Development and Evaluation of First Wall Materials for the National Ignition Facility

Several low-Z refractory materials are evaluated for use as the NIF first wall in terms of their cost, level of vacuum outgassing, and ability to survive laser light, target emissions and debris, and rigorous decontamination. The best performers contain B, C, or both, with B₄C being the best overall. It appears possible at this time that plasma-sprayed B₄C can be fabricated with low enough porosity and cost to be preferred over hot-pressed B₄C, the conservative choice.