Developments in X-ray laser pumping with travelling wave at Vulcan

Saturated output has been observed for both Ne and Ni-like X-ray lasers when pumped in the transient mode. As these 'normal' transitions display very high gain, attempts have been made to observe a 2p→2s inner shell transition in Ne-like ions, which scale well towards the water window. Modelling of the pump conditions for Ge lasing at 6.2 nm is presented. As the predicted gain is low the experiment was set up for 18 mm targets. Shots were taken on Ti, Fe. Ni and Ge. A ∼ 1.5 ps travelling wave pulse is applied at various times after the peak of a long, pre-forming pulse. Various pump conditions were attempted but no inner shell X-ray laser was detected.