Was the Livermore X-Ray Laser Pumped by Recombination?

We demonstrate that recombination pumping following rapid radiative cooling of an overstripped selenium plasma can quantitatively account for the observed gains of the J=2 to 1 Se xxv transitions in the recent successful Livermore x-ray-laser experiments. The absence of gain in the J=0 to 1 transition, hitherto unexplained, is fully consistent with this scenario.