Release and recompression measurements of multiple component reservoirs for strength drive experiments on the NIF

The ability to infer strength in materials driven with staged shocks requires the development and accurate measurement of a multiple-shock drive. We have developed such a drive for use in Ta strength experiments up to $\sim$ 5 Mbar [1], which utilizes an initial shock which is large enough to theoretically generate dislocations within the Ta itself. Our desire to investigate other materials, which melt at a lower pressure on their principle Hugoniot, along with the desire to have a drive with an initial shock below the homogeneous nucleation threshold of $\sim$ 660 kbar [2] has prompted us to design and develop a different $\sim$ 5 Mbar drive with a different initial shock. We report here on the proposed design and experimental results achieved at the National Ignition Facility of several of the new components of the drive -- specifically the lower density foam layer, an iodinated plastic layer, and an aluminum layer. \\[4pt] [1] PoP \textbf{19}, 056311 (2012).\\[0pt] [2] AIP Conf. Proceedings \textbf{1426}, 1379 (2012).