X-ray Thomson scattering for measuring dense beryllium plasma collisionality

We are developing a target platform that utilizes short-pulse (10 ps) generated hot electrons (∼200 keV) to isochorically heat solid density beryllium up to temperatures of several 10 eV. We use x-ray Thomson scattering to characterize the plasma conditions. X-rays from a Cl Ly-α line source at 2.96 keV are scattered off the plasma in forward direction where the inelastically scattered signal is sensitive to plasma oscillations. Besides Landau-damping the strong energy down-shifted plasmon signal is also broadened by electron-ion collisions which, in turn, allows to infer the collision rate and thus the conductivity in these plasmas. A precise knowledge of the collisionality in the parameter regime we are aiming at with these experiments is important to correctly model the conditions encountered during capsule implosions at the National Ignition Facility.