Bulletin of the American Physical Society
APS March Meeting 2015
Volume 60, Number 1
Monday–Friday, March 2–6, 2015; San Antonio, Texas
Session A34: Focus Session: Experimental Techniques and Results: Dynamic High-Pressure Physics |
Hide Abstracts |
Sponsoring Units: DMP Room: 210A |
Monday, March 2, 2015 8:00AM - 8:12AM |
A34.00001: Studying compressed matter physics at the Linac Coherent Light Source Siegfried Glenzer, Luke Fletcher With the advent of the Matter in Extreme Conditions instrument at the Linac Coherent Light Source a world-unique experimental capability has become available to study the physics of dynamically compressed solids. Our new high-energy-density science program at SLAC is aimed to take advantage of x-ray pulses with the highest peak brightness available today. In a single shot, the x-ray beam delivers 10$^{\mathrm{12}}$ x-ray photons in 50 fs focused to a spot of order 1 $\mu $m. This capability allows us to measure plasmons and to visualize the density and pressure evolution across melt lines by resolving correlations at distances comparable to atomic scales. Our data allow direct determination of pressure for validating theoretical models for the thermodynamics at high pressure. We will show how LCLS data test our theoretical models of compressed matter and will discuss future plans for the study of hot and dense matter. [Preview Abstract] |
Monday, March 2, 2015 8:12AM - 8:24AM |
A34.00002: Elastic precursor shock waves in tantalum at very high strain rates Jonathan Crowhurst, Michael Armstrong, Harry Radousky, Joseph Zaug, Sean Gates We have obtained data from micron-thick tantalum films using our ultrafast laser shock platform. By measuring free surface velocity time histories at breakout, and shock wave arrival times at different film thicknesses, we have been able to estimate the dependence of particle and shock velocities on propagation distances and strain rates. We will show how elastic precursor shock waves depend on strain rate in the regime up to and above 10$^{9}$ s$^{-1}$. We find that while elastic amplitudes are very large at very early times decay occurs rapidly as propagation distance increases. Finally we will consider the prospects for using these data to obtain the dynamic strength of tantalum at these very high strain rates. This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract No. DE-AC52-07NA27344 with Laboratory directed Research and Development funding (12ERD042). [Preview Abstract] |
Monday, March 2, 2015 8:24AM - 8:36AM |
A34.00003: X-ray scattering measurements of laser-driven shock compressed plastic and deuterated plastic targets Maxence Gauthier, Luke Fletcher, Alessandra Ravasio, Tilo D\"oppner, Siegfried Glenzer The study of materials under extreme conditions, i.e., high energy density, has gathered enormous scientific interest in various domains from inertial confinement fusion to planetary physics. The material response of plastic to shock and its behavior is important because of its common use as an ablator in inertial confinement fusion experiments. In this study, simultaneous measurements of spectrally and wavenumber resolved x-ray scattering emission from laser-shock compressed plastic foils allow us to study the structural transition from a polymer to a liquid-like state. The 527 nm, 2 GW laser system available at the MEC station of the LCLS facility has been used to compress CH and CD foils using laser-driven shocks. 40 to 57 $\mu$m thick CH and CD targets were compressed using 3 ns square pulses with total laser energy of 6 J per beam. A drive intensity of 3x10$^{13}$ W/cm$^{2}$ on each irradiated surface was used to generate high-pressure shock waves into the sample, while 8 keV x-rays from LCLS was used to probe the target. [Preview Abstract] |
Monday, March 2, 2015 8:36AM - 8:48AM |
A34.00004: Angularly resolved x-ray scattering measurements of shock and ramp compressed polycrysaalline diamond M.J. MacDonald, L.B. Fletcher, E.J. Gamboa, M. Gauthier, H.J. Lee, E. Galtier, A. Ravasio, A. Gleason, S. Hamel, J. Vorberger, D.O. Gericke, Z. Chen, D. Kraus, B. Barbrel, S. Funk, J.B. Hastings, S.H. Glenzer Direct measurements of the crystal structure of materials under shock and ramp compression can be obtained using 2D angularly resolved x-ray scattering at the MEC end station of the LCLS facility. Diamond has been proposed as an ablator material for inertial confinement fusion targets, requiring a better understanding how the crystal structure responds to dynamic compression. In this experiment we used the two 527 nm optical lasers to compress 25 and 50 $\mu m$ diamond foils. Each beam provided 6 J in 3 ns focused to an intensity of $4 \times 10^{14}$ W/cm${}^2$ with different pulse shapes to provide shock and ramp compression. Compression and lattice deformation measurements were made directly from angularly resolved x-ray scattering and compared to DFT simulations. [Preview Abstract] |
