Optimization of x-ray sources for proximity lithography produced by a high average power Nd:glass laser

We measured the conversion efficiency of laser pulse energy into x-rays from a variety of solid planar targets and a Xe gas puff target irradiated using a high average power Nd:glass slab laser capable of delivering 13 ns FWHM pulses at up to 20 J at 1.053 {mu}m and 12 J at 0.53 {mu}m. Targets where chosen to optimize emission in the 9-19 {Angstrom} wavelength band, including L-shell emission from materials with atomic numbers in the Z=24-30 and M-shell emission from Xe (Z=54). With 1.053 {mu}m a maximum conversion of 10% into 2{pi} sr was measured from solid Xe and type 302 stainless steel targets. At 0.527 {mu}m efficiencies of 12-18%/(2{pi} 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%/(2{pi} sr) when irradiated with 1.053 {mu}m