Ejecta Particle-Size Measurements from the Break-Up of Micro-Jets in Vacuum and Helium Gas Using Ultraviolet In-Line Fraunhofer Holography.

An ultraviolet (UV) in-line Fraunhofer holography diagnostic has been developed for making high-resolution spatial measurements of ejecta particles traveling at many mm/$\mu $sec. Recent results will be presented for high-explosive shock-driven tin ejecta experiments. Particle-size distributions will be shown that cover most of the ejecta velocities for experiments conducted in both a vacuum, and helium gas environments. In addition, a modification has been made to the laser system that produces two laser pulses separated by 6.8 ns. This double-pulsed capability allows a superposition of two holograms to be acquired at two different times, thus allowing ejecta velocities to be measured directly. Results from this double-pulsed experiment will be described.