Dynamic hohlraums as x-ray sources in high-energy density science
POSTER
Abstract
A new laser driven dynamic hohlraum (LDDH) backlighter has been evaluated using 10 of 60 beams of the Omega laser. The LDDH is filled with krypton that implodes to create an x-ray flash that satisfies requirements imposed by future experiments: (1) the flash spectrum extends $>$ 5.5 keV, well above the maximum x-ray energy ($\sim $3.5 keV) obtained from the previously ``best'' opacity backlighters (uranium M-shell emission backlighters); (2) the spectrum is smooth and featureless (intensity variation $<$6{\%} RMS), allowing absorption spectrometry through experimental samples; (3) the flash size is sufficiently small ($<$50 $\mu $m) for projection backlighting through future samples; (4) the flash is bright enough (and twice as bright as imploding hydrogen-filled capsules) for gated spectrometer measurements; and (5) the flash duration is optimized ($\approx $100 ps) for current and future generations of spectrometers. This enables opacity and temperature measurements through absorption spectrometry of materials in LTE at temperatures $>$150 eV, a crucial regime for future astrophysics and ignition fusion experiments at NIF.
*This work was performed under the auspices of the U. S. Department of Energy by the University of California, Lawrence Livermore National Laboratory under Contract No. W-7405-Eng-48.