South pole bang-time diagnostic on the National Ignition Facility

• Main Authors: MacPhee, A., Edgell, D., Bradley, D. K., Bond, E. J., Burns, S., Callahan, D. A., Celeste, J., Kimbrough, J., Mackinnon, A. J., Magoon, J., Eckart, M. J., Glebov, V., Hey, D., Lacielle, G., Kilkenny, J, Parker, J., Sangster, T. C., Shoup, M. J., Stoeckl, C., Thomas, T.
• Other Authors: United States. Department of Energy.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Lawrence Livermore National Laboratory 2012
• Subjects: Removal; Chemical Vapor Deposition; Compression; Plasma Diagnostics; 70 Plasma Physics And Fusion Technology; Mirrors; 36 Materials Science; Us National Ignition Facility; Monochromators; 42 Engineering; Response Functions; Graphite; Diamonds; Lasers; Implosions; Accuracy; South Pole; South pole
• Online Access: http://digital.library.unt.edu/ark:/67531/metadc846110/

The south pole bang-time (SPBT) diagnostic views National Ignition Facility (NIF) implosions through the lower hohlraum laser entrance hole to measure the time of peak x-ray emission (peak compression) in indirect drive implosions. Five chemical-vapor-deposition (CVD) diamond photoconductive detectors (PCD's) with different filtrations and sensitivities record the time-varying x rays emitted by the target. Wavelength-selecting highly oriented pyrolytic graphite (HOPG) crystal mirror monochromators increase the x-ray signal-to-background ratio by filtering for 11-keV emission. Diagnostic timing and the in-situ temporal instrument response function are determined from laser impulse shots on the NIF. After signal deconvolution and background removal, the bang time is determined to 45-ps accuracy. The x-ray 'yield' (mJ/sr/keV at 11 keV) is determined from the total area under the peak.