X-ray gain in neonlike ions from inner-shell ionization of sodiumlike ions by suprathermal electrons

We propose a new scheme for obtaining soft x-ray gains in neonlike ions. The scheme relies on inner-shell ionization of sodiumlike ions by suprathermal electrons. Since this amplifier will operate with, in principle, no population in the neonlike ground state, the power requirements for scaling to higher $Z$ may be reduced, and the problem of line trapping is eliminated. Model calculations for selenium are presented to verify measurable gain and the experimental feasibility of the scheme is briefly discussed.