Transient collisional excitation X-ray laser generation with picoseconds laser pulses

We have observed lasing on Ne-like 3s-3p line from titanium (32.4nm), Ni-like 4p-4d line from silver (13.9nm) and tin (11.9nm) with the transient collisional excitation (TCE) scheme that uses combination of a long prepulse ([MATH]) and a short main pulse ([MATH]). A gain coefficient of 23cm-1 was measured for plasma length up to 4mm with silver slab targets. We have also observed lasing on Ne-like and Ni-like lines with new TCE scheme that used pico-seconds laser pulse to generate plasma and observed strong improvement of x-ray laser gain coefficient. A gain coefficient of 14cm-1 was measured for plasma length up to 6mm with tin targets