Monte Carlo Studies of Bremsstrahlung Emissions for HEDP and Ignition Radiography

X-ray radiography is used for studying high energy density and ignition experiments. MeV x-rays generated via Bremsstrahlung emission during short-pulse high-intensity laser experiments are ideal for high resolution radiographs. This is due to their small source size (100 µms), short pulse (1-10 ps), and high energy. This work builds upon the investigation of laser driven radiography conducted at the Titan, Omega EP, and NIF ARC facilities. Presented here are two GEANT4 studies to model the x-ray source in order to improve radiography capabilities. A database of x-ray outputs was created using GEANT4 simulations of monoenergetic electrons incident to high-Z foils of varying thicknesses. This database estimates the x-ray number and output energy of any desired electron input, enabling us to better understand the experimental x-ray data and optimize future experiments. The second model draws from GEANT4 simulations with varying initial electron sources and analyzes discrepancies in the resulting source size and emission angle of the x-rays. The resolution of the x-ray radiograph can be found by analyzing the curved-knife edge-spread function from the simulations. This allows us to optimize the source size and emission angles of the electrons for the highest resolution radiographs.