboring an AAC expression plasmid.

If time permits, I will also present some very rece4nt work involving hair diffraction to detect a (non cancer) human disease state.

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****NOTE: Day & Time****

Wednesday, May 23, 2012
Time: 9am

Jacob Ruff
The Advanced Photon Source, Argonne National Laboratory

Presentation:  (Pdf)

"Shining Light on Materials in High Magnetic Fields"

Abstract:  In this talk, I will review recent efforts at the Advanced Photon Source to establish a suite of capabilities for synchrotron x-ray scattering in applied magnetic fields as high as 30 Tesla[1-3]. The combination of custom-built magnets and synchrotron light sources offers a unique microscopic perspective on the magnetoelastic properties of materials, which we are now learning to exploit. As an example of the science enabled by these efforts, I will present diffraction measurements of an iron arsenide superconductor in pulsed magnetic fields[4]. This orthorhombic crystal is shown to exhibit dynamic de-twinning driven by a pronounced anisotropy in the magnetic susceptibility. Tracking the non-trivial temperature dependence of this effect allows us to put new constraints on theories of "nematic" electronic phases in the iron arsenides. Potential future directions for novel studies of magnetic materials at synchrotrons will also be discussed, time permitting.

References:
[1] Z. Islam et al.; “A Portable High-field Pulsed-magnet System for Single-crystal X-ray Scattering Studies”, Rev. Sci. Instrum. 80, 113902 (2009)

[2] Z. Islam et al.; “A Single-solenoid Pulsed-magnet System for Single-Crystal Scattering Studies”, Rev. Sci. Instrum. 83, 035101 (2012)

[3] J.P.C. Ruff et al.; “Magnetoelastics of a Spin Liquid: X-Ray Diffraction Studies of Tb2Ti2O7 in Pulsed Magnetic Fields”, Phys. Rev. Lett. 105, 077203 (2010)

[4] J.P.C. Ruff et al.; “Susceptibility Anisotropy in an Iron Arsenide Superconductor Revealed by X-ray Diffraction in Pulsed Magnetic Fields”, arXiv:1204.5693v1 (2012)

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****NOTE: Day & Time****

Wednesday, May 9, 2012
Time: 9am

Jun-Sang Park
Cornell University

 

 

 

"Understanding the State of Polycrystalline Structural Alloys using High Energy Synchrotron X-rays"

Abstract:  As the demand for efficient, high-performance machines increases, quantifying the state of materials and understanding their micro-mechanical behavior are ever more important for designing and building these machines. High energy synchrotron radiation is an attractive tool for investigating the state and the micromechanical behavior of polycrystalline structural alloys. In this talk, two techniques will be presented.

In the first part of the talk, a method for quantifying the residual stress field in a polycrystalline material is described. An experimental setup that combines monochromatic high energy x-ray diffraction and a set of conical slits is described. The set of conical slits allows the non-destructive measurement of lattice strains for diffraction volumes located inside the material and is used to measure the strain pole figures (SPFs) for diffraction volumes located inside a polycrystalline component. Full three-dimensional residual stress field is determined by a bi-scale optimization scheme. In this scheme, the residual stress field satisfies the SPF measurements at the crystal length scale. At the macroscopic length scale, the residual stress field also satisfies equilibrium and imposed boundary conditions. To demonstrate the new method, a polycrystalline shrink-fit sample with a three-dimensional stress gradient was manufactured from a low solvus high refractory (LSHR) Ni-based superalloy. The residual stress field determined using the new method compares favorably with an analytic approximation of the stresses within the shrink-fit sample.

In the second part of the talk, a framework for understanding the micromechanical behavior of individual crystals embedded in a polycrystalline aggregate is described. This framework combines the synchrotron x-ray experiments and the polycrystal finite element simulation to understand the micromechanical behavior. A method for simulating diffraction spots from individual virtual crystals using the information obtained from a polycrystal finite element simulation is described. To demonstrate the method, a set of high energy diffraction data were collected while applying a uniaxial tension on a high strength copper specimen. The diffraction data were analyzed to determine the orientations and the stresses of the crystals in the diffraction volume. The crystal orientations were used to instantiate a virtual polycrystal and a slip-based polycrystal finite element simulations were performed. Using the information obtained from the finite element simulations, a set of virtual diffraction spots is generated. These virtual diffraction spots are compared to the experimental diffraction spots.

