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

4.41 Using time-resolved penumbral imaging to measure low x-ray emission signals from capsule implosions at the NIF

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

Paradise Point Resort & Spa

1404 Vacation Rd, San Diego, CA 92109

Speakers

David Bishel (Lawrence Livermore National Laboratory) Benjamin Bachmann (Lawrence Livermore National Laboratory) Austin Yi (Los Alamos National Laboratory) Dominik Kraus (Helmholtz-Zentrum Dresden-Rossendorf) Paul Neumayer (Gesellschaft für Schwerionenphysik) Alison Saunders (University of California, Berkeley) Michael MacDonald (University of California, Berkeley) Otto Landen (Lawrence Livermore National Laboratory) Laurent Divol (Lawrence Livermore National Laboratory) Tilo Doeppner (Lawrence Livermore National Laboratory)

Description

"We have developed an experimental platform at the National Ignition Facility to measure x-ray Thompson scattering (XRTS) spectra from indirectly-driven capsule implosions that create extreme density conditions near stagnation [1]. To account for shot-to-shot fluctuations in the implosion timing, we use x-ray self-emission at stagnation as a timing fiducial. Due to lower implosion velocity, low gas fill, and hot spot symmetry perturbations, the hot spot emission is 100 – 1000x weaker than that of standard ICF implosions. To address this challenge, we have developed and fielded a new pinhole-imaging snout that exploits time-resolved penumbral imaging [2,3]. Though use of 150 m diameter, penumbral-quality pinholes reduces the direct spatial resolution of the images, a 2D image can be reconstructed through analysis of the penumbra. Despite fluctuations of the x-ray flash intensity of up to 5x, the emission time history is strikingly similar from shot to shot, and slightly asymmetric with respect to peak x-ray emission. Emission times vary by up to 250 ps and can be determined with an accuracy of 50 ps. 1. D. Kraus et al, J. Phys.: Conf. Series 717, 012067 (2016). 2. B. Bachmann et al., Rev. Sci. Instrum. 85, 11D614 (2014). 3. B. Bachmann et al., Rev. Sci. Instrum. 87, 11E201 (2016)."

Primary author

David Bishel (Lawrence Livermore National Laboratory)

Presentation Materials

There are no materials yet.
Your browser is out of date!

Update your browser to view this website correctly. Update my browser now

×