Inertial Confinement Fusion (ICF) ignition targets require smooth and well-characterized deuterium/tritium (DT) ice layers. Los Alamos is developing Resonant Ultrasound Spectroscopy1 (RUS) to measure the internal pressure in the targets at room temperature after filling with DT. RUS techniques also can detect and measure the amplitudes of low modal surface roughness perturbations of the target shell interior.

The experiments required beryllium capsules with a nominal inside radius of 1 mm and a spherical outside radius of 3 mm. The capsules have various spherical harmonic contours up to mode 12 machined into their interior surfaces. The capsules are constructed from hemispheres using an epoxy adhesive2 and then filled to ∼270 atm with helium or deuterium gas.

This paper describes the adhesive joint design, machining techniques, and interior geometry inspection techniques. It also describes the fixtures needed to assemble, fill, and pressure test the capsules.