MIT team adapts neutron resonance transmission analysis for portability

June 23, 2021, 7:07AMNuclear News
Left: An experimental setup showing a shielded detector. Right: A DT neutron source showing three disks of 6Li doped glass scintillator mounted on a photomultiplier tube. (Photos: MIT)

Neutron resonance transmission analysis (NRTA) was developed by researchers at Los Alamos National Laboratory to identify unknown materials inside a sealed object using a beam of neutrons from a laboratory-scale apparatus. Recognizing that the potential nuclear security applications of NRTA were limited by the size and location of the apparatus, Areg Danagoulian, an associate professor in the Massachusetts Institute of Technology’s Department of Nuclear Science and Engineering, began about five years ago to consider how NRTA could be made portable to examine materials on location.

An MIT team effort to develop a first-of-a-kind, mobile NRTA apparatus with the ability to detect the elemental composition of specific materials was successful, and the team’s results were published on May 13 in Physical Review Applied. An article by Leda Zimmerman published on June 10 by the MIT Department of Nuclear Science and Engineering details several challenges the team faced, including procurement, shielding, and the coronavirus.

About NRTA: When bombarded with neutrons at specific energy levels, the nuclei of some materials will transition to an excited state. Scientists have developed a library of unique neutron resonance “fingerprints” for the isotopes of many elements, including heavier metallic elements such as uranium and plutonium, and elements with industrial uses such as silver and tungsten. With an understanding of these fingerprints, it is possible to identify an unknown nuclear-reactive material.

“Our fundamental goal was to enable on-site technology that could be used to identify any type of nuclear material,” said Ethan Klein, a doctoral student at MIT and first author of the paper. “We were able to demonstrate that even without the large, experimental setups of the national labs, our low-cost, portable system could accurately identify a range of materials.”

The team used a deuterium-tritium generator to direct neutrons through a tube at the target material, with a detector placed behind the target. In contrast to the apparatuses at national labs, which can reach hundreds of meters in length, the team’s entire setup occupied just 3 meters and could be moved by one person.

For more information about the team’s work and its potential applications, read the article online.

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