Fusion Science and Technology / Volume 59 / Number 1 / January 2011 / Pages 271-275
Technical Paper / Nineteenth Target Fabrication Meeting / dx.doi.org/10.13182/FST11-A11536
Fill tubes are being implemented to meet direct-drive National Ignition Facility (NIF) target designs and eliminate the need for permeation filling of targets. Significant improvements have been made to the fill tube designs for the NIF-scale CD and fast ignition targets to accommodate fuel-layering experiments at the University of Rochester Laboratory for Laser Energetics. The initial fill tube design had a number of issues that contributed to the nonuniformity of the deuterium (D2) ice layer and low fabrication yield of targets. Redesign of the entire target has significantly improved the D2 ice layering by reducing thermal perturbations. These design changes also made a more robust target that can survive the handling required in fabrication and testing. This paper will detail the target design aspects that were altered, including adjusting the fill tube aspect ratio, removing the thermally conductive support stalk, and adding a thermally conductive coating on the fill tube.