Laser prototype improves bomb detection

Scientists at the University of New South Wales (UNSW) have developed a prototype laser device capable of detecting tiny traces of explosive vapour, an invention that has the potential to put bomb sniffer dogs out of a job.

The prototype – a pulsed, quantum laser-based, cavity ring-down spectrometer – is being tested at the US government’s Los Alamos National Laboratory in New Mexico.

The laser machine is “about 100 times more sensitive and 100 times faster than any other detection device,” Associate Professor Charles Harb from UNSW’s School of Engineering and Information Technology said in an interview with UNSW’s quarterly publication Uniken.

The laser device could sniff bags travelling along a conveyor belt and instantly alert security personnel if it detects explosive vapours from a passing object, such as a suitcase.

The device could replace intrusive airport security checks such as pat downs and full body scans and bomb sniffer dogs, UNSW said.

According to Harb, the device uses mirrors to repeatedly pass through the vapour in a “figure-of-eight” path, which provides a more accurate measurement.

“We can measure the components of TNT very clearly, down to the tiny sub-millitorr pressures, in other words in the parts per billion range in atmosphere,” Harb said in his interview with Uniken.

Harb expected that it would take two years of testing and calibrating the prototype – to detect “unique signatures of other substances and different types of explosives” – before it’s ready for commercial use.

Harb and his team at UNSW began working on the device in 2005 when they were asked by the Australian Federal Police to create a machine that could assist with forensic investigations and detect explosive residue at crime scenes.

Harb said police wanted a machine that could work around-the-clock to “identify the actual type of explosive and check every suitcase passing on a conveyor belt”, which is something that sniffer dogs can’t do.

Harb and his team, Scientia Professor Ian Peterson and research associates Dr Toby Boyson and Dr Abhijit Kallapur, developed the device after receiving a grant from the Australian Research Council in 2009.