Downscattered neutron imaging

Images with 14 MeV neutrons of inertial confinement fusion (ICF) D,T fusion show the regions of most intense fusion burn, while images based on lower-energy “downscattered” neutrons can reveal regions of nonburning D,T fuel. The downscattered images can help to understand ICF implosion dynamics. Recording downscattered images is difficult because the images are relatively weak, and because they may be obscured by residual “afterglow” of more intense 14 MeV images. The effect of afterglow can be estimated by adding a sequence of images for neutron energies from 14 MeV down to the downscatteed energy of interest. The images will be subject to decay factors which depend on the time response of the neutron scintillator. Preliminary analyses suggest that afterglow will not prevent the recording of useful downscattered images.