Cryogenic micro-jet sources for HED science at the LCLS One of the main interest in high energy density (HED) physics is the investigation of warm and hot dense matter which Mother Nature provides in giant planets, stars or fusion implosions. In the laboratory such conditions can for instance be generated with high energy lasers driving shocks into the target material. The resulting plasma can be characterized by means of x-ray scattering at the LCLS which allows direct measure of density, temperature and also structure. In my talk I will introduce a cryogenic source providing liquid and solid micro-jet targets for HED experiments. I will present a first commissioning experiment for Hydrogen on laser driven ion acceleration which recently has been conducted at the MEC instrument of the LCLS. Prospective experiments with cryogenic jet-targets at the LCLS will be outlined.