Production Manufacturing of Gold-Depleted Uranium Layered Hohlraums for the National Ignition Facility

By making the hohlraum wall more opaque to the driver energy, the efficiency of X-ray conversion is improved with the addition of depleted uranium (DU) to a gold-only hohlraum [see T. J. Orzechowski et al., Phys. Rev. Lett., Vol. 77, p. 3545 (1996)]. The National Ignition Facility (NIF) point design for ignition requires a DU hohlraum, which is manufactured by General Atomics. The process of creating a hohlraum with multiple layers presents manufacturing challenges. To produce these components many steps are required. The processes for manufacturing an Au-lined DU hohlraum requires single-point diamond turning, sputter deposition, electroplating, chemical etch, and cleaning. These steps combined make a process that yields a fully intact Au-DU layered NIF ignition hohlraum.