He multi-particle backlighter for stopping-power experiments and for radiography of strong fields at the NIF

The D³He backlighter platform, based on implosions of D³He-filled capsules that generate mono-energetic 14.7-MeV and 3.0-MeV protons, has been used extensively with success at OMEGA and the NIF both for radiography of plasmas and their electromagnetic fields and for stopping-power studies. To significantly advance this work, a new tri-particle mono-energetic backlighter based on a DT³He gas-filled capsule implosion that provides 14.7-MeV and 3.0-MeV protons plus 9.5-MeV deuterons from the T+³He reaction is being developed at OMEGA. Initial tests using 860-µm-diameter, thin-glass capsules filled with 20:40:40 DT³He (atomic ratios) fuel produced 1e10,1e9, and 8e8 D3He-p, DD-p, and T3He-d yields, respectively. Other performance characteristics of the backlighter, including source size, burn duration and line widths are discussed. Radiographs of laser-driven foils and measurements of stopping power in cold beryllium were made with the backlighted particles and the results are shown. This work was supported by DOE, NLUF, LLNL, and LLE.