Fusion Science and Technology / Volume 55 / Number 3 / April 2009 / Pages 318-324
Technical Paper / Eighteenth Target Fabrication Specialists' Meeting
Targets were fabricated at Lawrence Livermore National Laboratory and were shot on the Omega laser to study the equation of state of nanoporous copper. The targets had a planar configuration and consisted of a 25-m-thick beryllium ablator, a 70-m-thick brominated-polystyrene preheat shield, and a 38-m-thick aluminum baseplate. A quartz window and a 30-m-thick nanoporous copper sample were bonded to the baseplate. The interface between the nanoporous copper and the aluminum baseplate was required to be as thin as possible so that it would not disturb the shock as it passed through the target. A process for bonding the nanoporous copper was developed that did not compact it or otherwise degrade its structure. An acceptable bond was achieved by sputtering a layer of indium-based solder onto the surface of the nanoporous copper and on the aluminum baseplate. The components were assembled and heated to melt the solder. The resulting solder interface had a thickness of ~1.5 m. The targets performed as expected in the experiments, and the interface between the nanoporous copper and the baseplate did not appear to significantly affect the shock as it passed through the target.