Fingering explosives

An emerging technology has helped researchers from the

to develop sensors they say can quickly and effectively detect chemical, biological, nuclear and explosive material.

A spectroscopic technique utilising mm/THz frequencies — between microwave and infrared on the electromagnetic spectrum — has enabled the team to detect spectral 'fingerprints' that identify explosives and chemicals.

The technology detects the energy levels of a molecule as it vibrates, and the frequency distribution of this energy provides a unique and reproducible spectral pattern — a 'fingerprint' that identifies the material.

Supported by the US Department of Defence and NASA, the research achieved three important goals.

The detection and measurement of poison gas 60m away to an accuracy of 10 parts/million using active sensing — where a wave is sent out and identification is carried out on its return.

Identifying chemicals relating to defence applications such as nuclear weapons from 600m using passive sensing — where the wave remains static, so the device can be left unattended anywhere.