A. Herring, OSU, uses tomography at 13 BMD to quantify pore scale trapping and to analyze how mechanisms affect the efficiency of capillary trapping of CO2 in saline aquifers.

Tomography at 13 BMD

A Best-Yet Cell Culture System for Age-Related Macular Degeneration

An international team utilizing 13-ID-E has developed a cell culture model that could help to develop earlier treatment strategies for age-related macular degeneration (AMD). Details in ANL Science Highlights based on press release from the University of Alabama at Birmingham.

A Best-Yet Cell Culture System for Age-Related Macular Degeneration

X-ray diffraction patterns from a diamond anvil cell (DAC).

X-ray diffraction is the most powerful technique for crystal structure determination. From left to right, patterns from a single crystal, polychrystalline, nano-cyrstalline and amorphous crystals.

X-ray diffraction patterns from a diamond anvil cell.

High pressure x-ray tomographic microscopy module

The HPXTM module helps researchers study the texture change of their sample under extreme pressure and temperature conditions by collecting in-situ HP/HT 3D x-ray tomographic images.

High Pressure X-ray Tomographic Microscopy Module sitting outside of the 250 ton press in 13 BMD.

GSECARS hosts experiments at 13 IDE for high school students in the Exemplary Student Research Program (ESRP) representing local area high schools. GSECARS Outreach

GSECARS Outreach

GSECARS is a national user facility
for frontier research in the earth sciences using synchrotron radiation at the
Advanced Photon Source, Argonne National Laboratory.

GSECARS provides earth scientists with access to the high-brilliance hard x-rays from this third-generation synchrotron light source. All principal synchrotron-based analytical techniques in demand by earth scientists are being brought to bear on earth science problems:

  • High-pressure/high-temperature crystallography and spectroscopy using the diamond anvil cell
  • High-pressure/high-temperature crystallography and imaging using the large-volume press
  • Powder, single crystal and interface diffraction
  • Inelastic x-ray scattering
  • X-ray absorption fine structure spectroscopy
  • X-ray fluorescence microprobe analysis
  • Microtomograph

► BEAMTIME
Register as a General User
Apply for Beamtime
Take APS Required Safety Training
Fill out Experiment Safety Assessment Form
 

DEADLINES
2018-2:  March 2, 2018, 11:59pm, CST
2018-3:  July 6, 2018, 11:59pm, CST


GSECARS 13 BMC User Phil Kong
Penn State, EMS Newsletter Spotlight

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Chromium is an intriguing heavy metal. While the reduced form of chromium acts as a nutrient and has a variety of industrial uses, its oxidized form, hexavalent chromium, is a carcinogen. Hexavalent chromium compounds have been shown to cause lung cancer in humans when inhaled. Furthermore, only manganese oxides can stimulate the oxidation of chromium. To investigate this phenomenon, Dr. Peter Heaney and I seek to better understand the chemical mechanism that governs the oxidation of chromium induced by birnessite, a robust and common variety of manganese oxides.

I had the fortunate opportunity to conduct my research using a synchrotron x-ray source at the Advanced Photon Source (APS), Argonne National Laboratory. There, I conducted synchrotron based x-ray diffraction and x-ray absorption spectroscopy to monitor the structure of birnessite as it reacted with aqueous chromium in real time. In addition, I monitored the oxidation state of chromium in the reacted solution to complement the x-ray data characterized birnessite sample during reaction. Beyond my research project, visiting APS has been an enriching experience for me as I got an insight into the lives of beamline scientists that work at the synchrotron. I think they have one of the most remarkable occupations conducting research at a cutting-edge facility on a daily basis.** Penn State Department of Geosciences, Newsletter, 2017-2018, page 6.


Science Highlights
 

Researchers at 13 IDD used a combination of a multichannel collimator with diamond anvil cells which enabled the measurement of structural changes in silica glass with total X-ray diffraction to previously unachievable pressures.

 

Significance
The combination of multichannel collimator and diamond anvil cells enabled the investigation of the real-space structure of an amorphous material >100 GPa. We have measured the structure of SiO2 glass by angle-dispersive X-ray diffraction up to 172 GPa. Our results are in agreement with existing data up to 50 GPa showing a sharp change from fourfold to sixfold Si–O coordination number (CN). However, at higher pressures, CN continuously increases to values beyond 6 without sharp structural changes. The behavior of SiO2 glass at high pressure serves as a model for more complex silicate glasses and melts. Thus, our results provide experimental insight into the structural evolution of silicate glasses and melts at ultrahigh pressures.

Fig1_crop75.jpg
X-ray structure factors S(Q) of SiO2 glass at selected pressures (in gigapascals) during compression.
 

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Dependence of OPF on A–O CN for SiO2 glass from this study and
GeO2 glass. We compare experimental data to calculated values
for the Fe2P-type and cotunnite structural polymorphs for SiO2 (red
left/right triangles) (30) and GeO2 (white up/down triangles) (32). Hereby, different directions of the symbols are for different cutoff values (2.1 and 2.5 A° ) for the O–O MEFIR distance calculations for these crystal structures. The dashed blue line represents the Kepler conjecture (KC) marking the densest possible OPF [0.74 (34)]. The black diamond represents an “ideal” hypothetical close-packed AO2 structure where both atoms have the same size and contribute to the close packing equally; thus, A–B coordination will be 12, but the OPF N is only two-thirds of the KC. The shaded areas are linear extrapolations from the ideal AO2 structure through the values of predicted crystalline high pressure phases to sixfold coordination. The magenta crosses show the results of the ab initio MD (AIMD) simulation for different densities (7–16 g/cm3 at 4,000 K).

Prescher, C., Prakapenka, V.B., Stefanski, J., Jahn, S., Skinner, L.B., Wang, Y.,  (2017). Beyond sixfold coordinated Si in SiO2 glass at
ultrahigh pressures
. PNAS Early Edition, DOI: 10.1073/pnas.1708882114


► Hydration Structure of the Barite (001)-Water Interface

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Abstract : The three-dimensional structure of the barite (001)–water interface was studied using in situ specular and nonspecular X-ray reflectivity (XR). Displacements of the barium and sulfate ions in the surface of a barite crystal and the interfacial water structure were defined in the analyses. The largest relaxations (0.13 Å lateral and 0.08 Å vertical) were observed for the barium and sulfate ions in the topmost unit cell layer, which diminished rapidly with depth. The best fit structure identified four distinct adsorbed species, which in comparison with molecular dynamics (MD) simulations reveals that they are associated with positions of adsorbed water, each of which coordinates one or two surface ions (either barium, sulfate, or both). These water molecules also adsorb in positions consistent with those of bariums and sulfates in the bulk crystal lattice. These results demonstrate the importance of combining high-resolution XR with MD simulations to fully describe the atomic structure of the hydrated mineral surface. The agreement between the results indicates both the uniqueness of the structural model obtained from the XR analysis and the accuracy of the force field used in the simulations.

Bracco, J.N., Lee, S.S.,  Stubbs, J.E., Eng, P.J., Heberling, F., Fenter, P., Stack, A.G. (2017). Hydration Structure of the Barite (001)–Water Interface: Comparison of X-ray Reflectivity with Molecular Dynamics Simulations. The Journal of Physical Chemistry, 121 (22), 12236-12248. DOI: 10.1021/acs.jpcc.7b02943