Improving 3D density reconstruction in ICF fuel using synthetic neutron imaging data

The Los Alamos National Laboratory Advanced Imaging team is currently adding two additional lines-of-sight to the neutron imaging diagnostic at the National Ignition Facility. The additional views will deliver 3D shape information on the burning fusion fuel and allow for a more detailed understanding of asymmetries at stagnation. The recently deployed first phase - a passive energy-integrated imaging system on the north pole - provides a second view of the hot spot, allowing 3D density reconstruction of the fuel assembly from neutron images for the first time under certain symmetry assumptions. Since neutron images are inherently time-integrated, we study the effect of burn averaging on the density reconstruction using synthetic neutron imaging data produced with the Chimera rad-hydro code. A particular focus is placed on hotspot movement during burn time, as hypothesized previously through comparison of neutron imaging density with neutron activation diagnostics.