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Poster Abstracts

 

 
"Effects of solvent additives on morphology evolution in small-molecule bulk heterojunction organic solar cells"

Maged Abdelsamie, Neil D. Treat, Kui Zhao, Ahmed R Kirmani, Guy O. Ngongang Ndjawa, Detlef‐M Smilgies, Natalie Stingelin , Guillermo C. Bazan and Aram Amassian

Abstract: Solvent additive processing has been adopted as a simple and effective way to control morphology and to improve device performance for several bulk heterojunction (BHJ) solar cell systems. In p-DTS(FBTTh2)2 :PC71BM BHJ system, optimized performance and morphology are obtained by inclusion of small quantity of the additive DIO into casting solution upon processing. However, the actual mechanism of the BHJ formation at the presence of additives is not well understood. We investigate the film formation in situ during processing in order to understand the mechanism of BHJ formation.

 

 
"Toward additive-free and annealing-free processing of highly efficient small-molecule bulk heterojunction solar cells"

Maged Abdelsamie, Neil D. Treat, Kui Zhao, Detlef‐M Smilgies, Natalie Stingelin , Guillermo C. Bazan and Aram Amassian

Abstract: The ease with which small-molecule donors crystallize during solution processing is directly linked to the need for solvent additives. Donor molecules that get trapped in disordered (H1) or liquid crystalline (T1) mesophases require additive processing to promote crystallization, phase separation, and efficient light harvesting. A donor material (X2) that crystallizes directly from solution yields additive-free and annealing-free solar cells with an efficiency of 7.6%.

 

 
"Germanium Collimating Channel Arrays For High Resolution, High Energy Confocal X-ray Fluorescence"

David Agyeman-Budu1, Sanjukta Choudhary2, Ian Coulthard3, Robert Gordon4, Emil Halin3, Arthur R Woll5
1Dept. of Materials Science and Engineering, Cornell University
2Geol. Sciences, Univ. of Saskatchewan
3Canadian Light Source
4Department of Physics, Simon Fraser University
5Cornell High Energy Synchrotron Source

Abstract: Confocal X-ray Fluorescence (CXRF) microscopy is an x-ray probe technique which enables the detection of x-ray fluorescence from a localized, micron-scale 3D volume of an extended, unthinned sample. The setup which consists of a pair of optics: a condenser and a collection optic are arranged such that overlap of their foci creates a 3D probe volume in space. This probe volume can be used to interrogate samples of interest. All implementation of this technique utilizes a polycapillary as the collection optic. Our approach on the other hand uses Collimating Channel Arrays (CCAs) which are lithographically fabricated channels in silicon and germanium substrates. CCAs are excellent collection optics in this regard since they demonstrate a nearly energy-independent resolution and are flexible to design.

From prior work [1, 2], due to the limited absorbing power of silicon, the useful energy range of use is limited to fluorescence emission below 10 keV. The use of germanium substrates here shows practical use for CXRF with a nearly energy-independent spatial depth resolution of 2.1 ± 0.17µm from 2-20 keV. Germanium CCA optics also have excellent background reduction compared to Silicon CCA optics in this energy range.

References:

[1] A R. Woll, D. Agyeman-Budu, D. H. Bilderback, D. Dale, A. Y. Kazimirov, M. Pfeifer, T. Plautz, T. Szebenyi, and G. Untracht, SPIE Optical Engineering + Applications, 8502, 85020K-85021-85014 (2012).
[2] AR Woll, D Agyeman-Budu, S Choudhury, I Coulthard, AC Finnefrock, R Gordon, E Hallin and J Mass, Journal of Physics: Conference Series, 493 (1), 012028 (2014)

 
"Block Copolymer Self-Assembly-Derived Synthesis of Mesoporous Gyroidal Superconductors"

Peter Beaucage, Spencer Robbins, James P. Sethna, Francis J. DiSalvo, R. Bruce Van Dover, Sol M. Gruner, Ulrich Wiesner

Abstract: Superconductors with mesoscale ordering and porosity are expected to have properties very different from their bulk counterparts. The exploration of these properties has been limited, however, by the lack of tunable, versatile, and robust wet-chemical synthesis methodologies to mesostructured superconductors. We report the synthesis of gyroidal NbN superconductors from gyroidal block copolymer self-assembly-derived niobium oxide. The resulting materials have a Tc of about 7.8K, a critical current density of 440 A cm-2 at 100 Oe and 2.5K, and a mesoscale lattice with the I4132 (alternating gyroid) structure with d100 spacings between 27 and 36 nm. We expect that block copolymer-inorganic hybrid co-assembly will prove to be a scalable, tunable platform for exploration of the impacts of mesoscale order and porosity on superconducting properties.

 

 
"Overcoming the limitations of silicon: First results from MM-PAD and Keck-PAD with CdTe sensors for experiments at up to 100 keV and beyond"

Julian Becker, Mark W. Tate, Katherine S. Shanks, Hugh T. Philipp, Joel T. Weiss, Prafull Purohit, Darol Chamberlain, Sol M. Gruner

Abstract: Pixel Array Detectors (PADs) consist of an x-ray sensor layer bonded pixel-by-pixel to an underlying readout chip. This approach allows both the sensor and the custom pixel electronics to be tailored independently to best match the x-ray imaging requirements. Silicon sensors have limited stopping power for x-rays above about 20 keV, suggesting need for sensors with higher atomic number. CdTe sensors have been mated to two different charge-integrating readout chips, the Keck PAD and the Mixed-Mode PAD (MM-PAD), both developed previously in our laboratory, and previously demonstrated when bonded to Si sensors.

Here we present results from first experiments at the CHESS beamline A2 and characterization measurements showing that both systems can be used for a wide range of experiments at up to 100 keV and beyond.

