A miniature ionization probe technique using a multilayer circuit board for the study of explosive phenomena in primary and secondary explosives

A miniature ionization probe technique using a multilayer circuit board has been developed. Full experimental details including construction of the boards, explosive charge preparation, and instrumentation are reported. Each copper layer in the circuit board functions as an ionization probe and optimum conditions were achieved with a probe density of 15/cm, i.e., probe separation about 0.75 mm. Explosive samples were studied in a geometry similar to that of practical fuze detonators: the pressed explosive columns were 5–8 mm long and masses ranged from 0.58 to only 0.08 g. Accurate, reproducible detonation velocity measurements have been obtained for the primary explosives service lead azide, at a wide range of densities, lead azide RD1343, silver azide and mercuric 5-nitrotetrazole, and the secondary explosive tetryl. Some potential improvements and future uses of the technique are discussed.