Silica, Metal Oxide, and Doped Aerogel Development for Target Applications

A variety of silica, metal oxide, and metal doped aerogels are being developed for use as laser target materials. Silica aerogels have been produced with controlled densities as low as 5 mg/cc, and have been produced as bulk molds. Recently, 100 mg/cc small beads and hollow shells have also been fabricated using microencapsulation techniques. Metal oxide aerogels such as tantalum oxide (Ta2O5) and tin oxide (SnO2) are two other low-density materials that have been fabricated. Aerogels with embedded metal particles are also of interest and several methods for producing these composite aerogels are being explored. Each method limits excessive aggregation of the metal so that the end product has a uniform loading of small metal particles. Ion implantation is being investigated as another method that allows more control of the metal doping. With ion implantation the metal dopant can be placed in a narrow distribution beneath the surface of an aerogel, and initial results of 1 MeV Au^- implanted in 67 mg/cc SiO2 are described