 
"Studying Martensitic Transformations Using High Energy Diffraction Microscopy"

Ashley Bucsek1, Harshad Paranjape1,2, Branden Kappes1, Darren Dale3, Margaret Koker3, Jun Young Peter Ko3, Aaron Stebner1
1Colorado School of Mines, Golden, CO, USA
2Northwestern University, Evanston, IL, USA
3Cornell High Energy Synchrotron Source, Ithaca, NY, USA

Abstract: Exciting advances are being made in the field of high energy diffraction microscopy (HEDM), including both data collection and corresponding data analysis methods. However, HEDM techniques are presently limited to “ideal” material systems—ones whose individual granular diffraction spots are clearly discernable. Such materials are typically comprised of large grains with relatively high crystal symmetry and small amounts of intragranular mosaicity. Yet, many “non-ideal” (in an HEDM-sense) material classes have long-lasting open questions that could be answered by HEDM if analysis tools could handle smaller grains, lower symmetry crystal structures, and larger amounts of mosaicity. One specific example is materials that undergo martensitic transformations. These materials are often highly deformed and consist of multiple phases. The martensite phase is usually comprised of smaller, non-equiaxed grains of relatively low symmetry (e.g., tetragonal, orthorhombic, monoclinic) and may be accompanied by significant plastic deformation. These microstructures result in diffuse, overlapping diffraction spots, even when they form from “ideal” HEDM austenite phases. We present three tools for adapting current HEDM data analysis frameworks for materials that undergo martensitic transformations, but can be applied to other “non-ideal” material system. We motivate the necessity for such tools by discussing three different example data sets collected at CHESS in connection with the scientific incentives for studying them. All three examples are single-crystal (in the austenite phase), but still have so much complexity that they require special analysis tools. The efficacy of these tools is demonstrated, and future analysis techniques for polycrystals are discussed.

 

 
"Experimental Determination of Non-woven Bond Strength Distributions"

Naigeng Chen1, Margaret K. A. Koker2, and Meredith N. Silberstein *1
1Sibley School of Mechanical and Aerospace Engineering, Cornell University, Ithaca, NY, USA
2Cornell High Energy Synchrotron Source, Cornell University, Ithaca, NY, USA

Abstract: Bond fracture greatly affects the strength and damage progression of many non-wovens. Here we present a novel combined experimental and simulation approach to extract the bond strength of a particular non-woven. The approach was implemented for a commercial polyprolylene non-woven. A small non-woven specimen was imaged by micro computed tomography (μCT) and then subjected to uniaxial tensile loading through complete failure. The geometry of the non-woven was imported from the μCT data into a discrete finite element model. Using known fiber properties, the bond properties were then determined by comparing the simulated load-displacement curve with the experimental load-displacement curve. The sensitivity of the load-displacement curve to bond strength distribution will also be presented.

 
"Phase Transition and Bandgap Tuning of Methylammonium Lead Iodide Perovskite under Pressure"

Jiye Fang

 

 
"An evaluation of geochemistry in the Upper Beaver deposit of the Kirkland Lake area: Towards a new gold exploration model"

K Feick1, N Banerjee1, M Masson2, R Zalnieriunas2
1Earth Sciences Department, University of Western Ontario, London, Ontario; 2Canadian Malartic Corporation, Upper Canada Mine Site, Dobie, Ontario

Abstract: Canadian Malartic Corporation (CMC) currently maintains the largest land holdings package in the Kirkland Lake gold camp. Recent work on the property is focused on developing a structural, chemical, and rheological framework for fluid-rock interactions, deposition mechanisms, and mineralization across the property. The objective of this study is to assist in the development of a new exploration model for CMC’s Upper Beaver project, a syenite-intrusion related deposit within the lode-gold dominated Kirkland Lake camp, by assessing trace element associations with gold mineralization to elucidate deposit formation and the source of the gold and to inform future exploration efforts. The project will utilize bulk-rock geochemical data acquired by CMC from drill hole and surface outcrop samples for their Upper Beaver deposit and surface sampling program to identify large-scale geochemical trends. Additional collected samples will undergo a combination of petrography, x-ray diffraction, scanning electron microscope, and synchrotron analysis to aid in determining trace element associations with gold. Ultimately the study aims to tie together mass amounts of bulk rock geochemical data with statistical and synchrotron analysis to distinguish spatial changes in trace element compositions and thereby providing a new framework for looking at fluid evolution, deposition mechanisms, and fluid-rock interactions, as well as providing novel trace element exploration vectors.

 

 
"Solution SAXS and in situ GISAXS Study of the Fabrication of Asymmetric Block Copolymer Membranes"

Yibei Gu, Rachel M. Dorin, Yuk Mun Li,¥ Qi Zhang, Kwan W. Tan, Deb́ora Salomon Marques, Hiroaki Sai, Ulla Vainio,§ William A. Phillip, Detlef-M. Smilgies, Klaus-Viktor Peinemann, Suzana P. Nunes and Ulrich Wiesner*†
Department of Materials Science and Engineering and ¥Robert Frederick Smith School of Chemical and Biomolecular Engineering, Cornell University, Ithaca, NY14850, US
Water Desalination and Reuse Center and Advanced Membrane and Porous Materials Center, King Abdullah University of Science and Technology (KAUST), Thuwal, 23955-6900, Saudi Arabia
§HASYLAB at DESY, Notkestr. 85, 22607 Hamburg, Germany
Department of Chemical and Biomolecular Engineering, University of Notre Dame, Notre Dame, Indiana 46556, United States
Cornell High Energy Synchrotron Source (CHESS), Cornell University, Ithaca, NY 14850, US

Abstract: Evaporation-induced asymmetric block copolymer membrane formation from diblock copolymer polystyrene-block-poly(4-vinylpyridine) (SV) and triblock terpolymer polyisoprene-block-polystyrene-block-poly(4-vinylpyridine) (ISV) was studied using solution Small-angle X-ray scattering (SAXS) analysis and in situ grazing incidence small-angle X-ray scattering (GISAXS). Solution SAXS analysis of SV in a ternary solvent system of 1,4-dioxane, tetrahydrofuran, and N,N-dimethylformamide, and ISV in a binary solvent system of 1,4-dioxane and tetrahydrofuran, reveals a concentration-dependent onset of ordered structure formation. Asymmetric membranes fabricated from casting solutions with polymer concentrations at or slightly below this ordering concentration possess selective layers with the desired nanostructure. In addition to rapidly screening possible polymer solution concentrations, solution SAXS analysis also predicts hexagonal and square pore lattices of the final membrane surface structure.

