The Department of Physics and Astronomy proudly presents a colloquium featuring Dr. Alexander Hexemer of the Lawrence Berkeley National Laboratory. Dr. Hexemer will present his talk, “Addressing the Data Challenge in Small Angle Scattering”, Tuesday, Oct. 20 at 4:10 p.m. in Webster B17.
Meet for refreshments before the lecture at 3:45 – 4:10 p.m. in the foyer on floor G above the lecture hall.
Abstract: The advent of high brightness sources, fast detectors and the increasing need of time-resolved experiments in small angle scattering has created an unprecedented data deluge and the needs for combining X-ray science with computer science. Over the last few years we have worked closely with our computational research and supercomputer division to enable the use of supercomputers at scattering beamlines. The dream of such a superfacility would be immediate feedback for scientist during experiments. Such Real-time feedback to scientists during beamtimes is a capability critically needed, however, this dream has not been realized yet. Scattering methods like SAXS and GISAXS (Grazing Incidence Small Angel X-Ray Scattering) generates reciprocal space data that cannot be directly analysed for the underlying material structure. Rather, reverse Monte Carlo and other fitting methods are employed to reverse engineer the sample material. HipGISAXS (High Performance GISAXS) has been developed to run scattering simulations on massively parallel platforms such as the Oak Ridge Supercomputer Titan (OLCF), scalable to thousands of GPUs. Further, with inverse modelling algorithms available in HipGISAXS, such as particle swarm optimization, it can handle a large number of simulations simultaneously during the structure fitting process. In September of 2014 HipGISAXS was used in a real time demonstration that married the SAXS/WAXS beamline at the ALS with the data handling and processing capabilities at NERSC, and simulation capabilities of running at-scale simulations on Titan at OLCF. To accomplish the goal of real time data analysis, we fed the data management and workflow SPOT Suite infrastructure running at NERSC directly with data taken at the beamline. The data was reduced automatically and pushed into CADES at ORN using the high-performance data transfer capabilities of Globus Online. The demo involved the printing of organic photovoltaics using a slot‐die printer installed at the SAXS/WAXS breeamline. Over the span of 3 days many different organic photovoltaics were printed at the beamline and the crystal structure evolution during drying was recorded using GIWAXS. The entire progress of data collection, movement and fitting was monitored on a web dashboard.
