Measurements of Ionic Structure in Shock Compressed Lithium Hydride from Ultrafast X-Ray Thomson Scattering

Abstract

We present the first ultrafast temporally, spectrally, and angularly resolved x-ray scattering measurements from shock-compressed matter. The experimental spectra yield the absolute elastic and inelastic scattering intensities from the measured density of free electrons. Laser-compressed lithium-hydride samples are well characterized by inelastic Compton and plasmon scattering of a K-alpha x-ray probe providing independent measurements of temperature and density. The data show excellent agreement with the total intensity and structure when using the two-species form factor and accounting for the screening of ion-ion interactions.

Single-shot measurements of plasmons in compressed diamond with an x-ray lasera)

“…13 Experiments have probed WDM heated by shocks, [14][15][16][17][18][19][20][21][22] radiation, [23][24][25] or particles 26,27 to temperatures of order 10 eV. There has been comparatively little study of matter near the transition from condensed to warm dense matter at pressures and temperatures beyond what is accessible in DACs.…”

Bent crystal spectrometer for both frequency and wavenumber resolved x-ray scattering at a seeded free-electron laser

“…Previous x-ray Thomson scattering studies that use laser-generated x-ray sources in the collective regime have often been insufficient at resolving lowdensity plasmas due to the large bandwidth of the input source spectrum. 17 The LCLS beam, in seeded mode operation, delivers approximately 10 12 x-ray photons in a micron-scale focal spot allowing measurements with high spectral resolution of E/E = 10 −4 , high wave-number resolution of k/k = 10 −2 , and high temporal resolution of 20-50 fs. Consequently, by employing highly efficient curved crystal spectrometers, 18,19 the plasmon spectrum can be observed and resolved in a single x-ray pulse.…”

Design of a paraxial inverse Compton scattering diagnostic for an intense relativistic electron beam

“…Thomson scattering has been used to measure n e and T e for low temperature and high temperature plasmas with n e < 10 21 m -3 [3]. In addition it has been used to measure n e , T e , and T i in solid density plasmas (n e > 10 28 m -3 ) [4][5][6][7][8].…”

“…X-ray Thomson scattering methods utilizing Bragg crystals is routinely used for Xray imaging in relatively the same energy range [6][7][8][14][15][16][17]. However they use X-ray laser probes to interrogate solid density plasmas and measure the Compton downshift.…”