Design and Construction of a High-speed Particle Detector for Heterogeneous Explosives Experiments [microform]

Detonation of heterogeneous mixtures of solid particles and liquid explosive has gained recent interest because particles can change the energy released in a reaction and alter the blast wave. Much about these interactions remain unknown due to the lack of field instrumentation to detect sub-millimeter sized particles traveling at high speed. A through-beam detector, incorporating a 16-element infrared photodiode array lit by infrared LED's, was developed. The IR beams are collimated through 1 mm diameter channels in two 8 mm thick parallel plates. Particles passing between these plates can interrupt the beams. Simulation tests, using pulsed light, showed that the detector is sensitive enough to detect particles as small as 430 mum in diameter at speeds of up to 2 km/s. The system is intended for detonation trials with heterogeneous charges of condensed explosive, but can be adapted for high-speed particles in many other applications.