We report on the experimental demonstration of saturated X-ray laser output
from collisionally pumped Ni-like Pd, Ag, and Sn at wavelengths of 14.7, 1
4.0, and 12.0 nm, respectively. Using a 100 ps drive pulse irradiation and
a 'twin-0.25%' prepulse configuration on flat slab targets, gain-length pro
ducts > 16 were obtained for the three elements. The drive power required f
or saturation was only 250 GW in a 100 ps pulse (25 J), corresponding to an
irradiance of 10 TW/cm(2). (C) 2000 Academie des sciences/Editions scienti
fiques et medicales Elsevier SAS.