Recent results on development of a table-top soft X-ray laser

Gain measurements have been performed in a recombining carbon plasma generated by a line focussed Nd-glass laser beam on a multi-fin target with the aim of developing a “table-top” soft X-ray laser. With a laser beam of only 4 J (2ns) and a 6 mm long target gain up to 7.1 cm−1 was measured for the C VI 18.2 nm line (gain-length ∼4.3). During these measurements high gain (6.5 cm−1) was also measured for the first time on the C VI 13.5 nm line (4−2 transition). These measurements were done in the process of preparation for two-target experiments. High gain was measured independently for two separate, identical 6 mm targets. Changes in the influx into the plasma of iron ions from “cooling” blades significantly affected the location of the gain region and can be used as a mechanism to control the gain region in two-target experiments.