Mesh-initiated detonation and effect of current-pulse wave form [pulsed power]

The development and manufacture of novel electrically exploding etched and coated copper mesh bridgewire designs to detonate coated PETN explosive on both singly curved and hemispherical surfaces are described. Two very low inductance circuit rigs are mentioned; a 470 J, 30 kV unit employing a 1 μF capacitor, and a 12 kJ, 30 kV unit employing a 28 μF capacitor. Both rigs utilise triggered three-electrode spark gaps to switch the capacitors to the mesh circuit elements. Chemically etched copper surface and novel through-hole plated mesh designs up to 150 mm sq are described, with breakout simultaneity within 100 ns and adjacent fuse site simultaneity within 40 ns. Through-hole plating techniques normally associated with printed circuit board manufacture have been modified to form the fuse sites and utilised to provide an even distribution of fuse sites over a hemispherical surface. Inner and outer copper coated surfaces form the current path to the fuse sites. The small holes produced during manufacture of the fuse sites provide both a key between the PETN explosive coating and the mesh surface and also confine the explosive, and thereby improve the detonation interface