Design and characterization of a hohlraum for dynamic radiography at the OMEGA EP (extended performance) laser system.

We present the results of the design and characterization of an Au hohlraum implemented at the OMEGA Extended Performance Laser System in the Laboratory for Laser Energetics in Rochester, NY, for the purpose of dual-species, simultaneous radiography of a dynamic object. Two long pulse ultraviolet lasers with a total energy of 6.8 kJ and a pulse duration of 4 ns were directed at the hohlraum to generate radiation to drive a shock through a physics package attached to its side. The hohlraum was experimentally characterized using the Velocity Interferometer System for Any Reflector (VISAR) diagnostic instrument. VISAR data analysis and simulations with the Free LAGrange (FLAG) and Helios codes result in a radiation temperature in the range of 140-146 eV. Simultaneous radiography with protons and x rays was achieved; however, discrepancies in experimental and simulated conditions made it difficult to resolve shock propagation.