M S Wallace, R F Heeter, Y P Opachich, A E Peterson, E C Dutra, P Cho, D C Mayes, B A Hobbs, R A Knight, C K Kenstler, C J Fontes, R Posadas, M Hohenberger, P M Kozlowski, H Johns, T J Urbatsch, T S Perry
The National Ignition Facility's soft x-ray opacity spectrometer (OpSpec) currently records time-integrated spectra from ∼550 to 2000 eV. To accomplish this, two elliptical acid-phthalate crystals with different shapes are used together. They are called the low energy and standard energy OpSpec channels and they span roughly 550-1000 and 1000-2000 eV, respectively. Replacing the crystal in the low-energy mount with a PET crystal gives a new higher-energy channel. Slight modifications to the shape of the ellipse give the new channel an energy range of 1750-3000 eV. The new geometry, testing results, and data from the NIF opacity campaign are discussed in this article.