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****NOTE: Day & Time****

Wednesday, May 2, 2012
Time: 9am

Dr. Pamela Whitfield
National Research Council Canada

 

 

 

"Advanced Powder Diffraction with Lab Instrumentation
- or doing things the hard way!"

Abstract:  I intend giving an overview of some of the different work that I’ve carried out at ICPET over the past number of years. Although the subject materials differ significantly (lithium battery cathode material, organic and minerals), powder diffraction is the thread that runs through all of the studies. Synchrotron and neutron diffraction also feature but the majority of the work was carried out using laboratory-based instrumentation. The facility at ICPET is very well equipped and the instrumentation setups are generally highly specialized and unusual for lab systems. In-situ and non-ambient measurements are of particular interest and where commercial equipment didn’t exist we designed and often built or assembled it in-house. Overcoming the challenges of lab diffractometers in terms of cramped space, limited number of wavelengths and not upsetting the radiation safety officer by drilling holes everywhere are all ongoing problems. A number of the topics involve such custom built sample environments where the designs overcome different issues and sometimes turn problems into positive advantages.

I intend covering the first 3 topics but can swap topics with the last 2 depending on interest...

• Complex refinement of cation-ordering in lithium battery materials using resonant and neutron powder diffraction
• Preferential orientation and structure determination from powder diffraction (SDPD)
• Custom in-situ gas pressure cells for lab diffractometers and synchrotrons
• Cleaner data from in-situ battery studies – new variable temperature stage, pouch cell design and application of grazing incidence diffraction
• Kryptonite - structure solution from powder diffraction data

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Friday, April 27, 2012

Fareh Pei-Jen Lin
Old Dominion University

"Effect of Impurities on the Superheating Field of Type II Superconductors"

Abstract:  We consider the effect of non-magnetic and magnetic impurities on the superheating field Hs in type-II superconductors. We solve the Eilenberger equations, which take into account the non-linear pairbreaking of Meissner screening currents, and calculate the superheating field for arbitrary temperatures and impurity concentrations in a single-band S-wave superconductor with a large Ginzburg-Landau parameter. At low temperatures non-magnetic impurities suppress a weak maximum in Hs (T ) which has been predicted for the clean limit, resulting instead in a maximum of Hs as a function of impurity concentration near clean limit. It is shown that non-magnetic impurities weakly affect Hs even in the dirty limit of large scattering rate, α ≫ 1. However, magnetic impurities suppress both Hs and the critical temperature Tc. The density of quasiparticle states N (Є) is strongly affected by an interplay of impurity scattering and current pairbreaking. We show that a clean superconductor at H = Hs is in a gapless state, but a quasiparticle gap Єg in N (Є) at H = Hs appears as the concentration of non-magnetic impurities increases. As the non-magnetic scattering rate increases above αc = 0.36, the quasiparticle gap Єg (α) at H = Hs increases, approaching Єg ≈ 0.32∆0 in the dirty limit, where ∆0 is the superconducting gap parameter at zero field. The effects of impurities on Hs can be essential for understanding non-linear surface resistance and superconductivity breakdown by strong RF fields.

 

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Friday, April 13, 2012

Dr. Konstantin Lekomtsev
University of London

 

"Coherent Diffraction Radiation as a Tool for Non-invasive Bunch Length Diagnostics"

 

 

Abstract:  In this seminar I will discuss Coherent Diffraction Radiation (CDR) phenomenon as a tool for longitudinal beam diagnostics. Precise knowledge of a longitudinal bunch profile is particularly important in the context of the luminosity challenge in the future linear colliders and therefore the development of a non-invasive and robust longitudinal beam diagnostic technique is very important.

CDR is emitted when a bunch of charged particles moves in the vicinity of an optical obstacle (for example a screen, or a slit between screens) and the wavelength of the radiation is larger or comparable to the bunch length. CDR has been experimentally investigated over the period of the last 20 years and has been proven to be very promising candidate for longitudinal diagnostics, due to its non-invasive nature and high radiation intensity.

