Dante As A Primary Temperature Diagnostic For The Nif Iron Opacity Campaign

The Opacity Platform on the National Ignition Facility (NIF) has been developed to measure iron opacities at varying densities and temperatures relevant to the solar interior and to verify recent experimental results obtained at the Sandia Z-machine, that diverge from theory. The first set of NIF experiments collected iron opacity data at similar to 150 eV to 160 eV and an electron density of similar to 7 x 10(21) cm(-3), with a goal to study temperatures up to similar to 210 eV, with electron densities of up to similar to 3 x 10(22) cm(-3). Among several techniques used to infer the temperature of the heated Fe sample, the absolutely calibrated DANTE-2 filtered diode array routinely provides measurements of the hohlraum conditions near the sample. However, the DANTE-2 temperatures are consistently low compared to pre-shot LASNEX simulations for a range of laser drive energies. We have re-evaluated the estimated uncertainty in the reported DANTE-2 temperatures and also the error generated by varying channel participation in the data analysis. An uncertainty of +/- 5% or better can be achieved with appropriate spectral coverage, channel participation, and metrology of the viewing slot.