Absorption Spectroscopy of direct-drive implosions with multiple dopants

The need to accurately predict radiation transport in stellar interiors and ICF targets provides a strong motivation for spectral opacities measurements of hot dense plasmas. In principle, laser-driven implosions could provide a platform to access extreme plasma conditions (ρ>ρ₀, T_e>400 eV), hard to reach by other methods. In this scheme, an element embedded in the shell is compressed by convergence, and heated by conduction from the central hotspot, which also provides a bright broadband x-ray source for absorption spectroscopy. Additionally, opacity measurements require knowledge of the source spectra, plasma conditions, and areal mass.  We present an experimental study of the feasibility of such a measurement in a simple case, associating two tracer elements in the shell of a direct-drive implosion. The first element is used as a thermometer to infer plasma conditions, while the second element is the sample of interest. Self-Emission Shadowgraphy of the implosion enables us to infer areal density. As a first step toward the future study of more astrophysically relevant elements, Titanium and Vanadium were used as tracers in this experiment performed on the OMEGA laser facility