A New Tri-Particle Backlighter For High-Energy-Density Plasmas (Invited)

A new tri-particle mono-energetic backlighter based on laser-driven implosions of (DTHe)-He-3 gas-filled capsules has been implemented at the OMEGA laser. This platform, an extension of the original (DHe)-He-3 backlighter platform, generates 9.5 MeV deuterons from the (THe)-He-3 reaction in addition to 14.7 and 3.0 MeV protons from the deuterium and helium-3 reactants. The monoenergetic 14.7 and 3.0 MeV protons have been used with success at OMEGA and the NIF for both radiography and stopping-power studies. There are several advantages of having a third particle to diagnose plasma conditions: an extra time-of-flight-separated radiograph and an improved ability to discern between electric and magnetic fields. In cases where the 3.0 MeV protons cannot penetrate an experiment, the benefit of the additional 9.5 MeV deuterons is magnified. This capability is well-suited for NIF experiments, where large fields and plasma densities often preclude useful 3.0 MeV proton data. The advantages are demonstrated with radiographs of OMEGA plasmas with magnetic and electric fields. Tests using backlighter-scale 420 mu m diameter thin glass capsules validate the platform's extended backlighting capability. The performance characteristics of this backlighter, such as source size and timing, are discussed.