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AbstractOpacity data are very important in high energy density physics experiments. Recent targets of alternating layers of either Al2Te3or Mg/Sn with a CH tamper have been made for obtaining these data. These targets are geometrically simple in the half-moon configuration of the metal compound coating to the pure CH tamper but require stringent procedural requirements to fabricate to the purity requirements. These specific targets require mass ratios of elements that proved to be difficult to obtain while also having the requirement of being pinhole-free and oxygen-free.

AbstractNeutron imaging diagnostics are needed for understanding the principles of fusion ignition. Current experiments on the University of Rochester OMEGA laser facility and future experiments at the NIF require a new level of complexity in neutron diagnostics that has not yet been achieved. Previous shots have fielded a one dimensional pinhole array to gather an image of a sphere’s neutron emission during the implosion. This one dimensional pinhole array that consisted of two pinholes on a plane was a challenging manufacturing task and was a substantial accomplishment for its time. Future neutron imaging diagnostics will require a two dimensional pinhole array to gather a more comprehensive set of data. This two dimensional pinhole array, consisting of 3 pinholes one three planes to form a 3x3 array of pinholes, added a new level of complexity to the manufacturability. A method for fabricating this pinhole array was developed and the finished instrument was fielded in July and October 2006. This paper describes the fabrication process to producing this pinhole array and shows some of the early data taken with it at the Omega facility.

AbstractInertial Confinement Fusion (ICF) energy hohlraums are composed of a high-Z material filled with foam. Because of the small pore size and transparency, silica aerogels are used in some ICF targets. The traditional synthesis of silica aerogels require sol-gel polymerization of silicon alkoxide followed by supercritical drying. Some constituents in sol-gel polymerization have been found to contribute to leaching of certain metals at the silica/metal interface. Since the hohlraums are composed of metals, possible chemical reactivity at the silica aerogel and metal hohlraum interface was investigated. The hohlraums studied are aluminum lined with either copper or copper/chromium. Upon initial inspection, the aerogel appeared transparent and uniform, however, closer inspection of the copper wall suggested possible leaching. Alternatively the quality of the aerogel in the copper-chromium hohlraum was very poor with the chromium layer of the hohlraum and some copper completely etched. Control experiments were used to determine the cause of the leaching. When copper is in the presence of sol-gel constituents, Cu2+ion formed, thus leaching copper from the hohlraum walls. In the presence of chromium, Cr2O72-or CrO42-was identified in solution with the Cu2+, these anions are believed to form copper chromite under the aerogel synthesis procedures utilized.