Accurate diagnostics for determining the mass distribution in next generation DTRA gas puff loads are essential for increasing plasma radiation source (PRS) predictability, efficiency and yield. Recently, laser induced fluorescence (LIF) has been used to diagnose the mass distribution in gas puffs. Comparison between LIF using an acetone tracer and laser interferometry measurements on a DTRA argon gas puff assembly show good agreement at plenum pressures below 30 psia. At higher pressures the results diverge with LIF yielding significantly higher density than interferometry measurements, possibly due to acetone clustering. In Phase I we will undertake planar laser induced fluorescence measurements on the previously diagnosed gas puff assembly but using nitric oxide (NO) as the tracer. NO and argon have essentially the same boiling point so no questions about tracer clustering should arise. Comparisons between NO LIF, acetone LIF and laser interferometry will be carried out. The overall goal of the Phase I and Phase II program is the development of a straightforwardly implemented LIF diagnostic that can be fielded in-situ on PRS systems to reliably, accurately and confidently diagnose the mass distribution of gas puff loads. The development of a reliable diagnostic for determining mass distribution in gas puff PRS loads could lead to substantial improvements in existing and future radiation source capability in terms of yield, power, and spectral fidelity. Applications for these XUV sources include nuclear weapons effects simulations, x-ray lithography, and material surface treatments.
