8:30 – 9:15
|Computational Science Projects at the APS|
9:15 – 10:00
Adam P. Hitchcock
(McMaster University, Canada)
|Nanoscale materials analysis by soft X-ray Scanning Transmission Microscopy|
8:30 – 9:15
Robert L. Leheny
(Johns Hopkins University)
|Microscopic dynamics underlying the nonlinear rheology of soft glassy materials|
9:15 – 10:00
(Elettra Sincrotrone Trieste)
|Hard X-ray biomedical imaging at Elettra: status and perspectives|
Senior Scientist, Group Leader
APS Chief Computational Scientist
Addressing the Computational Needs of APS Users
Available software very much limits the ability of scientists to obtain scientific results from their beamline experiments. The need for software has grown due to revolutionary use of area detection for x-ray experiments and by how these detectors have improved in performance. Another factor increasing the need for software development has been the success for synchrotrons in acquiring users who are experts in their scientific domain and want to apply synchrotron-based measurements in their work, but are not experts in synchrotron use and do not wish to become such. These users need easy-to-master data analysis tools, since they cannot invest as much time in learning as someone dedicating his/her career to synchrotron science. In the immediate, future x-ray detectors will continue generate data at increasingly faster rates and new light sources will produce beams with vastly greater brilliance and coherence. Keeping up with these data streams requires software that runs on massively parallel computers.
This presentation will provide an overview of software development projects at the APS and some of future directions.
Adam P. Hitchcock
Brockhouse Institute for Materials Research, McMaster University, Hamilton, ON, Canada
Nanoscale materials analysis by soft X-ray Scanning Transmission Microscopy
Soft X-ray scanning transmission microscopy (STXM) [1-3] is a powerful tool for nanoscale materials analysis, with significant advantages over analytical X-ray microscopies for studies of radiation sensitive materials, and for in situ and operando studies. Over 12 facilities are operational world-wide and several more are being developed. Ptychography (scanning coherent diffraction imaging) [3,4], which can be measured using soft X-ray STXMs, provides significant improvements in spatial resolution (3-14 nm relative to 15-30 nm for conventional STXM. 4D imaging – quantitative 3D imaging with spectroscopy at each voxel – can be performed with STXM  and ptychography . STXM and ptychography instrumentation at various facilities will be described, with emphasis on spectromicroscopy, the use of chemical mapping by imaging at multiple photon energies. A recently commissioned cryo-STXM  will be described and cryo-spectro-tomography results presented. Applications to be described include: electrode materials for polymer electrolyte membrane fuel cell (PEM-FC) devices [4,6,8,9], and alumina aerogels coated with zinc oxide by atomic layer deposition (ALD).
Research supported by NSERC, Canada Research Chairs, AFCC and the Catalyst Research for Polymer Electrolyte Fuel Cells (CaRPE-FC) network. STXM is performed on BL 10ID1 at the Canadian Light Source (CLS), which is supported by NSERC,CIHR, NRC and U. Saskatchewan, and on BL 22.214.171.124 at the Advanced Light Source (ALS). Ptychography is performed on BL 126.96.36.199 and 11.0.2 at the ALS. ALS is supported by Office of Basic Energy Science, Department of Energy. Ptychography processing is performed using SHARP, a program of the Center for Applied Mathematics for Energy Research Applications, LBNL.
 A.P. Hitchcock, Soft X-ray Imaging and Spectromicroscopy in Handbook on Nanoscopy, eds. G. Van Tendeloo, D. Van Dyck and S. J. Pennycook (Wiley, 2012).
 H. Ade and A.P. Hitchcock, Polymer 49 (2008) 643.
 D.A, Shapiro et al., Nat. Photonics 8 (2014) 765.
 A.P. Hitchcock, J. Electron Spectrosc. Rel. Phen. 200 (2015) 49-63
 G. Schmid, M. Obst, J. Wu and A.P. Hitchcock, 3D chemical imaging of nanoscale biological, environmental and synthetic materials by soft X-ray spectro-tomography in Characterization Tools for Nanoscience & Nanotechnology, Vol. 5 (Springer, Berlin, 2015)
 J. Wu et al. High resolution imaging of polymer electrolyte membrane fuel cell cathode layers by soft X-ray spectro-ptychography, J. Phys. Chem. C (2018) in press
 A.F.G. Leontowich et al., Cryo scanning transmission X-ray microscope optimized for spectro-tomography, Rev. Sci Inst. (submitted).
 A.P. Hitchcock, et al., J. Power Sources 266 (2014) 66
 A. Putz et al. J. Electrochemical Society 75 (2016) 3-23.
Robert L. Leheny
Microscopic dynamics underlying the nonlinear rheology of soft glassy materials
Small-angle x-ray photon correlation spectroscopy (XPCS) accesses dynamics on length scales from nanometers to hundreds of nanometers and time scales from milliseconds to hundreds of seconds that figure prominently in the rheological behavior of complex fluids, and the technique has provided numerous insights into the microscopic origins of the rheology of soft materials. This talk will review recent efforts and discuss future prospects to expand the repertoire of XPCS by using it to probe structural dynamics during in situ mechanical deformation and flow. Such rheo-XPCS experiments include those incorporating steady shear, large amplitude oscillatory shear (LAOS), or tensile strain. As specific examples, the talk will describe recent experiments that reveal the microscopic structural dynamics associated with yielding and stress relaxation in a set of disordered soft solid materials including nanocolloidal gels, clay suspensions, and soft nanocolloidal glasses.
On the behalf of the SYRMEP team
Elettra – Sincrotrone Trieste
Hard X-ray biomedical imaging at Elettra: status and perspectives
The Synchrotron Radiation for MEdical Physics (SYRMEP) beamline has been in operation for more than 20 years at the Elettra light source in Trieste. Biomedical research has been developed following three main directions, each corresponding to a resolution and dimension scale: clinical imaging with patients, studies on small animals, high resolution imaging (embryos, tissues, histologies, biomaterials, etc).
The beamline offers various setups allowing for imaging modalities with monochromatic and white beam, and moreover a radiological unit is used for mammographic studies on patients. Phase contrast imaging in Free Propagation modality and Analyzer Based Imaging are the most used imaging techniques.
The experimental setups are very flexible, suited for studying samples with dimensions ranging from a few mm to several cm, and cover a wide resolution range, with detectors’ pixel sizes varying from 0.9 micron to 100 microns.
The talk will give an overview of the latest achievements, highlighting the upgrade plans and the main research perspectives in view of the Elettra 2.0 program.