First measurements of mix in a metal shell fusion implosion using charged particle radiochemistry at the NIF

A primary objective for LLNL's Pushered Single Shell (PSS) campaign is to study the effect of metal-gas mix on fusion implosions. PSS implosions result in enhanced shell areal density by means of a graded density region near the capsule inner surface. The gradient is accomplished via a gradual inrease in the concentration of either a Cr or Mo dopant in the Be ablator, minimizing instability that would otherwise tend to destroy an ablator with a step-change in density. Recent PSS experiments have recorded the first demonstration of an independent radiochemical measurement of metal-fuel mix in a fusion implosion. The mix at the ablator-DT interface generates radio-isotopes of either Mn (for Cr dopant) or Tc (for Mo dopant) through charged-particle interactions, a process that is very sensitive to the amount and distribution of the fuel-ablator mix. Radiochemical analysis of solid-capture debris has successfully isolated and counted key Cr and Mn isotopes, the ratio of which is proportional to the mix. Post-shot simulations of the implosion run with a benchmarked model for the mix and that calculate the isotopic production will be compared with data.