Fast neutron imaging and reconstruction at NIF

Fast neutron source imaging is a critical diagnostic for many high-energy density experiments performed at the National Ignition Facility (NIF). These single-shot experiments generate short (sub-ns), high-yield (10^14 – 10^18) neutron bursts within a background of secondary particles. At lower yields, the shot noise complicates imaging, and for larger sources, makes it nearly impossible. This article explores techniques used at the NIF to improve fast neutron imaging capabilities and presents research into novel coded and penumbral apertures to extend imaging capabilities to weaker signals and wider fields of view. This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344 and was supported by the LLNL-LDRD Program under Project No. 22-ERD-022.