The dynamic effects of a thin metal plate during pulse heating and expansion into the liquid-vapor region

The dynamic response of lead targets 0.025 mm and 0.05 mm thick to heating by a 1.0 MeV electron beam for about 50 ns is described. The lead targets were contained between a thin titanium tamping layer and a thick layer of fused quartz. Measured and predicted peak stresses in the quartz for no gap between the lead and the confining surfaces were approximately 12 kbar and agreed within 1 kbar. Peak stresses decreased rapidly with gap size to values, at 0.025-mm gaps, of about 1 kbar for the 0.025-mm lead targets and 5 kbar for the 0.05-mm targets. Predicted and measured values of tamper velocity (momentum) were within 10% only when the lead and confining walls were in close contact. The observed velocities for even very small gaps were substantially below predictions.