During the course of the seminar I will discuss a novel two-target scheme for the CDR generation. The experimental demonstration of this scheme is a setup installed at the CLIC Test Facility (CTF3) at CERN. A new theoretical model which was developed specifically for the dual-target experimental setup will also be presented and compared with experimental data. The main concepts of the longitudinal diagnostics based on the analysis of the CDR spectrum will be introduced. The limitations of the Kramers-Kronig technique as a tool for bunch profiling, and Coherent Synchrotron Radiation background contribution in the CDR spatial distribution will be discussed.

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Friday, April 6, 2012

He Zhang
Michigan State University

 

"Fast Multipole Algorithm Using Differential Algebra for Space Charge Field Calculation and Low Emittance Lattice Design for Hefei Light Source Storage Ring"

 

Abstract:  A variant of the fast multipole method (FMM) using differential algebra will be presented. This algorithm allows the computation of the self-field for arbitrary and large distributions of charged particles in an efficient and accurate way. Given an ensemble of N particles, the computational expense scales as O(N). Some numerical examples of applying the algorithm in beam dynamic simulation will be presented.

A four-folded low emittance lattice for Hefei Light Source electron storage ring, which decreases the emittance from 166 nm*rad to 16 nm*rad, was proposed. Related beam dynamic topics, such as on momentum and off momentum dynamics, close orbit distortion and compensation, effects of insertion devices, are discussed.

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Friday, March 16, 2012

Alex Deyheim
ADC

"Advanced Design Consulting, Current Projects, Future Possibilities"

Abstract:  ADC offers a large assortment of synchrotron equipment including; High Precision Slits, Optical Tables, Micro Ion Chambers, Split Two Axis Ion Chambers, Mirror Systems, Monochromators, Spectrometers, Insertion Devices (EPU, Wiggler, Planar, In-Vacuum, Apple), ID Measurement System and many other Beamline Components.  Alex will discuss the following:

  1. A summary of Synchrotron Related Systems delivered and/or under construction for facilities around the world (APS, NSLS   and NSLS II, ALS, DLS, NSRRC, BESSY, DESY, CHESS, ESRF, BSRF, CAMD, NSRL, PAL, SSRF, IHEP, ANKA, KEK, ASP, SPring-8, ELETTRA, MAXLab, …)
  2. A summary of ADC’s History, sales volume, staffing….
  3. A summary of ADC’s facilities, equipment, capabilities (UHV capabilities, testing…)
  4. Describing ADC’s operation
  5. A summary of ADC’s High Precision Slits
  6. A summary of Synchrotron Beamline Components
  7. A summary of Insertion Devices delivered and under construction
  8. A summary of ADC’s Standard Motion Systems (Linear Stages, Goniometers, Vertical Jacks, Rotation stages)
  9. A summary of Custom High Precision Motion Systems ADC has delivered
  10. A summary of ADC’s Standard Optical Tables
  11. ADC’s Control & Electronic Capabilities

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****NOTE: Day****

Thursday, March 1, 2012

Dimitre Dimitrov
Tech-X

"Modeling and Simulations of Charge Carrier Effects in Diamond and GaAs for Cathode Applications"

Abstract:  High-fidelity modeling and simulations of electron emission physics are needed to better understand and address cathode-related issues. I will review work we have done to develop and implement algorithms in the VORPAL three-dimensional particle-in-cell code for modeling charge gain, transport, and emission from diamon-amplified cathodes. Emission of electrons in diamond experiments based on the promising diamond-amplifier concept was recently demonstrated. However, these emission experiments indicate that surface effects should be understood in detail to build cathodes with optimal properties. Transmission mode experiments have shown the potential to realize over two orders of magnitude charge amplification. We have made progress in understanding secondary electron generation and charge transport in diamond transmission-mode experiments with models we implemented in VORPAL. We have started to investigate algorithms for surface effects (band bending and electron affinity), charge trapping, and electron emission from diamond. I will present and discuss results from 3D VORPAL diamond-vacuum simulations with the integrated capabilities on generating electrons and holes, charge transport, and then emission of electrons from diamond into vacuum. Recently, we have also started to add capabilities for simulation of charge transport in a three-band GaAs. Results from GaAs simulations with these capabilities will also be presented and their relevance to cathode-related experiments will be discussed.

