Transient high gains at 196 Å produced by picosecond pulse heating of a preformed germanium plasma.

Simulations are presented for a collisionally pumped germanium slab target x-ray laser, irradiated with a Ins, 5 × 10¹² W cm⁻² background pulse and a 2ps, 10¹⁵ W cm⁻² main pulse, which starts 900ps after the beginning of the background pulse. Plasma regions with electron temperatures and densities of ~ 1 keV and 10²¹ cm⁻³ result in high small signal gain coefficients on the J=0-1 transitions at 196, 193 and 132Å. Raytracing calculations indicate the possibility of obtaining saturated output at 196Å for ~ 5ps from a 1cm length target if a travelling wave pumping scheme can be implemented. The calculations also suggest that significant output at 132Å should be observed with a far field deflected angle of ~ 8mrad.