Laser target fabrication activities in the United Kingdom

Abstract

Two main laser fabrication facilities exist in the United Kingdom (UK), one at AWRE and the other at the Central Laser Facility, Rutherford–Appleton Laboratory, which operates in support of a University research program. An overview of target microfabrication, characterization, and materials technology at these Laboratories are presented. Emulsion technology processes have been used to manufacture hollow polymer microspheres in a range of sizes. Large diameter spheres are used for individual targets and the smallest sizes are bulk packed to form a low density foam material. Polymeric foam materials are also made using the phase inversion method, plasma polymerization technique, and by a surface catalyst on compacted powder which is subsequently leached. Metal and polymer layer coatings for targets are carried out by thermal evaporation, sputtering, electroplating, plasma polymerization, and vapor phase pyrolysis techniques. Improved adhesion in multilayer foil targets is achieved by dynamic recoil mixing during the coating process. Ion beam milling and UV laser etching methods have been used to micromachine and structure targets. A range of optical, radiographic, and charged particle techniques are used to characterize targets. The use of laser generated x-ray backlighting for target material inspection is described.