Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Colorful Light at the End of the Tunnel for Radiation Detection

29.06.2012
Sandia Seeks Commercialization Partners for Promising “Spectral Shape Discrimination” Technology

A team of nanomaterials researchers at Sandia National Laboratories has developed a new technique for radiation detection that could make radiation detection in cargo and baggage more effective and less costly for homeland security inspectors.

Known as spectral shape discrimination (SSD), the method takes advantage of a new class of nanoporous materials known as metal-organic frameworks (MOFs). Researchers discovered that adding a doping agent to an MOF leads to the emission of red and blue light when the MOF interacts with high-energy particles emanated from radiological or nuclear material, enabling more effective detection of neutrons. Neutron detection is currently a costly and technically challenging endeavor due to the difficulty in distinguishing neutrons from ubiquitous background gamma rays.

Initial work on the use of MOFs for radiation detection was internally funded by Sandia’s Laboratory Directed Research and Development (LDRD) program, but subsequent funding for the project has come from the National Nuclear Security Administration’s (NNSA) Defense Nuclear Nonproliferation research office.

“Improving our radiation detection capabilities is crucial to advancing NNSA’s nonproliferation mission,” said Anne Harrington, NNSA’s deputy administrator for Defense Nuclear Nonproliferation. “Preventing the illicit movement of radiological and nuclear materials around the globe supports the president’s nuclear security objectives and helps to mitigate the threat of a nuclear terror attack.”

The new technology works with plastic scintillators, materials that fluoresce when struck by charged particles or high-energy photons, making it suitable for commercialization by companies who produce plastic and other organic scintillators used in radiation detection devices. Though work remains before it can move into the marketplace, Sandia is currently seeking commercial partners to license the technology.

(See a video clip at www.youtube.com/SandiaLabs that shows Sandia researchers demonstrating and explaining their work.)

Current radiation detection methods are limited in terms of speed and sensitivity, crucial elements for dynamic scenarios, such as border crossings, cargo screenings and nuclear treaty verification. This new technology monitors the color of light emissions, which have the potential to make the screening process easier and more reliable.

“We are approaching the problem from a materials-chemistry perspective,” said Sandia materials scientist Mark Allendorf. “Fundamentally, it is easier to monitor the color of light emissions rather than the rate at which that light is emitted. That’s the crux of this new approach.” Current radiation detection methods use time to discriminate between neutrons and gamma rays, requiring complex and costly electronics.

MOFs and dopants lead to more light

Allendorf and his team have been working with MOFs for more than five years. Early on, they discovered a fluorescent, porous MOF with superb scintillation properties, an important breakthrough and the first new class of scintillators found in decades. The MOF’s porosity is a key feature because it allows researchers to add other materials to fine-tune the scintillation.

The MOF’s nanoporosity triggered a new idea when team member Patrick Doty read about the use of dopants to increase the efficiency of organic light-emitting diodes (OLEDs). These dopants, usually compounds containing heavy metals such as iridium, dramatically increase OLED brightness by “scavenging” the excited-state energy in the device that was not converted to light. This energy represents as much as 75 percent of the possible light output.

Combining MOFs with OLED dopants led to a second breakthrough. By filling MOF pores with dopants, the team created a material that not only produces more light, but light of another color. Doty, a materials scientist working in Sandia’s radiation/nuclear detection materials and analysis department, hypothesized that the discovery could be applied to radiation detection.

The trick, Doty said, is to add just the right amount of dopant so that both the scavenged light and fluorescence from the excited MOF itself are emitted. Then the ratio of the intensities at the two wavelengths is a function of the type of high-energy particle interacting with the material. “That’s the critical thing,” Doty said. “SSD allows one particle type to be distinguished from another on the basis of the color of the emitted light.”

Because the ratio of neutrons to gamma rays is so low — on the order of one neutron to 105 gamma rays — the threshold at which current detectors can see neutrons is fairly high. Sandia calculations suggest that the threshold for detecting neutrons produced by fissionable material could be lowered substantially using SSD, perhaps improving the “figure of merit” by a factor of 10 compared to the current standards. “In principle, we could quadruple the sensitivity of the gold standard,” said Allendorf.

SSD also addresses another radiation detection problem — active interrogation. Using an active source to create a signal from special nuclear material is an effective means for detection, say Sandia researchers. But current detectors are often overwhelmed by the onslaught of gamma rays. The new materials developed at Sandia can be tuned for improved timing performance at high rates, and the new technology also could be used in radiation detectors for treaty verification.

Sandia National Laboratories is a multiprogram laboratory operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy’s National Nuclear Security Administration. With main facilities in Albuquerque, N.M., and Livermore, Calif., Sandia has major R&D responsibilities in national security, energy and environmental technologies, and economic competitiveness.

Sandia media relations contact: Mike Janes, mejanes@sandia.gov, (925) 294-2447

Mike Janes | EurekAlert!
Further information:
http://www.sandia.gov

More articles from Materials Sciences:

nachricht Topological material switched off and on for the first time
11.12.2018 | ARC Centre of Excellence in Future Low-Energy Electronics Technologies

nachricht Proteins imaged in graphene liquid cell have higher radiation tolerance
10.12.2018 | INM - Leibniz-Institut für Neue Materialien gGmbH

All articles from Materials Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Lethal combination: Drug cocktail turns off the juice to cancer cells

A widely used diabetes medication combined with an antihypertensive drug specifically inhibits tumor growth – this was discovered by researchers from the University of Basel’s Biozentrum two years ago. In a follow-up study, recently published in “Cell Reports”, the scientists report that this drug cocktail induces cancer cell death by switching off their energy supply.

The widely used anti-diabetes drug metformin not only reduces blood sugar but also has an anti-cancer effect. However, the metformin dose commonly used in the...

Im Focus: New Foldable Drone Flies through Narrow Holes in Rescue Missions

A research team from the University of Zurich has developed a new drone that can retract its propeller arms in flight and make itself small to fit through narrow gaps and holes. This is particularly useful when searching for victims of natural disasters.

Inspecting a damaged building after an earthquake or during a fire is exactly the kind of job that human rescuers would like drones to do for them. A flying...

Im Focus: Topological material switched off and on for the first time

Key advance for future topological transistors

Over the last decade, there has been much excitement about the discovery, recognised by the Nobel Prize in Physics only two years ago, that there are two types...

Im Focus: Researchers develop method to transfer entire 2D circuits to any smooth surface

What if a sensor sensing a thing could be part of the thing itself? Rice University engineers believe they have a two-dimensional solution to do just that.

Rice engineers led by materials scientists Pulickel Ajayan and Jun Lou have developed a method to make atom-flat sensors that seamlessly integrate with devices...

Im Focus: Three components on one chip

Scientists at the University of Stuttgart and the Karlsruhe Institute of Technology (KIT) succeed in important further development on the way to quantum Computers.

Quantum computers one day should be able to solve certain computing problems much faster than a classical computer. One of the most promising approaches is...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

ICTM Conference 2019: Digitization emerges as an engineering trend for turbomachinery construction

12.12.2018 | Event News

New Plastics Economy Investor Forum - Meeting Point for Innovations

10.12.2018 | Event News

EGU 2019 meeting: Media registration now open

06.12.2018 | Event News

 
Latest News

New discoveries predict ability to forecast dementia from single molecule

12.12.2018 | Health and Medicine

CCNY-Yale researchers make shape shifting cell breakthrough

12.12.2018 | Physics and Astronomy

Pain: Perception and motor impulses arise in the brain independently of one another

12.12.2018 | Health and Medicine

VideoLinks
Science & Research
Overview of more VideoLinks >>>