A NaF foil target was irradiated at an intensity of 6.0 x 10(14) W/cm(2) with a 28-psec, 526-nm, 23-J laser pulse. A space- and time-averaged gain coefficient of 4 +/- 1 cm(-1) was obtained for Na XI H-alpha at 5.42 nm. Computer simulation gives a peak time- and space-resolved gain of ~18 cm(-1).