Furthermore, an in-depth analysis during the self-assembly of doctor bladed solutions by in situ GISAXS shows transient ordered structures for two ISV terpolymers at intermediate evaporation times in the top surface layers of the films as a function of molar mass and solution concentration. Analysis of the GISAXS patterns revealed the evolution from disordered to ordered structures including a transition from body-centered cubic (BCC) to simple cubic (SC) lattices, and finally to an amorphous mesoscale structure. The BCC to SC transition solves an apparent structural puzzle resulting from comparisons of, on one side, earlier quiescent solution SAXS studies suggesting BCC terpolymer micelle structures at higher concentrations and, on the other side, electron microscopy studies consistent with SC lattices originating from polymer micelles in the top separation layer of asymmetric ISV membranes.

These studies suggest solution SAXS as a powerful tool for screening casting solution concentrations and predicting surface structure while in situ GISAXS offers insights into the structural evolution of asymmetric triblock terpolymer film formation, which may enable further optimization of self-assembly plus non-solvent induced phase separation (SNIPS) based high performance isoporous asymmetric block copolymer ultrafiltration membranes.

 

 
"How (and why) to quantify radiation damage in biological small-angle x-ray scattering"

Jesse B. Hopkins, Robert E. Thorne

Abstract: Small-angle X-ray scattering (SAXS) is a popular technique for acquiring low-resolution structural information about biological macromolecules in solution. Many of the practical limitations of the technique, such as minimum required sample volume, and of experimental design, such as sample flow cells, are necessary because the biological samples are sensitive to damage from the X-rays. Radiation damage typically manifests as aggregation of the sample, which makes the collected data unreliable or completely unusable. However, there has been little systematic investigation of the most effective methods to reduce damage rates, and results from previous damage studies are not easily compared to results from other beamlines. We describe a methodology for quantifying radiation damage in SAXS to achieve consistent results between different experiments, experimenters, and beamlines. We demonstrate these methods on radiation damage data collected from lysozyme, glucose isomerase, and xylanase, and find that no single metric is sufficient to describe radiation damage in SAXS for all samples. We find the radius of gyration, molecular weight, and integrated SAXS profile intensity to be a minimal set of parameters that capture all types of observed behavior. Radiation sensitivities derived from these parameters show large protein dependence, varying by up to six orders of magnitude between the different proteins tested. This work should enable consistent reporting of radiation damage effects, allowing systematic studies of the most effective minimization strategies.

Reference:
Hopkins, J. B., Thorne, R. E. Quantifying Radiation Damage in Small-Angle X-ray Scattering. J. Appl. Cryst. 49 (2016).

 

 
"Improvement of Diffraction Resolution of Protein Crystals by High-pressure Cryocooling"

Qingqiu Huang
MacCHESS, Cornell University

Abstract: Production of high quality crystals is one of the major obstacles in determining the three-dimensional structure of macromolecules by X-ray crystallography. It is fairly common that a visually well-formed crystal diffracts poorly, to a resolution too low to be suitable for structure determination. To improve the crystal quality (mostly the diffraction resolution), several types of post-crystallization treatments, such as dehydration, annealing and cross-linking, have been utilized. However, each of these treatments works for only a few crystals. A relatively frequent occurrence is that the quality of a crystal cannot be improved even after all current post-crystallization treatments have been tried. Therefore, new post-crystallization treatment methods are eagerly awaited. Here it is reported that high-pressure cryocooling (HPC) can improve the diffraction resolution of protein crystals. Using HPC at 350MPa, the diffraction resolution of the crystal of the Legionella effector lpg1496 has been improved from 2.5Å to 1.5Å. Using HPC at 200MPa, the diffraction resolution of the crystal of the ESCRT-III subunit snf7 has been improved from 2.4Å to 1.6Å. The mechanisms for these improvements have also been discussed.

 

 
"Quantitative X-ray fluorescence computed tomography for trace element mapping in biological samples"

Rong Huang1, Karin Limburg2, Darren Dale3, Mehis Rohtla4
1CHESS Cornell University, Ithaca, NY, USA
2SUNY College of Environmental Science and Forestry, Syrause, NY, USA
3CCMR, Cornell University, Ithaca, NY, USA
4University of Tartu, Estonia

Abstract: Different from X-ray absorption tomography, X-ray fluorescence computed tomography (XFCT) is no longer just a case of Radon transform in general but complicated by sample attenuation of both incident and fluorescent X-rays. Many algorithms have been developed to reconstruct XFCT with absorption corrections. Based on open source (absorption) tomography software and our own XFCT reconstruction method, we successfully performed quantitative XFCT reconstruction of trace elements inside biological sample. Numerical simulation demonstrated the accuracy of our reconstruction method on absorption correction. XFCT was performed with real biological sample, a fish eye lens. X-ray fluorescence (XRF) data was pre-processed with Praxes, a software developed in house at CHESS to wrap PyMCA which performs quantitative XRF data processing. Quantitative results of XFCT reconstruction agreed well with 2D SXFM mapping.

 

 
"Operando X-ray Microscopy and X-ray Diffraction of Lithium Sulfur Batteries"

Xin Huang1,2*, Seung-Ho Yu3*, Rong Huang2, Joel. D. Brock1,2, Héctor D. Abruña3
1Cornell High Energy Synchrotron Sources, 2School of Applied and Engineering Physics, 3Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853, USA

*Equal contributed

Abstract: Lithium-sulfur (Li-S) batteries have been extensively studied because sulfur has a high theoretical specific capacity (1672 mAh/g) and is abundant on earth. However, there are problems to be solved before practical use of Li-S battery can be realized, such as the production of a series of soluble polysulfide intermediate species in the battery operation. To improve the electrochemical properties of the Li-S battery, we need to further understand the detailed reaction mechanisms happening during the cycling of the battery.

In this poster, we present our results of using operando X-ray microscopy and X-ray diffraction to study the evolution of morphology as well as the crystal structure of the sulfur and lithium sulfide on the cathode while cycling the battery.

