HOLE DRILLING BREAKTHROUGH IN BE SHELLS

This is a brief memo look at the problem of determining whether one has broken through the inside plastic mandrel of a sputtered Be shell. This is important because the next step is the thermal removal of the mandrel, and failure to break through the plastic, even if through the Be, makes our process at best difficult. Described below are two possible approaches, the first somewhat high tech and maybe not possible, the second definitely low tech but certainly doable.