Safer ignition systems for explosives could take the shape of self-destructing lasers. Some of the first successful tests took place this week. Applications could span from the mining industry to car airbags, according to Bofors Bepab, the Swedish company developing the concept.
The technique is being developed to replace electrical ignition devices which are susceptible to accidental triggering by radio waves – for example from mobile telephones – due to metal wires and components behaving like antennae.
Bofors engineer Owe Englund, who came up with the new system, explained that his idea was based on a technique used in the mining industry. A high-powered laser beam is sent down a fibre optic cable (which would not be affected by radio waves) and sets off a sensitive secondary explosive primer. This in turn detonates the main explosive. However, such lasers are expensive, and the use of unstable primers is inherently extremely risky.
Lasers work by ‘pumping’ a medium with intense light or electrical discharges. Englund’s device places the lasing medium, a tiny microchip, inside the main explosive charge. When light is shone down the fibre-optic cable it ‘pumps’ the chip until it breaks down and explodes, acting as a detonator.
‘A microchip is cheaper to produce, and you can have a cheaper pumping device at the end of the cable,’ said Englund. It also eliminates the need for a primer. The first application he foresees is in the pyrotechnic charges used to trigger car airbags. Laser systems could also offer far greater timing precision for rock blasting. When multiple explosives are required to open an area, timing is critical. Electrical systems are also highly unsuitable for deep sea oil exploration, where ingress of water could cause the device to malfunction.
Englund also suggested that the military might be interested in finding uses for his device.