The Cutting Edge: Computing / Technology / Innovation : PLOWSHARES : High-Tech Blasting Caps Offer Safer Way to Set Off Explosives

Weapons experts who are trying to channel their skills into civilian projects in the post-Cold War era often have to venture far from their traditional specialties to find promising projects. But at least one team has found something right up its alley: blasting caps.

Explosives used in mining, oil fields and other industrial applications are set off by electronically controlled blasting caps that are so sensitive they can be accidentally fired by something as weak as a cellular phone transmission or a static electricity shock from the human body.

Scientists at New Mexico’s Los Alamos National Laboratory, birthplace of the atomic bomb, have come up with a high-tech blasting cap that greatly reduces the threat of such accidents. Initially developed as a way to more safely fire missiles and bombs, the new cap uses a laser to set off the explosive.

“The optical detonation system is safer than electrical systems because no naturally occurring event and few man-made events can deliver enough optical power to inadvertently fire the explosive,” said Dennis Paisley of the Detonation Systems Group.

Here’s how it works: A laser pulse is directed into one end of a quartz cable encased in rubber. The light beam travels down the cable and strikes a small aluminum cap on the other end. The intense light vaporizes a thin layer of the aluminum, generating a plasma gas that expands rapidly. The expanding gas then shoves the aluminum plate forward at the speed of a high-powered bullet, and the plate slams into a target of compressed explosive powder. The small charge explodes, setting off the main blast.

Los Alamos scientists believe the new system is so safe that workers could remain in the field during blasting sessions without the danger of accidentally setting off an explosion nearby. It has many other potential applications, such as replacing the electronic triggers in rocket launch systems, rendering them invulnerable to lightning strikes. And the action of the aluminum cap helps scientists study the effects of tiny objects hitting spacecraft.

Paisley believes the new system will replace older-style electronic blasting caps in mines and oil fields around the world.