Characterization of a high-efficiency x-ray spectrometer for warm-dense matter studies on the National Ignition Facility

X-ray Thomson scattering (XRTS) is a powerful diagnostic for understanding warm-dense matter, as it simultaneously encodes details of electron correlations, ionization, and the plasma thermodynamic state [S. H. Glenzer and R. Redmer, Rev. Mod. Phys. 81, 1625 (2009).] While on-going XRTS measurements at the National Ignition Facility (NIF) have challenged traditional descriptions of ionization [T. Döppner, et al., Nature 618, 270 (2023)], the scarcity of the data limits a global assessment of microscopic models of warm dense matter. A continuous, high-throughput scattering measurement would provide unprecedented access to the ion–plasma interaction while also characterizing the evolving thermodynamic state. To provide the required diagnostic capability, we have designed a high-efficiency x-ray spectrometer coupled to an x-ray streak camera for use on the NIF. This new streaked capability will record the scattering spectra from matter increasingly compressed in an implosion, mapping out the evolving electronic structure. This development furthermore opens the prospect to constrain the thermodynamic state of the scattering volume throughout a single experiment, posing benefits to other platforms including equation of state measurements in multiply shocked media.

This work was performed under the auspices of the U.S. Department of Energy and an appointment to the Office of Science, by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344. LLNL-ABS-2009139.