Design And First Use of the NIF Opacity Spectrometer

Recent experiments at the Sandia Z facility have raised questions about models used in calculating L-shell opacities of mid-Z elements. A platform is being developed to check these results at the National Ignition Facility (NIF). The NIF experiments require a new X-ray opacity spectrometer (OpSpec) for the iron L-shell X-ray band, spanning photon energies from 540 eV -- 2100 eV with a resolving power E/$\Delta $E \textgreater 700. The design of the OpSpec and photometric calculations based on expected opacity data are also presented. First use on NIF is expected in September 2016.