15-19 April 2018
Paradise Point Resort & Spa
America/Los_Angeles timezone

4.53 X-ray streaked Refraction Enhanced Radiography (RER) for inferring inflight ice-ablator density profiles of ICF capsule implosions

16 Apr 2018, 20:30
2h 1m
Paradise Point Resort & Spa

Paradise Point Resort & Spa

1404 Vacation Rd, San Diego, CA 92109

Speakers

Eduard Dewald (Lawrence Livermore National Laboratory) Otto Landen (Lawrence Livermore National Laboratory) Laurent Masse (Lawrence Livermore National Laboratory) Darwin Ho (Lawrence Livermore National Laboratory) Yuan Ping (Lawrence Livermore National Laboratory) Daniel Thorn (Lawrence Livermore National Laboratory) Nobuhiko Izumi (Lawrence Livermore National Laboratory) Laura Berzak Hopkins (Lawrence Livermore National Laboratory) Jeffrey Koch (NSTec)

Description

In the quest for reaching ignition of deuterium-tritium (DT) fuel capsule implosions, experiments on the National Ignition Facility have shown lower final fuel areal densities than simulated. Possible explanations for reduced compression are higher preheat that can increase the ice-ablator density jump and induce ablator-DT ice mix, or reverberating shocks. We are hence developing x-ray Refraction Enhanced Radiography (RER) to infer the inflight density profiles in layered fuel capsule implosions. The RER uses a 5 µm imaging slit backlit by a Ni 7.8 keV He-alpha laser driven x-ray source at 20 mm from the capsule to cast refracted images of the inflight capsule onto a streak camera in a high magnification (M~60x) setup. Our first experiments have validated our setup using an un-driven high density carbon capsule that recorded a streaked RER x-ray fringe from the carbon ablator surface consistent with raytracing calculations at the required ~ 6 µm and 25 ps resolution for implosions. Streaked RER will be applied to inflight layered capsule implosions using a hydrogen-tritium fuel mix rather than DT to reduce neutron yields and associated x-ray backgrounds. This work was performed under the auspices of the U.S. Department of Energy by LLNL under Contract DE-AC52-07NA27344.

Primary author

Eduard Dewald (Lawrence Livermore National Laboratory)

Co-authors

Otto Landen (Lawrence Livermore National Laboratory) Laurent Masse (Lawrence Livermore National Laboratory) Darwin Ho (Lawrence Livermore National Laboratory) Yuan Ping (Lawrence Livermore National Laboratory) Daniel Thorn (Lawrence Livermore National Laboratory) Nobuhiko Izumi (Lawrence Livermore National Laboratory) Laura Berzak Hopkins (Lawrence Livermore National Laboratory) Jeffrey Koch (NSTec)

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