We measured the conversion efficiency of laser pulse energy into keV x-rays from a variety of solid planar targets and a Xe gas puff target irradiated using a high average power Ndglass slab laser capable of delivering 13 ns FWHM pulses at up to 20 J at 1.053 pm and 12 J at 0.53 pm: wavelength band, including L-shell emission from materials with atomic numbers the range Z=24-30 and M-shell emission from Xe (Z=54). With 1.053 pm a maximum conversion of 11% into 2n sr was measured from solid Xe

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... rgets. At 0.527 pm efficiencies of 12-18%/(2n sr) were measured for all of the solid targets in the same wavelength band. The x-ray conversion efficiency from the Xe gas puff target was considerably lower, at about 3%/(2n sr) when irradiated with 1.053 p. Targets where chosen to optimize emission in the 10 -. 15