Scientists at the US Department of Energy’s (DOE) Brookhaven National Laboratory have been awarded US patent 6,608,677 for a portable device that quickly detects and identifies unknown chemical and biological substances from safe distances. The sensor may be useful as a tool to help improve security and could be used by emergency personnel or at sensitive locations, such as airports.
“The technology developed here at Brookhaven Lab represents a fundamentally new sensing paradigm, able to detect and identify unknown materials without requiring contact with the substance,” said Arthur Sedlacek, a researcher at Brookhaven and one of the two scientists that developed the sensor. The other is Mark Ray, formerly of Brookhaven Lab.
“Currently, when first responders come across an unknown chemical spill, the technology now available requires that they either get close to the substance or take a sample of the material for analysis, both of which have to be conducted prior to knowing what the material is,” Sedlacek continued. “Our sensor is specifically designed to detect and identify chemical spills and other ground contamination without requiring sample collection, thus providing the user with an inherently safer tool.”
The device, called a mini-Raman light detection and ranging (lidar) sensor, is able to analyse and identify many potentially harmful substances, such as gases, solid or liquid materials, contaminants, and pollutants, from a distance of approximately two to 50 metres. The identification process takes only minutes, and the sensor is small enough to be transported and carried by emergency responders.
“The mini-Raman sensor is a vast improvement over traditional lidar, which can only detect airborne substances that are kilometres away,” said Sedlacek.
The system works by illuminating the target substance with a laser beam, which consists of photons. The photons scatter off of the substance, are reflected back toward the sensor, and then collected by a telescope, one of the sensor’s components. Another component then analyses the scattering pattern.
Because every chemical and biological substance has a unique pattern, the sensor is able to determine the identity of the substance. It can be linked to a notebook computer that will display the results of the analysis, based on known data of tens of thousands of biological and chemical compounds.
In the event that the substance in question is not listed in the sensor’s database, its readout could be configured to indicate this. According to Sedlacek, work is currently underway to compile a library of harmful substances for the US Department of Defence, which could be used with the lidar system.