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MIT Scientists Improve Explosives Detection
New lasing polymer creates large increases in detection
sensitivity
CAMBRIDGE, Mass., April 14, 2005 – MIT researchers
have announced a scientific breakthrough that could greatly
improve explosives detection for military and civilian security
applications.
Scientists have developed a new polymer that greatly increases
the sensitivity of chemical detection systems for explosives
such as TNT (trinitrotoluene) when coupled to their new general
method for amplified chemical sensing. In the April 14 issue
of Nature, scientists describe a polymer that undergoes
lasing action at lower operating powers than previously observed,
and demonstrate that the stimulated light emission from the
lasing modes of the polymer displays inherently greater sensitivity
to explosives vapors.
Professor Tim Swager
(Chemistry) and Professor Vladimir
Bulovic (Electrical Engineering and Computer Science)
led the team that designed the novel semiconducting organic
polymer (SOP) and invented the new chemosensing method. When
exposed to ultraviolet light above a threshold intensity the
material undergoes a stimulated emission or a lasing process,
manifested by a directed beam of light emanating from the
thin SOP film. When TNT is present, it binds to the SOP surface
and quenches the beam.
Because the new polymer undergoes stimulated emission at
lower thresholds than earlier SOP materials, the intensity
of the ultraviolet light needed to start the lasing action
(pump power) is reduced by more than 10-fold. This lowers
the optical damage usually caused to organic molecules under
intense illumination in air. By adjusting the pump power to
just over the threshold needed for lasing, it is possible
to dramatically attenuate the lasing emission with parts-per-billion
doses of TNT vapor. The result is a 30-fold increase in the
detection sensitivity when the system is operating near the
lasing threshold.
“This amplification method is extremely general,”
said Swager, who has previously developed a range of polymeric
explosives detection systems. “I predict there will
be many new fluorescent sensory schemes based on this principle.”
Swager and Bulovic’s invention is part of a larger
program in sensing technology at MIT’s Institute for
Soldier Nanotechnologies (ISN), a research center devoted
to improving Soldier survivability through nanotechnology.
New technologies for explosives sensing could help protect
Soldiers from improvised explosive devices (IEDs), one of
the greatest threats facing Coalition forces in Iraq. Enhancing
the sensitivity of these detection systems could increase
the distance at which explosives can be identified, giving
the Soldiers greater “standoff” capabilities.
Swager’s previous work in explosives detection systems
has been licensed from MIT and commercialized by Nomadics,
Inc., an Oklahoma-based company working with the ISN. Their
Fido™ explosives detection system, which rivals the
detection ability of a trained dog, is currently undergoing
tests by the U.S. Army and Marine Corps in Iraq and by the
U.S. Air Force for cargo screening operations.
“The ISN has been very helpful in bringing this technology
to the attention of senior leaders of the Army and Marine
Corps,” said Dr. Larry Hancock from Nomadics. “We
are very excited by the successes we have had in field demonstrations
and we are working hard with the Army, Marine Corps, and Air
Force to meet their operational needs.”
According to Bulovic, the present innovation can greatly
increase the sensitivity of the Fido device. “What we
have done is add another layer of amplification to the most
sensitive TNT sensor available.”
Dr. Aimee Rose, a member of the team who made the discovery,
predicts it will save many lives, both military and civilian.
“To turn a laboratory discovery into a potentially life-saving
device has been an extremely gratifying experience,”
she said. “As a scientist, that is about as good as
it gets.”
About the Institute for Soldier Nanotechnologies
The Institute for Soldier Nanotechnologies
is a multidisciplinary research center established at MIT
in 2002 by a $50 million, five-year contract with the U.S.
Army. The goal is to offer the Soldier of the future unprecedented
advances in survivability through cutting-edge nanotechnology.
The ISN’s research focuses largely on materials and
devices that will better protect the Soldier from ballistic,
chemical, biological, and nuclear threats.
About Nomadics
Nomadics pursues research
and development of emerging technologies for homeland security,
national defense, and life sciences markets. The Nomadics
Technology Cultivation model is built on acquiring and cultivating
“game breaker” technologies and deriving value
by applying these technologies to the crying needs of the
day. Nomadics interests include sensing and instrumentation,
advanced materials, and nanotechnology. These have led to
the continuing development of an array of powerful new commercial
products that include ultra-sensitive explosive detection
systems for defense and homeland security.
Contacts:
Franklin Hadley
617-324-6413
fhadley@mit.edu
Aimee Rose
617-441-8871, x115
arose@nomadics.com
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