thedrifter
07-16-07, 07:48 AM
Sensing bombs from afar
Novel approaches to detecting explosives could be combined
By Erik Schechter - eschechter@militarytimes.com
Posted : July 23, 2007
On the morning of May 6, a few dozen Iraqis lined up outside an army recruiting center in the town of Abu Ghraib, west of Baghdad. Unbeknownst to the young Sunni men, a suicide bomber joined them in line. Fifteen were killed in the explosion and another 21 were wounded. Later that day, a car bomb in Baghdad slaughtered another 25 Iraqis.
And so it goes with disturbing regularity. Various sources confirm that in Iraq over the past year, fatal bombings numbered more than 1,400, with improvised explosive devices accounting for nearly one-third of all U.S. military deaths in theater.
Western governments and private industry have sought ways to detect bombs at safe distances. Everything from high-tech imaging equipment to trained honeybees has been tried, but so far, nothing quite does the job.
Enter ViaLogy. This California-based company has a patented method reputed to identify explosive traces from more than 100 meters away.
Called Reverse Photo-Acoustic Spectrometer technology, the multistep process entails bouncing sound beams off a targeted area. Should explosive residue be present, a weak identifying signal is emitted, which a special algorithm then isolates from the background clutter.
REPAS, if proven to work outside the lab, would be a lifesaver, but scientists at ViaLogy are careful not to oversell the technology. They know full well its limitations — and that earlier breakthroughs have not lived up to their billing.
Airports employ two types of bomb-detection technologies in checking passengers and their luggage: ion mobility spectrometry and nuclear quadrupole resonance. To work, both need to be close to their targets, a restriction that makes them virtually useless in a battlefield or urban environment.
If NQR and IMS lack the range for standoff explosive detection, why not bring the sensor closer and have it transmit to the human operator? This is the rationale behind two rather unusual ideas: the bomb-sniffing honeybee and the paintball gun-fired sensor. Unfortunately, neither idea panned out.
The bees could not operate at night, in rain or cold weather. A powerful explosive-detection sensor small enough to fit inside a paintball projectile still has to be developed.
After so many disappointments in the field of standoff detection, a natural skepticism has set in. But in late March, ViaLogy announced a deal with UT-Battelle, the company that manages the Oak Ridge National Laboratory for the Department of Energy, to combine respective technologies: Reverse Photo-Acoustic Spectrometer and Quantum Resonance Interferometry.
REPAS uses an ultrasonic transducer (not unlike a high-tech dog whistle) to run a narrow acoustic beam over the target area. Then, the same area is flashed with an infrared light until the frequency the explosive residue will absorb is hit. For example, TNT has an IR frequency of 1380 cm-1. Once the material starts absorbing the infrared beam, its molecules will heat up and expand.
“The tiny change in thickness is measured by bouncing [another] acoustic beam off the sample,” said Tom George, ViaLogy’s director for product development and nanofabrication. “Because the round-trip distance traveled by the sound wave is a tad bit shorter, the receiver sees a different part of the sound wave than it originally did when the sample was cold.”
The change in the acoustic wave helps identify the excited material. Were it not for the QRI algorithm, however, the investigator would have no way of finding the returning signal.
“We are dealing with extremely weak signals in a very cluttered, noisy background,” George said.
Thus, operating together, the two technologies promise to offer what so many have failed to achieve — real-time standoff explosives detection at a distance of more than 100 meters.
As for sensitivity, George insisted that REPAS can detect residue microns in thickness. It can also tell the difference — and this could be crucial for an urban war environment — between old gunpowder traces and a hidden grenade.
Thomas Thundat, along with colleagues Ming Su and David Hedden at ORNL’s Nanoscale Science and Devices Group, created REPAS after years of studying close-up detection technology. Thundat is still working on an “electronic noise” that would work beside NQR and ISM. But in 2003-04, he added standoff detection to his workload.
ViaLogy, which now shares rights in REPAS, sees it made into a 4-pound tool used by first responders, such as police officers, to conduct an initial survey when they arrive on a scene. Once explosives are detected, the subject or area is contained and other detection technologies are brought in to perform further tests.
Vandeep Gulati, ViaLogy co-founder and chief technical officer, said he believes that technique could employ a variety of beams. For instance, soldiers conducting door-to-door searches, where the standoff distance may be 10 meters or less, will use an acoustic beam device. But at a distance of 100 meters, a millimeter beam might be more useful.
Gulati imagines a helicopter- or drone-borne line-of-sight device that would scan for IEDs up to half a kilometer away.
“When the REPAS sensor is mounted on an aircraft, you have to worry about acoustic interference,” he said. “So that’s why we switch to lasers. Otherwise, we prefer to use cheaper technologies.”
