Expansion of the detonation products of lead azide via a supersonic nozzle

Abstract

The cloud of products formed following the detonation of lead azide (LA) contains gaseous species and solid particles. The dynamics of the detonation products expanding freely or through a supersonic nozzle into vacuum is unraveled via the temporal profiles of the pressure, the emission from Pb atoms and the attenuation of a He-Ne beam. The velocity of the fastest gaseous species is found from the onset of the pressure rise and the emission at a given distance from the LA sample, and the velocity of the fastest solid particles from the attenuation. In the free expansion, the respective velocities are 4.5±0.1 and 3.8±0.2 km/s and in the nozzle expansion 5.1±0.2 and 1.4±0.2 km/s. The expansion into atmospheric pressure air is also monitored and found to be much slower than that into vacuum. The utilization of nozzles as a means for obtaining a particle free, transparent medium of detonation products is stressed in the context of exploiting explosives for achieving chemical lasers in the visible wavelength region.