X-ray and ion measurements in laser produced plasma from gold-copper alloy targets

Abstract

Enhancement in x-ray emission from laser plasmas produced from an alloy of gold and copper (Au 0.43+Cu 0.57 atomic composition) has been observed in a narrow spectral region of 1.5–3.9Å. X-ray emission is observed to be as high as six to nine times as compared to pure copper and 1.5 to 1.8 times as compared to pure gold targets. In these experiments, a single pulse from a Nd:glass laser (λ=1.06μm) having an energy up to 2J and 500ps pulse duration was used to obtain a focused intensity of 1013–1014W∕cm2 on the targets. The results are explained on the basis of enhanced group Rosseland opacity (Rosseland mean over the spectral range under consideration) for the Au–Cu alloy target as compared to either of the pure targets.