Characterization of a cryogenic, high-pressure gas jet operated in the droplet regime

We report on the characterization of a cryogenically cooled high-pressure pulsed valve for laser-droplet interaction experiments. The gas jet can produce liquid droplets of a variety of gases over a wide range of temperature (100-300+/-0.25 K). Measurements of total mass flow for argon and krypton are presented as well as droplet size distributions obtained via dark-field shadowgraphy. Using light scattering, the temporal behavior of the valve is also investigated and the droplet flow speeds measured. The results are explained in terms of the phase diagrams for these gases and the dynamic operation of the valve. This characterization allows for properly interpreting yields of extreme ultraviolet emission from laser-irradiated droplet plasmas. (C) 2002 American Institute of Physics.