Fusion Science and Technology / Volume 51 / Number 4 / May 2007 / Pages 701-704
Aluminum oxide aerogel can be used as a backlighter target to provide a radiation source for diagnostics during ICF experiments. To demonstrate the feasibility of this type of target, it was necessary to cast thin pieces of aerogel for plasma emission studies of aluminum oxide. We were able to demonstrate density control over a range of 50-400 mg/cc, and, furthermore, cast the aerogel as a thin (0.6-0.7 mm), smooth monolith that did not require additional machining. The fabrication of these targets begins with a solution of aluminum chloride, ethanol, and water and is then catalyzed with propylene oxide to gel within molds to form the shape. Supercritical drying with carbon dioxide provides the dry aerogel. Various target densities were made by adjusting the relative amounts of starting materials and post treatment condition. The finished materials were characterized for density, pore size, and water content. Initial freestanding targets of 98 mg/cc have been fabricated and shot, and other similar targets of densities from 50-400 mg/cc have been fabricated for future experiments.