Monday, March 2, 2015 8:48AM - 9:00AM |
A34.00005: Equation of state measurements of shocked ammonia gas John Lang, Dana Dattelbaum, Peter Goodwin, Joshua Coe, Daniel Garcia Ammonia is one of the constituents of the fluid product mixture arising from explosives detonation. Few shock compression experiments have been performed on NH$_{3}$ in either the gas or condensed phase. Earlier work by Dick (J. Chem. Phys. \textbf{74}, 4053) and Mitchell, \textit{et al.} (J. Chem. Phys. \textbf{76}, 6273) examined the shock compressibility of liquid NH$_{3}$. Nellis, \textit{et al.} (Science \textbf{240}, 781) also performed experiments on liquid mixtures of NH$_{3}$ with water and isopropanol (a ``synthetic Uranus'') to develop an equation of state (EOS) for the outer planets. Here, we present the results from a series of gas gun-driven plate impact experiments on NH$_{3}$ gas at elevated initial density. PDV and VISAR optical diagnostics were used to directly measure shock velocities and particle velocities in the shocked gas, used in quantifying the principal Hugoniot locus, and pressure and density of the shocked gas.~ Emission was measured using both 5-color pyrometry and streak spectroscopy, from which we estimated the temperature of the shocked gas.~ The pressure and density measurements were in good agreement with results from simulations using the SESAME EOS for NH$_{3}$, however the measured temperatures were found to be consistently lower than in the simulations, and lower than shocked atomic gas species such as Ar. [Preview Abstract] |
Monday, March 2, 2015 9:00AM - 9:12AM |
A34.00006: Extreme dynamic compression with a table top laser Michael Armstrong, Jonathan Crowhurst, Harry Radousky, Joseph Zaug Recently, it was shown that the energy required for laser driven dynamic compression experiments varies as the third power of the compression time, where the compression time must be larger than the equilibration time in the sample. Traditional dynamic compression experiments typically have drive times greater than 10 ns, but a wide range of materials equilibrate on substantially faster time scales, which should enable such materials to be compressed on much shorter time scales. So, for materials which equilibrate on a sub-nanosecond time scale, ultrafast dynamic compression has the potential to substantially reduce the laser energy required to obtain highly compressed states of matter. This has been demonstrated for sub-Mbar pressures with \textless 100 $\mu $J energy laser drive pulses, where the laser drive energy per unit density change is as much as 10$^{\mathrm{9}}$ smaller than longer time scale experiments. Although these results are promising, extreme pressures (up to 10 Mbar) have not yet been observed with table-top scale laser systems. Here we present results for ultrafast laser driven shock experiments using up to 500x more drive intensity than our previous work, which, by conventional scaling, should result in dynamic pressures previously only accessible to facility scale instruments. [Preview Abstract] |
Monday, March 2, 2015 9:12AM - 9:24AM |
A34.00007: Dynamics of the shock-induced transition from graphite to warm dense diamond and liquid carbon D. Kraus, B. Barbrel, S. Frydrych, J. Helfrich, G. Schaumann, J. Vorberger, D.O. Gericke, L.B. Fletcher, M. Gauthier, S. Goede, E. Granados, H.J. Lee, B. Nagler, E. Gamboa, A. Ravasio, W. Schumaker, T. Doeppner, B. Bachmann, P. Neumayer, G. Gregori, M. Roth, S.H. Glenzer, R.W. Falcone We present novel experimental observations of the ion structure in warm dense carbon at pressures from 20 to 220 GPa and temperatures of several thousand Kelvins. Our experiments employ x-ray sources at kilo-joule class laser facilities and at the Linac Coherent Light Source to perform spectrally and angularly resolved x-ray scattering from shock-compressed graphite samples\footnote{D. Kraus et al., Phys. Rev. Lett 111, 255501 (2013)}. Using different types of graphite and varying drive laser intensity, we were able to probe conditions below and above the melting line, resolving the shock-induced graphite-to-diamond and graphite-to-liquid transitions on nanosecond time scale. Moreover, we have observed the dynamic formation of hexagonal diamond by shock-compression of highly oriented graphite samples. [Preview Abstract] |
Monday, March 2, 2015 9:24AM - 9:36AM |
