Bulletin of the American Physical Society
21st Biennial Conference of the APS Topical Group on Shock Compression of Condensed Matter
Volume 64, Number 8
Sunday–Friday, June 16–21, 2019; Portland, Oregon
Session E3: AETD: Detonation Diagnostics II |
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Chair: Philip Rae, LANL Room: Pavilion East |
Monday, June 17, 2019 3:30PM - 3:45PM |
E3.00001: Measurement and Characterization of a Two-Shock Explosive Drive. Jeremy Danielson, Amy Bauer In many of our dynamic experiments at Los Alamos, we use an explosive drive to deliver two shocks to a target surface. This multiple-shock loading is accomplished by reflecting shocks between tantalum layers and a metal target, similar to that employed by Buttler et al. We want a detailed understanding and prediction of this drive, which is complicated by two areas of uncertainty: relight across a shock transmission plate; and reflected shocks traversing reacted HE products. In this talk, we will present a number of experiments to make detailed measurements of reshock using optical velocimetry and proton radiography for both explosive and gun-driven HE drives; as well as modelling efforts calibrated against them. [Preview Abstract] |
Monday, June 17, 2019 3:45PM - 4:00PM |
E3.00002: Dynamic three-dimensional observation of corner turning in LX-17 with flash x-rays Joseph Tringe, Michael Zellner, Clifton Mortensen, Franco Gagliardi, Jerel Smith, Kyle Champley Detonation wave propagation in TATB-based explosives such as LX-17 is important to measure to understand explosives' performance, but the details of shock interactions with surfaces and interfaces are often inherently three dimensional. They are therefore challenging to observe with traditional diagnostics which rely on point measurements (e.g., with photonic Doppler velocimetry) or imaging with two-dimensional detectors or film. Flash x-rays are uniquely well-suited to observation of detonation phenomena due to short (\textasciitilde 25 ns) exposure times and the fact that x-ray contrast is correlated with spatially localized explosive density. Here we report results obtained with a few-view x-ray computed tomography (CT) approach to observe an asymmetrically-detonated LX-17 cylinder. 3D characterization of shock wave evolution is enabled by advanced reconstruction algorithms and a fifteen source multi-energy 3D flash x-ray imaging system. This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under contract DE-AC52-07NA27344. Lawrence Livermore National Security, LLC. [Preview Abstract] |
Monday, June 17, 2019 4:00PM - 4:15PM |
E3.00003: Improved coupling structures for microwave interferometry of detonation fronts. Owen Mays, Emer Baluyot, Mark Converse, Lisa Lauderbach, Ronald Kane, Clark Souers, Joseph Tringe Microwave interferometry (MI) provides several advantages over more traditional shock and deflagration front diagnostics. Most importantly, it directly interrogates these fronts, instead of measuring the evolution of containment surfaces or light from detonation breakout. The copper cylinders commonly employed in cylinder tests act as microwave cavities or waveguide structures. Experimental geometries with large dimensions (relative to the \textasciitilde cm-scale MI wavelength) result in artifacts in the MI signal due to higher order modes propagating in the explosive/metal system. We have developed a microwave coupling design to suppress higher order modes present in 1'' diameter cylinder tests (CYLEX) of high explosives. We demonstrate the effectiveness of this structure and show nanosecond-scale microwave tracking of detonation front velocity in cylinder tests with a variety of explosives diameters, materials, and MI frequencies. These results illustrate the importance of selecting appropriate microwave frequencies and coupling for specific experimental geometries. This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under contract DE-AC52-07NA27344. Lawrence Livermore National Security, LLC. LLNL-ABS-768453. [Preview Abstract] |
Monday, June 17, 2019 4:15PM - 4:30PM |
E3.00004: Detonation Electric Effect Measurements in PBX 9501 and Comparison with Hydrocode Calculations Carl Johnson, Kendra Van Buren, Henry Anaya, Lori Lynch, Juan-Antonio Vigil, Ernest Salazar, Francois hemez Detonation electric effect measurements have been completed during the detonation of small columns of PBX 9501. A novel system was developed using a reference plate and a signal plate with no components installed inside HE parts. Both reference and signal plates are insulated from each other as well as other conductors in the system. The duration of the measured signal agrees well with both simulation and other diagnostics fielded in the experiment. This measurement technique is inexpensive and useful to provide a positive indication of detonation (occurrence and duration) without interfering with other diagnostics present. Additionally, the signal measured is distinct from signals present naturally providing a `finger print' readily distinguishable against background noise. [Preview Abstract] |
Monday, June 17, 2019 4:30PM - 4:45PM |
E3.00005: Development of a Near Field Air Blast Measurement Device Nicholas Falcone, Nicholas Owens, Vasant Joshi Measurement of air blast pressures is a critical component in understanding the fundamental nature and characteristics of a detonation event. Blast measurements in the near-field are tough to characterize because of difficulty in collecting these data. Previous attempts to acquire data using a hydraulic system assumed a lossless transfer, which led to errors. A new device has been developed for collecting and surviving blast measurements at close distances to explosive events. This method uses indirect measurements through a gauge in a material train that allows transmitting shock to a protected piezoelectric sensor, which is cost effective, has sharp rise time, and is generally robust enough to withstand shock loading, unlike most commercial blast measurement sensors that cannot survive the extreme environment found in close proximity to a detonation or the post detonation fireball. To alleviate the damage to sensor, high strength steel rod takes the full force of the blast, which may incur some damage, but the waves travel, attenuated as they reach piezoelectric blast pressure sensor immersed in an incompressible fluid. Thus the limitation of the device is dictated by the strength of steel and not the piezoelectric sensor. This paper focuses on the details of device construction, calibration procedure, calibration curves, correlation of the device characteristics to actual blast measurements and observed deviations. [Preview Abstract] |
Monday, June 17, 2019 4:45PM - 5:00PM |
E3.00006: High Temperature Experiments By Using Porous Mixtures at the Dynamic Compression Sector at the Advanced Photon Source Gerrit Sutherland, Timothy Jenkins, Nicholas Lorenzo, Eric Johnson There is a desire to study the high temperature state of nanocrystalline diamond and to perform diffraction measurements. Our paper will focus on the technique to achieve the high temperatures. The samples were pressed to shape and were a mixture of Viton plastic, nanodiamonds, and hollow glass spheres. Simulations were used to assist in the design of experiments and incorporated equation of state (EOS) and models that follow. First, mixture theory to calculate a fully dense Hugoniot (Mie-Gruneisen EOS) for the ND/Viton mixture. Second, a P-alpha model enabled pressures and temperature predictions for porous ND/Viton mixtures. Predicted temperatures were well in excess of the melting temperature, as provided by the diamond phase diagram, for samples impacted by copper projectiles traveling at 5.3 km/s. We expect that this technique can be used allow powder diffraction measurements over large portions of a material's pressure-temperature phase space. Also, preliminary experimental diffraction measurements for nanodiamond mixtures will be presented. [Preview Abstract] |
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