 

 
"Quest for Ultra Strong Multilayer Graphene as X-ray Transparent SAXS/WAXS Window and Protein Crystal Wrapping Material"

Gabrielle Illavaa, Jeney Wiermana,b, Richard Gillilana & Sol M. Grunera,c
aCHESS, Cornell University, Ithaca, NY 14853
bField of Biophysics, Cornell University, Ithaca, NY 14853
cDepartment of Physics, Cornell University, Ithaca, NY 14853

Abstract: Graphene is a single atom thick hexagonal carbon lattice that is the strongest material known to humankind [1]. Because of this strength we are exploring its use as atomically thin, X-ray transparent and vacuum tight windows, as well as a material to hermetically wrap wet protein crystals for x-ray diffraction [2]. Reducing the mass of material between the X-ray source, sample, and detector is crucial to reducing x-ray background so as to be able to extract the highest quality data from diffraction experiments. Most graphene films utilize polymethylmethacrylate (PMMA) as a support layer. However, PMMA degrades upon exposure to an X-ray beam [3], and graphene is significantly weakened by the resultant contamination [1]. Therefore any amount of polymer on the graphene window would be problematic. Our solution is to grow large grain multi-layer graphene (LGMLG) that is strong enough to stand alone with no polymer backing. Initial diffraction tests at G1 show that there is a promisingly low background scatter. We believe this background scatter could be reduced by increasing the uniformity of the growth with further adaptation of the graphene recipe.

[1] Lee, C., Wei, X., Kysar, J.W., and Hone, J. (2008). “Measurement of the Elastic Properties and Intrinsic Strength of Monolayer Graphene”. Science (321) 385–388.
[2] Wierman, J.L., Alden, J.S., Kim, C.U., McEuen, P.L. and Gruner, S.M. (2013). “Graphene as protein crystal mounting material to reduce background scatter”. J. Appl. Cryst., (46) 1501-1507.
[3] Yates, B. W. and Shinozaki, D. M. (1993), “Radiation degradation of poly(methyl methacrylate) in the soft x-ray region”. J. Polym. Sci. B Polym. Phys., (31) 1779–1784.

 

 
"Phase Transition and Bandgap Tuning of Methylammonium Lead Iodide Perovskite under Pressure"

Shaojie Jiang,1 Ruipeng Li,2 Yanan Fang,3 Chenyu Wang,4 Zhongwu Wang,2 Timothy J. White,5 Tom Baikie3 and Jiye Fang1,4
1Materials Science and Engineering Program, State University of New York at Binghamton, Binghamton, New York 13902, United States
2Cornell High Energy Synchrotron Source, Cornell University, Ithaca, New York 14853, United States
3Energy Research Institute@NTU (ERI@N), Nanyang Technological University, Nanyang Drive, Singapore 637553, Republic of Singapore
4Department of Chemistry, State University of New York at Binghamton, Binghamton, New York 13902, United States
5School of Materials Science and Engineering, Nanyang Technological University, Nanyang Avenue, Singapore 639798, Republic of Singapore

Abstract: We report the pressure-induced crystallographic transitions and optical behavior of MAPbI3 using in-situ synchrotron X-ray diffraction and laser-excited photoluminescence spectroscopy. The tetragonal polymorph determined at ambient pressure transforms to a ReO3-type cubic phase at 0.3 GPa. Upon continuous compression to 2.7 GPa this cubic polymorph converts into a putative orthorhombic structure. Beyond 4.7 GPa it separates into crystalline and amorphous fractions. During decompression, this phase-mixed material undergoes distinct restoration pathways depending on the peak pressure. In-situ pressure-photoluminescence investigation suggests a reduction in bandgap with increasing pressure up to ~0.3 GPa and then an increase in bandgap up to a pressure of 2.7 GPa. This work lays the foundation for understanding the pressure-dependent phase transition of MAPbI3 and potentially enriches the toolkit for engineering perovskite polymorphs with exceptional optical properties.

 

 
"Development of Simultaneous Real-time X-ray Reflectivity Using Monochromatic Radiation"

Howie Jorress
CHESS, Cornell University

Abstract: Here we present our work on the development of a synchrotron based, monochromatic, real-time x-ray reflectivity measurement technique. We utilize a polycapillary x-ray optic to produce a converging fan of radiation which provides a range of simultaneous incident angles. Since the specular reflection dominates the diffracted signal, using a 2D detector allows us to collect a swath of the reflectivity curve simultaneously. Our capillary is capable of collecting up to 5° in 2θ with a focal distance of 22 cm. We demonstrate its real-time capabilities by measuring reflectivity curves around the anti-Bragg during epitaxial growth of LSMO on STO (100) by pulsed laser deposition.

 

 
"Tracking intermediate states of carbonic anhydrase during CO2 release"

Chae Un Kima,b, HyoJin Songc, Balendu Sankara Avvarud, Sol M. Grunera,e, SangYoun Parkc, and Robert McKennad
aCornell High Energy Synchrotron Source, Cornell University, Ithaca, NY 14853
bDepartment of Physics, Ulsan National Institute of Science and Technology, Ulsan 44919, Republic of Korea
cSchool of Systems Biomedical Science, Soongsil University, Seoul 06978, Republic of Korea
dDepartment of Biochemistry and Molecular Biology, College of Medicine, University of Florida, Gainesville, FL 32610
eDepartment of Physics, Cornell University, Ithaca, NY 14853

Abstract: Carbonic anhydrases are mostly zinc metalloenzymes that catalyze the reversible hydration/dehydration of CO2/HCO3.Previously, the X-ray crystal structures of CO2-bound holo (zinc-bound) and apo (zinc-free) human carbonic anhydrase IIs (hCA IIs) were captured at high resolution. In this study, we use the pressure cryocooling method to capture the gaseous carbon dioxide in crystals of carbonic anhydrase and then follow the sequential structure changes as the captured carbon dioxide is released. The obtained crystallographic “snapshots” enable us to visualize the water and protein motions that form a “proton wire” as the carbon dioxide exits the enzyme’s active site. Specifically it is found that two active site waters, WDW (deep water) and WDW′ (this study), replace the vacated space created on CO2 release, and another water, WI (intermediate water), is seen to translocate to the proton wire position W1. In addition, on the rim of the active site pocket, a water W2′ (this study), in close proximity to residue His64 and W2, gradually exits the active site, whereas His64 concurrently rotates from pointing away (“out”) to pointing toward (“in”) active site rotameric conformation. This study provides for the first time, to our knowledge, structural “snapshots” of hCA II intermediate states during the formation of the His64-mediated proton wire that is induced as CO2 is released. Comparison of the holo- and apo-hCA II structures shows that the solvent network rearrangements require the presence of the zinc ion.

