Polishing of beryllium capsules to meet NIF specifications

Abstract
Beryllium (Be) and copper (Cu) doped Be capsules are being developed for ignition on the National Ignition Facility (NIF). One approach uses bonding of machined Be parts while a second relies on sputter coating of Be onto a mandrel. Both approaches will require polishing in order to achieve the surface finish specifications required for ignition on NIF. This article describes a mechanical polishing process we have developed which achieves the needed surface finish for a Be NIF capsule. Characterization of the polished Be sphere is accomplished by a combination of AFM spheremapping, x-radiography and optical techniques.