A34.00008: Quantitative Results from Shockless Compression Experiments on Solids to Multi-Megabar Pressure Jean-Paul Davis, Justin Brown, Marcus Knudson, Raymond Lemke Quasi-isentropic, shockless ramp-wave experiments promise accurate equation-of-state (EOS) data in the solid phase at relatively low temperatures and multi-megabar pressures. In this range of pressure, isothermal diamond-anvil techniques have limited pressure accuracy due to reliance on theoretical EOS of calibration standards, thus accurate quasi-isentropic compression data would help immensely in constraining EOS models. Multi-megabar shockless compression experiments using the Z Machine at Sandia as a magnetic drive with stripline targets continue to be performed on a number of solids. New developments will be presented in the design and analysis of these experiments, including topics such as 2-D and magneto-hydrodynamic (MHD) effects and the use of LiF windows. Results will be presented for tantalum and/or gold metals, with comparisons to independently developed EOS. * Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85000. [Preview Abstract] |
Monday, March 2, 2015 9:36AM - 9:48AM |
A34.00009: EOS determination through microscopy- interferometry measurements: A low symmetry energetic materials case study Elissaios Stavrou, Joseph Zaug, Jonathan Crowhurst, Sorin Bastea, Mike Armstrong Measuring equation of state (EOS) of solid specimens under pressure usually involves the determination of the primitive cell volume using x-ray diffraction (XRD) measurements. However, in the case of low symmetry (e.g. triclinic) materials with twining features and large primitive cells, this can be problematic and ambiguous. In order to address this issue we examine the possibility of a direct approach which is based on measuring the surface area and thickness with microscopy and optical interferometry respectively. To test the validity of this approach applied to a crystalline material, we first compared our results from Triamino-Trinitrobenzene (TATB, SG P-1) with the published EOS, as determined with XRD measurements, by Stevens et al. (Propellants Explos. Pyrotech. 33, 286 (2008)). A near perfect match between the two sets of data has been observed. We also present the results of our study on the energetic material 5-nitro-2,4-dihydro-1,2,4,-triazol-3-one (a-NTO) which crystallizes as a four-component twin (Bolotina et al. ActaCryst. B61, 577 (2008)) with triclinic symmetry. No high-pressure XRD data have been published on a-NTO, probably due to its highly complex crystal structure, making this technique a viable way to probe the cold compression EOS of such compounds. [Preview Abstract] |
Monday, March 2, 2015 9:48AM - 10:00AM |
A34.00010: Pressure-induced antiferrodistortive phase transition in SrTiO3: common scaling of soft-mode with pressure and temperature Shih-Chang Weng, Ruqing Xu, Xinyue Fang, Ayman Said, Bogdan Leu, Yang Ding, Hawoong Hong, Peter Abbamonte, S.-L. Chang, T.-C. Chiang We report a study of the pressure-induced anitferrodistortive cubic-to-tetragonal phase transition in strontium titanate (SrTiO$_3$) at ambient temperature. High-resolution inelastic X-ray scattering measurements reveal the softening of a phonon mode ($R_{25}$) at the Brillouin zone boundary; a lattice distortion sets in at a critical pressure of 9.5 GPa, which corresponds to a critical volume reduction of $5.3\%$. Prior studies have shown that similar phonon softening and ensuing lattice distortion can be induced under ambient pressure by lowering the sample temperature through a critical temperature of 105 K. The relationship between the two phase transitions is clarified by comparing the power laws of the pressure and temperature dependences of the softening behavior and by first-principles calculations of the energetics of the system. [Preview Abstract] |
Monday, March 2, 2015 10:00AM - 10:12AM |
A34.00011: A new uniaxial strain measurement technique for improved strain homogeneity Mark Barber, Clifford Hicks, Stephen Edkins, Daniel Brodsky, Andrew Mackenzie Response to uniaxial distortion can be a powerful probe of the electronic properties of a solid. However, it is not a very commonly applied technique, chiefly because of the technical challenges of obtaining good strain homogeneity while applying significant pressures. In typical uniaxial pressure measurements, thin and wide samples are clamped between two anvils. Our approach uses a different, easier technique: cutting the sample into a long, narrow bar, and securing its two ends with epoxy across a vice. We have already demonstrated this technique with measurements on $\mathrm{Sr_2RuO_4}$. Here we explain the details of this technique and by using finite element simulations present the guidelines (readily achievable in experiments) that need to be followed in order to achieve high strain homogeneity. [Preview Abstract] |
