X-RAY LASER GAIN MEASUREMENTS IN A COLLISIONALLY EXCITED GERMANIUM PLASMA

We have used a novel beam-averaging technique that makes use of a segmented wedge array (SWA) to overlap several line foci and to produce a much more uniform linear plasma than has been obtained to date. With this focusing arrangement, laser gain was observed for the first time to our knowledge on a 2s2p63d-2s2p63p, J = 2-1 Ne-like transition at 198.99 angstrom. The experiments were carried out on the LP2 Nd:glass laser system operating at 1.06-mu-m with incident energies of approximately 125 J/cm of line focus. We also observed gain on five 3p-3s transitions, using both the SWA and crossed cylindrical lenses to produce the line focus.