Soft X-ray gain in Na-like copper and nickel ions

摘要

We report the observation of gain on the transitions 4d-5f, 4f-5g and 4f-6g in Na-like copper and on 4d-5f and 4f-6g in Na-like nickel. The corresponding wavelengths are 10.4 nm, 11.1 nm and 7.3 nm for copper, and 11.5 nm and 8.1 nm for nickel. The mechanism responsible for the gain is very likely recombination from neon-like ions. There are indications of gain at the lines 4d-5f and 4f-5g in other Na-like ions as well, e. g., in germanium for which the corresponding wavelenghts are 7.7 and 8.3 nm.