Prompt laser ignition and transition to detonation in a secondary explosive

摘要

A two-stage approach to achieving detonation in a secondary explosive was developed in previous studies in which ignition resulted from low-energy hot wires or from laser diodes. In the current study, this approach was examined in some detail for the case of ignition by a pulsed, solid-state (rod) laser. An initial series of experiments used Nd/glass, Nd/YAG, and Ti/sapphire lasers to investigate the ignition of graphite-doped HMX in highly confined optical fixtures that incorporated a fast piezoelectric pressure transducer. Experimental parameters included the laser power history and the explosive column length. The results of these experiments guided a second series of experiments in which the ignition column explosive was terminated by a thin rupture disc in contact with a transition column of low-density HMX or some other material. The transition column was terminated with a piezoelectric time-of-arrival detector for determining overall function times. Parameters investigated included different laser sources, rupture disc thicknesses, and the transition column explosive characteristics. Overall function times less than 50 microseconds were obtained, and trends established by the various parameter studies indicate that further reductions in function time can be achieved.