Micromechanical chips that pump chemicals and living cells around them are already being used to amplify DNA strands and make health diagnoses. Now a new use for these miniature microchip marvels is being patented in the US: blowing things up.
It's not quite as bad as it sounds: the idea is to make weapons magazines safer. When shells, bombs and rockets are stored near a combat front line there's always a risk that a stray piece of shrapnel or a bullet will strike one of the munitions - and if it hits the warhead's detonator (which includes a all initiating explosive charge) the whole lot could go sky high.
But Qinetiq, the Farnborough, UK-based defence lab, says the aller the detonator is, the less of a target it presents to bullets and shrapnel - and the lower the risk of an unintended explosion. So in US patent application 2013/0008334, published on 10 January, it outlines how a tiny, hard-to-hit detonator can be built by using the arrays of microcavities in modern microelectromechanical chips to store tiny amounts of initiating explosive.
Inventors Robert Claridge and David Combes say the really difficult part is getting the explosives into such a chip. Their patent harnesses capillary action to let chemical precursors trickle in, precipitating out explosives that deposit themselves in the chip's microcavities. Each type of weapon needs a different amount of initiator, so the choice of the number of chambers, and their width - between 10 and 100 micrometres - is up to the manufacturer.
Detonation is triggered by passing a current through a simple heater wire that passes through the microchip's cavities. In addition to presenting less of an accidental target, the pair say the all amounts of initiator used in their chip also reduces the chances of a weapon detonating due to physical shock, electrical spark and friction.
