Deuterium-tritium solid layer formation and characterization in a beryllium shell

Copper-doped beryllium ablators are part of the current baseline design for indirect drive hohlraum targets for use at the National Ignition Facility. Recent advances in phase-contrast enhanced x-ray imaging have made it possible to characterize solid deuterium-tritium layers inside of the optically opaque beryllium shells. The imaging system used for characterization will be described. We will report results of experiments to produce smooth D-T layers inside of a beryllium shell. We find that the D-T layer RMS roughness of modes 4-128 increases from 0.9 $\mu$m at 19.4 K to 1.3 $\mu$m at 18.3 K. We observe the layer to become smoother with time when held at 18.3 K.