HIGH-RESOLUTION OPTICAL MEASUREMENTS OF SURFACE-ROUGHNESS FOR BETA-LAYERED DEUTERIUM-TRITIUM SOLID INSIDE A REENTRANT COPPER CYLINDER

A high-resolution optical imaging system and custom-designed image ana lysis software are used to make surface roughness measurements for deu terium-tritium (D-T) solid layers, equilibrated inside a 2-mm-inside-d iameter re-entrant copper cylinder Several experiments are performed t hat yield D-T layer thicknesses of between 75 and 139 mu m, with equil ibration temperatures between 17.4 and 18.8 K. A 1024- x 1024-pixel ch arge-coupled-device imaging camera, coupled with a Maksutov-Cassegrain long-range microscope, produces a 2.5-mu m (single-pixel) image resol ution, The error function fitting of the image analysis data produces submicron resolution of the layer interior surface finish. The length scale for the cylinder inner bore is just over 6 mm, and the final lay er surface roughness for this length ranges from 3- to 1.7-mu m root-m ean-square. The feasibility is being explored of using these highly un iform and smooth D-T solid layers inside future targets for inertial c onfinement fusion reactors to produce surface finishes that will meet target design requirements for the National Ignition Facility. Techniq ues for improving the D-T solid layer surface finish are examined, lim itations of the current D-T cell configuration and fuel mix are discus sed, and cell configurations for future experiments are described.