Nuclear detectionEnhanced detection of nuclear events thanks to deep learning

A deep neural network running on an ordinary desktop computer is interpreting highly technical data related to national security as well as — and sometimes better than — today’s best automated methods or even human experts.

The progress tackling some of the most complex problems of the environment, the cosmos and national security comes from scientists at the Department of Energy’s Pacific Northwest National Laboratory who presented their work at the 11th MARC conference — Methods and Applications of Radioanalytical Chemistry — in April in Hawaii. Their work employs deep learning, in which machines are enabled to learn and make decisions without being explicitly programmed for all conditions.

PNNL says that the research probes incredibly complex data sets from the laboratory’s shallow underground lab, where scientists detect the faintest of signals from a planet abuzz in activity. In the laboratory buried 81 feet beneath concrete, rock and earth, thick shielding dampens signals from cosmic rays, electronics and other sources. That allows PNNL scientists to isolate and decipher signals of interest collected from anywhere on the planet.

Those signals signify events called radioactive decays, when a particle such as an electron is emitted from an atom. The process is happening constantly, through both natural and human activity. Scientists can monitor changes in levels of argon-37, which could indicate prior nuclear test activity, and argon-39, whose levels help scientists determine the age of groundwater and learn more about the planet.

The lab has accumulated data on millions of radioactive decay events since it opened in 2010. But it’s a noisy world out there, especially for scientists listening for very rare signals that are easily confused with signals of a different and frequently routine origin — for instance, a person flipping on a light switch or receiving a call on a cell phone.

PNNL scientist Emily Mace, who presented at MARC, is an expert in interpreting the features of such signals — when an event might indicate underground nuclear testing, for example, or a rapidly depleting aquifer. Much like physicians peruse X-rays for hints of disease, Mace and her colleagues pore over radioactive decay event data regularly to interpret the signals — their energy, timing,