Comparison of laser-produced plasma target materials for pumping the 109-nm Xe2+ Auger laser

We compared cadmium, copper, gold, and zinc targets to stainless steel for laser-produced plasma pumping the Xe²⁺ 109 nm laser. A unique target geometry allowed us to measure the laser output using two materials under identical conditions. Small signal gain coefficients and maximum output powers are presented for each material relative to stainless steel; we observed a ~20% improvement in the gain coefficient and a ~112% improvement in total energy using a cadmium target. This increase probably results from an improved overlap of the laser-produced plasma emission spectrum with the Xe inner shell 4d photoionization cross section, although published data to support this hypothesis are scarce and inconsistent