Combining X-Ray Thomson Scattering and X-Ray Raman Spectroscopy to Characterize Solid-Density Plasmas

X-ray Free Electron Lasers can produce solid-density plasmas by ultrafast isochoric heating and at the same time the brilliant X-rays allow for in situ diagnostics of unparalleled precision. Here we present experiments performed at the Linac Coherent Light Source and the European XFEL that for the first time combine X-ray Thomson scattering and X-ray Raman spectroscopy to study isochorically heated carbon allotropes and other carbon-containing sample materials. Our results provide unique insights into the isochoric heating process and the irradiance-dependent evolution of the electronic structure, while at the same time constraining temperature and ionization.