Researchers at the Oak Ridge National Laboratory in Tennessee announced in February the development of a chemical and biological sensor with an apparently unprecedented level of sensitivity. According to information released by the laboratory, this new ‘sniffer’ device has ‘implications that could be significant for anyone whose job is to detect explosives, biological agents and narcotics.’ The device consists of a digital camera, a laser, imaging optics, a signal generator, digital signal processing and various other components that can together detect tiny amounts of substances in the air. Mr Lavrik noted that the research team hoped to have a device ‘capable of detecting incredibly small amounts of explosives compared to today’s chemical sensors.’
As reported by the laboratory, the underlying concept of the sniffer is based on micro-scale resonators similar to the microcantilever probes used in atomic force microscopy that measure changes in resonance frequency according to changes in mass. To date, however, the difficulty of measuring and analysing tiny oscillation amplitudes—about the size of a hydrogen atom—has impeded the widespread application of such systems. Oak Ridge’s device works, according to its press release, by ‘deliberately hitting the microcantilevers with relatively large amounts of energy associated with a range of frequencies, forcing them into wide oscillation.’
Previously, as Panos Daktos from the laboratory explained, scientists wanted to avoid such high amplitude ‘because of the high distortion associated with that type of response.’ The sniffer, however, turns that difficulty into an advantage, ‘by tuning the system to a very specific frequency that is associated with the specific chemical or compound we want to detect.’ The research team envision this technology being miniaturised and incorporated into a handheld instrument that could be used by transport security screeners, police forces, and the military. With adequate levels of funding, Mr Daktos believes that a prototype could be developed within 6 to 18 months.
– David Cliff, London