OPTIMIZATION OF THE BRIDGE/POWDER INTERFACE FOR A LOW ENERGY SCB DEVICE

SCB devices capable of firing at energy levels less than 100 ^J are discussed. For the SCB bridge itself, low energy performance is achieved by using a small bridge size. SCB bridges of comparable mass and volume having different bridge thicknesses perform similarly in terms of their electrical characteristics, however, bridge thickness plays an important role in SCB ignition of energetic materials. The bridge thickness/particle size ratio was found to be more important than the bridge area/particle size ratio. Reliable SCB ignition of ball-milled BNCP was demonstrated at low compaction pressure levels. For recrystallized BNCP which was larger in particle size than the ball-milled BNCP, low energy SCB ignition was feasible only at higher compaction pressures. The particle size effect was also demonstrated using other energetic "first fire" materials, including lead azide and DXN-1. With proper selection of the first fire material, particularly with regard to particle size, SCB ignition is very reliable and is controlled by the all-fire level of the SCB bridge, itself. In other words, with an optimally configured SCB bridge/powder interface, one can be assured that, as long as sufficient energy is available to produce the SCB plasma, the energetic material will ignite. BACKGROUND