Preparations for Radiochemical Measurements of Double Shell Implosions

Future double shell implosion experiments will use high-Z materials, such as Mo or W, for the inner capsule. The wall material will be compressed to an extremely high density. The combination of high-Z and high density prevents x-ray diagnostics from being used. We will use a suite of nuclear diagnostics to infer conditions inside the fuel and also to diagnose physics experiments planned for this platform. A primary technique will be radiochemistry. We are exploring and qualifying the use of several different types of reactions for our experimental campaign. The first is Reaction in Flight (RIF) neutrons that measure the amount of long-range mixing. The second is an (a,n) reaction that measures short-range mixing. Finally, a (n,c) reaction is proposed to measure intermediate conditions. The first step to qualify these measurements is to determine the efficiency of the Radiochemical Analysis of Gaseous Samples (RAGS) instrument on NIF for the particular species of interest. We conducted a series of direct-drive capsule implosions to measure collecting efficiency and to confirm cross section data. Indirect drive experiments determined the effect of fission products from the DU hohlraum on the interpretation of the measurement. We will present the data gathered so far and its interpretation.