Bulletin of the American Physical Society
20th Biennial Conference of the APS Topical Group on Shock Compression of Condensed Matter
Volume 62, Number 9
Sunday–Friday, July 9–14, 2017; St. Louis, Missouri
Session L4: Experimental Developments IV: Pressure Generation |
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Chair: Brian Jensen, Los Alamos National Laboratory Room: Regency Ballroom A |
Tuesday, July 11, 2017 3:45PM - 4:00PM |
L4.00001: The Development of Patterned Samples to Study Shock Anisotropy in Crystalline Solids Dmitro Martynowych, Leora Cooper, Emma McBride, Suzanne Ali, Arianna Gleason, Marylesa Howard, Ben Ofori-Okai, Keith Nelson We present methods to generate and image converging shock waves in solid samples of consistent shape and crystallographic orientation. Using novel patterned samples, we extend our previously reported quasi-2D confined shock geometry to study crystalline and amorphous solids. Laser machining using ultrafast laser pulses creates uniform 50-$\mu $m radius disks out of a thin wafer affixed to a high-impedance substrate. A polymer layer is drop-cast to fill the machined-out voids surrounding the sample disks. Intense pump laser light irradiates a circular ``ring'' pattern around one of the disks, and absorption of the light by the polymer layer launches a shock wave that is transduced into the disk as it converges to a focus. Spatial and temporal details of the shock profile and the sample response are measured with single-shot multi-frame imaging. This technique can probe anisotropic responses to converging shock waves. [Preview Abstract] |
Tuesday, July 11, 2017 4:00PM - 4:15PM |
L4.00002: Development of 2D Shocks with Tunable Geometry and Profiles Leora Cooper, Emma McBride, Dmitro Martynowych, Suzanne Ali, Arianna Gleason, Marylesa Howard, Benjamin Ofori-Okai, Keith Nelson We have developed an experimental setup to generate and measure 2D-confined shocks with~adjustable spatial~geometry and temporal profile. The~technique is demonstrated for waveguide shocks in three geometries: planar, colliding planar, and cylindrically converging. The shock profile for the waves may be temporally adjusted to set the duration of the stable high-pressure period and the onset of release. The laser-induced shock is generated~with an intense pump laser pulse~by imaging a partially reflecting mask onto an absorbing sample~layer. The mask sets the geometry of the shock by specifying the spatial~shape~of the drive laser (e.g. a linear or ring pattern of light) on the sample. Absorption-induced volume changes generate the shock within the thin sample layer. Confinement of the shock within the sample~occurs through the high impedance mismatch between the~layer and stiff surrounding~substrates. The~method is~demonstrated~for liquid and solid samples using phase and amplitude-sensitive single-shot multi-frame imaging. [Preview Abstract] |
Tuesday, July 11, 2017 4:15PM - 4:30PM |
L4.00003: 100J Pulsed Laser Shock Driver for Dynamic Compression Research X. Wang, J. Sethian, J. Bromage, S. Fochs, D. Broege, J. Zuegel, R. Roides, R. Cuffney, G. Brent, J. Zweiback, Z. Currier, K. D'Amico, J. Hawreliak, J. Zhang, P. A. Rigg, Y. M. Gupta Logos Technologies and the Laboratory for Laser Energetics (LLE, University of Rochester) -- in partnership with Washington State University -- have designed, built and deployed a one of a kind 100J pulsed UV (351nm) laser system to perform real-time, x-ray diffraction and imaging experiments in laser-driven compression experiments at the Dynamic Compression Sector (DCS) at the Advanced Photon Source, Argonne National Laboratory. The laser complements the other dynamic compression drivers at DCS. The laser system features beam smoothing for 2-d spatially uniform loading of samples and four, highly reproducible, temporal profiles (total pulse duration: 5-15ns) to accommodate a wide variety of scientific needs. Other pulse shapes can be achieved as the experimental needs evolve. Timing of the laser pulse is highly precise (\textless200ps) to allow accurate synchronization of the x-rays with the dynamic compression event. Details of the laser system, its operating parameters, and representative results will be presented. [Preview Abstract] |
Tuesday, July 11, 2017 4:30PM - 4:45PM |
L4.00004: Recent advance in Isentropic compression experiments on PTS facility. Guilin Wang, Zhaohui Zhang, Shuai Guo, Qizhi Sun, Meng Wang The Primary Test Stand (PTS) facility is a pulsed power machine capable of delivering currents to loads of 5\textasciitilde 8 MA over times of 200-620 ns. As current flows in the opposite direction electrode plates, smoothly rising, time dependent magnetic pressures were generated on each electrode plates. With pulse shaping techniques, the ramped compression waves can propagate in electrodes and specimens without forming a shock. Photonic Doppler velocimetry (PDV) have application in shockless, free-surface or sample/window interface velocity measurements of different thickness samples, which were used for equation-of-state (EOS) studies of condensed matter. Analysis the velocity data with a backward integration techniques, the quasi-isentrope to \textasciitilde 1 Mbar of OFHC were inferred. Based on the application performance, confirms that PTS is a good experiment equipment for EOS and dynamic properties of different materials. [Preview Abstract] |
Tuesday, July 11, 2017 4:45PM - 5:00PM |
L4.00005: Accessing off-Hugoniot states via multilayer ring-up targets David McGonegle, Patrick Heighway, Marcin Sliwa, Justin Wark, Cynthia Bolme, Andrew Comley, Leora Cooper, Andrew Higginbotham, Ashley Poole, Emma McBride, Bob Nagler, Inhyuk Nam, Matt Seaberg, Bruce Remington, Robert Rudd, Chris Wehrenberg While laser shocks have long been used as a method for reaching high pressure states, their highly entropic nature limits the range of pressures over which a sample can be kept solid. Laser pulse shaping has been used to ramp compress samples while keeping them close to the isentrope, but this requires long laser pulses that are unavailable to most facilities or expensive pusher materials such as diamond or sapphire. We introduce a technique that uses a multilayer target with different impedance layers that result in the sample `ringing-up' to the desired pressure via a series of smaller shocks, keeping it cooler. We present data from a recent experiment performed at LCLS using this technique, allowing us to reach 170 GPa in Pb while keeping it solid. [Preview Abstract] |
Tuesday, July 11, 2017 5:00PM - 5:15PM |
L4.00006: ABSTRACT WITHDRAWN |
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