 

 
"Comparison of Supercrystals Made by Octahedra and Cubes"

Ruipeng Li, Zhongwu Wang
CHESS, Cornell University

Abstract: Nanocrystals (NCs) behave like atoms, functionalize with surface-coating molecules, and self-assemble into periodically ordered superlattice (SL). Recent advances on synthesis and assembly of NCs have been witnessed by fast growth of NC-assembled superlattices, made up of single, binary or ternary components over control of NC size, shape and composition. However, programmable design of supercrystals with expected structure for desirable applications is still constrained by limited understanding NC−ligand interactions in solvent-mediated NC assembly processes. Meanwhile, low penetration of electron beam used for structural characterization in electron microscopy provides information of only very thin layers, which differs significantly from large assembled samples.

We have grown large single supercrystals and developed ‘supercrystallography’ as a synchrotron-based Small/Wide Angle X-ray Scattering (SAXS/WAXS) approach for single supercrystal to overcome the low in-depth penetrating ability and resolve the structure of nanocrystal assembly from atomic to mesoscale. We collected a series of SAXS/WAXS images of supercrystal, which allow us to accurately reconstruct the shape orientations of NCs at various crystallographic sites and explore the inter-particle packing configurations. In situ SAXS measurements under high pressure offer additional insights into surface ligand density and nature of ligand–NC interactions, as well as the correlations between strain and lattice distortion, which present a primary image of various superlattice polymorphs to elucidate the superlattice transformations and associated developing pathways. These results provide detailed structural information towards controlled design and efficient materials-processing for fabrication of nano-based functional materials with tailored structures and desired properties.

 

 
"CONSEQUENCES OF THE TRIFLUOROMETHYL GROUP ON TRANSITION METAL ELECTRONIC STRUCTURE"

James Lukens

Abstract: Traditional trifluoromethylation reactions can be categorized under being either nucleophilic (-CF3) or electrophilic (+CF3), with nucleophilic CF3 introduction being the more heavily researched. Through a combination of spectroscopic and computational methods, we have shown the ability of the trifluoromethyl group to impart an “inverted ligand field” on traditional copper-based transition metal complexes (e.g. Cu(CF3)4-), in which the Cu(I) center is coordinated by three -CF3 and one +CF3.

 

 
"Domain Movements upon Activation of Phenylalanine Hydroxylase"

Steve P. Meisburger, Alexander B. Taylor, Crystal A. Khan, Shengnan Zhang, Paul F. Fitzpatrick, and Nozomi Ando
Department of Chemistry, Princeton University
Department of Biochemistry, University of Texas Health Science Center, San Antonio

Abstract: Phenylalanine is an essential amino acid used in protein and neurotransmitter synthesis that must be obtained from the diet. However, too much phenylalanine in the blood results in severe mental disability if u ntreated. This condition, known as phenylketonuria (PKU), affects about 1 in 10,000 children born in the US and is caused by mutations in the gene encoding phenylalanine hydroxylase (PheH), an enzyme which converts phenylalanine to tyrosine in the liver. In order to maintain safe phenylalanine levels, PheH is known to be allosterically activated by its substrate. Yet, despite decades of study, the changes in structure upon activation have been elusive. To characterize the domain rearrangements that occur during activation of this dynamic enzyme, we applied the solution-based structural technique small-angle X-ray scattering (SAXS). Size exclusion chromatography (SEC) was performed in-line with X-ray data collection, resulting in large datasets that were analyzed globally. We describe the first application of Evolving Factor Analysis (EFA), a powerful linear algebra technique for separating overlapping scattering components in a model-independent way. Together with complimentary information from crystallography and isothermal titration calorimetry, the SAXS data support a model in which phenylalanine binding stabilizes a regulatory domain dimer, exposing the active site to enable catalytic activity.

 

 
"Real Time Cooling Of Protein Crystals"

David Moreau

Abstract: One obstacles of variable temperature crystallography is rapid ice formation in the range T = 180 to 220K. Additionally, there remains a lack of understanding of the process of cooling protein crystals. Real-time cooling of protein crystals, where crystals are cooled and data is immediately obtained addresses this. Full data sets can be obtained in the delay between cooling and ice formation, also new insights into the cryocooling process can be deduced.

 

 
"Solidification pathway of perovskite material & its impact towards device performance"

Rahim Munir, Arif D.Sheikh, Maged Abdelsamie, Liyang Yu, Kui Zhao, Hanlin Hu, Taesoo Kim, Ruipeng Li, Detlef-M. Smilgies, Aram Amassian

Abstract: Solar energy is one of the reliable energy generation sources for the future. Perovskite solar cells introduced a way out with high power conversion efficiencies and low cost of processing. Although, perovskite based solar cells have achieved high PCE in short time span, still the basic understanding of formation of perovskite active layer lacks behind. To cater the need of deeper understanding of the processing parameters to form the active layer we have studied in-situ spin coating of perovskite material under high energy x-ray source. Our results indicates that this solution processing resembles sol-gel processing to form thin films.

 

 
"Solution processing of Organic Semiconductors: Evidence of Two step Nucleation"

Muhammad Rizwan Niazi, Ruipeng Li , Ahmad R Kirmani, Kui Zhao, Maged AbdelSamie , Er Qiang Li, John E. Anthony, Sigurdur T. Thoroddsen & Aram Amassian

Abstract: Organic electronics are attractive due to the promise of large-area, continuous roll-to-roll manufacturing of devices at potentially low-cost. We explore the solution-shearing process, similar to knife-coating and doctor-blading processes, but at lower angle of attack of the blade. This method is attractive as it is compatible with scalable continuous manufacturing. We observe evidence of an intermediate state of the solute formed in conditions of fast blade movement, using methods such as in situ microbeam x-ray diffraction, in situ optical microspot reflectometry and in situ polarized optical microscopy. We explore the consequences of this in terms of microstructure, morphology and OFET device performance.

