A view on the functioning mechanism of EBW detonators -part 1: electrical characterisation

Exploding Bridgewire (EBW) Detonators are in widespread use and have proven reliability and performance characteristics. Since their invention there have been numerous studies to identify the mechanism by which the exploding bridgewire initiates the explosive. However, there is still not a universally accepted mechanism. This paper is the first of three characterising the initiation of PETN in an exploding bridgewire detonator to understand the underlying mechanism. The approach taken was to understand the transfer of energy through the system, beginning with the fireset / bridgewire interactions. The measurement of current, time to bridgewire burst and the transient voltage across the bridgewire at burst have enabled the determination of the energy used in bursting the bridgewire. This in turn has led to the calculation of the energy efficiency of the fireset bridgewire system and an estimate of the energy delivered post bridgewire burst. The results of the experimental work will be presented, together with the implications for the initiation mechanism of PETN in an exploding bridgewire detonator.