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 New design improves performance of flexible wearable electronics
23.06.2017 | North Carolina State University

nachricht Plant inspiration could lead to flexible electronics
22.06.2017 | American Chemical Society

All articles from Materials Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Can we see monkeys from space? Emerging technologies to map biodiversity

An international team of scientists has proposed a new multi-disciplinary approach in which an array of new technologies will allow us to map biodiversity and the risks that wildlife is facing at the scale of whole landscapes. The findings are published in Nature Ecology and Evolution. This international research is led by the Kunming Institute of Zoology from China, University of East Anglia, University of Leicester and the Leibniz Institute for Zoo and Wildlife Research.

Using a combination of satellite and ground data, the team proposes that it is now possible to map biodiversity with an accuracy that has not been previously...

Im Focus: Climate satellite: Tracking methane with robust laser technology

Heatwaves in the Arctic, longer periods of vegetation in Europe, severe floods in West Africa – starting in 2021, scientists want to explore the emissions of the greenhouse gas methane with the German-French satellite MERLIN. This is made possible by a new robust laser system of the Fraunhofer Institute for Laser Technology ILT in Aachen, which achieves unprecedented measurement accuracy.

Methane is primarily the result of the decomposition of organic matter. The gas has a 25 times greater warming potential than carbon dioxide, but is not as...

Im Focus: How protons move through a fuel cell

Hydrogen is regarded as the energy source of the future: It is produced with solar power and can be used to generate heat and electricity in fuel cells. Empa researchers have now succeeded in decoding the movement of hydrogen ions in crystals – a key step towards more efficient energy conversion in the hydrogen industry of tomorrow.

As charge carriers, electrons and ions play the leading role in electrochemical energy storage devices and converters such as batteries and fuel cells. Proton...

Im Focus: A unique data centre for cosmological simulations

Scientists from the Excellence Cluster Universe at the Ludwig-Maximilians-Universität Munich have establised "Cosmowebportal", a unique data centre for cosmological simulations located at the Leibniz Supercomputing Centre (LRZ) of the Bavarian Academy of Sciences. The complete results of a series of large hydrodynamical cosmological simulations are available, with data volumes typically exceeding several hundred terabytes. Scientists worldwide can interactively explore these complex simulations via a web interface and directly access the results.

With current telescopes, scientists can observe our Universe’s galaxies and galaxy clusters and their distribution along an invisible cosmic web. From the...

Im Focus: Scientists develop molecular thermometer for contactless measurement using infrared light

Temperature measurements possible even on the smallest scale / Molecular ruby for use in material sciences, biology, and medicine

Chemists at Johannes Gutenberg University Mainz (JGU) in cooperation with researchers of the German Federal Institute for Materials Research and Testing (BAM)...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Plants are networkers

19.06.2017 | Event News

Digital Survival Training for Executives

13.06.2017 | Event News

Global Learning Council Summit 2017

13.06.2017 | Event News

 
Latest News

Quantum thermometer or optical refrigerator?

23.06.2017 | Physics and Astronomy

A 100-year-old physics problem has been solved at EPFL

23.06.2017 | Physics and Astronomy

Equipping form with function

23.06.2017 | Information Technology

VideoLinks
B2B-VideoLinks
More VideoLinks >>>