 

 
"Crystal structure of yeast V1-ATPase in the autoinhibited state"

Rebecca Oot

Abstract: The X-ray crystal structure of the V1-ATPase sector from S. cerevisiae was solved at ~ 7Ã… resolution. All seven subunits (15 protomers in total, with stoichiometry A3B3DE3G3HF) appear in the electron density map with two complexes in the ASU totaling 1.2 MDa. The structure reveals the V1 sector in its autoinhibited state, accompanied by a large scale domain rotation of subunit H. Further, using biochemical experiments we have identified a loop in subunit H responsible for enzyme inhibition.

 

 
"Understanding Nucleic Acid Structural Changes by Comparing Wide-Angle X-ray Scattering (WAXS) Experiments to Molecular Dynamics Simulations"

Suzette Pabit

Abstract: Wide-angle x-ray scattering (WAXS) is emerging as a powerful experimental tool for increasing the resolution of solution structure measurements of biomolecules. Here, we show the potential of WAXS to test all-atom molecular dynamics (MD) simulations and to provide insight in understanding how the trivalent ion cobalt(III) hexammine (CoHex) affects the structure of RNA and DNA helices. We find that MD simulations capture the RNA structural change that occurs due to addition of CoHex.

 

 
"Measuring the Evolution of Granular Stress Distributions using High Energy X-ray Diffraction and Micro-Tomography"

Darren Pagan, J. Lind, M.A. Homel, E.B. Herbold, M.C. Akin
Lawrence Livermore National Laboratory, Livermore, CA 94551

Abstract: Having the capability to measure stresses in the individual grains of a three dimensional assembly under load has long been a desire of the granular mechanics community. These data can greatly aid the development and testing of new micromechanical models. With new high-energy X-ray diffraction techniques performed at synchrotron light sources, these grain stress data are now possible to attain. Results are presented from a combined X-ray diffraction / micro-tomography experiment during the uniaxial compression of a collection of spherical, ruby single crystals. The evolution of a grain stresses of ~500 grains in the assembly, which were measured using X-ray diffraction, are shown. In addition, the relationships between the grains stresses and the topology of the grains, which were measured using micro-tomography, are also explored.

This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.

 

 
"High-Speed, High Dynamic Range Pixel Array Detector for Scanning Transmission Electron Microscopy"

Prafull Purohit1, Mark W. Tate1, Kayla X. Nguyen3, Darol Chamberlain2, David A. Muller4,5, Sol. M. Gruner1,2,5
1Laboratory of Atomic and Solid State Physics, Physics Department, Cornell University, Ithaca, NY
2Cornell High Energy Synchrotron Source (CHESS), Cornell University, Ithaca, NY
3Department of Chemistry and Chemical Biology, Cornell University, Ithaca, NY
4School of Applied and Engineering Physics, Cornell University, Ithaca, NY
5Kavli Institute for Nanoscale Science, Cornell University, Ithaca, NY

Abstract: This poster is an example of how progress in one area, namely developments in advanced x-ray detectors, enables advances in another area, in this case electron microscopy.

In scanning transmission electron microscopy (STEM), a highly focused beam of electrons is scanned over a thin specimen and transmitted electrons are recorded at each scan position. The electron diffraction pattern at every scan position provides rich, quantitative information about specimen such as crystal structure, defects, strain, and local fields, etc. However, in practice, such measurements are limited due to challenges in detecting the diffraction pattern with sufficient sensitivity, dynamic range and fast diffraction image acquisition time.

In order to meet these challenges, we have successfully developed an electron microscope pixel array detector (EMPAD), adapted from the mixed mode pixel array x-ray detector (MMPAD) previously developed by our group. The EMPAD has been used on a FEI Tecnai F20 and a Titan Themis STEM with electron energies ranging from 60 keV to 300 keV. The MMPAD consists of a 128x128 pixel detector with sufficient sensitivity for high signal-to-noise recording of each electron, yet has sufficient dynamic range to also capture millions of electrons/pixel/frame, all while framing at > 1 kHz. By recording the entire electron scattering pattern at each scan position, the MMPAD can be used to simultaneously compute all the standard modes of microscopy, including bright field, annular dark field, high-angle annular dark field, and differential phase contrast reconstructions from a single scan of the sample. In addition, this scattering information can be used for more complex analysis, such as the measurements of slight beam displacements to extract the Lorentz force on the beam, thereby allowing detection of atomic magnetic fields.

 

 
"The Mixed-Mode Pixel Array Detector Family"

Katherine S. Shanks1, Hugh T. Philipp1, Joel T. Weiss1,2, Julian Becker1,2, Mark W. Tate1, Prafull Purohit1, Darol Chamberlain2, and Sol M. Gruner1,2
1Department of Physics, Cornell University, Ithaca, NY 14853
2Cornell High Energy Synchrotron Source (CHESS), Cornell University, Ithaca, NY 14853

Abstract: We describe the development of a family of area detectors based on the Mixed-Mode Pixel Array Detector (MM-PAD), originally designed as a direct-detection x-ray camera with a Si sensor. The original MM-PAD is a photon-integrating pixel array detector optimized for experiments requiring a high frame rate and/or wide dynamic range. A mixed analog and digital readout scheme is used to achieve a pixel well depth of 4x107 8 keV photons while maintaining single-photon sensitivity. Due to the photon-integrating pixel front-end, the MM-PAD can tolerate a sustained hit rate of 108 photons/pixel/s, exceeding the hit rate limit of photon-counting PADs. Additionally, the MM-PAD can frame continuously at over 1 kHz. A tiled unit with 256 x 384 pixels has been used in a variety of experiments at CHESS, the APS, PETRA-III and the ESRF. Development has since expanded into a family of detectors: 1) a similar x-ray camera with a CdTe sensor for improved stopping power at x-ray energies above 20 keV, 2) a 128 x 128 pixel unit (EM-PAD) installed in an atomic-resolution scanning transmission electron microscope, and 3) a next-generation x-ray camera with improved high-flux performance, the High Dynamic Range PAD (HDR-PAD), presently in early-stage prototyping. See other posters in this session for more information on some of these detectors.

