Abstract. We discuss a proposed experiment on guiding of a high-repetition rate, 20 GW, CO 2 laser beam in a gas-filled hollow glass waveguide. Extended interaction of the 3ps pulses with a gas Kerr medium will be used for measurements of nonlinearity at 10 um, and supercontinuum generation followed by pulse compression. Feasibility of 3-5 keV X-ray production via HHG is presented.