Lab Wants to Slap Enemies Senseless

Kathleen G. Tatterson

LOS ALAMOS, N.M. -- Some folks think that the US military's vast stockpile of so-called antiquated weapons should be destined for the trash bin, when all they really need is a good slap. Scientists at Los Alamos National Laboratory are developing a new laser technique for detonating explosives that would make it possible to give existing weaponry new life.
Laser slapper detonators function similar to their electrical counterparts: They send a high-power energy pulse through a small conductive bridge, which touches off the detonator primer, setting off the explosion. With the new slapper, a Q-switched 1.06-µm laser, such as gadolinium scandium gallium garnet or Nd:YAG, sends a high-power pulse through an optical fiber to vaporize a thin metal film, which is launched through a short barrel. The shock from the film loads, or slaps, the high-density, pressed explosives, setting off the detonation.
Increased safety is the main advantage that laser slappers offer over electrical detonators, according to Tom Turner, staff scientist at Los Alamos. Because the devices require very high peak laser power (at least 1 MW) to operate, accidental detonation by lightning or other natural or human means is unlikely. "There is nothing in nature that will produce a megawatt pulse," explains Turner. "Even the light from a nearby nuclear explosion wouldn't be enough to set it off."
Additionally, because laser slappers transport pulses over fiber optics instead of conductive wires made of copper, they eliminate electrical hazards experienced with traditional electrical devices. And the use of insensitive, secondary explosives makes the laser slapper detonators safer to handle, manufacture and deploy.
The military could use the technique to retrofit current weapon stockpile using this technology, rather than using it to design new weapons. The US Department of Energy is funding the project under its Stockpile Stewardship Program, which focuses on the maintenance of weapons that have already been developed.