Hard x-ray (>100 keV) imager to measure hot electron preheat for indirectly driven capsule implosions on the NIF

We have fielded a hard x-ray (>100 keV) imager with high aspect ratio pinholes to measure the spatially resolved bremsstrahlung emission from energetic electrons slowing in a plastic ablator shell during indirectly driven implosions at the National Ignition Facility. These electrons are generated in laser plasma interactions and are a source of preheat to the deuterium-tritium fuel. First measurements show that hot electron preheat does not limit obtaining the fuel areal densities required for ignition and burn. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4731742]