Study of Stark Broadening of Krypton Helium-$\beta $ Lines and Estimation of Electron Density and Temperature in NIF Compressed Capsules*

The dHIRES (DIM based high resolution) x-ray spectrometer measures Kr He$\alpha $ and He$\beta $ spectra from NIF compressed capsules with 12-eV spectral and 30-ps temporal resolution. Comparison of the measured Kr He$\beta $ spectra with theoretical line shapes provides a measure of the time history of the electron density, n$_{\mathrm{e}}$. Electron temperatures, T$_{\mathrm{e}}$, are inferred by comparison of ratios of Li-like to He-like Kr line intensities to calculations by SCRAM. Spatial profile effects are calculated by averaging assumed optically thin SCRAM spectra over spherical shells defined by n$_{\mathrm{e}}$(r) and T$_{\mathrm{e}}$(r) from LASNEX. Comparisons of measured spectra with SCRAM and CRETIN-TOTAL simulations will be shown.