X-ray Thomson scattering from proton heated matter

Understanding the interaction of particle beams with solid matter is an important challenge in the study of material properties under extreme conditions, having particular relevance to fast-ignition schemes of inertial fusion. We present the first measurements of thermodynamic properties of proton-heated matter using spectrally resolved x-ray scattering, performed on the Titan laser at Lawrence Livermore National Laboratory. The petawatt laser beam was split into two beams; the first 10 ps, 80 J beam generated a proton beam from a 10µm Aluminum foil, while a second 150 J beam produced a 4.5 keV Titanium K-α x-ray pulse. The MeV protons heated a Boron Nitride target, creating a strongly coupled plasma. X-rays were scattered from the heated target onto a curved crystal spectrometer, probing the collective electron-electron oscillations of the system. Electron density and temperature are extracted from the dispersion and detailed balance of the up- and down-shifted plasmon signals.