Measurements of laser driven spallation in tin and zinc using an optical recording velocity interferometer system

Measurements of the dynamic strength, in tin and zinc, shocked by a high po wer pulsed laser to tens of kilobars pressures are reported. The strain rat es in these experiments are of the order of 10(7) s(-1), higher by two-to-t hree orders of magnitude than those reached with conventional shock generat ors like plane impacts or explosives. The free surface velocity time histor y, which is related to the spallation process, was measured with an optical recording velocity interferometer system. This diagnostic technique is non interfering and provides a highly accurate continuous measurement in time. The spall strength estimated from the free surface velocity profile was com pared with the theoretical upper limit for the spall strength, calculated f rom a wide range equation of state for metals. (C) 1999 American Institute of Physics. [S0021-8979(99)07319-3].