Ellie
Novel approaches to detecting explosives could be combined
By Erik Schechter - eschechter@militarytimes.com
Posted : July 23, 2007
On the morning of May 6, a few dozen Iraqis lined up outside an army recruiting center in the town of Abu Ghraib, west of Baghdad. Unbeknownst to the young Sunni men, a suicide bomber joined them in line. Fifteen were killed in the explosion and another 21 were wounded. Later that day, a car bomb in Baghdad slaughtered another 25 Iraqis.
And so it goes with disturbing regularity. Various sources confirm that in Iraq over the past year, fatal bombings numbered more than 1,400, with improvised explosive devices accounting for nearly one-third of all U.S. military deaths in theater.
Western governments and private industry have sought ways to detect bombs at safe distances. Everything from high-tech imaging equipment to trained honeybees has been tried, but so far, nothing quite does the job.
Enter ViaLogy. This California-based company has a patented method reputed to identify explosive traces from more than 100 meters away.
Called Reverse Photo-Acoustic Spectrometer technology, the multistep process entails bouncing sound beams off a targeted area. Should explosive residue be present, a weak identifying signal is emitted, which a special algorithm then isolates from the background clutter.
REPAS, if proven to work outside the lab, would be a lifesaver, but scientists at ViaLogy are careful not to oversell the technology. They know full well its limitations — and that earlier breakthroughs have not lived up to their billing.
Airports employ two types of bomb-detection technologies in checking passengers and their luggage: ion mobility spectrometry and nuclear quadrupole resonance. To work, both need to be close to their targets, a restriction that makes them virtually useless in a battlefield or urban environment.
If NQR and IMS lack the range for standoff explosive detection, why not bring the sensor closer and have it transmit to the human operator? This is the rationale behind two rather unusual ideas: the bomb-sniffing honeybee and the paintball gun-fired sensor. Unfortunately, neither idea panned out.
The bees could not operate at night, in rain or cold weather. A powerful explosive-detection sensor small enough to fit inside a paintball projectile still has to be developed.
After so many disappointments in the field of standoff detection, a natural skepticism has set in. But in late March, ViaLogy announced a deal with UT-Battelle, the company that manages the Oak Ridge National Laboratory for the Department of Energy, to combine respective technologies: Reverse Photo-Acoustic Spectrometer and Quantum Resonance Interferometry.
REPAS uses an ultrasonic transducer (not unlike a high-tech dog whistle) to run a narrow acoustic beam over the target area. Then, the same area is flashed with an infrared light until the frequency the explosive residue will absorb is hit. For example, TNT has an IR frequency of 1380 cm-1. Once the material starts absorbing the infrared beam, its molecules will heat up and expand.
“The tiny change in thickness is measured by bouncing [another] acoustic beam off the sample,” said Tom George, ViaLogy’s director for product development and nanofabrication. “Because the round-trip distance traveled by the sound wave is a tad bit shorter, the receiver sees a different part of the sound wave than it originally did when the sample was cold.”
The change in the acoustic wave helps identify the excited material. Were it not for the QRI algorithm, however, the investigator would have no way of finding the returning signal.
“We are dealing with extremely weak signals in a very cluttered, noisy background,” George said.
Thus, operating together, the two technologies promise to offer what so many have failed to achieve — real-time standoff explosives detection at a distance of more than 100 meters.
As for sensitivity, George insisted that REPAS can detect residue microns in thickness. It can also tell the difference — and this could be crucial for an urban war environment — between old gunpowder traces and a hidden grenade.
Thomas Thundat, along with colleagues Ming Su and David Hedden at ORNL’s Nanoscale Science and Devices Group, created REPAS after years of studying close-up detection technology. Thundat is still working on an “electronic noise” that would work beside NQR and ISM. But in 2003-04, he added standoff detection to his workload.
ViaLogy, which now shares rights in REPAS, sees it made into a 4-pound tool used by first responders, such as police officers, to conduct an initial survey when they arrive on a scene. Once explosives are detected, the subject or area is contained and other detection technologies are brought in to perform further tests.
Vandeep Gulati, ViaLogy co-founder and chief technical officer, said he believes that technique could employ a variety of beams. For instance, soldiers conducting door-to-door searches, where the standoff distance may be 10 meters or less, will use an acoustic beam device. But at a distance of 100 meters, a millimeter beam might be more useful.
Gulati imagines a helicopter- or drone-borne line-of-sight device that would scan for IEDs up to half a kilometer away.
“When the REPAS sensor is mounted on an aircraft, you have to worry about acoustic interference,” he said. “So that’s why we switch to lasers. Otherwise, we prefer to use cheaper technologies.”
Ellie