 

 
"X-Ray Raman Spectroscopy of Metal-Oxo Species at the Cornell High Energy Synchrotron Source"

Katharine Silberstein, Kenneth Finkelstein, Kyle Lancaster
Cornell High Energy Synchrotron Source, Cornell University, Ithaca, NY, USA

Abstract: X-ray Raman spectroscopy (XRS) is an inelastic scattering method that allows detection of low-energy (<3keV) spectroscopic signatures using high-energy x-rays, typically by exciting core electrons of low-Z elements such as carbon and oxygen. The signals look much like x-ray absorption near-edge spectroscopy (XANES), but the element K-edges (EK) are not otherwise accessible at CHESS. XRS enables the speciation of functional groups, as well as the determination of bond covalency between light-atom ligands and metal centers. Analyzer crystals are positioned to collect and reflect scattered photons at hard x-ray energy E1 as incident beam energy E0 is scanned in the vicinity of E1 + EK. This scattering is weak, so both high incident flux (within 1eV bandwidth), and large collection solid angle (at comparable energy resolution) are essential.

To perform XRS at CHESS, a new spectrometer design was required. CHESS has developed a 7-crystal system with high collection efficiency. The analyzers are mounted on a diffractometer arm to access a range of momentum-transfer values. Analyzer position is optimized depending on the desired EK to minimize Compton and other background scattering. An area detector images backscattered inelastic signals. The sample, as well as the incident and scattered beams, are contained within a helium atmosphere to reduce air scattering. In initial experiments, researchers tested the new spectrometer by measuring x-ray Raman spectra at K-edges of C in diamond and graphite; B and N in boron nitride; O in copper and zinc oxides; and Mg in magnesium chloride. Samples were prepared by pelletizing powders diluted with an appropriate amount of boron nitride for effective transmission.

This new capability will become an essential tool with wide applications after the CHESS upgrade is completed. Once components to improve signal/noise have been added to the spectrometer system, users will be able to probe the electronic structure of light atoms in molecules and systems of interest in a variety of sample environments: under high pressure; during a chemical reaction; or in low concentration. With the commissioning of XRS at C1, CHESS will become a destination for spectroscopists desiring information that would otherwise be obtained using soft X-rays in manners that impose constraints on sample scope.

 

 
"Finding the source of Fracture Failure in Al alloys with SAXS"

M. A. Singh1, S. Saimoto2, M. R. Langille2, J. Lévesque3, K. Inal4, A. R. Woll5
1Physics, Engineering Physics & Astronomy, Queen’s University, Kingston, ON, Canada K7L 3N6
2Mechanical & Materials Engineering, Queen’s University, Kingston, ON, Canada K7L 3N6
3Mechanical Engineering, Laval University, Québec, QC, Canada G1V 0A6
4Mechanical & Mechatronics Engineering, University of Waterloo, Waterloo, ON, Canada N2L 3G1
5Cornell University, 200L Wilson Laboratory, Ithaca, NY, USA 14853

Abstract: Our recent work on ductile failure of aluminum alloys suggests that the origin of nanovoids leading to fracture resides in the initial prepared stock material. Nanovoid growth occurs due to the generation of vacancies during plastic deformation. The volume fraction of vacancies produced can be predicted from the mechanical data and small angle X-ray scattering (SAXS) analysis methods were used to validate this prediction. While SAXS is a well-established tool for characterizing nanoscale structural details, applications to metal samples are complicated by the presence of scattering artifacts resulting from interaction of the x-ray probe with the metal matrix, a major obstacle when dealing with deformed metals. This work outlines a simple and efficient method of identifying and removing these artifacts in deformed Al-Mg-Si alloys to reveal the underlying nanovoid nucleation and growth. The process is applied to scattering data obtained using the CHESS G1 beamline. The information provided by this study will be used to develop a comprehensive understanding of the material design requirements for high strength –weight ratio Al alloys for specific applications in automotive engineering.

 

 
"Mine to Micron Characterization of Gold and Arsenic in the Dome Mine Ankerite Veins: Synchrotron X-ray Spectroscopy of Whole Rock Samples"

Jessica M. Stromberg, Lisa L. VanLoon, Neil R. Banerjee, Erik Barr

Abstract: The historic Dome mine in Timmins, Ontario has produced over 16 million ounces of gold to date, of which ~20% has been mined from its massive ankerite veins. Gold in the ankerites is present as multiple generations and is intimately related to pyrite mineralization, both as inclusions, fracture fill, as well as nanoparticles and/or in the pyrite crystal lattice. Secondary ion mass-spectrometry analysis indicates that invisible gold in Dome arsenian pyrites correlates with As content, and high-resolution transmission electron microscopy has identified it in arsenic rich inclusions in growth haloes.

The high flux and energy of a synchrotron light source allows for rapid, high resolution detection of trace metals and invisible gold by µXRF (x-ray fluorescence), and characterization of their spatial distribution. As well, the nature of invisible gold (speciation) can be identified using XANES (x-ray absorption near edge spectroscopy). The non-destructive nature of these analyses means that mineralogical context is preserved, and samples do not require extensive preparation or characterization, only a good understanding of their geologic context and a smooth surface. This represents a paradigm shift in the application of high resolution analysis for mining. Cut slabs, thin sections and corresponding offcuts have been mapped in their entirety at 20um resolution, providing unprecedented contextual trace element information which can be tied to mineralogy. In addition, large mineralized regions were mapped using XANES to identify variability and correlations in As and Au speciation. This information provides a new framework for investigating mineralizing fluids, fluid evolution, depositional mechanisms.

 

 
"Gyroidal Mesoporous Silicon Oxynitride Monoliths: A Mesoscale Matrix for Bicontinuous Hybrids"

Ethan Susca

Abstract: Polymer Self-Assembly is a versatile approach to structure materials beyond lithographic limits. Here a preceramic polymer is self-assembled with a block copolymer into the bicontinous double gyroid structure (Space group Ia3d, Q230). The structure survives pyrolysis under harsh atmospheres to form a mesoporous silicon oxynitride stable to 1450 ˚C. Gold is then deposited into this porous template to form a 3D ordered metamaterial composite.

