"Gas Cell" for X-Ray Opacity Measurements

X-ray opacities of low Z elements control the rate and the path of stellar evolution. High Energy Density (HED) experiments are being conducted at major facilities such as Sandia’s Z machine and LLNL’s National Ignition Facility (NIF) to quantitatively understand the increased “hot” opacity under HED conditions, as compared to “cold” opacity values in ambient environments. The accuracy of target areal densities used in HED experiments are limited by the published x-ray opacity databases which are used in data conversion. The databases can be improved by direct opacity measurements with modern equipment. We pioneer an “AutoEdge” x-ray absorption measurement system for x-ray database revisions on metal elements. In this work, we build an additional “gas cell” to allow for such measurements on gaseous elements. We will start with argon, to establish capabilities, and in the future, extend to oxygen which is particularly relevant to solar opacity.