Schematic illustration of shock wave profiles propagating from left to right in LiF single crystals. For LiF shocked along , a single elastic wave propagates. For LiF shocked along , a two-wave structure propagates consisting of an elastic wave and a slower traveling plastic wave. The Mg-doped LiF and the pure LiF shocked along  exhibit large and small amplitude elastic waves, respectively.
Sketch of the experimental arrangement. The ambient LiF crystal is oriented with a particular reciprocal lattice vector, , nominally parallel to the impact direction (-axis). is the scattering angle. The distance from the effective x-ray source to the sample (400 mm) is equal to the distance from the sample to the area detector. The face of the detector is perpendicular to the diffracted beam.
Picture of the experimental setup in hutch 16ID-D of HPCAT at the Advanced Photon Source.
Representative diffraction images for which the real space coordinates have been mapped linearly into reciprocal space. (a) and (b) show images from Expt. 1 of the 111 peak from unshocked and shocked LiF(111), respectively. (c) and (d) show images from Expt. 5 of the 200 peak from unshocked and shocked Mg-doped LiF(100), respectively. (e) and (f) show diffraction patterns, using two different sets of microstructural parameters, to simulate the experimental data shown in (d). All intensity scales have arbitrary units.
Binned cross sections of the measured [Figs. 4(c) and 4(d)] and simulated [Figs. 4(e) and 4(f)] diffraction patterns for Expt. 5. (a) shows binned vertical cross sections and (b) shows binned horizontal cross sections.
Measured lattice compression (on average) along the shock propagation direction and the corresponding calculated density compression are plotted. As described in Ref. 3, the dashed and solid lines are the expected relationships between the lattice and density compressions for uniaxial and isotropic lattice compressions, respectively.
(a) Shock-induced (100) microlattice-plane rotational spread (FWHM), , in LiF. The dashed lines represent linear fits to the data constrained to pass through the origin. (b) FWHM of diffraction peak, , in reciprocal space. The peak widths under ambient conditions are shown at zero stress and are caused primarily by instrumental broadening. Elastic compression along  is shown as a reference.
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