Development of a bright MeV photon source with compound parabolic concentrator targets on the National Ignition Facility Advanced Radiographic Capability (NIF-ARC) laser

Compound parabolic concentrator (CPC) targets are utilized at the National Ignition Facility Advanced Radiographic Capability (NIF-ARC) laser to enhance the acceleration of electrons and production of high energy photons, for laser durations of 10 ps and energies up to 2.4 kJ. A large enhancement of mean electron energy (> 2 x) and photon brightness (> 10x) is found with CPC targets compared to flat targets. Using multiple diagnostic techniques at different spatial locations and scaling by gold activation spatial data, photon spectra are characterized for E-photon = 0.5 - 30 MeV. Beam width and pointing variations are given. The efficient production of MeV photons at I-laser asymptotic to 2 x 10(18) W/cm(2) with CPCs is observed, with doses of > 10 rad in air at 1 m for E-photon > 0.5 MeV; these exceed those previously reported with laser-driven sources. Using this source, sub-mm resolution radiographs are generated through large areal density radiograph objects. These results are promising for the development of bright MeV x-ray and particle sources on Petawatt class laser systems. Published under an exclusive license by AIP Publishing.