Optimizing neutron imaging line of sight locations for maximizing sampling of the cold fuel density in inertial confinement fusion implosions at the National Ignition Facility

Journal Article · 24 October 2018 · Review of Scientific Instruments

DOI: https://doi.org/10.1063/1.5038815 · OSTI ID:1482000

Batha, S. H. ^[1]; Volegov, P. L. ^[1]; Fatherley, V. E. ^[1]; Geppert-Kleinrath, V.  ^[1]; Wilde, C. H. ^[1]

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1. Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

We report that neutron imaging provides a ready measurement of the shape of the “hot spot” core of an inertial confinement fusion implosion. The 14-MeV neutrons emitted by deuterium-tritium reactions are imaged at the National Ignition Facility using a pinhole array onto a scintillator, and the images are recorded on a camera. By changing the gate time of the camera, lower energy neutrons, downscattered by the cold fuel surrounding the hot spot, are recorded. The cold fuel density can be reconstructed using the two images. The kinematics of the scattering coupled with the scattering cross sections restrict the angular extent of the cold fuel sampled, with the backside of the implosion not being sampled at all. This work demonstrates the limited region of the cold fuel measured by the current line of sight (40%). Finally, at completion of the three planned lines of sight, 79% of the cold fuel will be sampled.

• Research Organization: Los Alamos National Laboratory (LANL)
• Sponsoring Organization: USDOE
• Grant/Contract Number: AC52-06NA25396
• OSTI ID: 1482000
• Report Number(s): LA-UR-18-23951
• Journal Information: Review of Scientific Instruments, Journal Name: Review of Scientific Instruments Journal Issue: 10 Vol. 89; ISSN 0034-6748
• Publisher: American Institute of Physics (AIP)Copyright Statement
• Country of Publication: United States
• Language: English