A drill, fill, and plug technique for fabricating laser fusion targets

We have devised a drill, fill, and plug technique to prepare targets with gases needed for direct measurement of compression using x‐ray spectroscopy. Gases such as Ar, Xe, Ne, D2S, and D2 have been sealed at pressures as high as 60 atm. inside hollow glass shells (microballoons). Each microballoon is filled through a micron or submicron sized hole which is sealed with a melted plug of comparable dimension. The hole is drilled using 80 ps laser pulses, and a plug is micromanipulated onto the hole under ambient atmospheric conditions. The plug material is then melted under conditions required for sealing. In some cases, gases are filled by diffusion through a previously melted plug material. Once filled, the pressure retention half‐life of the target is interferometrically determined. Targets prepared in this manner have been used in experiments which are diagnosed to have a volumetric compression ratio in excess of 1000.