Monday, March 2, 2015 10:12AM - 10:24AM |
A34.00012: Calorimetry at high-pressure using high-frequency Joule-heating Zachary Geballe, Viktor Struzhkin Calorimetric measurements of materials at 1 to 100 GPa of pressure would provide intriguing tests of condensed matter theories, sensitive probes of chemical reactions during high-pressure synthesis, and useful inputs for models of the Earth's interior. We present the design and first results of quantitative heat capacity measurements at \textgreater 10 GPa of pressure. High-frequency AC voltage heats a small metal strip pressed between diamond anvils, creating temperature oscillations whose amplitudes are determined from the higher harmonics of voltage. Thermal models show that frequencies \textgreater 100 kHz are required to contain heat in the ng-mass samples, while electrical models show that frequencies \textgreater 100 MHz are not practical. Our experimental results show that the heat capacity of iron and nickel can indeed be measured at high frequencies in diamond anvil cells, paving the way for studies of the energetics of a wide-variety of entropy-driven phase changes at high pressure. [Preview Abstract] |
Monday, March 2, 2015 10:24AM - 10:36AM |
A34.00013: High pressure, high magnetic field dilatometry experiment applied to strongly correlated electron systems Audrey Grockowiak, David Graf, William Coniglio, Ju-Hyun Park, Timothy Murphy, Scott Hannahs, Stanley Tozer Standard dilatometry techniques including capacitance measurements [1] have been developed and used for low temperature and high magnetic field measurements, but do not permit the use of high pressures. Following the experimental development of [2], we present a setup coupling Fiber Bragg Gratings (FBG) with pressure cells to map the whole magnetic field-pressure-temperature phase space of various systems as actinides and pnictides. FBG dilatometry measurements permit to achieve a resolution of $\Delta $L/L $\approx $ 3.10$^{-7}$ making it the most sensitive dilatometry technique. ``Mini-me'' piston cylinder cells developed at the NHMFL permit us to reach a pressure of 3 GPa, and their compact size allows them to be used in highly constrained sample volume of a portable dilution refrigerator, giving us the ability to do high pressure dilatometry studies in any high magnetic field facility at temperatures as low as 25 mK. We will present the setup along with preliminary results obtained on diverse test samples. \\[4pt] [1] Schmiedeshoff, G., Review of Scientifc Instruments, 77(12) (2006)\\[0pt] [2] Daou, R., Review of Scientific Instruments, 81(3) (2010) [Preview Abstract] |
Monday, March 2, 2015 10:36AM - 10:48AM |
A34.00014: Metallic carbon at high pressure and low temperature Katsuya Shimizu, Maeda Koki, Masafumi Sakata, Mutsuaki Murakami Graphite shows phase transition into hexagonal diamond by an application of pressure at room temperature. We have studied the pressure-induced phase transition to hexagonal or cubic diamond with Raman spectroscopy and resistance measurements using highly crystallized graphite films prepared by heat treatment of carbonized polyimide films. Inhomogeneous resistivity between current direction along ab-plain and c-axis was found to unite by squeezing at low temperature. [Preview Abstract] |
Monday, March 2, 2015 10:48AM - 11:00AM |
A34.00015: The influence of moisture content on the shock compression responses of brittle granular materials Kun Xue The irreversible energy-absorbing compaction processes of shocked particle layers change with the moisture content. The shock wave interaction with dry and wet granular layers is experimentally investigated to elucidate the moisture effects on the energy distribution in the brittle granular layers. It is found that the frictional and breakage dissipation combined as the plastic dissipation in the granular layers is increasingly mitigated by the increasing moisture content. The higher strain rate in the shock loaded wet granular layer leads to an increased number of debris as predicted by the theoretical analysis. Nevertheless the inter-particle moisture effectively lubricates the enhanced particle friction arising from the intensive particle rearrangement concomitant with the greater degree of particle breakage. As a result, the efficiency of the momentum transfer in the wet granular layer is significantly improved manifested by the much larger particle kinetic energy. Meanwhile the particle breakage mode transits from the corner grinding to the shear cleavage with moisture content as revealed by the SEM image of the recovered grains from shock wave experiments. [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