Three-dimensional reconstruction of neutron, gamma-ray, and x-ray sources using spherical harmonic decomposition

• Published in: Journal of applied physics 2017-11, Vol.122 (17)
• Main Authors: Volegov, P. L., Danly, C. R., Fittinghoff, D., Geppert-Kleinrath, V., Grim, G., Merrill, F. E., Wilde, C. H.
• Format: Article
• Language: English
• Subjects: 70 PLASMA PHYSICS AND FUSION TECHNOLOGY; Ablation; abstract harmonic analysis; Applied physics; Decomposition; Diagnostic software; Diagnostic systems; Engineering - Instrumentation related to nuclear science and technology, Nuclear science and engineering, Physics - Plasma physics; Gamma rays; ICF; Image reconstruction; Implosions; Inertial confinement fusion; integral transforms; isotopes; National Ignition Facility; neutron imaging; neutron sources; NIF; Omega; plasma confinement; Plasmas (physics); radioactive decay; Spherical harmonics; Stagnation; thermal effects; X ray sources; x-rays
• ISSN: 0021-8979; 1089-7550
• DOI: 10.1063/1.4986652

Neutron, gamma-ray, and x-ray imaging are important diagnostic tools at the National Ignition Facility (NIF) for measuring the two-dimensional (2D) size and shape of the neutron producing region, for probing the remaining ablator and measuring the extent of the DT plasmas during the stagnation phase of Inertial Confinement Fusion implosions. Due to the difficulty and expense of building these imagers, at most only a few two-dimensional projections images will be available to reconstruct the three-dimensional (3D) sources. In this paper, we present a technique that has been developed for the 3D reconstruction of neutron, gamma-ray, and x-ray sources from a minimal number of 2D projections using spherical harmonics decomposition. We present the detailed algorithms used for this characterization and the results of reconstructed sources from experimental neutron and x-ray data collected at OMEGA and NIF.