Low-Power Heterodyne Velocimetry of shocked metal surfaces

A low-power variant of a Heterodyne Velocimeter (HetV) based on a LLNL design\footnote{O.T. Strand \textit{et al}., \textit{Velocimetry using heterodyne techniques}, 26$^{th}$ Intl. Congress on High Speed Photography and Photonics, Sept. 19$^{th-}$24$^{th}$ 2004.} has been constructed to study motion of shocked metal systems. The system benefits from utilising a class 1 laser system enabling its safe usage and easy transfer between facilities. A number of experimental systems have been studied to establish the limits of the low power system including shocked metal targets on a large bore gas gun and H.E. driven systems. It is shown here how high quality absolute velocity measurements may be obtained from a variety of surface conditions without recourse to higher power lasers. Advanced analytical techniques have also been developed which complement the simple set-up and use of the HetV system which are presented here.