Slapper detonator

A slapper detonator, also called a chip slapper, is a component of explosives systems, primarily military, which both delivers large amounts of energy to the target explosive but is highly immune to accidental triggering. The technology was originally developed for the implosion systems of nuclear weapons, which must operate at extremely high speed.

One of the attractions of slapper detonators, which evolved from exploding bridge wire (EBW) detonators, first designed by Luis Alvarez duing the Manhattan Project, is that they are both extremely fast, and multiple detonators can be exploded in synchrony, or after controlled delays. They were developed at Lawrence Livermore National Laboratory as a second step built on the EBW detonator. The slapper uses the expanding foil plasma to drive a second foil or plastic film to "slap" the actual detonator, at extreme speed, into the explosive surface. It may be propelled completely by the plasma, but advanced designs use a magnetic field to supplement its speed. "Slappers are fairly efficient at converting electrical energy into flyer kinetic energy, it is not hard to achieve 25-30% energy transfer.

The heart of a slapper detonator is a high-density explosive pellet, possibly a plastic bonded explosive, pressed against an insulating disk with a hole in its center.

Against the disk is place the flying "slapper", made of a strong plastic such as Kapton or Mylar, covered with etched metal foil on one side. "A necked down section of the etched foil acts as the bridgewire. The high current firing pulse causes vaporization of the necked down section of the foil. This then shears the insulated flyer which accelerates down the barrel of the disk and impacts the explosive pellet. This impact energy transmits a shock wave into the explosive causing it to detonate."

Since the slapper has appreciable two-dimensional aspects compared to an exploding wire, it can initiate an area, not a line or point, of the explosive.

Versions, packaged in common integrated circuit containers and suitable for inclusion in military-grade printed circuit boards, are used in such applications as anti-tank missiles.