Micro Slapper Initiators

The well known Exploding Foil Initiator (EFI), also called slapper detonator, is formed by a small capacitor that is used to burst a very thin copper bridge to accelerate a dielectric flyer plates to high velocities enough to initiate the secondary explosive. The presented particular case uses an EFI formed by a capacitor up to 0.2μF charged until 3kV, and the copper bridges with 0.3x0.3mm and 0.4x0.3mm with 0.005 mm of thickness, allows to accelerate Kapton flyer plates with 25 μm of thickness until 5 km/s. The process of Shock to Detonation Transition (SDT) in explosive samples with 5mm of diameter by 10mm of height was characterized by an optical method based on 64 optical fibbers ribbon (250μm of diameter each fibber) connected to a fast electronic streak camera. The obtained results, a (x,t) diagram, with (1 ns) resolution, show continuously the shock to detonation transition regime and allowed the evaluation of the detonation velocity and the detonation wave front curvature. In that regime DW propagation presents oscillations in velocity around a mean detonation velocity value. The results also show the effects of flyer plate velocity, the initial density on the regime of the SDT and the DW irregularities.