Targets for laser-driven opacity measurements

Special laser targets have been designed and fabricated which allow the opacity of materials to be experimentally determined at elevated temperatures (kT ≤ 200 eV). A general description of the technique is presented, as well as the fabrication steps necessary to produce the targets. A uniform high temperature environment is provided by the use of small millimeter-sized hohlraums driven by the Nova laser at Lawrence Livermore National Laboratory. The material sample is placed within the hohlraum and is further illuminated by the X-rays produced by one or two of the Nova beams incident on a second material known as a back lighter. Thus far, silver and niobium opacity samples have been used, and each has required a different fabrication technique.