 

 
"ABC triblock copolymer self-assembly for the preparation of long range ordered isoporous membranes"

Burhannudin Sutisna, Valentina Musteata, Georgios Polymeropoulos, Detlef-M. Smilgies, Klaus-Viktor Peinemann, Nikos Hadjichristidis and Suzana P. Nunes

Abstract: Block copolymer self-assembly and non-solvent induced phase separation (NISP) are now being combined to fabricate membranes with narrow pore size distribution and high porosity. The method has the potential to be used with a broad range of tailor-made block copolymers to control functionality and selectivity for specific separations. In the present work we use this method to prepare asymmetric membranes with high porosity and regular pore size from a newly synthesized ABC terpolymer. To optimiz

 

 
"What's New at MacCHESS"

D. Szebenyi, R. Cerione, T.K. Chua, M. Cook, R. Gillilan, J. Hopkins, Q. Huang, I. Kriksunov, T. Lukk, W. Miller, D. Schuller, S. Smith and J. Wierman
MacCHESS, Cornell University, Ithaca, New York 14853

Abstract: MacCHESS conducts both core and collaborative research projects, and supports users doing "Macromolecular diffraction at CHESS". In 2015-2016, users employed CHESS facilities to collect crystallographic and small-angle solution scattering (BioSAXS) data on numerous molecules and complexes of biological interest. A sampling of users' important structural results, reported here, provides insight into how antibodies can neutralize a virus, how the antibiotic gramicidin is synthesized, and details of the biological effects of aspirin.

Developments in the major focus areas of MacCHESS include:

BioSAXS  – in-line SEC-SAXS is routinely available and increasingly popular; numerous software improvements have enhanced the user experience; design and procurement of apparatus for time-resolved studies is underway.

Pressure Cryocooling (HPC)  – a system has been developed for HPC using CO2 or O2, in order to trap these biologically active gases in crystals ; pressure-induced reduction of disorder, including high mosaicity and some forms of twinning, has been reported.

Microcrystallography  – use of intrinsic fluorescence to better visualize mounted crystals is routine; development of on-line confocal microscopy is continuing; equipment to produce a high-quality microbeam for serial microcrsytallography has been developed; investigation of graphene as a crystal mounting material is ongoing.

Dynamics  – development of sophisticated data analysis methods for diffuse scattering data is continuing.

Facility Upgrades  – equipment and procedures have been developed and refined to support multiple hutch/experiment combinations.

 
"Elemental Distribution in Goat Horns using Synchrotron Radiation Micro X-Ray Fluorescence (SR-µXRF) Analysis with the Maia Detector: A Quantitative Approach"

Mina Tehrani1,2, Arthur Woll3, Rong Huang3, Louisa Smieska3, Diana Guimarães2, and Patrick J. Parsons1,2
1Laboratory of Inorganic and Nuclear Chemistry, Wadsworth Center, New York State Department of Health (NYSDOH), Albany, NY
2Department of Environmental Health Sciences, School of Public Health, The University at Albany, Albany, NY
3Cornell High Energy Synchrotron Source (CHESS), Cornell University, Ithaca, NY

Abstract: Keratin tissues (e.g., hair, nails) are commonly used to assess environmental exposure due to their ability to incorporate trace elements and preserve elemental contents over time. However, reliability is diminished by lack of understanding of the mechanisms of elemental uptake and distribution, as well as by exogenous contamination. This study leveraged the CHESS Maia detector at the F3 beamline to perform SR-µXRF analysis of a model keratin tissue— horn from lead-dosed goats. A quantitative approach to measurement of Ca, S, Se, Cu, and Zn in horn was explored using pelletized hair reference materials and in-house horn quality control materials. Cross-sectional scans of 4 horns yielded qualitative and quantitative information. Elemental scans show a spatial distribution of Zn and S that is consistent with a Zn-cysteine binding mechanism, and suggest a possible antagonistic relationship for K-Ca. Contrary to previous studies, Zn did not appear to localize in pigmented regions of horn. Lead was not detected in the horns samples by µXRF. Preliminary findings may offer insights into the challenges faced with use of keratin samples for exposure assessment.

 

 
"Observation of transient phases during crystallization of solution-processed organic thin films"

Jing Wan

Abstract: We report an in-situ study of 2,7-dioctyl[1]benzothieno[3,2-b][1]benzothiophene (C8-BTBT) organic semiconductor thin film deposition from solution, which exhibits multiple transient phases during crystallization.

 

 
"Dynamic Range Extension Techniques for the HDR-PAD"

Joel Todd Weiss

Abstract: X-ray detector capabilities must advance in concert with synchrotron radiation light source technology to fully realize experimental possibilities. At present light source technology is outpacing detector development, and there is a dire need for new x-ray detectors capable of capturing wide dynamic range images. The High Dynamic Range Pixel Array Detector (HDR-PAD) is being developed at Cornell with the goal of extending dynamic range to 106 x-rays/pixel in a single XFEL or storage ring pulse while preserving single x-ray sensitivity. To satisfy detector needs at storage ring synchrotron sources, the detector will also be capable of tolerating a sustained flux of >1011 x-rays/pixel/s. These goals will be met by building on the architecture of the MM-PAD [1]. The MM-PAD uses a mixed analog and digital pixel with charge removal to prevent saturation of the integrating amplifier.

We describe three pixel architectures being pursued concurrently, each with a different charge removal mechanism. Their performance under constant, high level inputs is evaluated, and the next steps in HDR-PAD development are discussed.

 

 
"X-ray Capillary Beamline Improvements for Serial Microcrystallography at CHESS"

Jeney Wierman
MacCHESS, Cornell University

Abstract: In determining structure from protein crystals, the number of diffracted rays from the crystal, prior to irreversible radiation damage, decreases with crystal size. With any given source, there exists a lower limit to the size of a microcrystal where too few x-rays are collected per frame to determine the orientation of a small crystal using traditional methods. While our collaboration has helped push that boundary with the EMC algorithm (Loh & Elser, 2009) by reconstructing structure from “sparse” data of protein crystals with unknown orientations (Philipp et al., 2012; Ayyer et al., 2015), we also seek to push the lower limit on crystal size by increasing the flux density at our own source at Cornell High Energy Synchrotron Source (CHESS). By rebuilding beamlines A2 and G3 at CHESS with an emphasis on background reduction from scattering materials and creating a bright, clean micro-focused beam with a x-ray capillary, we showed that we can achieve 1e10 photons per second in a microfocused beam at beamline A2, and 1e12 photons per second in a microfocused beam at beamline G3. The results suggest that serial microcrystallography is feasible at CHESS.