Scintillator Characterization Measurements for Neutron Imaging in Inertial Confinement Fusion

The Los Alamos National Laboratory Advanced Imaging team is currently in the process of designing a novel neutron imaging system for the National Ignition Facility (NIF). The team has been providing 2D neutron imaging of the burning fusion fuel at NIF for years, revealing possible multi-dimensional asymmetries in the fuel shape of the inertial confinement fusion reactions, and therefore calling for additional views along new lines of sight. The selection of an ideal scintillator material for a position-sensitive detector system is the key component for the new design. The new imaging system will require several technological challenges to be met: high spatial resolution, high light output, and fast scintillator response to capture a primary fusion neutron image as well as lower-energy down-scattered neutrons. A comprehensive study of advanced scintillator materials has been carried out at the Los Alamos Neutron Science Center and the OMEGA Laser Facility in Rochester, NY. Neutron radiography using a fast-gated CCD camera system delivers resolution and light output measurements. We conclude the feasibility of a monolithic scintillator over a pixelated counterpart, and present the first resolution measurement of a deuterated plastic scintillator - a promising candidate for the new design.