The effects of gas on ejecta particle size distributions for shock loaded Sn

A strong shock wave reflecting from a metal surface can lead to ``ejected matter'' which are metal/liquid particles emitted from the metal gas/vacuum interface. The mass, size and velocity distributions will depend on a variety of conditions including the material properties of the metal under investigation as well as the shock loading conditions. Furthermore, if the particles are produced in a gas environment the particles can undergo further fragmentation due to the interactions the particles have with the gas. This can result in a size distribution that can vary significantly from that measured in a vacuum environment. We will present particle size distributions from shock loaded Sn samples that were measured in a vacuum and He gas environments. The measurements were conducted using a new high-resolution in-line Fraunhofer holography measurement technique.