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Friday, February 17, 2012

Dr. Julian Becker
DESY

Presentation:  (Pdf)

"Towards the Perfect Imager: Detector developments for next generation X-ray sources"

 

Abstract:  I will be starting with a short overview of our group’s activities to develop detectors for PETRA III, the world’s most brilliant synchrotron source, located on the DESY premises.

New challenges arise for detector builders when designing detectors for Free Electron Laser (FEL) sources. I will introduce the European XFEL, currently under construction at DESY, and the special requirements it puts on detector projects like the Adaptive Gain Integration Pixel Detector (AGIPD).

I will close with an example of the challenges and possibilities for X-ray photon correlation spectroscopy (XPCS) at the European XFEL using the AGIPD.

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Friday, February 3, 2012

David Schuller, Staff Scientist
MacCHESS, Cornell University

 

"Phasing of Quasi-racemic Protein Diffraction"

Presentation: Pdf

 

Abstract:  Dr. Schuller will be discussing 2 papers which are listed below:
1)  "X-ray Structure of Snow Flea Antifreeze Protein Determined by Racemic Crystallization of Synthetic Protein Enantiomers", Brad L. Pentelute, Zachary P. Gates, Valentina Tereshko, Jennifer Dashnau, Jane M. Vanderkooi, Anthony A. Kossiakoff, and Stephen B. H. Kent; J Am Chem Soc, 130, 9695-9701 (2008) http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2719301/?tool=pubmed

2)  "Single-wavelength Phasing Strategy for Quasi-racemic Protein Crystal Diffraction Data", MR Sawaya, BL Pentelute, SB Kent, and TO Yeates; Acta Crystallography. Sec D, 68: 62-8 (2012) http://scripts.iucr.org/cgi-bin/paper?S0907444911049985

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Friday, January 27, 2012

Darby Harris, Postdoc
Department of Plant Pathology and CHESS, Cornell University

"Cellulose Microfibril Crytallinity is Reduced by Mutating C-terminal Transmembrane Region Residues CESA1-A903V and CESA3-T942I"

Abstract:  The mechanisms underlying the biosynthesis of cellulose in plants are complex and still poorly understood. A central question concerns the mechanism of microfibril structure and how this is linked to the catalytic polymerization action of cellulose synthase (CESA). Furthermore, it remains unclear whether modification of cellulose microfibril structure can be achieved genetically, which could be transformative in a bio-based economy. To explore these processes in planta, we developed a chemical genetic toolbox of pharmacological inhibitors and corresponding resistance-conferring point mutations in the C-terminal transmembrane domain region of CESA1-A903V and CESA3-T942I in Arabidopsis thaliana. Using 13C solid-state nuclear magnetic resonance spectroscopy and synchrotron X-ray diffraction, we show that the cellulose microfibrils displayed reduced width and an additional cellulose C4 peak indicative of a degree of crystallinity that is intermediate between the surface and interior glucans of wild-type, suggesting a difference in glucan chain association during microfibril formation. Consistent with measurements of lower microfibril crystallinity, cellulose extracts from mutated CESA1A903V and CESA3T942I displayed greater saccharification efficiency than wild-type. Using live-cell imaging to track fluorescently labeled CESA, we found that these mutants show increased CESA velocities in the plasma membrane, an indication of increased polymerization rate. Collectively, these data suggest that CESA1A903V and CESA3T942I have modified microfibril structure in terms of crystallinity and suggest that in plants, as in bacteria, crystallization biophysically limits polymerization.

 

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Friday, January 20, 2012

Etienne Forest
KEK

"Orwell, Talman and I"

Abstract:  In 1987, I tried to explain the difference between a horizontally integrated code and a vertically integrated tracking code. Today, I like to call them democratic and totalitarian. The concept of the totalitarian code was perhaps invented by R. Talman who referred to TEAPOT as “exact”.  Embracing Talman’s concept, I added the claim that Courant-Snyder theory is its universal doctrine. Courant-Snyder is the party propaganda in its purest form.

I will explain these concepts using spin as an example, the delusional papers that we published, and “PTC“ (the North Korea of codes).

 

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