Bulletin of the American Physical Society
2005 14th APS Topical Conference on Shock Compression of Condensed Matter
Sunday–Friday, July 31–August 5 2005; Baltimore, MD
Session E3: Focus Session: Ultrafast in situ Diagnostics |
Hide Abstracts |
Chair: Alan Frank, Lawrence Livermore National Laboratory Room: Hyatt Regency Constellation D |
Monday, August 1, 2005 3:30PM - 4:00PM |
E3.00001: Time-Resolved X-Ray Probing of Dense and Heated Material Invited Speaker: I will describe experiments that measure the response of material to rapid laser heating. We employ time-resolved x-ray scattering techniques, and utilize both synchrotron-based and linear-accelerator-based short pulse x-ray sources to probe dense and heated materials. I will also describe the opportunities offered by the Linac Coherent Light Source x-ray free electron laser for future shock physics studies. [Preview Abstract] |
Monday, August 1, 2005 4:00PM - 4:30PM |
E3.00002: Ultrafast electron probes of structural dynamics Invited Speaker: Electrons over a wide range of energies can be used to characterize and determine molecular structures. This talk explores the combination of ultrafast-pulsed laser techniques with electron pulses covering a vast range of electron energies. At the very low end, it is shown that even electrons that are bound, albeit loosely, to molecular ions can be used to characterize unique aspects of molecular structure. Examples are the placement of atoms and functional groups within molecules, and the distribution of charges within the particles. Using time resolved measurements, we are able to observe charge transfer within isolated molecules, and the folding dynamics of flexible chain molecules. Electron pulses with high energy are used to elucidate structural dynamics of laser-excited molecular systems. In the usual high electron energy regime, 10's of kV, the experimentally achievable time resolution is restricted by the requirements of total charge flow on the one hand, and space-charge repulsion between electrons within a pulse on the other hand. The development of electron diffraction using very high energy (mega-electron Volt) electrons provides an opportunity to avoid such space-charge problems, potentially allowing for single shot electron diffraction measurements with a time resolution approaching 100 fs. The talk discusses experimental as well as theoretical aspects of the keV and MeV ultrafast time resolved electron diffraction experiments. [Preview Abstract] |
Monday, August 1, 2005 4:30PM - 4:45PM |
E3.00003: Fast Internal Temperature Measurements in PBX9501 Laura Smilowitz, Bryan Henson, Mary Sandstrom, Blaine Asay, Gary Parker, David Oschwald, Peter Dickson, Jerry Romero We have made spatially and temporally resolved temperature measurements internal to a thermal explosion in PBX9501. These measurements are made both by thermocouples with corrections applied to compensate for the thermocouple response time and with optical pyrometry. Our original goals were to test our kinetic model over a broader range of temperatures, to look for evidence of any late endotherms during final self heating, and to study the transition between ignition and ignition propagation. This meant we needed to be able to follow temperatures later into reaction (meaning further in time and closer to the ignition point). Our previous limit was 16ms prior to ignition limited only by the sampling rate on the logger. In order to sample faster, we switched to a direct voltage reading of the thermocouples and added fiber optic temperature measurements. In this talk, I will discuss our current capabilities for controlling and measuring the development of an ignition within a piece of heated PBX9501. [Preview Abstract] |
Monday, August 1, 2005 4:45PM - 5:00PM |
E3.00004: Assessment of In Situ Time Resolved Shock Experiments at Synchrotron Light Sources* J. Belak, J.H. Kinney, R. Hanks, C. May, R.S. Lee, J. Ilavsky, W.-K. Lee, K. Fezzaa, E.M. Dufresne, E. Landahl, J.P. Hessler Prior to fielding in situ time resolved experiments of shock wave loading at the Advanced Photon Source, we have performed feasibility experiments assessing a single photon bunch. Using single and poly-crystal Al, Ti, V and Cu shock to incipient spallation on the gas gun, samples were prepared from slices normal to the spall plane of thickness 100-500 microns. In addition, single crystal Al of thickness 500 microns was shocked to incipient spallation and soft recovered using the LLNL e-gun mini-flyer system. The e-gun mini-flyer impacts the sample target producing a 10's ns flat-top shock transient. Here, we present results for imaging, small-angle scattering (SAS), and diffraction. In particular, there is little SAS away from the spall plane and significant SAS at the spall plane, demonstrating the presence of sub-micron voids. $* $Use of the Advanced Photon Source was supported by the U. S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. W-31-109-Eng-38 and work performed under the auspices of the U.S. Department of Energy by University of California, Lawrence Livermore National Laboratory under Contract W-7405-Eng-48. [Preview Abstract] |
Monday, August 1, 2005 5:00PM - 5:15PM |
E3.00005: Dynamic Studies of Phase Transitions in f-electron Materials Using Photoluminescence Spectroscopy E.D. Emmons, T.E. Cowan, S. Duvvuri, G. Kaplan, R.G. Kraus, K.R. McCall, G. Mishra, J.S. Thompson, A.M. Covington We are currently investigating the feasibility of using photoluminescence spectroscopy to study solid-solid phase transitions in f-electron materials. Photoluminescence probes the electronic band structure of materials and is thus sensitive to temperature, pressure, and phase. Static photoluminescence studies are being performed in a diamond anvil cell in order to identify signatures of changes in the materials, particularly solid-solid phase transitions. These static studies will be used as a benchmark to guide future dynamic shock compression studies. Dynamic studies will involve using pulsed lasers both to shock f-electron materials and also to induce photoluminescence. Fast time-resolved spectroscopic techniques will be used to examine the photoluminescence emission as the shock wave compresses the material. Preliminary results will be presented. [Preview Abstract] |
Monday, August 1, 2005 5:15PM - 5:30PM |
E3.00006: Fragmentation Properties of Cerium and Copper M1 at Dynamic Volume Expansion Amangeldy Zhiembetov, Anatoly Mikhaylov, Georgii Smirnov In this work, for verification of the basic aspects of the material dispersion models under shock-wave loading, dynamic strength properties of copper M1 and cerium (Ce) were evaluated by the fragmentation method during volume expansion (crack-resistance, spall strength, dynamic yield strength, specific surface energy, dynamic viscosity) with use of cylindrical HE charges (explosion) and small-scale spherical HE charges with one-point initiation (implosion). In the used experimental method, samples of studied materials were subjected to controlled shock-wave effect in the testing devices of the chosen geometry. Parameters of melting of shock-compressed cerium samples during unloading were determined by the cavitation method based on recording of change of regimes of samples destruction and fragmentation during substance transition to the other aggregative state with use of pulse X-ray recording. [Preview Abstract] |
Follow Us |
Engage
Become an APS Member |
My APS
Renew Membership |
Information for |
About APSThe American Physical Society (APS) is a non-profit membership organization working to advance the knowledge of physics. |
© 2024 American Physical Society
| All rights reserved | Terms of Use
| Contact Us
Headquarters
1 Physics Ellipse, College Park, MD 20740-3844
(301) 209-3200
Editorial Office
100 Motor Pkwy, Suite 110, Hauppauge, NY 11788
(631) 591-4000
Office of Public Affairs
529 14th St NW, Suite 1050, Washington, D.C. 20045-2001
(202) 662-8700